Surgery_Schwartz

Surgery_Schwartz. was identified by indirect means (i.e., the host anti-body response); more modern techniques identify the presence of viral DNA or ribonucleic acid (RNA) using methods such as polymerase chain reaction. Similar to many fungal infections, most clinically relevant viral infections in surgical patients occur in the immunocompromised host, particularly those receiv-ing immunosuppression to prevent rejection of a solid organ allograft. Relevant viruses include adenoviruses, cytomegalo-virus, Epstein-Barr virus, herpes simplex virus, and varicella-zoster virus. Surgeons must be aware of the manifestations of hepatitis B and C viruses, as well as human immunodeficiency Table 6-2Sequential Organ Failure Assessment scoreSYSTEMSCORE01234RespiratoryPaO2/FiO2, mmHg (kPa)≥400 (53.3)<400 (53.3)<300 (40)<200 (26.7) with respiratory support<100 (13.3) with respiratory supportCoagulationPlatelets, × 103/μL≥150<150<100<50<20HepaticBilirubin, mg/dL (μmol/L)<1.2 (20)1.2–1.9 (20–32)2–5.9 (33–101)6–11.9


Surgery_Schwartz

Surgery_Schwartz. (26.7) with respiratory support<100 (13.3) with respiratory supportCoagulationPlatelets, × 103/μL≥150<150<100<50<20HepaticBilirubin, mg/dL (μmol/L)<1.2 (20)1.2–1.9 (20–32)2–5.9 (33–101)6–11.9 (102–204)>12 (204)CardiovascularMAP ≥70 mmHgMAP <70 mmHgDopamine <5 or dobutamineDopamine 5.1–15 or epinephrine ≤0.1 or norepinephrine ≤0.1Dopamine >15 or epinephrine >0.1 or norepinephrine >0.1CNSGCS score1513–1410–126–9<6RenalCreatinine, mg/dL (μmol/L)<1.2 (110)1.2–1.9 (110–170)2–3.4 (171–299)3.5–4.9 (300–440)>5 (440)Urine output, mL/24 hours<500<200MAP = mean arterial pressure; PaO2 = partial pressure of oxygen; FiO2 = fraction of inspired oxygen; CNS = central nervous system; GCS = Glasgow Coma ScaleCatecholamine doses in μg/kg/minuteReproduced with permission from Vincent JL, Moreno R, Takala J, et al: The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. On behalf of the Working Group on Sepsis-Related Problems of the European Society of Intensive


Surgery_Schwartz

Surgery_Schwartz. et al: The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. On behalf of the Working Group on Sepsis-Related Problems of the European Society of Intensive Care Medicine, Intensive Care Med. 1996 Jul;22(7):707-710.Brunicardi_Ch06_p0157-p0182.indd 16201/03/19 4:46 PM 163SURGICAL INFECTIONSCHAPTER 6virus infections, including their capacity to be transmitted to healthcare workers (see “General Principles”). Prophylactic and therapeutic use of antiviral agents is discussed elsewhere in this textbook.PREVENTION AND TREATMENT OF SURGICAL INFECTIONSGeneral PrinciplesManeuvers to diminish the presence of exogenous (surgeon and operating room environment) and endogenous (patient) microbes are termed prophylaxis and consist of a variety of mechanical and chemical modalities. The Centers for Disease Control and Prevention (CDC) publishes updated, evidence-based guidelines on best practices for prevention of surgical site infections. Important


Surgery_Schwartz

Surgery_Schwartz. and chemical modalities. The Centers for Disease Control and Prevention (CDC) publishes updated, evidence-based guidelines on best practices for prevention of surgical site infections. Important principles in prophylaxis can be grouped into factors pertaining to skin preparation, antimicrobial therapy, and patient physiological management.Patient skin preparation should begin the night before a planned surgical procedure with a full body bath or shower using soap or an antiseptic agent. Hair removal from an opera-tive site should be performed in the operating room with clippers rather than with a razor, to avoid creating nicks in the skin that could foster bacterial growth. Prior to incision, the skin should be cleansed with an alcohol-based antiseptic agent. There is no clear evidence that use of antimicrobial-containing fluids for either irrigation or soaking prosthetic materials is beneficial in preventing infections. Preoperative antimicrobial therapy should be administered when


Surgery_Schwartz

Surgery_Schwartz. use of antimicrobial-containing fluids for either irrigation or soaking prosthetic materials is beneficial in preventing infections. Preoperative antimicrobial therapy should be administered when appropriate, based on clinical guidelines, and occur within a time frame that allows bactericidal con-centration of the agent in tissues before the incision is made. Physiological management of the intraoperative patient includes maintenance of euglycemia (serum glucose <200 mg/dL) and normothermia, and optimization of tissue oxygenation.20Source ControlThe primary precept of surgical infectious disease therapy con-sists of drainage of all purulent material, debridement of all infected, devitalized tissue and debris, and/or removal of foreign bodies at the site of infection, plus remediation of the underlying cause of infection.21 This is termed source control. A dis-crete, walled-off purulent fluid collection (i.e., an abscess) 2Table 6-3Common pathogens in surgical patientsGram-positive


Surgery_Schwartz

Surgery_Schwartz. the underlying cause of infection.21 This is termed source control. A dis-crete, walled-off purulent fluid collection (i.e., an abscess) 2Table 6-3Common pathogens in surgical patientsGram-positive aerobic cocci Staphylococcus aureus Staphylococcus epidermidis Streptococcus pyogenes Streptococcus pneumoniae Enterococcus faecium, E faecalisGram-negative aerobic bacilli Escherichia coli Haemophilus influenzae Klebsiella pneumoniae Proteus mirabilis Enterobacter cloacae, E aerogenes Serratia marcescens Acinetobacter calcoaceticus Citrobacter freundii Pseudomonas aeruginosa Stenotrophomonas maltophiliaAnaerobes Gram-positive Clostridium difficile Clostridium perfringens, C tetani, C septicum Peptostreptococcus spp. Gram-negative Bacteroides fragilis Fusobacterium spp.Other bacteria Mycobacterium avium-intracellulare Mycobacterium tuberculosis Nocardia asteroids Legionella pneumophila Listeria monocytogenesFungi Aspergillus fumigatus, A niger, A terreus, A flavus Blastomyces


Surgery_Schwartz

Surgery_Schwartz. avium-intracellulare Mycobacterium tuberculosis Nocardia asteroids Legionella pneumophila Listeria monocytogenesFungi Aspergillus fumigatus, A niger, A terreus, A flavus Blastomyces dermatitidis Candida albicans Candida glabrata, C paropsilosis, C krusei Coccidiodes immitis Cryptococcus neoformans Histoplasma capsulatum Mucor/RhizopusViruses Cytomegalovirus Epstein-Barr virus Hepatitis A, B, C viruses Herpes simplex virus Human immunodeficiency virus Varicella zoster virusTable 6-4Antifungal agents and their characteristicsANTIFUNGALADVANTAGESDISADVANTAGESAmphotericin BBroad-spectrum, inexpensiveRenal toxicity, premeds, IV onlyLiposomal Amphotericin BBroad-spectrumExpensive, IV only, renal toxicityAzolesFluconazoleIV and PO availabilityNarrow-spectrum, drug interactionsItraconazoleIV and PO availabilityNarrow spectrum, no CSF penetrationDrug interactions, decreased cardiac contractilityPosaconazoleBroad-spectrum, zygomycete activityPO onlyVoriconazoleIV and PO availability,


Surgery_Schwartz

Surgery_Schwartz. and PO availabilityNarrow spectrum, no CSF penetrationDrug interactions, decreased cardiac contractilityPosaconazoleBroad-spectrum, zygomycete activityPO onlyVoriconazoleIV and PO availability, broad-spectrumIV diluent accumulates in renal failure, Visual disturbancesEchinocandinsAnidulofungin, Caspofungin, micafunginBroad-spectrumIV only, poor CNS penetrationBrunicardi_Ch06_p0157-p0182.indd 16301/03/19 4:46 PM 164BASIC CONSIDERATIONSPART Irequires drainage, either surgically or via percutaneous drain insertion. An ongoing source of contamination (e.g., bowel per-foration) or the presence of an aggressive, rapidly spreading infection (e.g., necrotizing soft tissue infection) invariably requires expedient, aggressive operative intervention, both to remove contaminated material and infected tissue (e.g., radical debridement or amputation) and to remove the initial cause of infection (e.g., bowel resection). Delay in operative interven-tion, whether due to misdiagnosis or the need


Surgery_Schwartz

Surgery_Schwartz. tissue (e.g., radical debridement or amputation) and to remove the initial cause of infection (e.g., bowel resection). Delay in operative interven-tion, whether due to misdiagnosis or the need for additional diagnostic studies, is associated with increased morbidity and occasional mortality. Other treatment modalities such as antimi-crobial agents, albeit critical, are of secondary importance to effective surgery with regard to treatment of surgical infections. Rarely, if ever, can an aggressive surgical infection be cured only by the administration of antibiotics, and never in the face of an ongoing source of contamination.22Appropriate Use of Antimicrobial AgentsA classification of antimicrobial agents, mechanisms of action, and spectrums of activity is shown in Table 6-5. As discussed previously, prophylaxis consists of the administration of an anti-microbial agent or agents prior to initiation of certain specific types of surgical procedures in order to reduce the number of


Surgery_Schwartz

Surgery_Schwartz. previously, prophylaxis consists of the administration of an anti-microbial agent or agents prior to initiation of certain specific types of surgical procedures in order to reduce the number of microbes that enter the tissue or body cavity. Agents are selected according to their activity against microbes likely to be present at the surgical site, based on knowledge of host microflora. For example, patients undergoing elective colorectal surgery should receive antimicrobial prophylaxis directed against skin flora, gram-negative aerobes, and anaerobic bacteria. There are a wide variety of agents that meet these criteria with recently published guidelines.23By definition, prophylaxis is limited to the time prior to and during the operative procedure; in the vast majority of cases only a single dose of antibiotic is required, and only for certain types of procedures (see “Surgical Site Infections”). However, patients who undergo complex, prolonged procedures in which the duration of the


Surgery_Schwartz

Surgery_Schwartz. dose of antibiotic is required, and only for certain types of procedures (see “Surgical Site Infections”). However, patients who undergo complex, prolonged procedures in which the duration of the operation exceeds the serum drug half-life should receive an additional dose or doses of the antimicrobial agent.23 There is no evidence that administration of postopera-tive doses of an antimicrobial agent provides additional benefit, and this practice should be discouraged, as it is costly and is associated with increased rates of microbial drug resistance. Guidelines for prophylaxis are provided in Table 6-6.Empiric therapy is the use of antimicrobial agents when the risk of a surgical infection is high, based on the underlying disease process (e.g., ruptured appendicitis), or when signifi-cant contamination during surgery has occurred (e.g., inad-equate bowel preparation or considerable spillage of colon contents). Obviously, prophylaxis merges into empiric therapy in situations in which


Surgery_Schwartz

Surgery_Schwartz. contamination during surgery has occurred (e.g., inad-equate bowel preparation or considerable spillage of colon contents). Obviously, prophylaxis merges into empiric therapy in situations in which the risk of infection increases markedly because of intraoperative findings. Empiric therapy also is often employed in critically ill patients in whom a potential site of infection has been identified and severe sepsis or septic shock occurs. Empiric therapy should be limited to a short course of treatment (3 to 5 days) and should be curtailed as soon as pos-sible based on microbiologic data (i.e., absence of positive cul-tures) coupled with improvements in the clinical course of the patient.Empiric therapy can merge into therapy of established infection in some patients. However, among surgical patients, the manner in which therapy is employed, particularly in rela-tion to the use of microbiologic data (culture and antibiotic sensitivity patterns), differs depending on whether the


Surgery_Schwartz

Surgery_Schwartz. surgical patients, the manner in which therapy is employed, particularly in rela-tion to the use of microbiologic data (culture and antibiotic sensitivity patterns), differs depending on whether the infection is monomicrobial or polymicrobial. Monomicrobial infections frequently are nosocomial infections occurring in postoperative patients, such as UTIs, pneumonia, or bacteremia. Evidence of systemic inflammatory response syndrome (fever, tachycardia, tachypnea, or elevated leukocyte count) in such individuals, coupled with evidence of local infection (e.g., an infiltrate on chest roentgenogram plus a positive Gram stain in bronchoal-veolar lavage samples) should lead the surgeon to initiate empiric antibiotic therapy. An appropriate approach to antimi-crobial treatment involves de-escalation therapy, where initial antimicrobial selection is broad, with a narrowing of agents based on patient response and culture results. Initial drug selec-tion must be based on initial evidence


Surgery_Schwartz

Surgery_Schwartz. therapy, where initial antimicrobial selection is broad, with a narrowing of agents based on patient response and culture results. Initial drug selec-tion must be based on initial evidence (gram-positive vs. gram-negative microbes, yeast), coupled with institutional and unit-specific drug sensitivity patterns. It is important to ensure that antimicrobial coverage chosen is adequate, since delay in appropriate antibiotic treatment has been shown to be associated with significant increases in mortality. A critical component of this approach is appropriate collection of culture specimens to allow for thorough analysis, since within 48 to 72 hours culture and sensitivity reports will allow refinement of the antibiotic regimen to select the most efficacious agent.Although the primary therapeutic modality to treat polymicrobial surgical infections is source control, antimicro-bial agents play an important role. Culture results are of lesser importance in managing these types of infections,


Surgery_Schwartz

Surgery_Schwartz. modality to treat polymicrobial surgical infections is source control, antimicro-bial agents play an important role. Culture results are of lesser importance in managing these types of infections, as it has been repeatedly demonstrated that only a limited cadre of microbes predominate in the established infection, selected from a large number present at the time of initial contamination. Invariably it is difficult to identify all microbes that comprise the initial polymicrobial inoculum. For this reason, the antibiotic regimen should not be modified solely on the basis of culture informa-tion, as it is less important than the clinical course of the patient. As long as appropriately broad-spectrum coverage for aerobic and anaerobic microbes is provided, a worsening of the patient’s clinical course should direct the surgeon to investigate whether effective source control has been achieved.24 Duration of anti-biotic administration should be decided at the time the drug regimen is


Surgery_Schwartz

Surgery_Schwartz. clinical course should direct the surgeon to investigate whether effective source control has been achieved.24 Duration of anti-biotic administration should be decided at the time the drug regimen is prescribed. As mentioned previously, prophylaxis is limited to a single dose administered immediately prior to creating the incision. Empiric therapy should be limited to 3 to 5 days or less and should be curtailed if the presence of a local site or systemic infection is not revealed.25 In fact, prolonged use of empirical antibiotic therapy in culture-negative critically ill patients is associated with increased mortality, highlighting the need to discontinue therapy when there is no proven evidence of infection.26Therapy for monomicrobial infections follows standard guidelines: 3 to 5 days for UTIs, 7 to 8 days for pneumonia, and 7 to 14 days for bacteremia. Longer courses of therapy in this setting do not result in improved care and are associated with increased risk of superinfection


Surgery_Schwartz

Surgery_Schwartz. for UTIs, 7 to 8 days for pneumonia, and 7 to 14 days for bacteremia. Longer courses of therapy in this setting do not result in improved care and are associated with increased risk of superinfection by resistant organisms.27-29 There is some evidence that measuring and monitoring serum procalcitonin trends in the setting of infection allows earlier cessation of antibiotics without decrement in the rate of clini-cal cure.30 Antibiotic therapy for osteomyelitis, endocarditis, or prosthetic infections in which it is hazardous to remove the device consists of prolonged courses of treatment for 6 to 12 weeks. The specific agents are selected based on analysis of the degree to which the organism is killed in vitro using the minimum inhibitory concentration (MIC) of a standard pure 34Brunicardi_Ch06_p0157-p0182.indd 16401/03/19 4:46 PM 165SURGICAL INFECTIONSCHAPTER 6Table 6-5Antimicrobial agentsANTIBIOTIC CLASS, GENERIC NAMETRADE NAMEMECHANISM OF ACTIONORGANISMS PyogenesMSSAMRSAS


Surgery_Schwartz

Surgery_Schwartz. 16401/03/19 4:46 PM 165SURGICAL INFECTIONSCHAPTER 6Table 6-5Antimicrobial agentsANTIBIOTIC CLASS, GENERIC NAMETRADE NAMEMECHANISM OF ACTIONORGANISMS PyogenesMSSAMRSAS epidermidisEnterococcusVREE coliP aeruginosaANAEROBESPenicillinsCell wall synthesis inhibitors (bind penicillin-binding protein)Penicillin G1000+/–0001NafcillinNallpen, Unipen110+/–00000PiperacillinPipracil1000+/–011+/–Penicillin/a-lactamase inhibitor combinationsCell wall synthesis inhibitors/β-lactamase inhibitorsAmpicillin/sulbactamUnasyn110+/–1+/–101Ticarcillin/clavulanateTimentin110+/–+/–0111Piperacillin/tazobactamZosyn1101+/–0111First-generation cephalosporinsCell wall synthesis inhibitorsCefazolin, cephalexinAncef, Keflex110+/–00100Second-generation cephalosporinsCell wall synthesis inhibitorsCefoxitinMefoxin110+/–00101CefotetanCefotan110+/–00101CefuroximeCeftin110+/–00100Thirdand fourth-generation cephalosporinsCell wall synthesis


Surgery_Schwartz

Surgery_Schwartz. cephalosporinsCell wall synthesis inhibitorsCefoxitinMefoxin110+/–00101CefotetanCefotan110+/–00101CefuroximeCeftin110+/–00100Thirdand fourth-generation cephalosporinsCell wall synthesis inhibitorsCeftriaxoneRocephin110+/–00100CeftazidimeFortaz1+/–0+/–00110CefepimeMaxipime110+/–00110CefotaximeCefotaxime110+/–001+/–0CeftarolineTeflaro111100100(Continued)Brunicardi_Ch06_p0157-p0182.indd 16501/03/19 4:46 PM 166BASIC CONSIDERATIONSPART ICarbapenemsCell wall synthesis inhibitorsImipenem-cilastatinPrimaxin1101+/–0111MeropenemMerrem110100111ErtapenemInvanz1101001+/–1AztreonamAzactam000000110AminoglycosidesAlteration of cell membrane, binding and inhibition of 30S ribosomal subunitGentamicin010+/–10110Tobramycin, amikacin010+/–00110FluoroquinolonesInhibit topo-isomerase II and IV (DNA synthesis inhibition)CiprofloxacinCipro+/–10100110LevofloxacinLevaquin1101001+/–0GlycopeptidesCell wall synthesis inhibition (peptidoglycan synthesis


Surgery_Schwartz

Surgery_Schwartz. topo-isomerase II and IV (DNA synthesis inhibition)CiprofloxacinCipro+/–10100110LevofloxacinLevaquin1101001+/–0GlycopeptidesCell wall synthesis inhibition (peptidoglycan synthesis inhibition)VancomycinVancocin111110000Quinupristin-dalfopristinSynercidInhibits 2 sites on 50S ribosome (protein synthesis inhibition)11111100+/–Table 6-5Antimicrobial agentsANTIBIOTIC CLASS, GENERIC NAMETRADE NAMEMECHANISM OF ACTIONORGANISMS PyogenesMSSAMRSAS epidermidisEnterococcusVREE coliP aeruginosaANAEROBES(Continued)Brunicardi_Ch06_p0157-p0182.indd 16601/03/19 4:46 PM 167SURGICAL INFECTIONSCHAPTER 6LinezolidZyvoxInhibits 50S ribosomal activity11111100+/–DaptomycinCubicinBinds bacterial membrane, results in depolarization, lysis111111000RifampinInhibits DNA-dependent RNA polymerase1111+/–0000ClindamycinCleocinInhibits 50S ribosomal activity110000001MetronidazoleFlagylProduction of toxic intermediates (free radicals)000000001MacrolidesInhibit 50S ribosomal activity (protein synthesis


Surgery_Schwartz

Surgery_Schwartz. 50S ribosomal activity110000001MetronidazoleFlagylProduction of toxic intermediates (free radicals)000000001MacrolidesInhibit 50S ribosomal activity (protein synthesis inhibition)Erythromycin1+/–0+/–00000AzithromycinZithromax110000000ClarithromycinBiaxin110000000Trimethoprim-sulfamethoxazoleBactrim, SeptraInhibits sequential steps of folate metabolism+/–10/–00100TetracyclinesBind 30S ribosomal unit (protein synthesis inhibition)MinocyclineMinocin11000000+/–DoxycyclineVibromycin1+/–000010+/–=TigacyclineTygacil111111101E coli = Escherichia coli; MRSA = methicillin-resistant Staphylococcus aureus; MSSA = methicillin-sensitive S aureus; P aeruginosa = Pseudomonas aeruginosa; S epidermidis = Staphylococcus epidermidis; S pyogenes = Streptococcus pyogenes; VRE = vancomycin-resistant Enterococcus1 = reliable activity; +/– = variable activity; 0 = no activity.The sensitivities printed here are generalizations. The clinician should confirm sensitivity patterns at the locale where the patient


Surgery_Schwartz

Surgery_Schwartz. = reliable activity; +/– = variable activity; 0 = no activity.The sensitivities printed here are generalizations. The clinician should confirm sensitivity patterns at the locale where the patient is being treated since these patterns may vary widely depending on location.Brunicardi_Ch06_p0157-p0182.indd 16701/03/19 4:46 PM 168BASIC CONSIDERATIONSPART ITable 6-6Prophylactic use of antibioticsSITEANTIBIOTICALTERNATIVE (E.G., PENICILLIN ALLERGIC)Cardiovascular surgeryCefazolin, cefuroximeVancomycin, clindamycinGastroduodenal areaSmall intestine, nonobstructedCefazolinClindamycin or vancomycin + aminoglycoside or aztreonem or fluoroquinoloneBiliary tract: open procedure, laparoscopic high riskCefazolin, cefoxitin, cefotetan, ceftriaxone, ampicillin-sulbactamClindamycin or vancomycin + aminoglycoside or aztreonem or fluoroquinoloneMetronidazole + aminoglycoside or fluoroquinoloneBiliary tract: laparoscopic low riskNoneNoneAppendectomy, uncomplicatedCefoxitin, cefotetan, cefazolin +


Surgery_Schwartz

Surgery_Schwartz. aminoglycoside or aztreonem or fluoroquinoloneMetronidazole + aminoglycoside or fluoroquinoloneBiliary tract: laparoscopic low riskNoneNoneAppendectomy, uncomplicatedCefoxitin, cefotetan, cefazolin + metronidazoleClindamycin + aminoglycoside or aztreonem or fluoroquinoloneMetronidazole + aminoglycoside or fluoroquinoloneColorectal surgery, obstructed small intestineCefazolin or ceftriaxone plus metronidazole, ertapenem, cefoxitin, cefotetan, ampicillin-sulbactamClindamycin + aminoglycoside or aztreonem or fluoroquinolone, metronidazole + aminoglycoside or fluoroquinoloneHead and neck; clean contaminatedCefazolin or cefuroxime + metronidazole, ampicillin-sulbactamClindamycinNeurosurgical proceduresCefazolinClindamycin, vancomycinOrthopedic surgeryCefazolin, ceftriaxoneClindamycin, vancomycinBreast, herniaCefazolinClindamycin, vancomycinData from Pieracci FM, Barie PS. Management of severe sepsis of abdominal origin, Scand J Surg. 2007;96(3):184-196.inoculum of 105 CFU/mL of the


Surgery_Schwartz

Surgery_Schwartz. herniaCefazolinClindamycin, vancomycinData from Pieracci FM, Barie PS. Management of severe sepsis of abdominal origin, Scand J Surg. 2007;96(3):184-196.inoculum of 105 CFU/mL of the organism isolated from the site of infection or bloodstream. Sensitivities are reported in rela-tion to the achievable blood level of each antibiotic in a panel of agents. The least toxic, least expensive agent to which the organism is most sensitive should be selected. Serious or recru-descent infection may require therapy with two or more agents, particularly if a multidrug-resistant pathogen is causative, limit-ing therapeutic options to drugs to which the organism is only moderately sensitive. Commonly, an agent may be administered intravenously for 1 to 2 weeks, followed by treatment with an oral drug. However, this should only be undertaken in patients who demonstrate progressive clinical improvement, and the oral agent should be capable of achieving high serum levels as well (e.g.,


Surgery_Schwartz

Surgery_Schwartz. an oral drug. However, this should only be undertaken in patients who demonstrate progressive clinical improvement, and the oral agent should be capable of achieving high serum levels as well (e.g., fluoroquinolones).The 2016 Surgical Infection Society guidelines on man-agement of intra-abdominal infection recommend antibiotic duration of no more than 24 hours in patients with traumatic bowel perforation who receive surgical treatment within 12 hours, gastroduodenal perforations operated upon within 24 hours, ischemic nonperforated bowel, and gangrenous acute appen-dicitis or cholecystitis without perforation. More extensive intraperitoneal infection (perforated appendicitis, for example) should have treatment limited to 4 days. Patients with a greater degree of contamination may require longer courses of therapy; as in all facets of clinical practice, the therapeutic plan must be individualized to the patient. In the later phases of postopera-tive antibiotic treatment of serious


Surgery_Schwartz

Surgery_Schwartz. longer courses of therapy; as in all facets of clinical practice, the therapeutic plan must be individualized to the patient. In the later phases of postopera-tive antibiotic treatment of serious intra-abdominal infection, the absence of an elevated white blood cell (WBC) count, lack of band forms of PMNs on peripheral smear, and lack of fever (<38°C [100.5°F]) provide close to complete assurance that infection has been eradicated.31 There is also emerging data that suggest following a patient’s procalcitonin level may provide the clinician with useful information regarding whether an infection has resolved and allow more expedient cessation of therapy.32,33 Patients who do not improve with 5 to 7 days of antibiotic therapy should be reevaluated for inadequate source control or a new extra-abdominal source of infection.Allergy to antimicrobial agents must be considered prior to prescribing them. First, it is important to ascertain whether a patient has had any type of allergic


Surgery_Schwartz

Surgery_Schwartz. extra-abdominal source of infection.Allergy to antimicrobial agents must be considered prior to prescribing them. First, it is important to ascertain whether a patient has had any type of allergic reaction in association with administration of a particular antibiotic. However, one should take care to ensure that the purported reaction consists of true allergic symptoms and signs, such as urticaria, bron-chospasm, or other similar manifestations, rather than indiges-tion or nausea. Penicillin allergy is quite common, the reported incidence ranging from 0.7% to 10%. Although avoiding the use of any β-lactam drug is appropriate in patients who mani-fest significant allergic reactions to penicillins, the incidence of cross-reactivity appears low for all related agents, with 1% cross-reactivity for carbapenems, 5% to 7% cross-reactivity for cephalosporins, and extremely small or nonexistent cross-reactivity for monobactams.34Severe allergic manifestations, such as anaphylaxis, to a


Surgery_Schwartz

Surgery_Schwartz. for carbapenems, 5% to 7% cross-reactivity for cephalosporins, and extremely small or nonexistent cross-reactivity for monobactams.34Severe allergic manifestations, such as anaphylaxis, to a specific class of agents generally preclude the use of any agents in that class, except under circumstances in which use of a certain drug represents a lifesaving measure. In some centers, patients undergo intradermal testing using a dilute solution of a particular antibiotic to determine whether a severe allergic reac-tion would be elicited by parenteral administration. A pathway, including such intradermal testing, has been effective in reduc-tion of vancomycin use to 16% in surgical patients with reported allergy to penicillin.35 This type of testing rarely is employed because it is simpler to select an alternative class of agent. Should administration of a specific agent to which the patient is Brunicardi_Ch06_p0157-p0182.indd 16801/03/19 4:46 PM 169SURGICAL INFECTIONSCHAPTER 6allergic


Surgery_Schwartz

Surgery_Schwartz. an alternative class of agent. Should administration of a specific agent to which the patient is Brunicardi_Ch06_p0157-p0182.indd 16801/03/19 4:46 PM 169SURGICAL INFECTIONSCHAPTER 6allergic become necessary, desensitization using progressively higher doses of antibiotic can be undertaken, providing the ini-tial testing does not cause severe allergic manifestations.Misuse of antimicrobial agents is rampant in both the inpa-tient and outpatient settings, and is associated with an enormous financial impact on healthcare costs, adverse reactions due to drug toxicity and allergy, the occurrence of new infections such as Clostridium difficile colitis, and the development of multiagent drug resistance among nosocomial pathogens. Each of these factors has been directly correlated with overall drug administration. It has been estimated that in the United States in excess of $20 billion is spent on antibiotics each year.36 The responsible practitioner limits prophylaxis to the period


Surgery_Schwartz

Surgery_Schwartz. drug administration. It has been estimated that in the United States in excess of $20 billion is spent on antibiotics each year.36 The responsible practitioner limits prophylaxis to the period dur-ing the operative procedure, does not convert prophylaxis into empiric therapy except under well-defined conditions, sets the duration of antibiotic therapy from the outset, curtails antibi-otic administration when clinical and microbiologic evidence does not support the presence of an infection, and limits therapy to a short course in every possible instance. Prolonged treat-ment associated with drains and tubes has not been shown to be beneficial.INFECTIONS OF SIGNIFICANCE IN SURGICAL PATIENTSSurgical Site InfectionsSurgical site infections (SSIs) are infections of the tissues, organs, or spaces exposed by surgeons during performance of an invasive procedure. SSIs are classified into incisional and organ/space infections, and the former are further subclas-sified into superficial (limited


Surgery_Schwartz

Surgery_Schwartz. exposed by surgeons during performance of an invasive procedure. SSIs are classified into incisional and organ/space infections, and the former are further subclas-sified into superficial (limited to skin and subcutaneous tissue) and deep incisional categories.37,38 The development of SSIs is related to three factors: (a) the degree of microbial contamina-tion of the wound during surgery; (b) the duration of the proce-dure; and (c) host factors such as diabetes, malnutrition, obesity, immune suppression; and a number of other underlying disease states. Table 6-7 lists risk factors for development of SSIs. By definition, an incisional SSI has occurred if a surgical wound drains purulent material or if the surgeon judges it to be infected and opens it.Surgical wounds are classified based on the presumed mag-nitude of the bacterial load at the time of surgery (Table 6-8).39 Clean wounds (class I) include those in which no infection is present; only skin microflora potentially


Surgery_Schwartz

Surgery_Schwartz. based on the presumed mag-nitude of the bacterial load at the time of surgery (Table 6-8).39 Clean wounds (class I) include those in which no infection is present; only skin microflora potentially contaminate the wound, and no hollow viscus that contains microbes is entered. Class I D wounds are similar except that a prosthetic device (e.g., mesh or valve) is inserted. Clean/contaminated wounds (class II) include those in which a hollow viscus such as the respiratory, alimentary, or genitourinary tracts with indigenous bacterial flora is opened under controlled circumstances without significant spillage of contents.While elective colorectal cases have classically been included as class II cases, a number of studies in the last decade have documented higher SSI rates (9–25%). One study iden-tified two-thirds of infections presenting after discharge from hospital, highlighting the need for careful follow-up of these patients.40 Infection is also more common in cases involving entry into


Surgery_Schwartz

Surgery_Schwartz. two-thirds of infections presenting after discharge from hospital, highlighting the need for careful follow-up of these patients.40 Infection is also more common in cases involving entry into the rectal space.41 In a recent single-center quality improvement study using a multidisciplinary approach, one group of clinicians has demonstrated the ability to decrease SSI from 9.8% to 4.0%.425Table 6-7Risk factors for development of surgical site infectionsPatient factors Older age Immunosuppression Obesity Diabetes mellitus Chronic inflammatory process Malnutrition Smoking Renal failure Peripheral vascular disease Anemia Radiation Chronic skin disease Carrier state (e.g., chronic Staphylococcus carriage) Recent operationLocal factors Open compared to laparoscopic surgery Poor skin preparation Contamination of instruments Inadequate antibiotic prophylaxis Prolonged procedure Local tissue necrosis Blood transfusion Hypoxia, hypothermiaMicrobial factors Prolonged hospitalization (leading to


Surgery_Schwartz

Surgery_Schwartz. of instruments Inadequate antibiotic prophylaxis Prolonged procedure Local tissue necrosis Blood transfusion Hypoxia, hypothermiaMicrobial factors Prolonged hospitalization (leading to nosocomial organisms) Toxin secretion Resistance to clearance (e.g., capsule formation)Table 6-8Wound class, representative procedures, and expected infection ratesWOUND CLASSEXAMPLES OF CASESEXPECTED INFECTION RATESClean (class I)Hernia repair, breast biopsy1–2%Clean/contaminated (class II)Cholecystectomy, elective GI surgery (not colon)2.1–9.5%Clean/contaminated (class II)Colorectal surgery4–14%Contaminated (class III)Penetrating abdominal trauma, large tissue injury, enterotomy during bowel obstruction3.4–13.2%Dirty (class IV)Perforated diverticulitis, necrotizing soft tissue infections3.1–12.8%Brunicardi_Ch06_p0157-p0182.indd 16901/03/19 4:46 PM 170BASIC CONSIDERATIONSPART IContaminated wounds (class III) include open acciden-tal wounds encountered early after injury, those with extensive


Surgery_Schwartz

Surgery_Schwartz. 16901/03/19 4:46 PM 170BASIC CONSIDERATIONSPART IContaminated wounds (class III) include open acciden-tal wounds encountered early after injury, those with extensive introduction of bacteria into a normally sterile area of the body due to major breaks in sterile technique (e.g., open cardiac massage), gross spillage of viscus contents such as from the intestine, or incision through inflamed, albeit nonpurulent tis-sue. Dirty wounds (class IV) include traumatic wounds in which a significant delay in treatment has occurred and in which necrotic tissue is present, those created in the presence of overt infection as evidenced by the presence of purulent material, and those created to access a perforated viscus accompanied by a high degree of contamination. The microbiology of SSIs is reflective of the initial host microflora such that SSIs fol-lowing creation of a class I wound are invariably caused by skin microbes found on that portion of the body, while SSIs subsequent to a class


Surgery_Schwartz

Surgery_Schwartz. of the initial host microflora such that SSIs fol-lowing creation of a class I wound are invariably caused by skin microbes found on that portion of the body, while SSIs subsequent to a class II wound created for the purpose of elec-tive colon resection may be caused by either skin microbes or colonic microflora, or both.Surgical management of the wound is a critical determi-nant of the propensity to develop an SSI. In healthy individuals, classes I and II wounds may be closed primarily, while skin closure of class III and IV wounds is associated with high rates of incisional SSIs (∼25–50%). The superficial aspects of these latter types of wounds should be packed open and allowed to heal by secondary intention, although selective use of delayed primary closure has been associated with a reduction in inci-sional SSI rates.43 One clear example based on data from clini-cal trials is that class III wounds in healthy patients undergoing appendectomy for perforated or gangrenous


Surgery_Schwartz

Surgery_Schwartz. with a reduction in inci-sional SSI rates.43 One clear example based on data from clini-cal trials is that class III wounds in healthy patients undergoing appendectomy for perforated or gangrenous appendicitis can be primarily closed as long as antibiotic therapy directed against aerobes and anaerobes is administered. This practice leads to SSI rates of approximately 3% to 4%.44Recent investigations have studied the effect of additional maneuvers in an attempt to further reduce the rate of SSIs. The adverse effects of hyperglycemia on WBC function have been well described.45 A number of studies in patients undergoing several different types of surgery describe increased risk of SSI in patients with hyperglycemia, and the 2017 CDC guidelines for prevention of surgical site infection recommend maintaining blood glucose <200 mg/dL (11.1 mmol/L) in all patients during the perioperative period.46-48The respective effects of body temperature and the level of inhaled oxygen during surgery on


Surgery_Schwartz

Surgery_Schwartz. maintaining blood glucose <200 mg/dL (11.1 mmol/L) in all patients during the perioperative period.46-48The respective effects of body temperature and the level of inhaled oxygen during surgery on SSI rates also have been studied, and both hypothermia and hypoxia during surgery are associated with a higher rate of SSI. There is conflicting evi-dence regarding whether supplying higher levels of inhaled oxy-gen to perioperative patients reduces the rate of SSI. Although an initial study provided evidence that patients who received high levels of inhaled oxygen during colorectal surgery devel-oped fewer SSIs,49 a later meta-analysis suggested that the over-all benefit is small and may not warrant use.50 The 2017 CDC guidelines, however, support administration of increased FiO2 during surgery and after extubation in patients with normal pul-monary function receiving general anesthesia as there has been some evidence of benefit.20,51 Further evaluation via multicenter studies is needed


Surgery_Schwartz

Surgery_Schwartz. and after extubation in patients with normal pul-monary function receiving general anesthesia as there has been some evidence of benefit.20,51 Further evaluation via multicenter studies is needed prior to implementation of hyperoxia as stan-dard therapy, but it is clear that intraoperative hypothermia and hypoxia should be prevented.Effective therapy for incisional SSIs consists solely of incision and drainage without the additional use of antibiotics. Antibiotic therapy is reserved for patients in whom evidence of significant cellulitis is present, or who concurrently manifest a systemic inflammatory response syndrome. The open wound often is allowed to heal by secondary intention, with dressings being changed as the clinical team deems appropriate. The use of topical antibiotics and antiseptics to further wound healing remains unproven, although anecdotal studies indicate their potential utility in complex wounds that do not heal with routine measures.52 Despite a paucity of


Surgery_Schwartz

Surgery_Schwartz. and antiseptics to further wound healing remains unproven, although anecdotal studies indicate their potential utility in complex wounds that do not heal with routine measures.52 Despite a paucity of prospective studies, vacuum-assisted closure is increasingly used in management of large, complex open wounds and can be applied to wounds in loca-tions that are difficult to manage with dressings (Fig. 6-1).53,54 One also should consider obtaining wound cultures in patients who develop SSIs and who have been hospitalized or reside in long-term care facilities due to the increasing incidence of infec-tion caused by multidrug-resistant organisms.In the United States, hospitals are required to conduct sur-veillance for the development of SSIs for a period of 30 days ABFigure 6-1. Negative pressure wound therapy in a patient after amputation for wet gangrene (A) and in a patient with enterocutaneous fistula (B). It is possible to adapt these dressings to fit difficult anatomy and provide


Surgery_Schwartz

Surgery_Schwartz. wound therapy in a patient after amputation for wet gangrene (A) and in a patient with enterocutaneous fistula (B). It is possible to adapt these dressings to fit difficult anatomy and provide appropriate wound care while reducing frequency of dressing change. It is important to evaluate the wound under these dressings if the patient demonstrates signs of sepsis with an unidentified source, since typical clues of wound sepsis such as odor and drainage are hidden by the suction apparatus.Brunicardi_Ch06_p0157-p0182.indd 17001/03/19 4:46 PM 171SURGICAL INFECTIONSCHAPTER 6after the operative procedure.55 Such surveillance has been associated with greater awareness and a reduction in SSI rates, probably in large part based upon the impact of observation and promotion of adherence to appropriate care standards. Begin-ning in 2012, all hospitals receiving reimbursement from the Centers for Medicare & Medicaid Services (CMS) are required to report SSIs.A recent refinement of risk indexes


Surgery_Schwartz

Surgery_Schwartz. care standards. Begin-ning in 2012, all hospitals receiving reimbursement from the Centers for Medicare & Medicaid Services (CMS) are required to report SSIs.A recent refinement of risk indexes has been implemented through the National Healthcare Safety Network, a secure, web-based system of surveillance used by the CDC for surveillance of healthcare-associated infections. This refinement utilized data reported from 847 hospitals in nearly one million patients over a 2-year period to develop procedure-specific risk indices for SSIs.56SSIs are associated with considerable morbidity and occasional lethality, as well as substantial healthcare costs and patient inconvenience and dissatisfaction.57 A number of healthcare organizations within the United States are interested in evaluating performance of hospitals and physicians with respect to implementing processes that support delivery of stan-dard of care. One major process of interest is reduction in SSIs, since the morbidity (and


Surgery_Schwartz

Surgery_Schwartz. performance of hospitals and physicians with respect to implementing processes that support delivery of stan-dard of care. One major process of interest is reduction in SSIs, since the morbidity (and subsequent cost) of this complication is high. Several of these organizations are noted in Table 6-9. Appropriate guidelines in this area incorporating the principles discussed previously have been developed and disseminated.58 However, observers have noted that adherence to these guide-lines has been poor.59 Most experts believe that better adherence to evidence-based practice recommendations and implementing systems of care with redundant safeguards will result in reduc-tion of surgical complications and better patient outcomes. More important, the CMS, the largest third-party insurance payer in the United States, has required reporting by hospitals of many processes related to reduction of surgical infections, including appropriate use of perioperative antibiotics. This information,


Surgery_Schwartz

Surgery_Schwartz. in the United States, has required reporting by hospitals of many processes related to reduction of surgical infections, including appropriate use of perioperative antibiotics. This information, which is reported publicly by hospitals, has led to significant improvement in reported rates of these process measures. How-ever, the effect of this approach on the incidence of SSIs is not known at this time.Intra-Abdominal InfectionsMicrobial contamination of the peritoneal cavity is termed peri-tonitis or intra-abdominal infection and is classified according to etiology. Primary microbial peritonitis occurs when microbes invade the normally sterile confines of the peritoneal cavity via hematogenous dissemination from a distant source of infec-tion or direct inoculation. This process is more common among patients who retain large amounts of peritoneal fluid due to ascites, and among those individuals who are being treated for renal failure via peritoneal dialysis. These infections


Surgery_Schwartz

Surgery_Schwartz. more common among patients who retain large amounts of peritoneal fluid due to ascites, and among those individuals who are being treated for renal failure via peritoneal dialysis. These infections invariably are monomicrobial and rarely require surgical intervention. The diagnosis is established based on identification of risk factors as noted previously, physical examination that reveals diffuse tenderness and guarding without localized findings, absence of a surgically treatable source of infection on an imaging study, and the presence of more than 250 neutrophils/mL in fluid obtained via paracentesis.60 Cultures typically will demonstrate the presence of gram-positive organisms in patients undergoing peritoneal dialysis. In patients without this risk factor, the most common etiologic organisms are E coli, K pneumoniae, and S pneumoniae. Treatment consists of administration of an anti-biotic to which the organism is sensitive; often 14 to 21 days of therapy are required. Removal


Surgery_Schwartz

Surgery_Schwartz. organisms are E coli, K pneumoniae, and S pneumoniae. Treatment consists of administration of an anti-biotic to which the organism is sensitive; often 14 to 21 days of therapy are required. Removal of indwelling devices, if present, may be required for effective therapy of recurrent infections.Secondary microbial peritonitis occurs subsequent to con-tamination of the peritoneal cavity due to perforation or severe inflammation and infection of an intra-abdominal organ. Exam-ples include appendicitis, perforation of any portion of the gas-trointestinal tract, or diverticulitis. As noted previously, effective therapy requires source control to resect or repair the diseased organ; debridement of necrotic, infected tissue and debris; and administration of antimicrobial agents directed against aerobes and anaerobes.61 This type of antibiotic regimen should be cho-sen because in most patients the precise diagnosis cannot be established until exploratory laparotomy is performed, and the most


Surgery_Schwartz

Surgery_Schwartz. aerobes and anaerobes.61 This type of antibiotic regimen should be cho-sen because in most patients the precise diagnosis cannot be established until exploratory laparotomy is performed, and the most morbid form of this disease process is colonic perforation, due to the large number of microbes present. A combination of agents or single agents with a broad spectrum of activity can be used for this purpose; conversion of a parenteral to an oral regi-men when the patient’s ileus resolves provides results similar to those achieved with intravenous antibiotics. Effective source control and antibiotic therapy is associated with low failure rates and a mortality rate of approximately 5% to 6%; inability to control the source of infection is associated with mortality greater than 40%.62The response rate to effective source control and use of appropriate antibiotics has remained approximately 70% to 90% over the past several decades.63 Patients in whom stan-dard therapy fails typically


Surgery_Schwartz

Surgery_Schwartz. response rate to effective source control and use of appropriate antibiotics has remained approximately 70% to 90% over the past several decades.63 Patients in whom stan-dard therapy fails typically develop one or more of the follow-ing: an intra-abdominal abscess, leakage from a gastrointestinal anastomosis leading to postoperative peritonitis, or tertiary (persistent) peritonitis. The latter is a poorly understood entity that is more common in immunosuppressed patients in whom peritoneal host defenses do not effectively clear or sequester Table 6-9Quality improvement organizations of interest to surgeons in the United StatesABBREVIATIONORGANIZATIONWEBSITENSQIPNational Surgical Quality Improvement Programacsnsqip.orgIHIInstitute for Healthcare Improvementwww.ihi.orgCMSCenters for Medicare & Medicaid Serviceswww.medicare.govwww.cms.gov/NCQANational Committee for Quality Assurancewww.ncqa.orgSISSurgical Infection Societywww.sisna.orgCDCCenters for Disease Control and


Surgery_Schwartz

Surgery_Schwartz. for Medicare & Medicaid Serviceswww.medicare.govwww.cms.gov/NCQANational Committee for Quality Assurancewww.ncqa.orgSISSurgical Infection Societywww.sisna.orgCDCCenters for Disease Control and Preventionwww.cdc.gov/HAI/ssi/ssi.htmlBrunicardi_Ch06_p0157-p0182.indd 17101/03/19 4:46 PM 172BASIC CONSIDERATIONSPART Ithe initial secondary microbial peritoneal infection. Microbes such as E faecalis and faecium, S epidermidis, C albicans, and P aeruginosa commonly are identified, typically in combina-tion, and their presence may be due to their lack of responsive-ness to the initial antibiotic regimen, coupled with diminished activity of host defenses. Unfortunately, even with effective antimicrobial agent therapy, this disease process is associated with mortality rates in excess of 50%.64Formerly, the presence of an intra-abdominal abscess mandated surgical reexploration and drainage. Today, the vast majority of such abscesses can be effectively diagnosed via abdominal computed


Surgery_Schwartz

Surgery_Schwartz. 50%.64Formerly, the presence of an intra-abdominal abscess mandated surgical reexploration and drainage. Today, the vast majority of such abscesses can be effectively diagnosed via abdominal computed tomographic (CT) imaging techniques and drained percutaneously. Surgical intervention is reserved for those individuals who harbor multiple abscesses, those with abscesses in proximity to vital structures such that percutaneous drainage would be hazardous, and those in whom an ongoing source of contamination (e.g., enteric leak) is identified. The necessity of antimicrobial agent therapy and precise guidelines that dictate duration of catheter drainage have not been estab-lished. A short course (3 to 5 days) of antibiotics that possess aerobic and anaerobic activity seems reasonable so long as the patient has good clinical response to therapy, and most practi-tioners leave the drainage catheter in situ until it is clear that cavity collapse has occurred, output is less than 10 to 20 mL/d,


Surgery_Schwartz

Surgery_Schwartz. the patient has good clinical response to therapy, and most practi-tioners leave the drainage catheter in situ until it is clear that cavity collapse has occurred, output is less than 10 to 20 mL/d, no evidence of an ongoing source of contamination is present, and the patient’s clinical condition has improved.33Organ-Specific InfectionsHepatic abscesses are rare, currently accounting for approximately 15 per 100,000 hospital admissions in the United States. Pyogenic abscesses account for approximately 80% of cases, the remaining 20% being equally divided among parasitic and fungal forms.65 Formerly, pyogenic liver abscesses mainly were caused by pyle-phlebitis due to neglected appendicitis or diverticulitis. Today, manipulation of the biliary tract to treat a variety of diseases has become a more common cause, although in nearly 50% of patients no cause is identified. The most common aerobic bacteria iden-tified in recent series include E coli, K pneumoniae, and other enteric bacilli,


Surgery_Schwartz

Surgery_Schwartz. a more common cause, although in nearly 50% of patients no cause is identified. The most common aerobic bacteria iden-tified in recent series include E coli, K pneumoniae, and other enteric bacilli, enterococci, and Pseudomonas spp., while the most common anaerobic bacteria are Bacteroides spp., anaero-bic streptococci, and Fusobacterium spp. C albicans and other related yeast cause the majority of fungal hepatic abscesses. Small (<1 cm), multiple abscesses should be sampled and treated with a 4to 6-week course of antibiotics. Larger abscesses are generally amenable to percutaneous drainage, with parameters for antibiotic therapy and drain removal similar to those men-tioned previously. Splenic abscesses are extremely rare and are treated in a similar fashion. Recurrent hepatic or splenic abscesses may require operative intervention—unroofing and marsupialization or splenectomy, respectively.Secondary pancreatic infections (e.g., infected pancreatic necrosis or pancreatic abscess)


Surgery_Schwartz

Surgery_Schwartz. abscesses may require operative intervention—unroofing and marsupialization or splenectomy, respectively.Secondary pancreatic infections (e.g., infected pancreatic necrosis or pancreatic abscess) occur in approximately 10% to 15% of patients who develop severe pancreatitis with necro-sis. The surgical treatment of this disorder was pioneered by Bradley and Allen, who noted significant improvements in out-come for patients undergoing repeated pancreatic debridement of infected pancreatic necrosis.66 Care of patients with severe acute pancreatitis includes staging with dynamic, contrast-enhanced helical CT scan to evaluate the extent of pancreatitis (unless significant renal dysfunction exists, in which case one should forego the use of contrast material) coupled with the use of one of several prognostic scoring systems. Patients who exhibit clinical signs of instability (e.g., oliguria, hypoxemia, large-volume fluid resuscitation) should be carefully monitored in the ICU and undergo


Surgery_Schwartz

Surgery_Schwartz. prognostic scoring systems. Patients who exhibit clinical signs of instability (e.g., oliguria, hypoxemia, large-volume fluid resuscitation) should be carefully monitored in the ICU and undergo follow-up contrast CT examination when renal function has stabilized to evaluate for development of local pancreatic complications (Fig. 6-2). Routine use of pro-phylactic antibiotics to prevent infected pancreatic necrosis is not indicated. Early enteral feeding using nasojejunal feeding tubes placed past the ligament of Treitz has been associated with decreased development of infected pancreatic necrosis, possibly due to a decrease in gut translocation of bacteria.67,68The presence of secondary pancreatic infection should be suspected in patients whose systemic inflammatory response (fever, elevated WBC count, or organ dysfunction) fails to resolve, or in those individuals who initially recuperate, only to develop sepsis syndrome 2 to 3 weeks later. CT-guided aspira-tion of fluid from the


Surgery_Schwartz

Surgery_Schwartz. WBC count, or organ dysfunction) fails to resolve, or in those individuals who initially recuperate, only to develop sepsis syndrome 2 to 3 weeks later. CT-guided aspira-tion of fluid from the pancreatic bed for performance of Gram stain and culture analysis can be useful. A positive Gram stain or culture from CT-guided aspiration, or identification of gas within the pancreas on CT scan, mandate surgical intervention.The approach of open necrosectomy with repeated debridements, although life-saving, is associated with sig-nificant morbidity and prolonged hospitalization. Efforts to reduce the amount of surgical injury, while still preserving the improved outcomes associated with debridement of the infected sequestrum, have led to a variety of less invasive approaches, including endoscopic and laparoscopic techniques.69 There are a limited number of randomized trials reporting the use of these new techniques. An important concept common to all of these approaches, however, is the


Surgery_Schwartz

Surgery_Schwartz. and laparoscopic techniques.69 There are a limited number of randomized trials reporting the use of these new techniques. An important concept common to all of these approaches, however, is the attempt to delay surgical interven-tion, since a number of trials have identified increased mortality when intervention occurs during the first 2 weeks of illness.Data supporting the use of endoscopic approaches to infected pancreatic necrosis include nearly a dozen case series and a randomized trial.70,71 The reported mortality rate was 5%, with a 30% complication rate. Most authors noted the common requirement for multiple endoscopic debridements (similar to the open approach), with a median of four sessions required. Fewer series report experience with the laparoscopic approach, either transgastric or transperitoneal, entering the necrosis through the transverse mesocolon or gastrocolic ligament. Lap-aroscopic intervention is limited by the difficulty in achieving Figure


Surgery_Schwartz

Surgery_Schwartz. either transgastric or transperitoneal, entering the necrosis through the transverse mesocolon or gastrocolic ligament. Lap-aroscopic intervention is limited by the difficulty in achieving Figure 6-2. Contrast-enhanced CT scan of pancreas 1.5 weeks after presentation showing large central peripancreatic fluid col-lection (arrow).Brunicardi_Ch06_p0157-p0182.indd 17201/03/19 4:46 PM 173SURGICAL INFECTIONSCHAPTER 6Figure 6-3. Infected pancreatic necrosis. (A) Open necrosectomy specimen with pancreatic stent in situ. It is important to gently debride only necrotic pancreatic tissue, relying on repeated opera-tion to ensure complete removal. (B) For video-assisted retroperito-neal debridement (VARD), retroperitoneal access is gained through radiologic placement of a drain, followed by dilation 2 to 3 days later. (C) Retroperitoneal cavity seen through endoscope during VARD.BCmultiple debridements and the technical expertise required to achieve an adequate debridement. In 9 case series,


Surgery_Schwartz

Surgery_Schwartz. 2 to 3 days later. (C) Retroperitoneal cavity seen through endoscope during VARD.BCmultiple debridements and the technical expertise required to achieve an adequate debridement. In 9 case series, mortality in a total of 65 patients was 6%.72Debridement of necrosis through a lumbar approach has been advocated by a number of authors. This approach, devel-oped with experience in a large number of patients,73 has been subjected to a single-center, randomized, prospective trial.74 This approach includes delay of intervention when possible until 4 weeks after the onset of disease. Patients receive transgastric or preferably retroperitoneal drainage of the sequestrum. If patients do not improve over 72 hours, they are treated with video-assisted retroperitoneal drainage (VARD), consisting of dilation of the retroperitoneal drain tract and debridement of the pancreatic bed (Fig. 6-3). Repeat debridements are performed as clinically indi-cated, with most patients requiring multiple


Surgery_Schwartz

Surgery_Schwartz. of dilation of the retroperitoneal drain tract and debridement of the pancreatic bed (Fig. 6-3). Repeat debridements are performed as clinically indi-cated, with most patients requiring multiple debridements. In the trial reported, patients randomized to VARD (n = 43) compared to those randomized to the standard open necrosectomy (n = 45) had a decreased incidence of the composite endpoint of compli-cations and death (40% vs. 69%), with comparable mortality rate, hospital, and ICU lengths of stay. Patients randomized to VARD had fewer incisional hernias and occurrences of new-onset diabe-tes, as well as less need for pancreatic enzyme supplementation.It is apparent that patients with infected pancreatic necro-sis can safely undergo procedures that are more minimal than the gold-standard open necrosectomy with good outcomes. However, to obtain good outcomes these approaches require an experienced multidisciplinary team consisting of interventional radiologists, gastroenterologists,


Surgery_Schwartz

Surgery_Schwartz. open necrosectomy with good outcomes. However, to obtain good outcomes these approaches require an experienced multidisciplinary team consisting of interventional radiologists, gastroenterologists, surgeons, and others. Impor-tant concepts for successful management include careful pre-operative planning, delay (if possible) to allow maturation of the fluid collection, and the willingness to repeat procedures as necessary until nonviable tissue has been removed.Infections of the Skin and Soft TissueThese infections can be classified according to whether sur-gical intervention is required. For example, superficial skin and skin structure infections such as cellulitis, erysipelas, and lymphangitis invariably are effectively treated with antibiotics alone, although a search for a local underlying source of infec-tion should be undertaken. Generally, drugs that possess activity against the causative gram-positive skin microflora are selected. Furuncles or boils may drain spontaneously or


Surgery_Schwartz

Surgery_Schwartz. source of infec-tion should be undertaken. Generally, drugs that possess activity against the causative gram-positive skin microflora are selected. Furuncles or boils may drain spontaneously or require surgical incision and drainage. Antibiotics are prescribed if significant cellulitis is present or if cellulitis does not rapidly resolve after surgical drainage. Community-acquired methicillin-resistant S aureus (MRSA) infection should be suspected if infection persists after treatment with adequate drainage and administra-tion of first-line antibiotics. These infections may require more aggressive drainage and altered antimicrobial therapy.75Aggressive soft tissue infections are rare, difficult to diag-nose, and require immediate surgical intervention plus adminis-tration of antimicrobial agents. Failure to rapidly recognize and treat these infections results in an extremely high mortality rate (∼80–100%), and even with expedient therapy mortality rates are high (16–24%).76 Eponyms


Surgery_Schwartz

Surgery_Schwartz. agents. Failure to rapidly recognize and treat these infections results in an extremely high mortality rate (∼80–100%), and even with expedient therapy mortality rates are high (16–24%).76 Eponyms and differing classifications in the past has led to a hodgepodge of terminology—such as Meleney’s synergistic gangrene, Fournier’s gangrene, rapidly spreading cellulitis, gas gangrene, and necrotizing fasciitis—regarding these serious infections. Today it seems best to delin-eate them based on the soft tissue layer(s) of involvement 6Brunicardi_Ch06_p0157-p0182.indd 17301/03/19 4:46 PM 174BASIC CONSIDERATIONSPART I(e.g., skin and superficial soft tissue, deep soft tissue, and mus-cle) and the pathogen(s) that cause them.Patients at risk for these types of infections include those who are elderly, immunosuppressed, or diabetic, and/or who suf-fer from peripheral vascular disease, though extremely aggressive necrotizing soft tissue infections (often caused by streptococci) have been


Surgery_Schwartz

Surgery_Schwartz. elderly, immunosuppressed, or diabetic, and/or who suf-fer from peripheral vascular disease, though extremely aggressive necrotizing soft tissue infections (often caused by streptococci) have been described among healthy individuals as well. The com-mon thread among these host factors appears to be compromise of the fascial blood supply, and if this is coupled with the introduc-tion of exogenous microbes, the result can be devastating.Initially, the diagnosis is established solely upon a constel-lation of clinical findings, not all of which are present in every patient. Not surprisingly, patients often develop sepsis syndrome or septic shock without an obvious cause. The extremities, perineum, trunk, and torso are most commonly affected, in that order. Careful examination should be undertaken for an entry site such as a small break or sinus in the skin from which grayish, turbid semipurulent material (“dishwater pus”) can be expressed, as well as for the presence of skin changes


Surgery_Schwartz

Surgery_Schwartz. for an entry site such as a small break or sinus in the skin from which grayish, turbid semipurulent material (“dishwater pus”) can be expressed, as well as for the presence of skin changes (bronze hue or brawny induration), blebs, or crepitus. The patient often develops pain at the site of infection that appears to be out of proportion to any of the physical manifestations. Any of these findings man-dates immediate surgical intervention, which should consist of incision and direct visualization of potentially infected tissue (including deep soft tissue, fascia, and underlying muscle) and radical resection of affected areas. Radiologic studies should not be undertaken in patients in whom the diagnosis seriously is con-sidered, as they delay surgical intervention and frequently pro-vide confusing information. Unfortunately, surgical extirpation of infected tissue frequently entails amputation and/or disfigur-ing procedures; the surgeon must bear in mind that incomplete procedures are


Surgery_Schwartz

Surgery_Schwartz. information. Unfortunately, surgical extirpation of infected tissue frequently entails amputation and/or disfigur-ing procedures; the surgeon must bear in mind that incomplete procedures are associated with higher rates of morbidity and mortality and debride all nonviable tissue (Fig. 6-4).During the procedure, a Gram stain should be performed on tissue fluid. Antimicrobial agents directed against gram-positive and gram-negative aerobes and anaerobes (e.g., van-comycin plus a carbapenem), as well as high-dose aqueous penicillin G (16,000,000 to 20,000,000 U/d), the latter to treat clostridial pathogens, should be administered. Approximately 50% of such infections are polymicrobial, the remainder being caused by a single organism such as S pyogenes, P aeruginosa, or C perfringens. The microbiology of these polymicrobial infections is similar to that of secondary microbial peritonitis, with the exception that gram-positive cocci are more commonly encountered. Most patients should be


Surgery_Schwartz

Surgery_Schwartz. of these polymicrobial infections is similar to that of secondary microbial peritonitis, with the exception that gram-positive cocci are more commonly encountered. Most patients should be returned to the operat-ing room on a scheduled basis to determine if disease progres-sion has occurred. If so, additional resection of infected tissue and debridement should take place. Antibiotic therapy can be refined based on culture and sensitivity results, particularly in the case of monomicrobial soft tissue infections. Hyperbaric oxygen therapy may be of use in patients with infection caused by gas-forming organisms (e.g., C perfringens), although the evidence to support efficacy is limited to underpowered studies and case reports. In the absence of such infection, hyperbaric oxygen therapy has not been shown to be effective.77Postoperative Nosocomial InfectionsSurgical patients are prone to develop a wide variety of nosoco-mial infections during the postoperative period, which include SSIs,


Surgery_Schwartz

Surgery_Schwartz. been shown to be effective.77Postoperative Nosocomial InfectionsSurgical patients are prone to develop a wide variety of nosoco-mial infections during the postoperative period, which include SSIs, UTIs, pneumonia, and bacteremia. SSIs are discussed ear-lier, and the latter types of nosocomial infections are related to prolonged use of indwelling tubes and catheters for the purpose of urinary drainage, ventilation, and venous and arterial access, respectively.The presence of a postoperative UTI should be considered based on urinalysis demonstrating WBCs or bacteria, a positive test for leukocyte esterase, or a combination of these elements. The diagnosis is established after >104 CFU/mL of microbes are identified by culture techniques in symptomatic patients, or >105 CFU/mL in asymptomatic individuals. Treatment for 3 to 5 days with a single antibiotic directed against the most common organ-isms (e.g., E Coli, K pneumoniae) that achieves high levels in the urine is appropriate. Initial


Surgery_Schwartz

Surgery_Schwartz. individuals. Treatment for 3 to 5 days with a single antibiotic directed against the most common organ-isms (e.g., E Coli, K pneumoniae) that achieves high levels in the urine is appropriate. Initial therapy is directed by Gram stain results and is refined as culture results become available. Postop-erative surgical patients should have indwelling urinary catheters removed as quickly as possible to avoid the development of a UTI.Prolonged mechanical ventilation is associated with nos-ocomial pneumonia. These patients present with more severe disease, are more likely to be infected with drug-resistant pathogens, and suffer increased mortality compared to patients who develop community-acquired pneumonia. The diagnosis of pneumonia is established by presence of purulent sputum, elevated leukocyte count, fever, and new chest X-ray abnor-malities, such as consolidation. The presence of two of the clini-cal findings, plus chest X-ray findings, significantly increases the likelihood of


Surgery_Schwartz

Surgery_Schwartz. leukocyte count, fever, and new chest X-ray abnor-malities, such as consolidation. The presence of two of the clini-cal findings, plus chest X-ray findings, significantly increases the likelihood of pneumonia.78 Consideration should be given to performing bronchoalveolar lavage to obtain samples for Gram stain and culture. Some authors advocate quantitative cultures as a means to identify a threshold for diagnosis.79 Surgical patients should be weaned from mechanical ventilation as soon as feasi-ble, based on oxygenation and inspiratory effort, as risk of pneu-monia increases with increased time on mechanical ventilation.Infection associated with indwelling intravascular cathe-ters is a common problem among hospitalized patients. Because of the complexity of many surgical procedures, these devices are increasingly used for physiologic monitoring, vascular access, drug delivery, and hyperalimentation. Among the sev-eral million catheters inserted each year in the United States,


Surgery_Schwartz

Surgery_Schwartz. these devices are increasingly used for physiologic monitoring, vascular access, drug delivery, and hyperalimentation. Among the sev-eral million catheters inserted each year in the United States, approximately 25% will become colonized, and approximately 5% will be associated with bacteremia. Duration of catheteriza-tion, insertion or manipulation under emergency or nonsterile conditions, use for hyperalimentation, and the use of multilu-men catheters increase the risk of infection. Use of a central line insertion protocol that includes full barrier precautions and chlorhexidine skin prep has been shown to decrease the inci-dence of infection.80 Although no randomized trials have been performed, peripherally inserted central venous catheters have a catheter-related infection rate similar to those inserted in the subclavian or jugular veins.81Many patients who develop intravascular catheter infec-tions are asymptomatic, often exhibiting solely an elevation in the blood WBC count.


Surgery_Schwartz

Surgery_Schwartz. to those inserted in the subclavian or jugular veins.81Many patients who develop intravascular catheter infec-tions are asymptomatic, often exhibiting solely an elevation in the blood WBC count. Blood cultures obtained from a peripheral site and drawn through the catheter that reveals the presence of the same organism increase the index of suspicion for the pres-ence of a catheter infection. Obvious purulence at the exit site of the skin tunnel, severe sepsis syndrome due to any type of organism when other potential causes have been excluded, or bacteremia due to gram-negative aerobes or fungi should lead to catheter removal. Selected catheter infections due to low-virulence microbes such as S epidermidis can be effectively treated in approximately 50% to 60% of patients with a 14to 21-day course of an antibiotic, which should be considered when no other vascular access site exists.82 The use of antibi-otic-bonded catheters and chlorhexidine sponges at the insertion


Surgery_Schwartz

Surgery_Schwartz. with a 14to 21-day course of an antibiotic, which should be considered when no other vascular access site exists.82 The use of antibi-otic-bonded catheters and chlorhexidine sponges at the insertion Brunicardi_Ch06_p0157-p0182.indd 17401/03/19 4:46 PM 175SURGICAL INFECTIONSCHAPTER 6FIGURE 6-4. Necrotizing soft tissue infection. (A) This patient presented with hypotension due to severe late necrotizing fasci-itis and myositis due to β-hemolytic streptococcal infection. The patient succumbed to his disease after 16 hours despite aggressive debridement. (B) This patient presented with spreading cellulites and pain on motion of his right hip 2 weeks after total colectomy. Cellulitis on right anterior thigh is outlined. (C) Classic dishwater edema of tissues with necrotic fascia. (D) Right lower extremity after debridement of fascia to viable muscle.site has been associated with lower rates of colonization.83 Use of ethanol or antimicrobial catheter “locks” have shown prom-ise in


Surgery_Schwartz

Surgery_Schwartz. Right lower extremity after debridement of fascia to viable muscle.site has been associated with lower rates of colonization.83 Use of ethanol or antimicrobial catheter “locks” have shown prom-ise in reducing incidence of infection in dialysis catheters.84 The surgeon should carefully consider the need for any type of vascular access devices, rigorously attend to their maintenance to prevent infection, and remove them as quickly as possible. Use of systemic antibacterial or antifungal agents to prevent catheter infection is of no utility and is contraindicated.SepsisAs previously discussed, sepsis is increasing in incidence, with more than 1.1 million cases estimated per year in the United States with an annual cost of $24 billion. This rate is expected to increase as the population of aged in the United States increases. One third of sepsis cases occur in surgical pop-ulations and sepsis is a major cause of morbidity and mortality.85 The treatment of sepsis has improved over the


Surgery_Schwartz

Surgery_Schwartz. aged in the United States increases. One third of sepsis cases occur in surgical pop-ulations and sepsis is a major cause of morbidity and mortality.85 The treatment of sepsis has improved over the last decade, with mortality rates dropping to under 30%. Factors contributing to this improvement relate both to recent randomized prospective trials demonstrating improved outcomes with new therapies, and to improvements in the process of care delivery to the sepsis patient. The “Surviving Sepsis Campaign,” a multidisciplinary group that develops treatment recommendations, published guidelines incorporating evidence-based sepsis treatment strate-gies most recently in 2016.15,86 These guidelines are summarized in Table 6-10.ABCDBrunicardi_Ch06_p0157-p0182.indd 17501/03/19 4:46 PM 176BASIC CONSIDERATIONSPART IPatients presenting with sepsis should receive resuscitation fluids early in the course of therapy. While former guidelines advocated fluids until the patient’s central venous


Surgery_Schwartz

Surgery_Schwartz. CONSIDERATIONSPART IPatients presenting with sepsis should receive resuscitation fluids early in the course of therapy. While former guidelines advocated fluids until the patient’s central venous pressure was 8 to 12 mmHg, newer guidelines recommend using dynamic monitoring systems (such as ultrasound) as well as assessment of physiological response to fluids by evaluating variables such as heart rate, blood pressure, and urine output to determine ade-quate resuscitation volumes. Resuscitation endpoints include achieving a goal mean arterial pressure of ≥65 mmHg, urine output of ≥0.5 mL/kg per hour, and normalization of serum lac-tate. Delaying this resuscitative step for as little as 3 hours has been shown to result in worse outcomes.87 Resuscitation may necessitate placement of a central venous catheter.A number of studies have demonstrated the importance of early empiric antibiotic therapy in patients who develop sep-sis or nosocomial infection; the Surviving Sepsis guidelines


Surgery_Schwartz

Surgery_Schwartz. venous catheter.A number of studies have demonstrated the importance of early empiric antibiotic therapy in patients who develop sep-sis or nosocomial infection; the Surviving Sepsis guidelines advocate for initiation of treatment within the first hour of the patient’s care. This therapy should be initiated as soon as pos-sible with broad-spectrum antibiotics directed against the most likely organisms. Use of institutionand unit-specific sensitivity patterns are critical in selecting an appropriate agent for patients with nosocomial infection. Obtain appropriate cultures before Table 6-10Summary of Surviving Sepsis Campaign guidelinesInitial Evaluation and Infection IssuesInitial resuscitation: Begin resuscitation immediately in patients with hypotension or elevated serum lactate with resuscitation goal of at least 30 mL/kg IV crystalloid given in the first 3 hours.Ongoing fluid administration should be guided by physiologic response as measured by clinical variables (e.g., heart


Surgery_Schwartz

Surgery_Schwartz. resuscitation goal of at least 30 mL/kg IV crystalloid given in the first 3 hours.Ongoing fluid administration should be guided by physiologic response as measured by clinical variables (e.g., heart rate, blood pressure, urine output) and/or other invasive or noninvasive monitoring.Resuscitation goals include mean arterial pressure >65 mmHg, urine output >0.5 mL/kg per h, and mixed venous oxygen saturation >65%.Target resuscitation to normalize lactate in patients with elevated lactate levels.Diagnosis: Obtain appropriate cultures prior to antibiotics, but do not delay antibiotic therapy. Imaging studies should be performed promptly to confirm a source of infection.Antibiotic therapy: Begin IV antibiotic therapy as early as possible and within the first hour after recognition of severe sepsis/septic shock. Use broad spectrum antibiotic regimen with penetration into presumed source, reassess regimen daily with de-escalation as appropriate, discontinue antibiotics in 7 to 10 days for


Surgery_Schwartz

Surgery_Schwartz. sepsis/septic shock. Use broad spectrum antibiotic regimen with penetration into presumed source, reassess regimen daily with de-escalation as appropriate, discontinue antibiotics in 7 to 10 days for most infections, stop antibiotics for noninfectious issues. Consider the use of serial procalcitonin levels, which may allow earlier cessation of antibiotic therapy.Source control: Establish anatomic site of infection as rapidly as possible; implement source control measures as soon as possible after initial resuscitation. Remove intravascular access devices if potentially infected.Hemodynamic Support and Adjunctive TherapyFluid therapy: Fluid resuscitate using crystalloid, with continued fluid challenges so long as hemodynamic parameters continue to improve (i.e., for so long as the patient remains fluid-responsive). Albumin may be used as an adjunct if large volumes of crystalloid are required, but hydroxyethyl starch and gelatin-based fluids should not be used.Vasopressors/Inotropic


Surgery_Schwartz

Surgery_Schwartz. remains fluid-responsive). Albumin may be used as an adjunct if large volumes of crystalloid are required, but hydroxyethyl starch and gelatin-based fluids should not be used.Vasopressors/Inotropic Therapy: Maintain MAP of >65 mmHg. Centrally-administered norepinephrine is the first-line choice. Add vasopressin if needed to raise MAP or to reduce norepinephrine requirement. Epinephrine is an alternative to vasopressin but has greater risk of reduced splanchnic blood flow. Dopamine is an appropriate alternative only in select patients (bradycardia, low risk of arrhythmia), and there is no role for low-dose “renal protection” dopamine. Phenylephrine is not recommended. Insert arterial catheters for patients requiring vasopressors. Consider dobutamine infusion for persistent hypotension after appropriate resuscitation and use of vasopressor agents.Steroids: Consider intravenous hydrocortisone (dose <300 mg/day) for adult septic shock when hypotension responds poorly to fluids and


Surgery_Schwartz

Surgery_Schwartz. after appropriate resuscitation and use of vasopressor agents.Steroids: Consider intravenous hydrocortisone (dose <300 mg/day) for adult septic shock when hypotension responds poorly to fluids and vasopressors.Other Supportive TherapyBlood product administration: Transfuse red blood cells when hemoglobin decreases to <7.0 g/dL in the absence of extenuating circumstances (e.g., myocardial ischemia, hemorrhage). It is not necessary to use fresh frozen plasma to correct INR abnormalities in the absence of bleeding. Consider prophylactic transfusion of platelets when counts are less than 10,000/mL in the absence of bleeding, <20,000/mL if there is a risk of bleeding, and <50,000 in the setting of active bleeding or need for procedure.Mechanical ventilation: Target an initial tidal volume of 6 mL/kg body weight and plateau pressure of <30 cm H2O in patients with acute lung injury. Use PEEP to avoid lung collapse. Adopt a conservative fluid strategy. In the setting of sepsis-induced ARDS


Surgery_Schwartz

Surgery_Schwartz. 6 mL/kg body weight and plateau pressure of <30 cm H2O in patients with acute lung injury. Use PEEP to avoid lung collapse. Adopt a conservative fluid strategy. In the setting of sepsis-induced ARDS with PaO2/FiO2 ratio <150, use prone ventilation over continued supine position or high-frequency oscillatory ventilation. Use a weaning protocol to evaluate the potential for discontinuing mechanical ventilation. Pulmonary artery catheter placement is not indicated for routine monitoring.Sedation: Minimize sedation using specific titration endpoints.Glucose control: Use protocolized approach to blood glucose management targeting upper blood glucose target of 180 mg/dL.Prophylaxis: Use stress ulcer (proton pump inhibitor or H2 blocker) and deep venous thrombosis (low-dose unfractionated or fractionated heparin) prophylaxis.Limitation of support: Discuss advance care planning with patients and families and set realistic expectations.Data from Rhodes A, Evans LE, Alhazzani W, et al:


Surgery_Schwartz

Surgery_Schwartz. or fractionated heparin) prophylaxis.Limitation of support: Discuss advance care planning with patients and families and set realistic expectations.Data from Rhodes A, Evans LE, Alhazzani W, et al: Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016, Intensive Care Med. 2017 Mar;43(3):304-377.Brunicardi_Ch06_p0157-p0182.indd 17601/03/19 4:46 PM 177SURGICAL INFECTIONSCHAPTER 6starting antibiotics so that appropriate de-escalation of therapy can take place when results return, but only if doing so does not delay the initiation of treatment.In patients who require vasopressor therapy, the first-line agent should be norepinephrine. This can be augmented with vasopressin, if needed, to achieve MAP ≥65 mmHg. It is impor-tant to titrate therapy based on other parameters such as mixed venous oxygen saturation and plasma lactate levels to reduce the risk of vasopressor-induced perfusion deficits. Patients who have persistently poor perfusion


Surgery_Schwartz

Surgery_Schwartz. based on other parameters such as mixed venous oxygen saturation and plasma lactate levels to reduce the risk of vasopressor-induced perfusion deficits. Patients who have persistently poor perfusion despite adequate fluid resus-citation may require addition of inotropic agents (epinephrine, dobutamine) or adjunctive therapy with low-dose corticoste-roids (hydrocortisone 200 mg/day).86Patients with acute lung injury associated with sepsis should receive mechanical ventilation with tidal volumes of 6 mL/kg and pulmonary airway plateau pressures of ≤30 cm H2O. Finally, red blood cell transfusion should be reserved for patients with hemoglobin of <7 g/dL, with a more liberal trans-fusion strategy reserved for those patients with severe coronary artery disease, ongoing blood loss, or severe hypoxemia.86Resistant OrganismsPenicillin was first available for widespread clinical use in the 1940s, and within a year resistant strains of S aureus had emerged. There are two major factors


Surgery_Schwartz

Surgery_Schwartz. severe hypoxemia.86Resistant OrganismsPenicillin was first available for widespread clinical use in the 1940s, and within a year resistant strains of S aureus had emerged. There are two major factors responsible for antibiotic resistance. First, there may be a genetic component innate to an organism that prevents the effect of a particular antibiotic. For instance, if an organism does not have a target receptor specific to the mechanism of action of a particular antibiotic, the antibi-otic will not be effective against this organism. A good example is penicillin and gram-negative organisms, as these microbes lack penicillin-binding proteins. The second component driv-ing resistance is inducible and related to natural selection. Over generations of exposure to a particular antibiotic, selection pres-sure will drive proliferation of more organisms resistant to that antibiotic. This acquired antibiotic resistance can be mutational, leading to changes in the chromosomal makeup of the


Surgery_Schwartz

Surgery_Schwartz. selection pres-sure will drive proliferation of more organisms resistant to that antibiotic. This acquired antibiotic resistance can be mutational, leading to changes in the chromosomal makeup of the microbe, or it can be extrachromosomal, induced by transfer of exog-enous genetic material in the form of a plasmid or transposon. In either case, cellular mechanisms of resistance that develop include target site modification, changes in bacterial permeabil-ity or antibiotic uptake, activation of drug efflux systems, and drug deactivation. Given that millions of kilograms of antibiot-ics are used annually in people, in agriculture, and for animal use, environmental selection pressures are high, and antibiotic resistance has now been described in all classes of antibiotics in common use. Antibiotic resistance comes at a high cost, with a significant increase in mortality associated with infection from resistant organisms, and an economic cost of billions of dollars per year.There are


Surgery_Schwartz

Surgery_Schwartz. Antibiotic resistance comes at a high cost, with a significant increase in mortality associated with infection from resistant organisms, and an economic cost of billions of dollars per year.There are several drug-resistant organisms of interest to the surgeon. MRSA most commonly occurs as a hospitalassociated infection in chronically ill patients who have received multiple courses of antibiotics. However, strains of MRSA have emerged in the community among patients without preexisting risk factors for disease.75 These strains, which produce a toxin known as Panton-Valentine leukocidin, make up an increasingly high percentage of surgical site infections since they are resis-tant to commonly employed prophylactic antimicrobial agents.88 Extended spectrum β-lactamase (ESBL)-producing strains of enterobacteriaceae, originally geographically localized and infrequent, have become much more widespread and common in the last decade.89 These strains, typically Klebsiella species or E coli,


Surgery_Schwartz

Surgery_Schwartz. of enterobacteriaceae, originally geographically localized and infrequent, have become much more widespread and common in the last decade.89 These strains, typically Klebsiella species or E coli, produce a plasmid-mediated inducible β-lactamase. Commonly encountered plasmids also confer resistance to many other antibiotic classes. A common laboratory finding with ESBL is sensitivity to first-, second-, or third-generation cephalosporins, with resistance to other agents. Unfortunately, use of this seemingly active agent leads to rapid induction of resistance and failure of antibiotic therapy. The appropriate anti-biotic choice in this setting is a carbapenem.While Enterococcus was considered a low-virulence organ-ism in the past, infections caused by E faecium and faecalis have been found to be increasingly severe, especially in the immu-nocompromised host. The last decade has seen increased iso-lation of a vancomycin-resistant strain of Enterococcus. This resistance is


Surgery_Schwartz

Surgery_Schwartz. been found to be increasingly severe, especially in the immu-nocompromised host. The last decade has seen increased iso-lation of a vancomycin-resistant strain of Enterococcus. This resistance is transposon-mediated via the vanA gene and is typically seen in E faecium strains. A real infection control con-cern is potential for transfer of genetic material to S aureus in a host coinfected with both organisms. This is thought to be the mechanism behind emerging cases of vancomycin resistance in S aureus.90Blood-Borne PathogensThe risk of human immunodeficiency virus (HIV) transmission from patient to surgeon is low. As of May 2011, there had been six cases of surgeons with HIV seroconversion from a possible occupational exposure, with no new cases reported since 1999. Of the numbers of healthcare workers with likely occupationally acquired HIV infection (n = 200), surgeons were one of the lower risk groups (compared to nurses at 60 cases and nonsur-geon physicians at 19 cases).91 The


Surgery_Schwartz

Surgery_Schwartz. workers with likely occupationally acquired HIV infection (n = 200), surgeons were one of the lower risk groups (compared to nurses at 60 cases and nonsur-geon physicians at 19 cases).91 The estimated risk of transmis-sion from a needlestick from a source with HIV-infected blood is estimated at 0.3%. Transmission of HIV (and other infections spread by blood and body fluid) from patient to healthcare worker can be minimized by observation of universal precau-tions, including: (a) routine use of barriers (gloves, gown, mask, eye protection) when anticipating contact with blood or body fluids, (b) washing hands and other skin surfaces immediately after contact with blood or body fluids, and (c) careful handling and disposal of sharp instruments during and after use.Postexposure prophylaxis for HIV has significantly decreased the risk of seroconversion for healthcare workers with occupational exposure to HIV. Steps to initiate postexposure prophylaxis should be initiated within hours for


Surgery_Schwartz

Surgery_Schwartz. HIV has significantly decreased the risk of seroconversion for healthcare workers with occupational exposure to HIV. Steps to initiate postexposure prophylaxis should be initiated within hours for the most effec-tive preventive therapy. Postexposure prophylaxis with a three-drug regimen should be initiated for healthcare workers with significant exposure to patients with an HIV-positive status. If a patient’s HIV status is unknown, it may be advisable to begin postexposure prophylaxis while testing is carried out, particu-larly if the patient is at high risk for infection due to HIV (e.g., has had a history of intravenous drug use). Generally, postexpo-sure prophylaxis is not warranted for exposure to sources with unknown status, such as deceased persons or needles from a sharps container.92The risks of acquiring HIV infection for surgeons are related to the prevalence of HIV infection in the patient popula-tion, the probability of transmission from a percutaneous injury suffered


Surgery_Schwartz

Surgery_Schwartz. risks of acquiring HIV infection for surgeons are related to the prevalence of HIV infection in the patient popula-tion, the probability of transmission from a percutaneous injury suffered while caring for an infected patient, the number of such injuries sustained, and the use of postexposure prophylaxis. Average risk of HIV seroconversion is 0.3% from a percutane-ous exposure, and 0.09% from a mucous membrane exposure. The overall risk is influenced by the degree of viral inoculum 7Brunicardi_Ch06_p0157-p0182.indd 17701/03/19 4:46 PM 178BASIC CONSIDERATIONSPART Itransmitted from patient to surgeon, with greater risk of sero-conversion associated with hollow-bore needle injury, with larger-volume blood transmission, with direct introduction of infected blood into an artery or vein, and in exposure to blood with higher viral load. One study in Glasgow, Scotland, cal-culated annual risks and found a range in seroconversion rates from 1 in 200,000 for general surgeons not utilizing


Surgery_Schwartz

Surgery_Schwartz. in exposure to blood with higher viral load. One study in Glasgow, Scotland, cal-culated annual risks and found a range in seroconversion rates from 1 in 200,000 for general surgeons not utilizing postexpo-sure prophylaxis to as low as 1 in 10,000,000 with use of routine postexposure prophylaxis after significant exposures.92,93Hepatitis B virus (HBV) is a DNA virus that affects only humans. Primary infection with HBV generally is self-limited, but it can cause fulminant hepatitis or progress to a chronic car-rier state. Death from chronic liver disease or hepatocellular cancer occurs in roughly 30% of chronically infected persons. Surgeons and other healthcare workers are at high risk for this blood-borne infection and should receive the HBV vaccine; children are routinely vaccinated in the United States.94 This vaccine has contributed to a significant decline in the number of new cases of HBV per year in the United States, from approxi-mately 250,000 annually in the 1980s to 3350 in


Surgery_Schwartz

Surgery_Schwartz. United States.94 This vaccine has contributed to a significant decline in the number of new cases of HBV per year in the United States, from approxi-mately 250,000 annually in the 1980s to 3350 in 2010.95,96Hepatitis C virus (HCV), previously known as non-A, non-B hepatitis, is a RNA flavivirus first identified in the late 1980s. This virus is confined to humans and chimpanzees. A chronic carrier state develops in 75% to 80% of patients with the infection, with chronic liver disease occurring in three-fourths of this subgroup. The number of new infections per year has declined since the 1980s due to routine testing of blood donors for the virus. Fortunately, HCV is not transmitted efficiently through occupational exposures to blood, with the seroconver-sion rate after accidental needlestick approximately 1.8%.97 To date, a vaccine to prevent HCV infection has not been devel-oped. Experimental studies in chimpanzees with HCV immu-noglobulin using a model of needlestick injury have


Surgery_Schwartz

Surgery_Schwartz. approximately 1.8%.97 To date, a vaccine to prevent HCV infection has not been devel-oped. Experimental studies in chimpanzees with HCV immu-noglobulin using a model of needlestick injury have failed to demonstrate a protective effect, and no effective antiviral agents for postexposure prophylaxis are available. Treatment of patients with HCV infection historically included ribavirin and pegylated gamma interferon; the development of novel direct-acting antiviral agents such as sofosbuvir, boceprevir, and tela-previr has led to changes in this strategy.98,99BIOLOGIC WARFARE AGENTSSeveral infectious organisms have been studied by the United States and the former Soviet Union and presumably other entities for potential use as biologic weapons. Programs involving biologic agents in the United States were halted by presidential decree in 1971. However, concern remains that these agents could be used by rogue states or terrorist organi-zations as weapons of mass destruction, as they are


Surgery_Schwartz

Surgery_Schwartz. States were halted by presidential decree in 1971. However, concern remains that these agents could be used by rogue states or terrorist organi-zations as weapons of mass destruction, as they are relatively inexpensive to make in terms of infrastructure development. Given these concerns, physicians, including surgeons, should familiarize themselves with the manifestations of infection due to these pathogens. The typical agent is selected for the ability to be spread via the inhalational route, as this is the most efficient mode of mass exposure. Several potential agents are discussed in the following sections.Bacillus anthracis (Anthrax)Anthrax is a zoonotic disease occurring in domesticated and wild herbivores. The first identification of inhalational anthrax as a disease occurred among woolsorters in England in the late 1800s. The largest recent epidemic of inhalational anthrax occurred in 1979 in Sverdlovsk, Russia, after accidental release of anthrax spores from a military


Surgery_Schwartz

Surgery_Schwartz. among woolsorters in England in the late 1800s. The largest recent epidemic of inhalational anthrax occurred in 1979 in Sverdlovsk, Russia, after accidental release of anthrax spores from a military facility. Inhalational anthrax develops after a 1to 6-day incubation period, with nonspe-cific symptoms, including malaise, myalgia, and fever. Over a short period of time these symptoms worsen, with development of respiratory distress, chest pain, and diaphoresis. Character-istic chest roentgenographic findings include a widened medi-astinum and pleural effusions. Rapid antigen tests are under development for identification of this gram-positive rod, so a key element of establishing the diagnosis is eliciting an expo-sure history. Postexposure prophylaxis consists of administra-tion of either ciprofloxacin or doxycycline.100 If an isolate is demonstrated to be penicillin-sensitive, the patient should be switched to amoxicillin. Inhalational exposure followed by the development of symptoms


Surgery_Schwartz

Surgery_Schwartz. ciprofloxacin or doxycycline.100 If an isolate is demonstrated to be penicillin-sensitive, the patient should be switched to amoxicillin. Inhalational exposure followed by the development of symptoms is associated with a high mortality rate. Treatment options include combination therapy with cip-rofloxacin, clindamycin, and rifampin. Clindamycin is added to block toxin production, while rifampin penetrates into the central nervous system and intracellular locations.Yersinia pestis (Plague)Plague is caused by the gram-negative organism Y pestis. The naturally occurring disease in humans is transmitted via flea bites from rodents. It was the first biologic warfare agent, and was used in the Crimean city of Caffa by the Tartar army, whose soldiers catapulted bodies of plague victims at the Genoese. When plague is used as a biologic warfare agent, clinical manifestations include epidemic pneumonia with blood-tinged sputum if aerosolized bacteria are used, or bubonic plague if fleas are