10.14639/0392-100X-N1617
Objective. The aim of this study was to investigate the ability of Peak Nasal Inspiratory Flow (PNIF) and Peak Nasal Expiratory Flow (PNEF) measures to predict symptoms of nasal obstruction. Methods. This is a cross-sectional study, carried out in 131 individuals (64 with symptomatic allergic rhinitis and 67 asymptomatic) aged between 16 and 50 years.Results. PNIF and PNEF were higher among non-rhinitis. In the curve analysis (receiver operating characteristic), a value of 115 was found for PNIF with a sensitivity of 98.4% and specificity of 87.5% (AUC = 0.99, p &lt; 0.001) and 165 in PNEF with a sensitivity of 65.7% and specificity of 85.1% (AUC = 0.92, p &lt; 0.001).Conclusions. PNIF and PNEF values were lower in patients with AR compared to asymptomatic cases. Our findings present reference values of PNIF and PNEF in the evaluation of nasal obstruction symptoms and reinforce the importance to complement more refined assessment of patients’ symptoms. PNEF can be a valuable tool in screening patients and to complement PNIF measurement.
text/xml
1827-675X
1617
en
Emanuel Sávio  Cavalcanti Sarinho
http://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
rhinitis
Accuracy of peak nasal flow to determine nasal obstruction in patients with allergic rhinitis
Text.Serial.Journal
https://www.actaitalica.it/
42
Rhinology
2022-05-16
2021-04-16
2022-05-23
2022-05-23
155-161
1
Emanuel Sávio  Cavalcanti Sarinho
2022/05/16
10.14639/0392-100X-N1617
155
Universidade Federal de Pernambuco-Recife, Brazil and Center for Allergy and clinical immunology research at clinical hospital, Recife, Brazil
1827-675X
rhinitis
en
161
Accuracy of peak nasal flow to determine nasal obstruction in patients with allergic rhinitis
https://www.actaitalica.it/article/download/1617/794
42
ACTA OTORHINOLARYNGOLOGICA ITALICA 2022;42:155-161; doi: 10.14639/0392-100X-N1617




Rhinology


Accuracy of peak nasal flow to determine nasal
obstruction in patients with allergic rhinitis
Accuratezza del flusso nasale di picco nella determinazione dell’ostruzione respiratoria
nasale nella rinite allergica
Gardênia Maria Martins de Oliveira1, Marco Aurélio de Valois Correia Júnior2,3, Emilia Chagas Costa3,
Georgia Véras de Araújo Gueiros Lira3, José Ângelo Rizzo3, Steve Hunter4, Nádia Gaua4,
Emanuel Sávio Cavalcanti Sarinho3
1
  Department Cardio-Respiratory Physiotherapy, Centro Universitário Leão Sampaio, Juazeiro do Norte-CE Brazil; 2 Post-Graduation
Program in Herbiatrics and Physical education Universidade de Pernambuco, Brazil; 3 Universidade Federal de Pernambuco-Recife,
Brazil and Center for Allergy and clinical immunology research at clinical hospital; 4 Sport and Exercise Science Research Centre,
School of Applied Sciences, London South Bank University, London, United Kingdom


SUMMARY
Objective. The aim of this study was to investigate the ability of Peak Nasal Inspiratory
Flow (PNIF) and Peak Nasal Expiratory Flow (PNEF) measures to predict symptoms of
nasal obstruction.
Methods. This is a cross-sectional study, carried out in 131 individuals (64 with sympto-
matic allergic rhinitis and 67 asymptomatic) aged between 16 and 50 years.
Results. PNIF and PNEF were higher among non-rhinitis. In the curve analysis (receiver
operating characteristic), a value of 115 was found for PNIF with a sensitivity of 98.4% and
specificity of 87.5% (AUC = 0.99, p < 0.001) and 165 in PNEF with a sensitivity of 65.7%
and specificity of 85.1% (AUC = 0.92, p < 0.001).
Conclusions. PNIF and PNEF values were lower in patients with AR compared to asymp-
tomatic cases. Our findings present reference values of PNIF and PNEF in the evaluation
of nasal obstruction symptoms and reinforce the importance to complement more refined            Received: April 16, 2021
assessment of patients’ symptoms. PNEF can be a valuable tool in screening patients and to       Accepted: December 15, 2021
complement PNIF measurement.
                                                                                                 Correspondence
KEY WORDS: diagnostic techniques, nasal obstruction, respiratory system, rhinitis                Marco Aurélio de Valois Correia Junior
                                                                                                 Post-Graduation Program in Herbiatrics and
                                                                                                 Physical education Universidade de Pernambuco,
RIASSUNTO
                                                                                                 Luiz Guimarães street 411, 301-a. Poço da Panela,
Obiettivo. Lo scopo di questo studio è indagare la capacità delle misure del flusso di picco     Recife, Pernambuco, Brazil
inspiratorio nasale (PNIF) e del flusso di picco espiratorio nasale (PNEF) nell’ostruzione       Tel. +55 81992520056
respiratoria nasale.                                                                             E-mail: marcovalois@gmail.com
Metodi. Si tratta di uno studio trasversale, condotto su 131 soggetti (64 con rinite allergica
sintomatica e 67 asintomatici) di età compresa tra 16 e 50 anni.
                                                                                                   How to cite this article: de Oliveira GMM, Cor-
Risultati. PNIF e PNEF erano più alti nei pazienti senza rinite. Nell’analisi, il valore di
                                                                                                   reia Junior MAV, Costa EC, et al. Accuracy of
PNIF è risultato essere 115, con una sensibilità del 98,4% e una specificità dell’87,5%
                                                                                                   peak nasal flow to determine nasal obstruction
(AUC = 0,99, p < 0,001) e mentre il valore di PNEF è risultato essere 165, con una sensi-          in patients with allergic rhinitis. Acta Otorhi-
bilità del 65,7% e una specificità di 85,1% (AUC = 0,92, p < 0,001).                               nolaryngol Ital 2022;42:155-161. https://doi.
Conclusioni. I valori di PNIF e PNEF erano inferiori nei pazienti con rinite allergica             org/10.14639/0392-100X-N1617
rispetto agli asintomatici. I nostri risultati mostrano i valori di riferimento delle misure
PNIF e PNEF nella valutazione dei sintomi di ostruzione nasale e rafforzano l’importanza         © Società Italiana di Otorinolaringoiatria
di integrare tali dati con la valutazione sintomatologica dei pazienti. La misurazione del       e Chirurgia Cervico-Facciale
PNEF e PNIF, può essere uno strumento prezioso per lo screening dei pazienti con ostru-
zione nasale.                                                                                                   OPEN ACCESS

PAROLE CHIAVE: tecniche diagnostiche, ostruzione nasale, apparato respiratorio, rinite           This is an open access article distributed in accordance with
                                                                                                 the CC-BY-NC-ND (Creative Commons Attribution-Non-
                                                                                                 Commercial-NoDerivatives 4.0 International) license. The
                                                                                                 article can be used by giving appropriate credit and mentio-
Introduction                                                                                     ning the license, but only for non-commercial purposes and
                                                                                                 only in the original version. For further information: https://
Nasal obstruction is a frequent complaint in patients with allergic rhinitis                     creativecommons.org/licenses/by-nc-nd/4.0/deed.en




                                                                                                                                                         155
G.M.M. de Oliveira et al.




(AR) 1-4. Studies have shown that this symptom has a sig-        and especially no history of nasal obstruction, confirmed
nificant impact on quality of life, work productivity and        by a clinical symptom score adapted by Gomes et al. 8.
sleep quality 1-4. Patients with persistent and more intense
forms of AR even in asymptomatic phases may experience           Inclusion and exclusion criteria
constant mucosal inflammation and chronic nasal obstruc-         Patients of both sexes, aged 16 to 50 years with a diag-
tion resulting from mucosal inflammation and mucus se-           nosis of persistent allergic rhinitis were included 11. Inclu-
cretion 1.                                                       sion criteria for the control group were: a final score value
In clinical practice nasal obstruction is difficult to quan-     of zero and the visual analog scale for nasal obstruction
tify 2. Initial investigations are usually performed based       (VAS), with its final value also being zero. Those with di-
on patients’ subjective perception 3. However, subjective        agnosed with asthma or a history suggestive of asthma who
perception of obstruction involves complex mechanisms            had a positive response to any of the following data in their
and some authors 2-5 argue that in addition to the patient’s     clinical history were excluded: previous wheezing crisis,
impression, the association of objective measures may be         tiredness, recurrent wheezing after physical activity with-
recommended to complement the assessment.                        out investigation, dry night cough for no apparent reason
Peak nasal inspiratory flow (PNIF) and peak nasal expira-        or other respiratory diseases that compromise pulmonary
tory flow (PNEF) are techniques that have been proposed as       or nasal function. Other exclusion criteria were: those who
objective methods to help in understanding nasal obstruc-        were on regular medication for nasal symptoms including
tion. PNIF was shown to have good accuracy 6-8, although         topical corticosteroids and systemic vasoconstrictors, anti-
there are no precise diagnostic parameters for PNEF 4,9. The     histamines at the time of the study, or who had used them
main advantage of this objective technique is the fact that      for four weeks prior to the study. Those who used nasal
it is a low-cost, non-invasive, easy-to-perform method that      decongestants in the last 48 hours, patients with endoscopic
can be performed in multiple settings, such as clinics, hos-     findings of marked septum deviation and signs suggestive
pitals and the individual’s own home 6,7.                        of concomitant acute infectious sinusitis. Smokers, asth-
The increasing use of objective methods in research has          matics, or individuals with upper respiratory tract infection
raised questions about the value that these measures add         at the time or 15 days before data collection and cognitive
to clinical evaluation 6-10. This study was conducted to: (i)    alteration that compromised the technique.
further investigate the contribution of objective methods to
clinical practice in the evaluation of nasal patency, notably    Instruments and data collection
on PNIF and PNEF measurements in patients with rhinitis
and without allergic rhinitis and (ii) assess the ability of     Definition of clinical diagnosis
these measures in predicting the symptoms of obstruction,        The clinical diagnosis of AR was established by a special-
including patients who have difficulty in perceiving their       ist physician based on patient history, physical examination
symptoms, to help as a complementary measure in diag-            and allergic skin test for aeroallergens. Persistent rhinitis
nosis.                                                           was classified by the same specialist according to modified
                                                                 ARIA 12 (Allergic Rhinitis and its Impact on Asthma) cri-
                                                                 teria based on the presence of one or more of the six nasal
Materials and methods                                            signs or symptoms that included: nasal congestion, sneez-
                                                                 ing, rhinorrhoea, pruritus, oropharynx, nasal and ocular
Study design and population                                      pruritus for more than four days a week or more than four
This is a cross-sectional clinical study conducted at the Al-    weeks before admission. All patients had positive aeroal-
lergology and Immunology Service of the Clinical Hospital        lergen pick-tests.
of the Federal University of Pernambuco, Recife, Pernam-
buco, Brazil. Volunteers were the groups of patients with        Clinical evaluations
allergic rhinitis, screened by the regular flow of care in al-   Patients from both the rhinitis and non-rhinitis groups un-
lergy and immunology clinics, otorhinology and allergy           derwent subjective evaluation (visual analog scale and clin-
of the institution and the control group was composed of         ical score) and objective evaluations of the PNIF and PNEF
individuals without a diagnosis of AR and no respiratory         by independent examiners.
complaints.                                                      Patients with AR were referred to one of the researchers
The comparison group was recruited from a university en-         after consultation with a specialist, prior to any prescribed
vironment and consisted of people with no clinical diag-         drug intervention. Initially they were asked about the per-
nosis of allergic rhinitis, no complaints of nasal symptoms      ception of nasal obstruction using the VAS presented in



156
                                                                                                               Peak nasal flow in allergic rhinitis




a colour grading, taking as reference light blue, at the far      tion through the nose with their lips closed after maximum
right of the scale that corresponded to the absence of nasal      inspiration from the residual volume. Three measurements
obstruction and at the far left, represented by red colour        were taken in a row, the largest one being considered, con-
that corresponded to the nose completely blocked. Subse-          sidering a variation between them of up to 10%.
quently, they marked a point on the scale that seemed to
them more corresponding to their nasal obstruction state.         Statistical analysis
The colour grading presented to the patients was visual-          Data were analysed using the Statistical Package for the
ised by the researcher on a scale numbered from 0 to 10,          Social Sciences (SPSS, version 20.0). The Kolmogorov-
graduated in mm and after the patient registration the corre-     Smirnov test was applied to test the normality assumption.
sponding point was recorded by the researcher. To perform         Mean and SD were used to present continuous variables,
the visit, it was necessary that patients had no doubts about     while categorical data were presented using absolute and
the appointment.                                                  relative frequencies. Bilateral values of p were calculated,
The clinical score of nasal symptoms, adapted by Gomes et         and the significance level adopted was 5%. T test was used
al. 8, was used to evaluate the intensity of rhinitis through     to evaluate the comparison between the means in the dif-
nasal symptoms that included: nasal congestion, sneezing,         ferent groups and the Spearman correlation coefficient was
rhinorrhoea, oropharyngeal, nasal and ocular pruritus. We         performed to assess the association between the PNIF and
used a scale from zero to 3 points, where zero indicated          PNEF value with the VAS value for nasal obstruction with-
absence of symptoms, 1 mild symptom point, well toler-            in the allergic rhinitis group.
ated, does not interfere with sleep or daily activities, 2 well   To assess the cutoff point of PNIF and PNEF, a ROC curve
defined symptom points, uncomfortable, interfering only           was plotted and the area under the curve was calculated.
with activities that require greater concentration, but does      From the value found in PNIF and PNEF we calculated the
not interfere with the patient’s routine, 3 points intense        positive predictive value, negative predictive value, positive
symptoms, very uncomfortable, poorly tolerated, making            likelihood ratio and negative likelihood ratio.
it difficult to sleep and carry out daily activities. The total
score ranged from 0 to 18 points allowing AR to be classi-        Results
fied as mild (1-6 points), moderate (7-12 points), or severe
(13-18 points) 8,11. The comparison group performed the           A total of 131 individuals (69.5% men) participated in the
same subjective measures as the criterion for inclusion in        study, of which 67 (51.1%) in the Control group. Among
the study with the final VAS result and the nasal symptom         the 64 subjects with rhinitis, most had moderate rhinitis
score equal to zero.                                              (65.6%) (Tab. I). There was no association between the
                                                                  PNIF and PNEF with the VAS for nasal obstruction within
Evaluation of objective measures                                  the allergic rhinitis group (r = -0.072 with p = 0.572 and
Patients with allergic rhinitis were asked to perform nasal       r = -0.221 with p = 0.079, respectively).
hygiene to eliminate secretion prior to verification of the       PNIF and PNEF were higher among non-rhinitis, even
PNIF and PNEF. The PNIF was measured by the nasal in-
spiratory peak flow meter (In-Check Nasal Clement Clarke,
                                                                  Table I. General characteristics of recruited individuals.
England), with the patient sitting comfortably wearing a
face mask that was held by one of the researchers’ hands           Variable                                                          Total
                                                                                                                                   (n = 131)
on the patient’s face, with a pressure necessary to prevent
                                                                   Age (years)                                                      26.8 ± 8
air leakage. Patients were instructed to perform maximal
                                                                   Sex
inspiratory effort through the nose with the lips closed. The
manoeuver was repeated three times, and the largest of the           Male                                                          91 (69.5)
three measurements was recorded, with a variation up to              Female                                                        40 (30.5)
10%.                                                               Education level
PNEF measurements were obtained using the peak expira-               Undergraduate                                                 75 (57.2)
tory flow meter (Assess peak flow meter respironics, New             Graduate                                                      56 (42.8)
Jersey) where a face mask was fitted through a universal           Symptom score system (allergic rhinitis, n = 64)
connector. The patient was seated in a comfortable position,         Light                                                         13 (20.3)
with the mask fixed by the hand of one of the researchers            Moderate                                                      42 (65.6)
on the face, with a pressure necessary to prevent air leak-          Severe                                                        09 (14.1)
age. Patients were instructed to perform maximal expira-          Data were expressed as mean ± standard deviation or absolute numbers (%).




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G.M.M. de Oliveira et al.




Table II. Peak nasal inspiratory flow and Peak nasal expiratory flow by sex.
 Variable                                         Sex                                              Rhinitis                                     Without rhinitis
 PNIF                                                     All                                 65.94 ± 18.32 ª                                   130.73 ± 26.64 ª
                                                         Male                                  70.0 ± 15.95 b                                   145.0 ± 29.75 b g
                                                        Female                                  65.0 ± 18.84 c                                  120.5 ± 18.63 c g
 PNEF                                                     All                                 108.36 ± 56.87 d                                  212.54 ± 48.88 d
                                                         Male                                  130.8 ± 71.54 e                                  232.9 ± 50.47 e h
                                                        Female                                 103.2 ± 52.39 f                                  198.0 ± 42.62 f h
Data were expressed mean ± standard deviation. Same letters indicated statistically significant differences between pairs, considering p < 0.01 from test t onwards for independent
samples. PNIF: Peak nasal inspiratory flow; PNEF: Peak nasal expiratory flow.



when separated by gender (Tab. II). In non-rhinitic patients,                               struction 4-11. This symptom is particularly important in pa-
men had higher peak flows.                                                                  tients with persistent allergic rhinitis because even during
Figure 1 shows the analysis of the ROC curve for the PNIF                                   asymptomatic periods of the disease, mucosal inflamma-
(sensitivity of 98.4% and specificity of 87.5%) and PNEF                                    tion and nasal congestion may persist to a lesser extent 4-11.
(sensitivity of 65.7% and specificity of 85.1%), with area                                  However, some patients may find it difficult to reliably
under the ROC curve of 0.99 and 0.92 (95% CI, 0.97 to                                       identify the presence and the intensity of nasal obstruc-
1.00 and 0.92 to 0.97, respectively; both p < 0.005).                                       tion due to chronic symptoms or lack of normal breathing.
The predictive values (positive and negative), accuracy, and                                Standardised measures may be an interesting alternative to
likelihood ratio values (positive and negative) are shown in                                complement the assessment of these patients by making
Table III.                                                                                  them more aware of nasal obstruction These measures may
                                                                                            also be used in epidemiological research 4-11.
                                                                                            Teixeira et al. 11, studying PNIF as a tool for assessing nasal
Discussion
                                                                                            patency in 78 individuals aged 19 to 67 years without rhi-
This study examined the utility of PNIF and PNEF meas-                                      nitis and with allergic rhinitis reported lower PNIF values
urements as objective precision parameters for the diag-                                    (114 l/min) in individuals with rhinitis compared to those
nosis of obstruction in patients with allergic rhinitis. Our                                without allergic rhinitis (154.3 l/min). Thus, reduced nasal
results show lower PNIF and PNEF values in patients with                                    flow in patients with allergic rhinitis may be a proxy for
AR compared to normal individuals and present reference                                     nasal obstruction, because the nasal flow of these patients
values in the understanding of the evaluation of nasal ob-                                  is quantitatively limited in relation to the normal values de-
struction symptoms in rhinitis.                                                             scribed 6,13. To date no reference values have been described
Most patients with allergic rhinitis are affected by nasal ob-                              for adult patients with nasal obstruction, and therefore the




Figure 1. Area under the curve from peak nasal inspiratory flow (PNIF - A) and peak nasal expiratory flow (PNEF-B). AUC: Area under the curve; CI: confidence
interval.



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                                                                                                                                 Peak nasal flow in allergic rhinitis




Table III. Sensitivity, specificity, predictive values and likelihood of peak nasal inspiratory flow and peak nasal expiratory flow.
                                                                                                 PNIF                                        PNEF
                                                                                        (Cutoff point = 115)                         (Cutoff point = 165)
 Sensitivity                                                                                 98.4                                          87.5
 Specificity                                                                                 65.7                                          85.1
 Positive predictive value (VPP)                                                             73.3                                          84.8
 Negative predictive value (VPN)                                                             97.8                                          87.7
 Accuracy                                                                                    81.7                                          86.3



interpretation of these reductions is limited in terms of their                      PNIF increases with the improvement of nasal obstruction
clinical impact. However, studies have shown that a 20 l/                            symptoms 1,23. However, due to the complexity of subjec-
min difference is clinically significant due to the high intra                       tive perception, the correlation between PNIF and nasal
and inter-individual variability of PNIF results 14.                                 symptoms has been questioned by several studies 7,20.
The study by Klossek et al. 15, evaluated the PNIF of normal                         Recently, there has been an attempt to further investigate
individuals in the French population and presented normal                            PNIF and PNEF as a diagnostic tool for clinical prac-
values below those found in other countries 13,16 and in our                         tice, although these procedures have usually been studied
comparison group. However, it is important to consider the                           separately and there is no consensual way of correlating
difficulty in establishing standardised PNIF measurements,                           them 24. In our study, we further tested the ability of PNIF
since ethnic factors as well as individual characteristics                           and PNEF to predict nasal obstruction symptoms through
such as height, age and gender may influence the measure-                            the performance of the ROC curve for PNIF and PNEF.
ment 15. In a recent study 17, unilateral PNIF was evaluated                         Both methods performed well in identifying the presence
and normal values for adults were presented with values                              of rhinitis, as indicated by the area under the curve (AUC)
similar to those already described in the literature, showing                        for PNIF (AUC = 0.99) and for PNEF (AUC = 0.92). It is
a positive correlation for gender, height and inverse cor-                           noteworthy that PNIF and PNEF are not accurate instru-
relation with age. However, when considering unilateral                              ments in the diagnosis of rhinitis seen in an isolated way,
PNIF and PEF, only height was a significant variable 17.                             but can give information on nasal patency. In the diagnostic
In our research, the heights of the rhinitis and non-rhinitis                        pathway of rhinitis and rhinosinusitis, they are useful tools
groups were similar (162.6 ± 7 and 165.0 ± 9, respectively,                          to collect data on severity of disease. In the same manner,
p > 0.05).                                                                           positive predictive values ​​indicate that PNIF showed lower
Reference values of the PNEF for the adult population are                            performance, since among patients with altered PNIF, the
not widely reported in the literature 18. Values around 260 l/                       probability of rhinitis was 73%, compared to 84.8% for
min have been reported as possible normality, although                               PNEF. However, the inverse occurs with the analysis of
there is no range of altered values expected for individuals                         negative predictive values, since PNIF has a higher value
with allergic rhinitis 19. Therefore, this hinders the ability                       (NPV = 97.8) than PNEF (NPV = 87.7). When analysed
to predict PNEF results in patients with AR and without                              globally, in terms of accuracy, which indicates the propor-
rhinitis.                                                                            tion of correct answers in relation to all possible outcomes,
Our group previously demonstrated a strong positive cor-                             PNEF presents better overall performance (PNIF = 81.7
relation between PNIF and PNEF (c.c = 0.74). However,                                and PNEF = 86.3).
despite this correlation, PNEF had little explanatory capac-                         The same degree of specificity found in our study was also
ity (R2 = 0.551) over PNIF. Therefore, it would not be rec-                          observed by Starling-Schwanz et al. 9 when evaluating the
ommended to replace PNIF measures with PNEF only 19.                                 reproducibility of PNIF in patients with rhinitis. The au-
Some authors have suggested whenever possible the asso-                              thors demonstrated that PNIF measurements may reflect
ciation of objective measures to better evaluate the obstruc-                        the severity of nasal rhinitis symptoms in young adults. The
tion symptom in allergic rhinitis 7,20. PNIF has often been                          use of PNIF has also been evaluated in patients undergoing
studied in association with PEF, as reduced PNIF values                              tonsil removal surgery. Bathala and Eccles 25 demonstrated
may express reduced ventilatory capacity rather than nasal                           that 72% of patients had a 22% increase in PNIF values
obstruction 21.                                                                      after tonsillectomy.
Historically, PNIF has been successfully used for drug                               A recent study evaluated PNIF after patients underwent
evaluation in the treatment of allergic rhinitis in adults,                          functional rhinoseptoplasty. In that study, Fuller et al. 24,
young people and children 22. Part of the studies show that                          demonstrated that the Nasal Obstruction Symptom Evalu-



                                                                                                                                                               159
G.M.M. de Oliveira et al.




ation (NOSE) score is lower in patients with higher nasal      Ethical consideration
PNIF values, which indicates a convergence between the         The study was approved by the institution’s Ethics Com-
two methods regarding the improvement of airway patency.       mittee (nº 063/11). All parents or guardians and adoles-
Despite this, the data revealed a weak correlation between     cents signed terms of informed consent as requested by the
the two measures. Thus, these authors consider the use of      Brazilian regulatory agency.
PNIF as a diagnostic measure, although they emphasise the      The research was conducted ethically, with all study pro-
possibility of this tool as a follow-up measure in the prog-   cedures being performed in accordance with the require-
nosis of patients undergoing septum correction surgery.        ments of the World Medical Association’s Declaration of
A possible limitation of the study was not to carry out a      Helsinki.
follow-up of these patients according to clinical response
to treatment to evaluate the change of parameter settings.     References
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                                                               13
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revised the manuscript.                                             Rhin15.180




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