Revista Americana de Medicina Respiratoria - Volumen 21, Número 2 - Junio 2021

Artículos Originales

Patient Intolerance and Compliance with Positive Airway Pressure Treatment Outpatient Consultations Profile in a Sleep Unit

Autor : Blanco Magalí 1,2 Ernst Glenda2,3 Salvado Alejandro1 Borsini Eduardo1,2

1Center for Respiratory Medicine. Hospital Británico de Buenos Aires 2Sleep and Ventilation Unit. Hospital Británico de Buenos Aires 3Scientific Advisory Committee. Education and Research Hospital Británico de Buenos Aires

Correspondencia :


Introduction: Treatment with positive pressure may cause adverse effects. In order to know the compliance and intolerance profile, we analyzed the behaviors established by physiotherapists of a Sleep Unit.

Materials and Methods: Observational, retrospective, cross-sectional study. We included patients older than 18 years with positive pressure referred to the kinesiological consultation.

Results: 244 patients were evaluated during four years: 165 men (67%), age 65.7 ± 11.6 years, BMI (Body Mass Index) 31.0 ± 5.4 (kg/m2), 61% of which used fixed CPAP (Continuous Positive Airway Pressure), 29% auto-adjusting CPAP, 8% bilevel devices, 147 (60%) nasal masks, 52 (21%) oronasal masks; 37 pads (15%), and 92 (36%) thermohumidifiers.

Reasons for consultation were: therapy control, 239 (61%); intolerance, 67 (17%), and calibration, 51 (13%).

Compliance (hours/night) was 4.61 ± 2.1, with a percentage of nights > 4 hours of 67 ± 36%. We didn’t find any difference in the com­pliance of the first and the second year (4.5 vs. 5.0 hours/night) p > 0.13, but the value was higher after 600 days of therapy (p < 0.05).

141 patients (57%) showed some complications, the most frequent being leaks (19%) or intolerance to the masks (10%). 97% of the patients resolved the intolerance with 194 behaviors: explanation of how to use the mask, 94 (48%); calibration, 44 (22%); information, 45 (23%); titration, 13 (6%), and referral to the pulmonologist, 14 (7%).

Conclusions: Two thirds of the patients complied with the positive pressure treatment and half of the patients showed intolerance. The specialized kinesiological consultation can contribute to the identification and resolution of difficulties that may arise during therapy.

Key words: Sleep apnea syndrome, CPAP treatment, Adherence

Recibido: 06/30/2020
Aceptado: 11/08/2020


CPAP therapy is the first-line treatment of moderate and severe sleep apneas of obstructive mecha­nisms (OSA)1-2. Its efficacy depends on the compliance and intolerance of multifactor origin, which are frequent in the initial phases of treatment3-7.

A multidisciplinary team is essential to contribute to the treatment with continuous positive airway pressure (CPAP) in patients with sleep-related breathing disease. Personalized care and a precision medicine approach determine that the treatment should take into account the preferences and indi­vidual responses to treatment8-13.

Various studies show that health professionals other than physicians may have a broad and diverse role during follow-up and clinical management of patients with OSA or patients who require CPAP or noninvasive ventilation (NIV)8-12. The education of patients and treatment follow-up are important tasks in this regard10-12, as well as the identification and resolution of the main secondary effects3, 12, 13.

On the other hand, the CPAP devices record data that allow for the evaluation of the patients’ per­formance by monitoring compliance, leaks, the level of therapeutic pressure and residual events. This is a useful way of evaluating efficacy with time and through different interventions8-14 and the devices are crucial to the identification of intolerance.

With the aim of knowing the level of compliance, the consultation profile, and causes of intolerance, we proposed to analyze the behaviors determined in a Sleep Unit through a specialized consultation unit conducted by physiotherapists.


– To know the level of compliance, the causes of intolerance to CPAP treatment and the behaviors determined for its resolution.

Materials and Methods

Study Design

Observational, retrospective, cross-sectional study in only one center.

We reviewed systematically collected data of outpatient consultations between January 2016 and January 2020, obtained from a medical office specialized in CPAP adaptation and follow-up that belongs to the Sleep Unit of a community hospital.

This study was approved by the Institutional Review Board of the Hospital Británico (CRIHB, for its acronym in Spanish) in accordance with the ethical principles of the Declaration of Helsinki and successive amendments (CRIHB #1030 protocol, approved on 15 August, 2020).


The study included OSA patients older than 18 years who were evaluated in the sleep medicine spe­cialized consultation unit coordinated by a respiratory physiotherapist. Patients were referred for monitoring of CPAP treatment, education and training in the use of the device or demonstration of how to use the interfaces.

We took into account the consultation of patients without previous experience and also those who had completed the adaptation; also, patients diagnosed with obesity hypoventilation syndrome, periodic breathing and those requiring other modes of treatment with positive pressure (ventilation with two levels of pressure, servo-controlled ventilation).

During the daily physiotherapist consultation, the indication of CPAP therapy or noninvasive ven­tilation given by the respective attending pulmonologists was kept the same with no modification or intervention, as usually happens in our Sleep Unit.

Patients who didn’t need positive pressure treatment or suffered another sleep-related, non-respi­ratory disease were excluded.

Information regarding compliance, efficacy and tolerance to CPAP/NIV therapy

The baseline Apnea-Hypopnea Index (AHI) was obtained from the polysomnography (PSG) or respiratory polygraphy (RP) records, and the Body Mass Index (BMI) was registered from the sleep study reports.

We took into consideration the information received during the patients’ consultation with regard to: reason for consultation, duration of therapy, mean use and percentage of nights with > 4 hours’ use in the last 30 days, and intolerance events related to the devices told by each patient (pressure, auto-perceived leaks and humidification level of inhaled air).

Objective follow-up data were obtained from the information downloaded from the devices’ memory (SD Card) by means of the following software: Encore™ Pro II Philips-Respironics™, ResScan™ of ResMed™, ResSmart™ of BMC Medical™, or else by means of the online Air View™ platform (remote monitoring) of ResMed™.

We confirmed the masks that were used and the main adverse effects or lesions related to the in­terfaces.

Information about the effective pressure was obtained from the visual analysis of the pressure/time curve. When available, data regarding compliance, mean leaks and residual apnea-hypopnea index (rAHI) were registered in events per hour (ev/h).

Statistical Analysis

Data were presented as percentages of the categorical variables. Continuous variables with normal distribution are expressed as number and percentage (n; %) or mean and standard deviation; and variables without normal distribution are expressed as median and percentile (25-75%).

For the comparison of differences, we used the Mann-Whitney or Fisher tests or χ2, depending on the type of variables. For the comparison of different therapy pressures, we carried out a linear regression analysis. For the statistical analysis we used Graph Pad Prism-8.02™ software.


244 patients were evaluated in 388 visits for four years. 165 patients were men (67%); age, 65.7 ± 11.6 years, BMI (kg/m2) 31.0 ± 5.4. Table 1 summarizes the characteristics of the study population.

Table 1. Characteristics of the population under study

The diagnosis was established by polysomnography (43%), home respiratory polygraphy (50%) or both (6%). Six patients showed mild OSA (2%), 66 (27%) had moderate OSA and there were 155 cases (63%) of severe OSA. 7% were respiratory sleep-related diseases other than OSA.

At the moment of the consultation, 61% of patients used fixed pressure CPAP, 29% auto-adjusting CPAP and 8% bilevel devices. At the moment of the evaluation, 147 patients used nasal masks (60%); 52 oronasal masks (21%); 37 pads (15%), and 92 patients (36%) used thermohumidification systems.

53 (21%) patients had undergone more than 1 year of treatment with positive pressure devices; less than one year, 102 patients (41%); and 89 patients started treatment with kinesiological support (36%).

After analyzing the visits (more than one per patient), we found out that the reasons for consulta­tion were mainly therapy control (239; 61%), intolerance (67; 17%) and CPAP calibration (51; 13%). Table 2 shows the reasons for referral and initial consultation.

Table 2. Frequent reasons for referral to kinesiological consultation

Compliance with positive pressure treatment (hours/night) was 4.6 ± 2.1, with a proportion of nights > 4 hours of use for 30 days before consultation of 67 ± 36%. 94 patients (38%) showed compliance with > 75% of the nights. (Table 3)

Table 3. Data of therapy and compliance as from the download of software in the devices (built-in software)

We didn’t find any difference in compliance when comparing the first and second year of CPAP use (4.5 vs. 5.0 hours/night) p > 0.13 (Figure 1). However, the percentage of nights using the device > 4 hours was higher relating to longer duration of therapy, evidencing this difference 600 days after start­ing the treatment (Figure 2) p < 0.05.

Figure 1. Compliance ≥ 4 hours/night regarding duration of treatment with positive pressure (< 1 vs. ≥ 1 year).
Figure 2. Minimum compliance (> or < 4 hours/night) regarding the duration of treatment.

141 patients (57%) showed intolerance, most frequently leaks (42; 19%) and events related to the mask or thermohumidification (Table 4 and Figure 3). In 138 cases (97%), the intolerance could be identified and resolved during the kinesiological consultation.

Table 4. Causes of intolerance after kinesiological evaluation
Figure 3. Main causes of intolerance to treatment with positive pressure.

Within the group with > 1 year of treatment (n; 53), 36 patients showed intolerance (67%), though 34 (64%) complied with the therapy more than 4 hours/night and 30 (56%) complied with > 4 hours of use, > 75% of the nights, within 30 days before consultation. (Table 5)

Table 5. Compliance and intolerance profile in patients with > 1 year of treatment

Finally, 194 behaviors were determined for the resolution of intolerance events detailed in Table 6.

Table 6. Interventions determined for the resolution of intolerance events


This work exposes the complexity of OSA patients’ follow-up during treatment with positive airway pressure.

In our population, one third of patients with CPAP required interventions related to the device or the mask, or needed guidance to follow the treatment, or solve the intolerance or the treatment’s adverse effects.

In OSA patients who are in the adjustment or follow-up phase, the work model of our unit takes into account the participation of the respiratory physiotherapist with bi-directional referral to and from the pulmonologist. Mid-term follow-up (the first six months) is the period in which the main second­ary effects are produced, which, if adequately resolved, determine success in terms of acceptance and maintenance of therapy in the long-term12. The role of the non-medical staff at the Sleep Unit may be a control point in the semiology of the patient and his/her equipment, and include sleep lab technicians, nurses and physiotherapists.

In this cohort of patients, compliance was acceptable (near 70%), with a mean use > 4 hours/night similar to that described in other works, both national and international16-20. However, thanks to specialized consultations it was possible to identify frequent events of intolerance and create positive feed-back that lets the patient and the attending staff interact in order to solve them3.

The most predominant reason for consultation was referral for treatment adherence control. Objec­tive data about compliance are fundamental for making decisions during follow-up11-14; but the clinical evaluation allowed for the identification of intolerance events, a predictive factor for treatment with­drawal, even in patients who consulted about daily data download from the device.

It has been suggested that in our country the poor contact with the reference hospital complicates CPAP treatment continuity21. There is low quality preliminary evidence regarding the granting of equipment, thus the monitoring clinical work is hierarchically organized in reference units22.

Also, other frequent clinical problems were identified: allergic or irritable rhinitis, insomnia and bad sleep hygiene, which motivated referrals to the respective attending physicians, ensuring multi­disciplinary work3,12,13.

Published data exposed the fact that the first 2-4 weeks after the start of treatment with positive pressure are crucial for favoring adherence, since it is during this period that intolerance is frequently identified3. However, we could identify lower adherence in patients with > 1 year of CPAP (tradition­ally considered as adapted to therapy), as described by Morrone et al, who showed 67% compliance > 5 hours/night after 1-year follow-up in a protocolized environment15. Surprisingly, in this series, the differences in the compliance profile could be seen after 600 nights of treatment, exposing the need to continue follow-up and analysis of intolerance beyond the first year.

Procedures during the stages of adaptation, titration, and monitoring of compliance and efficacy of positive pressure require specific instruments3,14 (software management, knowledge of different therapy devices, use of masks, knowledge of cognitive-behavioral strategies, understanding of sleep question­naires, standardized clinical behavioral protocols, etc.), which turn the kinesiological consultation into a current discipline that is part of those conforming the multidisciplinary team that must offer solutions for OSA and related disorders23.

Finally, our work is retrospective and includes the typical limitations of this type of design. Also, attendance to this model of specific consultation depends on medical referral, representing a bias and a limitation that complicates interpretation and doesn’t allow the extrapolation of results to other systems of organization.


Two thirds of OSA patients evaluated in a clinical interview by physiotherapists use positive pressure more than 4 hours per night, and half of the patients show intolerance even after the period of adaptation.

The specialized kinesiological consultation may contribute to the identification and resolution of difficulties, applying a protocol based on education and training, interface selection and mid- and long-term follow-up.

Conflicts of interest: The authors declare they have no conflict of interest with the issue related to this original text.

This work was carried out without funding.


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