Use of continuous positive airway pressure in drainage of pleural effusion: Educational intervention for evidence-based practice.

OBJECTIVE: To create an educational intervention for health professionals and test its effectiveness in implementing the use of CPAP in hospitalized patients with pleural effusion undergoing thoracic drainage. METHODS: This implementation study was developed in 5 hospitals in Brazil and one in Belgium within four phases: (I) Situational diagnosis (professionals and patients' knowledge about CPAP usage for drained pleural effusion and checking medical records for the last 6 months); (II) Education and training of professionals; (III) New situational diagnosis (equal to phase I); (IV) Follow-up for two years. RESULTS: 65 professionals, 117 patients' medical records, and 64 patients were enrolled in this study. Initially, only 72% of medical records presented a description of interventions. CPAP usage was mentioned in only one patient with a chest tube. After phase III, the number of professionals who used CPAP for their patients with drained pleural effusion increased from 28.8% to 66.7%, p < 0.001. Similarly, the acceptability of this therapy for this clinical situation also increased among professionals from 6.4 ± 1.3 to 7.8 ± 1.4, p < 0.001. However, before the implementation, only one medical record described the use of CPAP in one patient with drained pleural effusion. After two years, the use of CPAP therapy by healthcare professionals for patients with drained thoracic drainage was sustained in 3 hospitals. CONCLUSIONS: The educational intervention for the use of CPAP in patients with drained pleural effusion was effective for health professionals. Results were sustained after two years in three of the six hospitals.

"Skeletal surgical approach in Down Syndrome with Obstructive Sleep Apnea."

Failing to address Obstructive Sleep Apnea (OSA) in Down Syndrome (DS) patients can have serious consequences, leading to increased mortality. Moreover, a notable portion of individuals find it challenging to tolerate Continuous Positive Airway Pressure (CPAP). Therefore, this study aims to share our experiences in treating adult DS patients with moderate to severe OSA who don't tolerate CPAP using various surgical approaches. A retrospective analytical study including 20 DS with moderate to severe/very severe OSA who had no tolerance to Continuous Positive Airway Pressure (CPAP) was conducted. Regarding the individual skeletal characteristics of each patient various orthognathic surgery techniques were performed. Two in-hospital polysomnographies (PSG) were undertaken for every patient; one before the surgical procedure, while another was performed between 6 and 60 months of the follow-up post-surgery period. Polysomnographic variables were analyzed in this study such as AHI, ODI, and T90, which all showed statistically significant improvement after surgery with a p value in the Wilcoxon test <0,01. These results have remained stable over time, with no recurrences of OSA observed over the five years of follow-up. Thus, orthognathic surgery may be the only viable option for individuals with DS who are unable to tolerate CPAP.

Continuous positive airway pressure ventilation in dogs with acute cardiogenic pulmonary edema is associated with improved clinical parameters and reduced diuretic and oxygen requirements.

OBJECTIVE: To retrospectively compare efficacy of a continuous positive airway pressure (CPAP) helmet against standard oxygen supplementation (STD) administered by nasal cannulae in dogs with acute cardiogenic pulmonary edema (ACPE). ANIMALS: 83 dogs (STD group, n = 41; CPAP group, 42) hospitalized for ACPE (January 2019 to April 2021). METHODS: Mean respiratory rate, heart rate, systolic arterial pressure, and rectal body temperature were compared between and within groups before and at 1 (T1), 2 (T2), 3 (T3), 6 (T6), and 12 (T12) hours from the beginning of STD/CPAP therapy. Duration of oxygen supplementation, hospitalization time, total diuretic dose, additional pharmacological interventions and mortality rates were compared between groups. The veterinary bedside lung ultrasound in emergency score, thoracic radiographs, and arterial blood parameters were compared between and within groups before and at the end of CPAP/STD therapy. RESULTS: Within both groups, clinical parameters decreased during the observation period. Mean respiratory rate and heart rate were significantly lower in the CPAP group than the STD group at T1, T2, T3, T6, and T12. Mean systolic arterial pressure was significantly lower in the CPAP group than the STD group at T2, T3, T6, and T12. Mean oxygen supplementation duration, cumulative loop diuretic dose, and both veterinary bedside lung ultrasound in emergency score and arterial PaCO2 at the end of CPAP/STD therapy were significantly lower in the CPAP group than the STD group. No significant differences were observed in hospitalization time and mortality rates. CLINICAL RELEVANCE: The addition of helmet CPAP compared with standard oxygen administration showed a faster clinical improvement with lower cumulative loop diuretic and shorter oxygen supplementation in dogs hospitalized for ACPE.

Safety and effectiveness of bubble continuous positive airway pressure as respiratory support for bronchiolitis in a pediatric ward.

The results of several clinical trials suggest that continuous positive airway pressure (CPAP) for acute bronchiolitis can be more effective than high-flow nasal cannula (HFNC). The use of HFNC involved a minimum reduction (5%) in admissions to the pediatric intensive care unit (PICU) in our hospital. Our main aim was to evaluate its safety and effectiveness as respiratory support for patients with bronchiolitis in a pediatric general ward. A secondary goal was to compare the admissions to PICU and the invasive mechanical ventilation (IMV) rate of patients treated with HFNC and those treated with HFNC/b-CPAP during the 2018-2019 and 2019-2020 epidemic seasons, respectively. Two prospective single-centre observational studies were performed. For the main aim, a cohort study (CS1) was carried out from 1st of November 2019 to 15th of January 2020. Inclusion criteria were children aged up to 3 months with bronchiolitis treated with b-CPAP support when HFNC failed. Epidemiological and clinical parameters were collected before and 60 min after the onset of CPAP and compared between the responder (R) and non-responders (NR) groups. NR was the group that required PICU admission. One hundred fifty-eight patients were admitted to the ward with bronchiolitis and HFNC. Fifty-seven out of one hundred fifty-eight required b-CPAP. No adverse events were observed. Thirty-two out of fifty-seven remained in the general ward (R-group), and 25/57 were admitted to PICU (NR-group). There were statistically significant differences in respiratory rate (RR) and heart rate (HR) between both groups before and after the initiation of b-CPAP, but the multivariable models showed that the main differences were observed after 60 min of therapy (lower HR, RR, BROSJOD score and FiO2 in the R-group). For the secondary aim, another cohort study (CS2) was performed comparing data from a pre-b-CPAP bronchiolitis season (1st of November 2018 to 15th January 2019) and the b-CPAP season (2019-2020). Inclusion criteria in pre-b-CPAP season were children aged up to 3 months admitted to the same general ward with moderate-severe bronchiolitis and with HFNC support. Admissions to PICU during the CPAP season were significantly reduced, without entailing an increase in the rate of IMV. CONCLUSION: The implementation of b-CPAP for patients with bronchiolitis in a pediatric ward, in whom HFNC fails, is safe and effective and results in a reduction in PICU admissions. WHAT IS KNOWN: • Bronchiolitis is one of the most frequent respiratory infections in children and one of the leading causes of hospitalization in infants. • Several studies suggest that the use of continuous positive airway pressure (CPAP) for acute bronchiolitis can be more effective than the high flow nasal cannula (HFNC). CPAP is a non-invasive ventilation (NIV) therapy used in patients admitted to pediatric intensive care unit (PICU) with progressive moderate-severe bronchiolitis. There is little experience in the literature on the use of continuous positive airway pressure (CPAP) for acute bronchiolitis in a general ward. WHAT IS NEW: • CPAP could be safely and effectively used as respiratory support in young infants with moderate-severe bronchiolitis in a general ward and it reduced the rate of patients who required PICU admission. • Patients' heart and respiratory rate and their FiO2 needs in the first 60 minutes may help to decide whether or not to continue the CPAP therapy in a general ward.

Patients with Epiglottic Collapse Are Less Adherent to Autotitrating Positive Airway Pressure Therapy for Obstructive Sleep Apnea.

Rationale: The anatomic orientation of the epiglottis is such that it points in the opposite direction to inspiratory flow, thereby potentially making positive airway pressure (PAP) treatment challenging in patients with epiglottic collapse. However, no previous studies have analyzed PAP adherence in these patients. Objectives: This study aimed to analyze adherence to autotitrating PAP (APAP) treatment in patients with epiglottic collapse. Methods: We performed an age- and sex-matched case-control study. On the basis of their overnight level-I polysomnogram, patients were prescribed APAP in a tertiary hospital between July 2018 and March 2019. The site of airway collapse was diagnosed with drug-induced sleep endoscopy. Demographic factors, sleep questionnaire, polysomnography, and APAP usage statistics were analyzed. Results: Eighteen patients with epiglottic collapse (epi-group) and 36 without epiglottic collapse (control group) were analyzed. We found that 22.8% of patients in the epi-group terminated APAP within 2 weeks, whereas only 2.8% of patients in the control group terminated APAP within 2 weeks (P = 0.048). The percentage of days with usage over 4 hours was significantly lower in the epi-group (64.6% vs. 75.6%; P = 0.008). In addition, the adherence failure rate was 66.7% in the epi-group and 33.3% in the control group (P = 0.039). Patients with epiglottic collapse were also found to have lower body mass index, which is an unfavorable predictor of APAP adherence. Conclusions: This study suggests that patients with epiglottic collapse have a higher APAP adherence failure rate than patients without epiglottic collapse. Thus, patients with epiglottic collapse should be followed closely during treatment, and alternative therapies should probably be considered for these patients.

Predictive factors for CPAP failure in obstructive sleep apnea patients.

OBJECTIVES: Some patients with obstructive sleep apnea (OSA) do not respond to Continuous Positive Airway Pressure (CPAP) and for these patients, Bi-level PAP is the next level modality. This study by a theory driven hierarchical approach, tries to identify the predictors for CPAP failure among OSA patients. METHODOLOGY: The potential predictors for the model were identified from a theoretical framework rooted in clinical examination, laboratory parameters, and polysomnographic variables pertaining to OSA patients. All patients of OSA who underwent manual titration with CPAP or Bi-level PAP (in case of CPAP Failure) between June 2015 and October 2017 were included in model building. This study compared five competitive models blocks deliberated by increasing order of diagnostic complexity and availability of resources. The fitting of the model was determined by both internal and external validation. RESULTS: Among the five competitive models, the selected model has the significant deviance reduction (-2LL = 121.99, X2 = 25.55, P < 0.0001) from the baseline model (-2LL = 217.356). This logistic regression model consists of the following binary predictors - Age >60 years (odds ratio [OR] = 3.23 [1.27-8.23]), body mass index >35 Kg/m2 (OR = 4.25 [1.78-10.13]), forced expiratory volume <60% (OR = 7.33 [2.83-18.72]), apnea-hypopnea index >75 (OR = 4.31 [1.61-11.56]) and T90 > 30% (OR = 6.67 [2.57-17.36]). CONCLUSION: These five factors (acronym as BIPAP) may aid to the clinical decision-making by predicting failure of CPAP and therefore may assist in more vigilant clinical care.

Effect of Continuous Positive Airway Pressure on Arrhythmia in Atrial Fibrillation and Sleep Apnea: A Randomized Controlled Trial.

Rationale: Sleep apnea (SA) is highly prevalent in patients with atrial fibrillation (AF), and both conditions are associated with adverse cardiovascular outcomes.Objectives: To determine the effect of continuous positive airway pressure (CPAP) on AF burden.Methods: This open-label, parallel-group, randomized controlled trial included patients with paroxysmal AF and moderate to severe SA (apnea-hypopnea index ⩾15). A computerized system randomized eligible patients (1:1) to 5 months' treatment with CPAP plus usual care (CPAP, n = 55) or usual care alone (control, n = 54). The outcome assessment was blinded. The planned primary outcome was the difference between CPAP treatment and control groups in change of AF burden (percentage of time in AF) as measured by implantable loop recorder.Measurements and Main Results: A total of 579 patients with paroxysmal AF had respiratory polygraphy, of whom 244 (42%) had moderate to severe SA. Of these, 158 (65%) participated in the CPAP run-in period, of whom 39 (25%) patients did not tolerate the treatment. A total of 108 patients were available for the primary analysis. The mean time in AF decreased from 5.6% at baseline to 4.1% during the last 3 months of CPAP intervention and from 5.0% to 4.3% in the control group. The adjusted between-group difference at follow-up was -0.63 (95% confidence interval, -2.55 to 1.30) percentage points (P = 0.52). Seven serious adverse events (13%) occurred in the CPAP group, and two (4%) occurred in the control group.Conclusions: In patients with paroxysmal AF and SA, treatment with CPAP did not result in a statistically significant reduction in the burden of AF.Clinical trial registered with www.clinicaltrials.gov (NCT02727192).

An algorithm for the sedation of patients with obstructive sleep apnea by non-anesthesiologists.

OBJECTIVE: Patients with obstructive sleep apnea (OSA) are at risk for adverse events when moderate sedation is administered by nurse protocols (NAMS) under the guidance of non-anesthesiologists. An algorithm was applied for the appropriate section of patients to receive NAMS and the application of continuous positive airway pressure (CPAP). METHODS: An algorithm was developed for patients with OSA who were scheduled for gastroenterology, radiology, and cardiology procedures using NAMS. Those with normal airways and without contraindications for NAMS were classified as CPAP-independent (CPAP-I; not routinely used) or CPAP-dependent (CPAP-D; always used). CPAP machines were brought in by CPAP-D patients or supplied by the hospital and set at a patient's routine setting or 10 cm H2O if not known. CPAP-D patients for procedures for which CPAP could not be applied were done under anesthesia care. We retrospectively examined this program for the 2008-2018 period. RESULTS: Since the inception of this protocol in 2008, 803 patients with OSA safely underwent procedures using either personal CPAP or CPAP provided by the hospital. CONCLUSIONS: Patients with OSA can safely have NAMS for procedures when CPAP is applied based on a protocol that considers airway evaluation, the procedure, and whether there is dependence upon CPAP.

Evaluation of the Relationship Between the Required Pressure Level in Continuous Positive Airway Pressure Treatment and Voice in Patients With Obstructive Sleep Apnea Syndrome.

OBJECTIVE: The aim of this study was to investigate the effect of obstructive sleep apnea syndrome on voice, the relationship between the required pressure levels in continuous positive airway pressure (CPAP) and voice, and the effects of CPAP therapy on voice. MATERIAL AND METHODS: A total of 73 subjects consisting of 53 patients and 20 control subjects were included in the study. The patient group was further divided into low- (Group A) and high- (Group B) pressure groups according to the required pressure level. All subjects underwent acoustic sound analysis to evaluate fundamental frequency (F0), jitter, shimmer, and noise-to-harmonics ratio (NHR). Acoustic voice analysis was repeated after 3 months of regular CPAP treatment in the patient group. The mean F0, jitter, shimmer, and NHR values of the patient group and control group were compared. Intergroup comparisons were also performed between Group A and the control group, and between Group B and the control group. Finally, before and after CPAP treatment values of mean F0, jitter, shimmer, and NHR were compared in Group A and Group B. RESULTS: The mean shimmer and NHR values of the patient group were significantly higher than the control group (P = 0.01 and P = 0.023, respectively). The mean shimmer and NHR values of Group B were statistically higher than the control group (P = 0.002 and P < 0.001, respectively). The mean jitter, shimmer, and NHR values after CPAP treatment were significantly lower than those measured before CPAP treatment in Group B (P = 0.003, P = 0.001, and P = 0.001, respectively). CONCLUSION: Voice is negatively affected in obstructive sleep apnea syndrome patients who require high pressure in CPAP treatment. CPAP treatment leads to improved voice in these patients.

Observational Study on Safety of Prehospital BLS CPAP in Dyspnea.

Introduction Continuous positive airway pressure (CPAP) improves outcomes in patients with respiratory distress. Additional benefits are seen with CPAP application in the prehospital setting. Theoretical safety concerns regarding Basic Life Support (BLS) providers using CPAP exist. In Delaware's (USA) two-tiered Emergency Medical Service (EMS) system, BLS often arrives before Advanced Life Support (ALS). Hypothesis This study fills a gap in literature by evaluating the safety of CPAP applied by BLS prior to ALS arrival. METHODS: This was a retrospective, observational study using Quality Assurance (QA) data collected from October 2009 through December 2012 throughout a state BLS CPAP pilot program; CPAP training was provided to BLS providers prior to participation. Collected data include pulse-oximetry (spO2), respiratory rate (RR), heart rate (HR), skin color, and Glasgow Coma Score (GCS) before and after CPAP application. Pre-CPAP and post-CPAP values were compared using McNemar's and t-tests. Advanced practitioners evaluated whether CPAP was correctly applied and monitored and whether the patient condition was "improved," "unchanged," or "worsened." RESULTS: Seventy-four patients received CPAP by BLS; CPAP was correctly indicated and applied for all 74 patients. Respiratory status and CPAP were appropriately monitored and documented in the majority of cases (98.6%). A total of 89.2% of patients improved and 4.1% worsened; CPAP significantly reduced the proportion of patients with SpO224, and cyanosis (P<.01). The GCS improved from mean (standard deviation [SD]) 13.9 (SD=1.9) to 14.1 (SD=1.9) after CPAP (mean difference [MD]=0.17; 95% CI, -0.49 to 0.83; P=.59). The HR decreased from 115.7 (SD=53) to 105.1 (SD=37) after CPAP (MD=-10.9; 95% CI, -3.2 to -18.6; P<.01). The SpO2 increased from 80.8% (SD=11.4) to 96.9% (SD=4.2) after CPAP (MD=17.8; 95% CI, 14.2-21.5; P<.01). CONCLUSION: The BLS providers were able to determine patients for whom CPAP was indicated, to apply it correctly, and to appropriately monitor the status of these patients. The majority of patients who received CPAP by BLS providers had improvement in their clinical status and vital signs. The findings suggest that CPAP can be safely used by BLS providers with appropriate training. Sahu N , Matthews P , Groner K , Papas MA , Megargel R . Observational study on safety of prehospital BLS CPAP in dyspnea. Prehosp Disaster Med. 2017;32(6):610-614.

Ventilation with facial mask in the prone position for radiotherapy procedures in children.

OBJECTIVES: Ventilation of patients undergoing procedures in the prone position represents a challenge for the anesthesiologist, especially when trying to avoid tracheal intubation. This study aimed to test the effectiveness and safety of a prototype designed for pediatric facial mask ventilation in the prone position. MATERIAL AND METHODS: A prospective descriptive study was conducted on 105 sedations performed in 3 children scheduled for radiotherapy treatment of posterior fossa desmoplastic medulloblastoma (6 and 4 y.o. males), and neuroblastoma in temporal area (4 y.o. male). Induction and maintenance of sedation were conducted with sevoflurane in oxygen, maintaining spontaneous ventilation. After achieving loss of consciousness and immobility, the patients were placed in the prone position. Their heads were fixed with the forehead and face supported by a prototype made with a cast of expanded polystyrene (EPS), which held the facial mask (connected to a Mapleson D circuit), and the back of the head immobilized with a layer of thermoplastic material. Time variables and complications were recorded. RESULTS: All sedations were performed according to the planned protocol. All patients maintained oxygen saturation levels above 95%, and no complications were reported. Daily hospital length of stay including the procedure and post anesthetic recovery was 54.4±7.9 min (mean±SD). CONCLUSIONS: The prototype and the sedation technique with face mask in the prone position employed were effective and safe, allowing the completion of the radiotherapy sessions and securing the airway in a minimally invasive way, maintaining adequate ventilation, light sedation and enabling early hospital discharge.

Lung recruitment can improve oxygenation in patients ventilated in continuous positive airway pressure/pressure support mode.

BACKGROUND: Recruitment maneuvers are often used in critical care patients with hypoxemic respiratory failure. Although continuous positive airway pressure/pressure support (CPAP/PS) ventilation is a frequently used approach, but whether lung recruitment also improves oxygenation in spontaneously breathing patients has not been investigated yet. The primary objective was to analyze the effect of recruitment maneuver on oxygenation in patients ventilated in CPAP/PS mode. METHODS: Following baseline measurements PEEP was increased by 5 cmH2O. Recruitment maneuver was applied for 40 s with 40 cmH2O of PS. Measurements of the difference in PaO2/FiO2 and airway parameters measured by the ventilator were recorded immediately after recruitment then 15 and 30 min later. Thirty patients ventilated in CPAP/PS mode with a PEEP ≥5 cmH2O were enrolled in this prospective, observational study if their PaO2/FiO2 ratio was <300 mmHg or required an FiO2 >0.5. RESULTS: Following recruitment maneuver patients were considered as non-responders (NR, n = 15) if difference of PaO2/FiO2 <20% and responders (R, n = 15) if difference of PaO2/FiO2 ≥20%. In the NR-group, PaO2/FiO2 decreased non-significantly from baseline: median [interquartile], PaO2/FiO2 = 176 [120-186] vs. after recruitment: 169 [121-182] mmHg, P = 0.307 while in the R-group there was significant improvement: 139 [117-164] vs. 230 [211-323] mmHg, P = 0.01. At the same time points, dead space to tidal volume ratio (Vds/Vte) significantly increased in the NR-group Vds/Vte = 32 [27-37] vs. 36 [25-42]%, P = 0.013 but no significant change was observed in the R-group: 26 [22-34] vs. 27 [24-33]%, P = 0.386. CONCLUSION: Recruitment maneuver improved PaO2/FiO2 ratio by ≥20% in 50% of patients ventilated in CPAP/PS mode.

Application of continuous positive airway pressure in the delivery room: a multicenter randomized clinical trial

This study evaluated whether the use of continuous positive airway pressure (CPAP) in the delivery room alters the need for mechanical ventilation and surfactant during the first 5 days of life and modifies the incidence of respiratory morbidity and mortality during the hospital stay. The study was a multicenter randomized clinical trial conducted in five public university hospitals in Brazil, from June 2008 to December 2009. Participants were 197 infants with birth weight of 1000-1500 g and without major birth defects. They were treated according to the guidelines of the American Academy of Pediatrics (APP). Infants not intubated or extubated less than 15 min after birth were randomized for two treatments, routine or CPAP, and were followed until hospital discharge. The routine (n=99) and CPAP (n=98) infants studied presented no statistically significant differences regarding birth characteristics, complications during the prenatal period, the need for mechanical ventilation during the first 5 days of life (19.2 vs 23.4%, P=0.50), use of surfactant (18.2 vs 17.3% P=0.92), or respiratory morbidity and mortality until discharge. The CPAP group required a greater number of doses of surfactant (1.5 vs 1.0, P=0.02). When CPAP was applied to the routine group, it was installed within a median time of 30 min. We found that CPAP applied less than 15 min after birth was not able to reduce the need for ventilator support and was associated with a higher number of doses of surfactant when compared to CPAP applied as clinically indicated within a median time of 30 min.

Acute effects of different levels of continuous positive airway pressure on cardiac autonomic modulation in chronic heart failure and chronic obstructive pulmonary disease.

INTRODUCTION: Non-invasive ventilation may improve autonomic modulation and ventilatory parameters in severely disabled patients. The aim of the present study was to evaluate the physiological influence of acute treatment with different levels of continuous positive airway pressure (CPAP) on the autonomic balance of heart and respiratory responses in patients with stable chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). MATERIALS AND METHODS: A COPD group (n = 10), CHF group (n = 8) and healthy subjects (n = 10) were evaluated. The participants were randomized to receive three different levels of CPAP on the same day: sham ventilation (Sham), 5 cmH(2)0 (CPAP5) and 10 cmH(2)0 (CPAP10) for 10 min. Respiratory rate, end tidal carbon dioxide (E(T)CO(2)), peripheral oxygen saturation (SpO(2)), heart rate (HR), blood pressure and heart rate variability in the time and frequency domains were measured during spontaneous breathing and under the sham, CPAP5 and CPAP10 conditions. RESULTS: All groups experienced a reduction in E(T)CO(2) values during treatment with CPAP (p < 0.05). CPAP increased SpO(2) and HR in the COPD group (p < 0.05). The COPD group also had lower RMSSD values during treatment with different levels of CPAP when compared to the control group (p < 0.05). In the CHF group, CPAP5 and CPAP10 increased the SDNN value (p < 0.05). CPAP10 reduced the SDNN value in the COPD group (p < 0.05). CONCLUSION: The findings suggest that CPAP may cause improvements in the neural control of heart rate in patients with stable COPD and CHF. For each patient, the "best CPAP level" should be defined as the best respiratory response and autonomic balance.

Uso de CPAP nasal en el largo plazo en síndrome de apnea-hipopnea del sueño / Long-term continuous positive airway pressure (CPAP) use in obstructive sleep apnea

Background: The use of CPAP is the conventional therapy for the Obstructive Sleep Apnea Syndrome (OSAS). Aim To establish the proportion of OSAS patients with CPAP indication who use it in the long-term and to determine predictive factors of adherence. Patients and Methods: Structured survey through personal interview or phone call, applied to all patients who had polisomnographically documented OSAS and CPAP titration at the Pontificia Universidad Católica de Chile Sleep Disorders Center between January 1998 and November 2001. Patients were divided in "Permanent Users" (Group I) and "Non Users" (Group II). Results: Of 440 patients that fulfilled inclusion criteria, 162 (32.8 percent) answered the survey. Seventy percent (114/162) of these patients had used CPAP and 86 percent (98/114) continued to use it at the time of the interview, with a mean follow-up of 12.3 months (Group I 60.5 percent of the interviewed population). Group II included 64 patients (39.5 percent of the interviewed patients). Among the latter, 25 percent (16/64) stopped using CPAP due to intolerance, 25 percent (16/64) could not use it because of economical restrictions, 20.5 percent (13/64) preferred other therapies and 29.5 percent (15/64) merely refused treatment. Predictors of long-term use of CPAP were number of respiratory events (p <0.01), hypersomnolence (p <0.01) and age (p =0.03). Conclusions: Approximately two thirds of patients with OSAS, with an indication for CPAP, continue to use this therapy in the long term in a Chilean population. This figure is similar to other reports from abroad. It is also possible to identify predictive factors for CPAP discontinuation in this population.