Objective: To evaluate the construct validity and reproducibility of the six-minute step test (6MST) in individuals with obstructive sleep apnea (OSA) treated with continuous positive airway pressure (CPAP). Methods: We evaluated 48 volunteers diagnosed with OSA and treated with CPAP for at least two months. The volunteers underwent the six-minute walk test (6MWT) and the 6MST, in random order and on different days, with an interval of, at most, seven days between the two tests. Results: A moderate positive correlation was found between the distance walked on the 6MWT and the number of steps climbed on the 6MST (r = 0.520; p < 0.001). There was no significant difference between the two 6MSTs in terms of the number of steps climbed (121.7 ± 27.1 vs. 123.6 ± 26.7). Reproducibility for performance on the 6MST and for cardiovascular variables was considered excellent (intraclass correlation coefficient > 0.8). Regarding cardiovascular responses, the 6MST produced higher values than did the 6MWT for HR at six minutes, percent predicted maximum HR, and leg fatigue at six minutes, as well as for systolic blood pressure at six minutes and at one minute of recovery. Conclusions: The 6MST is valid and reproducible, producing greater cardiovascular stress than does the 6MWT. However, the 6MST is also characterized as a submaximal test for the assessment of exercise tolerance in individuals with OSA treated with CPAP.

Keywords: Sleep apnea, obstructive; Reproducibility of results; Exercise test; Exercise tolerance.

Objective: To determine whether the use of a gel pillow with side cutouts designed to accommodate a continuous positive airway pressure (CPAP) mask and reduce head temperature improves the efficacy of and adherence to auto-CPAP therapy. Methods: Twenty-three consecutive CPAP-naïve patients with obstructive sleep apnea were enrolled in the study. Patients were given an auto-CPAP machine with an appropriate CPAP mask and were instructed to use CPAP for 15 nights. They were instructed to sleep with their own pillow (the control pillow) from nights 1 to 5 and with either a foam pillow or a gel pillow, both of which had side cutouts, for 5 consecutive nights each, in random order. After night 15, auto-CPAP machine data were downloaded and patients rated their satisfaction with each pillow on a visual analog scale. Results: Twenty-two patients completed the protocol. The pressures administered, residual apnea-hypopnea index, air leaks, and mean duration of CPAP use did not differ among the periods during which each pillow was used. Patients were significantly more satisfied with the gel pillow than with the control pillow and the foam pillow (p = 0.022 and p = 0.004, respectively), their level of satisfaction with the gel pillow correlating significantly with excessive daytime sleepiness (r2 = 0.19; p = 0.0443). Conclusions: Among obstructive sleep apnea patients treated with nasal CPAP, the use of a gel pillow with side cutouts appears to have no impact on treatment effectiveness. Nevertheless, such patients seem to prefer a gel pillow over other types of pillows.

Keywords: Sleep; Continuous positive airway pressure; Sleep apnea, obstructive; Masks.

Objective: To evaluate systematically the effects of continuous positive airway pressure (CPAP) on blood pressure in patients with resistant hypertension and obstructive sleep apnea (OSA). Methods: The Cochrane Library, PubMed, ScienceDirect, and the Web of Science were searched for studies investigating the effects of CPAP on blood pressure in patients with resistant hypertension and OSA. The selected studies underwent quality assessment and meta-analysis, as well as being tested for heterogeneity. Results: Six randomized controlled trials were included in the meta-analysis. The pooled estimates of the changes in mean systolic blood pressure and mean diastolic blood pressure (as assessed by 24-h ambulatory blood pressure monitoring) were −5.40 mmHg (95% CI: −9.17 to −1.64; p = 0.001; I2 = 74%) and −3.86 mmHg (95% CI: −6.41 to −1.30; p = 0.00001; I2 = 79%), respectively. Conclusions: CPAP therapy can significantly reduce blood pressure in patients with resistant hypertension and OSA.

Keywords: Continuous positive airway pressure; Sleep apnea, obstructive; Hypertension; Meta-analysis.

Objective: To study the impact that heated humidification instituted in the beginning of automatic positive airway pressure (APAP) therapy has on compliance with and the side effects of the treatment. Methods: Thirty-nine treatment-naïve patients with obstructive sleep apnea were randomized into two groups to receive APAP using one of two modalities: with heated humidification (APAPwith group); and without heated humidification (APAPw/o group).Patients were evaluated at 7 and 30 days after APAP initiation. The following parameters were analyzed: compliance with treatment (mean number of hours/night); side effects (dry nose or mouth, nasal obstruction and rhinorrhea); daytime sleepiness (Epworth sleepiness scale score) and subjective comfort (visual analog scale score). Patients were also evaluated in terms of residual apnea-hypopnea index (AHI), as well as mean pressures and leaks registered in the ventilators. Results: There were no differences between the two groups in terms of mean age (APAPwith: 57.4 ± 9.2; APAPw/o: 56.5 ± 10.7 years), AHI (APAPwith: 28.1 ± 14.0; APAPw/o: 28.8 ± 20.5 events/hour of sleep), baseline Epworth score (APAPwith: 11.2 ± 5.8; APAPw/o: 11.9 ± 6.3) and initial nasal symptoms. Compliance was similar in both groups (APAPwith: 5.3 ± 2.4; APAPw/o: 5.2 ± 2.3 h/night). There were no differences in any of the other parameters analyzed. Conclusions: The introduction of heated humidification at the beginning of APAP therapy provided no advantage in terms of treatment compliance or side effects of treatment.

Keywords: Humidity; Positive-pressure respiration/adverse effects; Patient compliance.

Background: Nasal and pharyngeal symptoms are common in patients with obstructive sleep apnoea (OSA) treated with nasal continuous positive airway pressure (CPAP). However, these symptoms are common in OSA patients even before the treatment. Objectives: Determine the impact of nasal CPAP on nasal and pharyngeal symptoms in OSA patients. Method: Thirty-five adult patients (28 males), age 54±10 years old, with OSA diagnosed by polissonography. All patients answered to a questionnaire about the presence and quantification of sneezing, rhinorrhea, nasal pruritus, obstruction and bleeding, nasal and pharyngeal dryness. The questionnaire was answered before and after at least three months of CPAP therapy. Results: The apnea-hypopnea index was 50±25 events per hour. Twenty six patients (74%) presented at least one naso-pharingeal symptom before treatment. Nasal obstruction was the most common symptom, being referred by 18 patients (51%). Among the patients that were initially assymptomatic (n=9), 78% developed adverse nasal reactions to CPAP. In contrast, among the patients that presented nasal symptoms before treatment, there was a significant reduction in nasal obstruction, nasal and throat dryness scores as well as nasal bleeding after CPAP therapy. Conclusions: Nasal na pharyngeal symptoms are frequent in OSAS patients. CPAP therapy may originate nasal symptoms in patients previously assymptomatic, as well as reduce the intensity of these symptoms in patients that are previously symptomatic.

Keywords: Obstructive sleep apnea syndrome. Nasal obstruction. Continuous positive airway pressure, compliance.

Continuous positive airway pressure (CPAP) is the gold standard for the treatment of obstructive sleep apnea (OSA). Although CPAP was originally applied with a nasal mask, various interfaces are currently available. This study reviews theoretical concepts and questions the premise that all types of interfaces produce similar results. We revised the evidence in the literature about the impact that the type of CPAP interface has on the effectiveness of and adherence to OSA treatment. We searched the PubMed database using the search terms "CPAP", "mask", and "obstructive sleep apnea". Although we identified 91 studies, only 12 described the impact of the type of CPAP interface on treatment effectiveness (n = 6) or adherence (n = 6). Despite conflicting results, we found no consistent evidence that nasal pillows and oral masks alter OSA treatment effectiveness or adherence. In contrast, most studies showed that oronasal masks are less effective and are more often associated with lower adherence and higher CPAP abandonment than are nasal masks. We concluded that oronasal masks can compromise CPAP OSA treatment adherence and effectiveness. Further studies are needed in order to understand the exact mechanisms involved in this effect.

Keywords: Sleep apnea, obstructive; Continuous positive airway pressure; Masks.

Objective: To determine whether different levels of CPAP improve the lung volumes and capacities of healthy subjects immersed in water. Methods: This was a randomized clinical trial, conducted between April and June of 2016, involving healthy female volunteers who were using oral contraceptives. Three 20-min immersion protocols were applied: control (no CPAP); CPAP5 (CPAP at 5 cmH2O); and CPAP10 (CPAP at 10 cmH2O). We evaluated HR, SpO2, FVC, FEV1, the FEV1/FVC ratio, peak expiratory flow rate (PEFR), and FEF25-75%) at three time points: pre-immersion; 10 min after immersion; and 10 min after the end of each protocol. Results: We evaluated 13 healthy volunteers. The CPAP10 protocol reversed the restrictive pattern of lung function induced by immersion in water, maintaining pulmonary volumes and capacities for a longer period than did the CPAP5 protocol. Conclusions: When the hemodynamic change causing a persistent lung disorder, only the application of higher positive pressures is effective in maintaining long-term improvements in the pulmonary profile.

Keywords: Physical therapy modalities; Noninvasive ventilation; Continuous positive airway pressure.

Objective: To analyze the effects of the continuous positive airway pressure (CPAP), with 30% of FiO2 and in compressed air, used during the performance of submaximal physical activity on an ergometric treadmill. Materials and methods: Nine male individuals with COPD were submitted to physical activity on the ergometric treadmill using CPAP with 30% FiO2 .The authors evaluated the behavior of the spirometric parameters, the forced vital capacity (FVC), the forced expiratory volume in the first second (FEV1) before and after physical activity, the respiratory frequency (f), the arterial oxygen saturation (SaO2), the cardiac frequency (cf), the systolic arterial pressure (SAP), and the diastolic arterial pressure (DAP) at rest and during physical activity. Results and conclusion: Results have shown that, when using CPAP in both situations analyzed, there has been an increase in the FVC and a decrease in f and in cf with statistically significant difference (α = 0.05). SaO2 has showned a significantly higher mean when CPAP was used with 30% of FiO2 (α = 0.05). The FEV1, the SAP and DAP have maintained the same value in the statistical analyses.

Keywords: Exercise test. Forced expiratory volume. Vital capacity.

Objective: To establish normative values and a reference equation for the number of steps climbed during the six-minute step test (6MST) in healthy adults, and to assess the reliability of the test and of the equation. Methods: This was a multicenter cross-sectional study involving 468 healthy volunteers (age range: 18-79 years) recruited from the general community in six research laboratories across different regions of Brazil, which is a country with continental dimensions. The 6MST was performed twice (30-min interval), and clinical, demographic, and functional variables were evaluated. An independent sample of 24 volunteers was evaluated to test the reference equation a posteriori. Results: The number of steps had excellent test-retest reliability (intraclass correlation coefficient = 0.96 [95%CI: 0.95-0.97]), and the mean number of steps was 175 ± 45, the number being 14% greater in males than in females. The best performance on the test was correlated with age (r = -0.60), sex (r = 0.28), weight (r = 0.13), height (r = 0.41), BMI (r = -0.22), waist circumference (r = -0.22), thigh circumference (r = 0.15), FVC (r = 0.54), and physical activity level (r = 0.17; p < 0.05 for all). In the regression analysis, age, sex, height, and weight explained 42% of the variability of the 6MST. Normative values were established for the 6MST according to age and sex. There was no difference between the 6MST values from the independent sample and its predicted values (157 ± 29 steps vs. 161 ± 25 steps; p = 0.47; 97% of predicted values). Conclusions: The normative values and the reference equation for the 6MST in this study seem adequate to accurately predict the physical functional performance in adults in Brazil.

Keywords: Exercise test; Physical functional performance; Patient outcome assessment; Reference values; Regression analysis.

Objective: Obstructive sleep apnea syndrome (OSAS) has a high prevalence and carries significant cardiovascular risks. It is important to study new therapeutic approaches to this disease. Positional therapy might be beneficial in reducing the apnea-hypopnea index (AHI). Imaging methods have been employed in order to facilitate the evaluation of the airways of OSAS patients and can be used in order to determine the effectiveness of certain treatments. This study was aimed at determining the influence that upper airway volume, as measured by cervical CT, has in patients diagnosed with OSAS. Methods: This was a quantitative, observational, cross-sectional study. We evaluated 10 patients who had been diagnosed with OSAS by polysomnography and on the basis of the clinical evaluation. All of the patients underwent conventional cervical CT in the supine position. Scans were obtained with the head of the patient in two positions (neutral and at a 44° upward inclination), and the upper airway volume was compared between the two. Results: The mean age, BMI, and neck circumference were 48.9 ± 14.4 years, 30.5 ± 3.5 kg/m2, and 40.3 ± 3.4 cm, respectively. The mean AHI was 13.7 ± 10.6 events/h (range, 6.0-41.6 events/h). The OSAS was classified as mild, moderate, and severe in 70%, 20%, and 10% of the patients, respectively. The mean upper airway volume was 7.9 cm3 greater when the head was at a 44° upward inclination than when it was in the neutral position, and that difference (17.5 ± 11.0%) was statistically significant (p = 0.002). Conclusions: Elevating the head appears to result in a significant increase in the caliber of the upper airways in OSAS patients.

Keywords: Sleep apnea, obstructive/prevention and control; Sleep apnea, obstructive/therapy; Tomography.

Objective: To determine whether airway narrowing during obstructive events occurs predominantly at the retropalatal level and results from dynamic changes in the lateral pharyngeal walls and in tongue position. Methods: We evaluated 11 patients with severe obstructive sleep apnea (OSA) and 7 healthy controls without OSA during wakefulness and during natural sleep (documented by full polysomnography). Using fast multidetector CT, we obtained images of the upper airway in the waking and sleep states. Results: Upper airway narrowing during sleep was significantly greater at the retropalatal level than at the retroglossal level in the OSA group (p < 0.001) and in the control group (p < 0.05). The retropalatal airway volume was smaller in the OSA group than in the control group during wakefulness (p < 0.05) and decreased significantly from wakefulness to sleep only among the OSA group subjects. Retropalatal pharyngeal narrowing was attributed to reductions in the anteroposterior diameter (p = 0.001) and lateral diameter (p = 0.006), which correlated with an increase in lateral pharyngeal wall volume (p = 0.001) and posterior displacement of the tongue (p = 0.001), respectively. Retroglossal pharyngeal narrowing during sleep did not occur in the OSA group subjects. Conclusions: In patients with OSA, upper airway narrowing during sleep occurs predominantly at the retropalatal level, affecting the anteroposterior and lateral dimensions, being associated with lateral pharyngeal wall enlargement and posterior tongue displacement.

Keywords: Multidetector computed tomography; Oropharynx; Sleep apnea, obstructive; Polysomnography; Diagnostic imaging; Sleep.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease in which most patients die of respiratory failure. Although volume-targeted non-invasive bilevel positive airway pressure (BPAP) ventilation has been studied in patients with chronic respiratory failure of various etiologies, its use in ALS has not been reported. We present the case of a 66-year-old woman with ALS and respiratory failure treated with volume-targeted BPAP ventilation for 15 weeks. Weekly data downloads showed that disease progression was associated with increased respiratory muscle weakness, decreased spontaneous breathing, and increased use of non-invasive positive pressure ventilation, whereas tidal volume and minute ventilation remained relatively constant.

Keywords: Amyotrophic lateral sclerosis; Respiratory insufficiency; Hypoventilation; Intermittent positive-pressure ventilation; Sleep.

In 1993 the first Brazilian cluster of Hantavirus Cardiopulmonary Syndrome (HCPS) was described in Juquitiba, SP. Since then, there have been descriptions of new cases specially on the southeast and south states of Brazil. Only in 2002 there were observed the first three cases of HCPS in our city: São Carlos. One of our patients was successfully supported with CPAP through facial mask. This is the first severe case of acute respiratory failure induced by Hantavirus that was successfully managed with this kind of respiratory strategy.

Keywords: Noninvasive Ventilation, CPAP, Hantavirus Pulmonary and Cardiovascular Syndrome, Acute Hipoxemic Respiratory Failure.

Objective: To estimate the prevalence of obstructive sleep apnea syndrome (OSAS) in children and adolescents with sickle cell anemia (SCA); to investigate the possible correlation between mean annual hemoglobin level and total sleep time with SpO2 < 90%, as well as between mean annual hemoglobin level and total sleep time with SpO2 < 80%; and to investigate the possible correlation between apnea-hypopnea index (AHI) and painful crisis. Methods: The study involved 85 patients with SCA. The patients completed a questionnaire, were submitted to polysomnography and underwent clinical evaluation (by a pediatrician and an otolaryngologist). An AHI > 1 was considered indicative of a diagnosis of OSAS. Results: The prevalence of OSAS was 10.6%. We found a negative correlation between mean annual hemoglobin level and total sleep time with SpO2 < 90% (r = −0.343; p = 0.002), as well as between mean annual hemoglobin level and total sleep time with SpO2 < 80% (r = −0.270; p = 0.016). There was no association between AHI and painful crisis. Conclusions: The prevalence of OSAS in this population was high (10.6%). Therefore, it is important to identify signs of OSAS as soon as possible and to determine the mean annual hemoglobin level because of the inverse correlation between that level and the total sleep time with SpO2 < 90% or < 80%.

Keywords: Prevalence; Sleep apnea, obstructive; Anemia, sickle cell; Polysomnography; Sleep apnea syndromes.

Objective: To evaluate quality of life in elderly patients with obstructive sleep apnea (OSA) who have a pacemaker. Methods: This was a cross-sectional study involving elderly patients (≥ 60 years of age) with a pacemaker. The dependent variable was quality of life, as evaluated with the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36). Sociodemographic and clinical parameters, including anxiety and depression (Hospital Anxiety and Depression Scale score), as well as the presence of OSA (defined as an apnea-hypopnea index ≥ 15 events/h), were analyzed as independent variables. Patients with cognitive/neurological deficits or decompensated heart failure were excluded. Results: We evaluated 72 patients, 17 (23.6%) of whom presented OSA. Of those 17 patients, 9 (52.9%) were male. The mean age was 72.3 ± 9.3 years. A diagnosis of OSA was not associated with gender (p = 0.132), age (p = 0.294), or body mass index (p = 0.790). There were no differences between the patients with OSA and those without, in terms of the SF-36 domain scores. Fourteen patients (19.4%) presented moderate or severe anxiety. Of those 14 patients, only 3 (21.4%) had OSA (p = 0.89 vs. no OSA). Twelve patients (16.6%) had moderate or severe depression. Of those 12 patients, only 2 (16.6%) had OSA (p = 0.73 vs. no OSA). Conclusions: In elderly patients with a pacemaker, OSA was not found to be associated with quality of life or with symptoms of anxiety or depression.

Keywords: Quality of life; Aged; Sleep apnea, obstructive.

Objective: To analyze the shuttle walk test, and its respective retest, comparing children with cystic fibrosis (CF) to normal children. Methods: The children were divided into two groups: the CF group, composed of children in whom the diagnosis had been confirmed through sweat testing; and the control group, composed of normal children with no history of pulmonary diseases and no alterations in respiratory function. The children were submitted to at least two consecutive tests, 30 min apart. We evaluated distance walked, cardiac overload, peripheral oxygen saturation (SpO2) and subjective perception of exertion (dyspnea at rest scale and Borg dyspnea scale). Results: A total of 28 children were evaluated. Ages ranged from 7 to 15 years (11.57 ± 2.50 and 11.28 ± 1.85 years for the CF and control groups, respectively). The Borg scale scores were significantly higher in the controls (p = 0.007). No differences were found regarding cardiac overload and SpO2. In relation to the intergroup retest, the controls presented significant improvements on the second test, both in the distance walked and in dyspnea at rest (p = 0.014 and p = 0.036, respectively). The CF group presented a significant improvement only in the dyspnea at rest score (p = 0.168 and p = 0.042, respectively). Conclusion: The cardiac overload imposed by the test did not differ between the groups. The greater fatigue at the beginning of the second test suggests that the 30 min rest between the tests was insufficient.

Keywords: Cystic fibrosis; Exercise test; Heart rate.

Objective: To test the efficiency of the Bird Mark 7 ventilator adapted to deliver continuous positive airway pressure (CPAP) in noninvasive positive pressure ventilation. Methods: This was an experimental study using a mechanical model of the respiratory system. A Bird Mark 7 ventilator was supplied with 400 and 500 kPa and tested at CPAP of 5, 10 and 15 cmH2O. The following variables were analyzed: difference between the preset CPAP and the CPAP actually attained CPAP (trueCPAP); area of airway pressure at the CPAP level employed (AREACPAP); and tidal volume generated. Results: Adapting the Bird Mark 7 to offer CPAP achieved the expected tidal volume in all situations of inspiratory effort (normal or high), ventilator pressure supply (400 or 500 kPa) and CPAP value (5, 10 or 15 cmH2O). At a CPAP of 5 or 10 cmH2O, the trueCPAP was near the preset level, and the AREACPAP was near zero. However, at a CPAP of 15 cmH2O, the value remained below the preset, and the AREACPAP was high. Conclusion: The efficiency of Bird Mark 7 adaptation in offering CPAP was satisfactory at 5 and 10 cmH2O but insufficient at 15 cmH2O. If adapted as described in our study, the Bird Mark 7 might be an option for offering CPAP up to 10 cmH2O in areas where little or no equipment is available.

Keywords: Ventilators, mechanical; Positive-pressure respiration; Continuous positive airway pressure.

Objective: To translate the Quebec Sleep Questionnaire (QSQ), a specific instrument for the assessment of quality of life in patients with sleep obstructive apnea, into Portuguese and to create a version that is cross-culturally adapted for use in Brazil. Methods: The Portuguese-language version was developed according to a rigorous methodology, which included the following steps: preparation; translation from English into Portuguese in three versions; reconciliation to a single version; back-translation of that version into English; comparison and harmonization of the back-translation with the original version; review of the Portuguese-language version; cognitive debriefing; text review; and arrival at the final version. Results: The Portuguese-language version of the QSQ for use in Brazil had a clarity score, as measured by cognitive debriefing, ranging from 0.81 to 0.99, demonstrating the consistency of translation and cross-cultural adaptation processes. Conclusions: The process of translating the QSQ into Portuguese and creating a version that is cross-culturally adapted for use in Brazil produced a valid instrument to assess the quality of life in patients with obstructive sleep apnea.

Keywords: Obstructive sleep apnea, Quality of life; Translations; Validation studies.