The objective of this article was to describe a new method for assessing expiratory flow limitation during spontaneous breathing, using the negative expiratory pressure test to identify patients at risk for obstructive sleep apnea. Upper airway collapsibility is evaluated by measuring decreases in flow and in expired volume in the first 0.2 seconds after negative expiratory pressure application at 10 cmH2O. The negative expiratory pressure test is easily applied and could be adopted for the evaluation of expiratory flow limitation caused by upper airway obstruction in patients with obstructive sleep apnea.

Keywords: Sleep apnea, obstructive/diagnosis; Sleep apnea, obstructive/prevention and control; Airway resistance.

Objectives: (i) To assess the anthropometric measurements, along with the clinical characteristics and quality of life profiles of the studied patients; (ii) To determine the occurrence and severity of Obstructive Sleep Apnea (OSA), using polysomnography; and (iii) To identify the best anthropometric and clinical indicators to predict OSA in obese patients who are candidates for bariatric surgery. Methods: a prospective observational study conducted in a private clinic, using consecutive sampling of patients eligible for bariatric surgery with a BMI = 40, or with a BMI of = 35 kg/m² accompanied by comorbidities associated with obesity. Results: Sixty patients were initially selected, of whom 46 agreed to take part in the preoperative evaluation. OSA was observed in 76% of patients, 59% of whom had moderate-to-severe OSA, with a predominance of men in these groups. Among the variables suggesting statistical difference between groups, waist-to-hip ratio (WHR) was the only clinical factor associated with scores the apnea hypopnea index (AHI) = 15, with a cut-off value of 0.95. The results showed that patients scoring above 0.95 are three times more likely to have moderate-to-severe apnea. Conclusion: The best risk factor for the prognostic of moderate-to-severe OSA was presenting a WHR score with a cut-off value of 0.95 or above.

Keywords: Obstructive sleep apnea; Bariatric surgery; Anthropometry; Waist-to-hip ratio.

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.

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.

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 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.

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.

A apneia obstrutiva do sono (AOS) é caracterizada por obstruções recorrentes das vias aéreas superiores durante o sono que ocorrem no nível da faringe. Apesar de a análise cefalométrica ser um importante método no diagnóstico das deformidades craniofaciais, a TC e a ressonância magnética vêm se destacando como os principais métodos de imagem para a investigação das eventuais causas da AOS que, na maioria das vezes, é multifatorial. Esses métodos permitem uma excelente avaliação nos diversos planos anatômicos do eventual sítio da obstrução, o que permite uma melhor avaliação clínica e abordagem cirúrgica. O presente ensaio pictórico tem como objetivo descrever os aspectos que devem ser avaliados no diagnóstico por imagem dos principais fatores predisponentes para a AOS.

Keywords: Síndromes da apneia do sono; Imagem por ressonância magnética; Tomografia computadorizada por raios X.

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 determine the prevalence of risk factors for obstructive sleep apnea syndrome in interstate bus drivers. Methods: This study involved 262 professional interstate bus drivers employed by a Brazilian company headquartered in the Federal District. The drivers were evaluated using a questionnaire designed to assess respiratory sleep disorders, the Epworth Sleepiness Scale, test of sustained attention, test of divided attention and anthropometric measurements. Results: Body weight was found to be above the ideal in 68% of the drivers evaluated, 34% of which had a neck circumference = 42 cm. During the study period, the drivers reported using tobacco (27%), cola-based soft drinks (55%), alcohol (65%) and coffee (88%). The Epworth Sleepiness Scale score was = 10 points in 28%. Snoring was reported by 36%, sleep apnea by 5%, a sensation of suffocation during sleep by 12%, restless sleep by 29% and drowsiness while driving by 48%. There were 42% who had been involved in transit accidents, 7.6% of which were attributed to hypersomnolence. Those scoring higher than 10 of the Epworth Sleepiness Scale presented lower levels of sustained attention. In addition, a reduction in divided attention was found to correlate with greater daytime sleepiness and larger neck circumference. Conclusion: The rate of stimulant use found in the group of drivers evaluated is alarming. The high prevalence of daytime sleepiness indicates that attentiveness is reduced in this population.

Keywords: Automobile driving; Sleep apnea, obstructive; Work schedule tolerance; Psychometrics; Risk factors; Attention; Questionnaires

Objective: To identify risk factors for respiratory complications after adenotonsillectomy in children ≤ 12 years of age with obstructive sleep apnea who were referred to the pediatric ICU (PICU). Methods: A cross-sectional historical cohort study analyzing 53 children after adenotonsillectomy who met predetermined criteria for PICU referral in a tertiary level teaching hospital. The Student's t-test, Mann-Whitney test, and chi-square test were used to identify risk factors. Results: Of the 805 children undergoing adenotonsillectomy between January of 2006 and December of 2012 in the teaching hospital, 53 were referred to the PICU. Twenty-one children (2.6% of all those undergoing adenotonsillectomy and 39.6% of those who were referred to the PICU) had respiratory complications. Of those 21, 12 were male. The mean age was 5.3  2.6 years. A high apnea-hypopnea index (AHI; p = 0.0269), a high oxygen desaturation index (ODI; p = 0.0082), a low SpO2 nadir (p = 0.0055), prolonged orotracheal intubation (p = 0.0011), and rhinitis (p = 0.0426) were found to be independent predictors of respiratory complications. Some of the complications observed were minor (SpO2 90-80%), whereas others were major (SpO2 ≤ 80%, laryngospasm, bronchospasm, acute pulmonary edema, pneumonia, and apnea). Conclusions: Among children up to 12 years of age with OSA, those who have a high AHI, a high ODI, a low SpO2 nadir, or rhinitis are more likely to develop respiratory complications after adenotonsillectomy than are those without such characteristics.

Keywords: Postoperative complications; Tonsillectomy; Sleep apnea, obstructive.

Symptoms of sleep-disordered breathing, especially obstructive sleep apnea syndrome (OSAS), are common in asthma patients and have been associated with asthma severity. It is known that asthma symptoms tend to be more severe at night and that asthma-related deaths are most likely to occur during the night or early morning. Nocturnal symptoms occur in 60-74% of asthma patients and are markers of inadequate control of the disease. Various pathophysiological mechanisms are related to the worsening of asthma symptoms, OSAS being one of the most important factors. In patients with asthma, OSAS should be investigated whenever there is inadequate control of symptoms of nocturnal asthma despite the treatment recommended by guidelines having been administered. There is evidence in the literature that the use of continuous positive airway pressure contributes to asthma control in asthma patients with obstructive sleep apnea and uncontrolled asthma.

Objective: To identify the main predictive factors for obtaining a diagnosis of obstructive sleep apnea (OSA) in patients awaiting bariatric surgery. Methods: Retrospective study of consecutive patients undergoing pre-operative evaluation for bariatric surgery and referred for in-laboratory polysomnography. Eight variables were evaluated: sex, age, neck circumference (NC), BMI, Epworth Sleepiness Scale (ESS) score, snoring, observed apnea, and hypertension. We employed ROC curve analysis to determine the best cut-off value for each variable and multiple linear regression to identify independent predictors of OSA severity. Results: We evaluated 1,089 patients, of whom 781 (71.7%) were female. The overall prevalence of OSA-defined as an apnea/hypopnea index (AHI) ≥ 5.0 events/h-was 74.8%. The best cut-off values for NC, BMI, age, and ESS score were 42 cm, 42 kg/m2, 37 years, and 10 points, respectively. All eight variables were found to be independent predictors of a diagnosis of OSA in general, and all but one were found to be independent predictors of a diagnosis of moderate/severe OSA (AHI ≥ 15.0 events/h), the exception being hypertension. We devised a 6-item model, designated the NO-OSAS model (NC, Obesity, Observed apnea, Snoring, Age, and Sex), with a cut-off value of ≥ 3 for identifying high-risk patients. For a diagnosis of moderate/severe OSA, the model showed 70.8% accuracy, 82.8% sensitivity, and 57.9% specificity. Conclusions: In our sample of patients awaiting bariatric surgery, there was a high prevalence of OSA. At a cut-off value of ≥ 3, the proposed 6-item model showed good accuracy for a diagnosis of moderate/severe OSA.

Keywords: Polysomnography; Sleep apnea, obstructive; Bariatric surgery.

Objective: To assess the frequency of variation in forced expiratory volume in one second after bronchodilator use in a sample of patients with chronic obstructive pulmonary disease, correlating such variation with clinical and demographic variables and evaluating the frequency of response presented in forced vital capacity, slow vital capacity, inspiratory capacity, residual volume, airway resistance and specific airway conductance. Methods: A total of 64 patients with chronic obstructive pulmonary disease were submitted to whole body plethysmography, and reversibility of bronchoconstriction after the administration 400 µg of fenoterol was quantified. Results: A response in forced expiratory volume in one second was observed in 31% of the patients. Excluding patients presenting a response in forced expiratory volume in one second, 5% presented responses in 5 of the other 6 parameters, 10% presented responses in 4 parameters, 17.5% in 3 parameters, 27.5% in 2 parameters, and 25% in only 1 parameter. Conclusion: When included in the evaluation of bronchodilator response together with forced expiratory volume in one second, static lung volumes, airway resistance and airway conductance allowed a broader evaluation of those patients presenting a functional pharmacodynamic response. These results are in accordance with the observation that bronchodilator use provides clinical improvement and relief of dyspnea to many patients with chronic obstructive pulmonary disease, even to those in whom such treatment leads to no improvement in forced expiratory volume in one second.

Keywords: Pulmonary disease, chronic obstructive/drug therapy; Bronchodilator agents/therapeutic use; Airway resistance/drug effects; Respiratory function tests; Vital capacity; Forced expiratory volume

Objective: To investigate the extent to which exercise is associated with symptoms in patients with severe obstructive sleep apnea (OSA). Methods: We included subjects with an apnea-hypopnea index (AHI) > 30 events/h who completed validated sleep and exercise questionnaires. We compared symptom frequency/scores between exercisers and nonexercisers, adjusting for the usual confounders. Results: The sample included 907 nonexercisers and 488 exercisers (mean age, 49 ± 14 years; mean AHI, 53 ± 20 events/h; 81% men). Nonexercisers and exercisers differed significantly in terms of obesity (72% vs. 54%), the mean proportion of sleep in non-rapid eye movement stage 3 sleep (9 ± 8% vs. 11 ± 6%), and tiredness (78% vs. 68%). Nonexercisers had a higher symptom frequency/scores and poorer sleep quality. Adjustment for exercise weakened the associations between individual symptoms and the AHI, indicating that exercise has a mitigating effect. In binary logistic models, exercise was associated with approximately 30% lower adjusted questionnaire1 score > 2, tiredness; poor-quality sleep, unrefreshing sleep, and negative mood on awakening. Although the odds of an Epworth Sleepiness Scale score > 10 were lower in exercisers, that association did not withstand adjustment for confounders. Conclusions: Exercise is associated with lower frequency/intensity of symptoms in patients with severe OSA. Because up to one third of patients with severe OSA might exercise regularly and therefore be mildly symptomatic, it is important not to rule out a diagnosis of OSA in such patients.

Keywords: Sleep apnea syndromes; Exercise; Sleepiness; Polysomnography.

Objective: To determine the prevalence of obstructive sleep apnea syndrome (OSAS), as well as to identify factors associated with a greater risk of developing OSAS, among truck drivers. Methods: The study population comprised 209 truck drivers (mean age, 38.8 years; 98.5% males) at two branches of a transportation company. The mean body mass index was 26.5 ± 4.4 kg/m2. The participants completed questionnaires regarding sociodemographic data, physical activity and OSAS. The prevalence of OSAS was estimated using the Berlin Questionnaire, associations between OSAS and the factors studied being assessed through univariate and multivariate regression analysis. Results: The prevalence of OSAS in the population was 11.5%. Of the 209 truck drivers, 72 (34.5%) reported having fallen asleep while driving and 81 (38.7%) reported snoring. The following variables were found to present statistically significant associations with OSAS: informal employment (OR = 0.27; p = 0.01); body mass index ≥ 25 kg/m2 (OR = 13.64; p = 0.01); and poor sleep quality (OR = 3.00; p = 0.02). Conclusions: The prevalence of OSAS in this study was lower than that reported in other studies of truck drivers and yet higher that that observed for the general population. In addition, our results suggest that work characteristics, such as employment status, are associated with OSAS. These data show the relevance of considering work activity in studies of factors associated with OSAS.

Keywords: Sleep apnea, obstructive; Sleep disorders; Questionnaires.