Obstructive sleep apnea and pulmonary function in patients with severe obesity before and after bariatric surgery: a randomized clinical trial.

BACKGROUND: The increasing prevalence of obesity in both developed and developing countries is one of the most serious public health problems and has led to a global epidemic. Obesity is one of the greatest risk factors of obstructive sleep apnea (OSA), which is found in 60 to 70% of obese patients mainly due to the buildup of fat tissue in the upper portion of the thorax and neck. The aim of the present randomized clinical trial is to assess daytime sleepiness, sleep architecture and pulmonary function in patients with severe obesity before and after bariatric surgery. METHODS: This randomized, controlled trial, was designed, conducted, and reported in accordance with the standards of The CONSORT (Consolidated Standards of Reporting Trials) Statement. Patients were divided into a bariatric surgery group and control group. The clinical evaluation was performed at the Sleep Laboratory of the Nove de JulhoUniversity (Sao Paulo, Brazil) and consisted of the collection of clinical data, weight, height, body mass index (BMI), measurements of neck and abdomen circumferences, spirometry, maximum ventilatory pressure measurements, standard overnight polysomnography (PSG) and the administration of the Berlin Questionnaire and Epworth Sleepiness Scale. RESULTS: Fifty-two patients participated in the present study and performed PSG. Out of these, 16 underwent bariatric surgery. After surgery, mean BMI decreased from 48.15 ± 8.58 to 36.91 ± 6.67 Kg/m(2). Significant differences were found between the preoperative and postoperative periods regarding neck (p < 0.001) and waist circumference (p < 0.001), maximum inspiratory pressure (p = 0.002 and p = 0.004) and maximum expiratory pressure (p = 0.001 and p = 0.002) for women and men, respectively, as well as sleep stage N3 (p < 0.001), REM sleep (p = 0.049) and the apnea-hypopnea index (p = 0.008). CONCLUSIONS: Bariatric surgery effectively reduces neck and waist circumference, increases maximum ventilatory pressures, enhances sleep architecture and reduces respiratory sleep disorders, specifically obstructive sleep apnea, in patients with severe obesity. TRIAL REGISTRATION: THE PROTOCOL FOR THIS STUDY WAS REGISTERED WITH THE WORLD HEALTH ORGANIZATION (UNIVERSAL TRIAL NUMBER: U1111-1121-8873) and Brazilian Registry of Clinical Trials - ReBEC (RBR-9k9hhv).

Observational study on efficacy of negative expiratory pressure test proposed as screening for obstructive sleep apnea syndrome among commercial interstate bus drivers--protocol study.

BACKGROUND: Obstructive sleep apnea (OSA) is a respiratory disease characterized by the collapse of the extrathoracic airway and has important social implications related to accidents and cardiovascular risk. The main objective of the present study was to investigate whether the drop in expiratory flow and the volume expired in 0.2 s during the application of negative expiratory pressure (NEP) are associated with the presence and severity of OSA in a population of professional interstate bus drivers who travel medium and long distances. METHODS/DESIGN: An observational, analytic study will be carried out involving adult male subjects of an interstate bus company. Those who agree to participate will undergo a detailed patient history, physical examination involving determination of blood pressure, anthropometric data, circumference measurements (hips, waist and neck), tonsils and Mallampati index. Moreover, specific questionnaires addressing sleep apnea and excessive daytime sleepiness will be administered. Data acquisition will be completely anonymous. Following the medical examination, the participants will perform a spirometry, NEP test and standard overnight polysomnography. The NEP test is performed through the administration of negative pressure at the mouth during expiration. This is a practical test performed while awake and requires little cooperation from the subject. In the absence of expiratory flow limitation, the increase in the pressure gradient between the alveoli and open upper airway caused by NEP results in an increase in expiratory flow. DISCUSSION: Despite the abundance of scientific evidence, OSA is still underdiagnosed in the general population. In addition, diagnostic procedures are expensive, and predictive criteria are still unsatisfactory. Because increased upper airway collapsibility is one of the main determinants of OSA, the response to the application of NEP could be a predictor of this disorder. With the enrollment of this study protocol, the expectation is to encounter predictive NEP values for different degrees of OSA in order to contribute toward an early diagnosis of this condition and reduce its impact and complications among commercial interstate bus drivers. TRIAL REGISTRATION: Registro Brasileiro de Ensaios Clinicos (local acronym RBEC) [Internet]: Rio de Janeiro (RJ): Instituto de Informaçao Cientifica e Tecnologica em Saude (Brazil); 2010 - Identifier RBR-7dq5xx. Cross-sectional study on efficacy of negative expiratory pressure test proposed as screening for obstructive sleep apnea syndrome among commercial interstate bus drivers; 2011 May 31 [7 pages]. Available from http://www.ensaiosclinicos.gov.br/rg/RBR-7dq5xx/.

Sleep study, respiratory mechanics, chemosensitive response and quality of life in morbidly obese patients undergoing bariatric surgery: a prospective, randomized, controlled trial.

BACKGROUND: Obesity is a major public health problem in both developed and developing countries alike and leads to a series of changes in respiratory physiology. There is a strong correlation between obesity and cardiopulmonary sleep disorders. Weight loss among such patients leads to a reduction in these alterations in respiratory physiology, but clinical treatment is not effective for a long period of time. Thus, bariatric surgery is a viable option. METHODS/DESIGN: The present study involves patients with morbid obesity (BMI of 40 kg/m2 or 35 kg/m2 to 39.9 kg/m2 with comorbidities), candidates for bariatric surgery, screened at the Santa Casa de Misericórdia Hospital in the city of Sao Paulo (Brazil). The inclusion criteria are grade III morbid obesity, an indication for bariatric surgery, agreement to participate in the study and a signed term of informed consent. The exclusion criteria are BMI above 55 kg/m2, clinically significant or unstable mental health concerns, an unrealistic postoperative target weight and/or unrealistic expectations of surgical treatment. Bariatric surgery candidates who meet the inclusion criteria will be referred to Santa Casa de Misericórdia Hospital and will be reviewed again 30, 90 and 360 days following surgery. Data collection will involve patient records, personal data collection, objective assessment of HR, BP, neck circumference, chest and abdomen, collection and analysis of clinical preoperative findings, polysomnography, pulmonary function test and a questionnaire on sleepiness. DISCUSSION: This paper describes a randomised controlled trial of morbidly obese patients. Polysomnography, respiratory mechanics, chemosensitive response and quality of life will be assessed in patients undergoing or not undergoing bariatric surgery. TRIAL REGISTRATION: The protocol for this study is registered with the Brazilian Registry of Clinical Trials - ReBEC (RBR-9k9hhv).