title: Observational study on efficacy of negative expiratory pressure test proposed as screening for obstructive sleep apnea syndrome among commercial interstate bus drivers--protocol study.
abstract: 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
  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.
  
  
  CONCLUSIONS
  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.
  
  
  BACKGROUND
  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/.
authors.affiliation: Master's and Doctoral Degree Programs in Rehabilitation Sciences, Nove de Julho, University, Sao Paulo, Brazil.
authors.forename: Raquel P
authors.initials: RP
authors.lastname: Hirata
authors.forename: Isabella C
authors.initials: IC
authors.lastname: Aguiar
authors.forename: Sergio R
authors.initials: SR
authors.lastname: Nacif
authors.forename: Lilian C
authors.initials: LC
authors.lastname: Giannasi
authors.forename: Fernando S S
authors.initials: FS
authors.lastname: Leitão Filho
authors.forename: Israel R
authors.initials: IR
authors.lastname: Santos
authors.forename: Salvatore
authors.initials: S
authors.lastname: Romano
authors.forename: Newton S
authors.initials: NS
authors.lastname: Faria
authors.forename: Paula N
authors.initials: PN
authors.lastname: Nonaka
authors.forename: Luciana M M
authors.initials: LM
authors.lastname: Sampaio
authors.forename: Claudia S
authors.initials: CS
authors.lastname: Oliveira
authors.forename: Paulo T C
authors.initials: PT
authors.lastname: Carvalho
authors.forename: Geraldo
authors.initials: G
authors.lastname: Lorenzi-Filho
authors.forename: Alberto
authors.initials: A
authors.lastname: Braghiroli
authors.forename: Adriana
authors.initials: A
authors.lastname: Salvaggio
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Insalaco
authors.forename: Luis V F
authors.initials: LV
authors.lastname: Oliveira
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D008403:Mass Screening; D024821:Metabolic Syndrome / Q000453:epidemiology*; D018986:Motor Vehicles; D019370:Observation; D017286:Polysomnography; D015203:Reproducibility of Results; D012107:Research Design; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology; D013147:Spirometry; D011795:Surveys and Questionnaires