title: [The analysis of risk factors correlated to pulmonary hypertension in obstructive sleep apnea syndrome patients during awake state].
abstract: OBJECTIVE
  To investigate the development of pulmonary hypertension in obstructive sleep apnea syndrome (OSAS) patients and to analyze the correlated factors.
  
  
  METHODS
  Pulmonary arterial pressure was monitored by right cardiac catheterization in 15 OSAS patients, and simultaneously polysomnography was performed. Blood gas analysis and lung function were also measured.
  
  
  RESULTS
  Pulmonary arterial pressure at awake state was correlated positively to mean maximal pulmonary pressure during sleep, body mass index (BMI) and hemoglobin (Hb), but negatively to PaO2, the percent predicted forced vital capacity (FVC% pred). Compared with OSAS patients without pulmonary hypertension, the BMI, PaCO2, and Hb of OSAS patients with pulmonary hypertension increased significantly, while FVC% pred and PaO2 decreased. Stepwise linear regression indicated that pulmonary arterial pressure at awake state was closely correlated with mean maximal pressure during sleep (beta = 0.35, standard error 0.10, R(2) = 0.89, P = 0.006) and PaCO2 (beta = 0.72, standard error 0.27, R(2) = 0.94, P = 0.022), and mean maximal pulmonary arterial pressure during sleep was closely correlated to PaCO2, BMI, PaO2 and the ratio of arterial pressure and oxygen concentration during rapid eye movement sleep (RDeltaPAP/DeltaSpO2). The regression equation was y' = -152.70 + 1.92 PaCO2 + 1.37 BMI + 0.67 PaO2 + 16.29 RDeltaPAP/DeltaSpO2.
  
  
  CONCLUSIONS
  Pulmonary arterial pressure increasing in OSAS patients is induced mainly by hypercapnia and hypoxia at day time, and related to forced ventilation capacity, BMI and the ratio of pulmonary arterial pressure and oxygen concentration variation during rapid eye movement sleep. There was no obvious relation between pulmonary arterial pressure and apnea index.
authors.affiliation: Institute of Respiratory Disease, First Affiliated Hospital of China Medical University, Shenyang 110001, China.
authors.forename: Xue-wei
authors.initials: XW
authors.lastname: Feng
authors.forename: Jian
authors.initials: J
authors.lastname: Kang
authors.forename: Hua
authors.initials: H
authors.lastname: Wen
authors.forename: Zan-feng
authors.initials: ZF
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Qiu-yue
authors.initials: QY
authors.lastname: Wang
authors.forename: Run-jiang
authors.initials: RJ
authors.lastname: Yu
mesh_terms: D000328:Adult; D015992:Body Mass Index; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010092:Oximetry; D017286:Polysomnography; D012123:Pulmonary Ventilation; D011669:Pulmonary Wedge Pressure; D012044:Regression Analysis; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000503:physiopathology