Effect of Bi-Level Positive Airway Pressure (BIPAP) Ventilation on Gas Exchange, Body Mass Index, and Body Composition in Patients with Obesity Hypoventilation Syndrome


1 Pulmonary Ward, Bamdad Respiratory and Sleep Research Center, Isfahan University of Medical Sciences, Isfahan, Iran

2 Department of Internal Medicine, Medical School, Isfahan University of Medical Sciences, Isfahan, Iran.


Background: This study aimed to assess the outcomes of bi-level positive airway pressure (BIPAP) therapy among patients with obesity hypoventilation syndrome (OHS).
Materials and Methods: In this prospective observational study, a total of 30 patients with OHS, who were subjected to BIPAP therapy, were included. The peripheral capillary oxygen saturation (SPO2), partial pressure of carbon dioxide (PCO2), body mass index (BMI), and body composition indices, including total body fat (TBF), total body protein (TBP), total body mineral (TBM), and total body water (TBW), were measured using standard procedures at baseline and one week, one month, and six months after the onset of treatment. Changes in the variables over time were evaluated using repeated measures analysis of variance (ANOVA). The correlation between changes in the body composition indices and changes in gas exchange was also assessed by Pearson’s correlation coefficient test at three time points from the baseline.
Results: The results revealed that all study variables, except for TBF, changed significantly during the study in both males and females (p <0.001). There was a significant positive association between changes in PCO2 and changes in TBM after six months (r=0.4, p <0.05), whereas a significant inverse correlation was found between changes in PCO2 and changes in TBW after six months (r=-0.39, p <0.05). However, no significant correlation was found between changes in gas exchange and changes in BMI or other body composition indices after six months.
Conclusion: The present results indicated no significant association between the improvement of gas exchange and changes in BMI, TBP, and TBF during the study. However, further large-scale studies are required to examine the effects of BIPAP therapy on body composition in patients with OHS.