Continuous positive airway pressure in clinically stable patients with mild-to-moderate obesity hypoventilation syndrome and obstructive sleep apnoea

Respirology. 2013 Oct;18(7):1135-42. doi: 10.1111/resp.12131.


Background and objective: The use of continuous positive airway pressure (CPAP) treatment in patients with obesity hypoventilation syndrome (OHS) and obstructive sleep apnoea (OSA) was evaluated, and factors that might predict CPAP treatment failure were determined.

Methods: A sleep study was performed in 29 newly diagnosed, clinically stable OHS patients. CPAP treatment was commenced if the apnoea-hypopnoea index was >15. Lung function, night-time oximetry, blood adipokine and C-reactive protein levels were assessed prospectively on enrollment and after 3 months. Treatment failure at 3 months was defined as daytime arterial partial pressure of carbon dioxide (PaCO(2)) >45 mm Hg and/or oxygen saturation (SpO(2)) <90% for >30% of the night-time oximetry study.

Results: All patients had severe OSA (median apnoea-hypopnoea index = 74.7 (62-100) with a nocturnal mean SpO(2) of 81.4 ± 7), and all patients were treated with CPAP. The percentage of time spent below 90% saturation improved from 8.4% (0.0-39.0%) to 0.3% (0.4-4.0%). Awake PaCO(2) decreased from 50 (47-53) mm Hg to 43 (40-45) mm Hg. Seven patients failed CPAP treatment after 3 months. PaCO(2) at 1 month and mean night-time SpO(2) during the first night of optimal CPAP were associated with treatment failure at 3 months (odds ratio 1.4 (1.03-1.98); P = 0.034 and 0.6 (0.34-0.93); P = 0.027).

Conclusions: CPAP treatment improves night-time oxygenation and daytime hypoventilation in selected clinically stable OHS patients who also have OSA. Patients with worse night-time saturation while on CPAP and higher daytime PaCO(2) at 1 month were more likely to fail CPAP treatment.

Trial registration: NCT00938977.

Keywords: continuous positive airway pressure; night-time oxyhaemoglobin saturation; obesity; obesity hypoventilation syndrome; obstructive sleep apnoea syndrome.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipokines / metabolism
  • Aged
  • C-Reactive Protein / metabolism
  • Carbon Dioxide / metabolism
  • Continuous Positive Airway Pressure / methods*
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Obesity Hypoventilation Syndrome / metabolism
  • Obesity Hypoventilation Syndrome / therapy*
  • Oximetry
  • Oxyhemoglobins / metabolism
  • Polysomnography
  • Prospective Studies
  • Retrospective Studies
  • Severity of Illness Index*
  • Sleep Apnea, Obstructive / metabolism
  • Sleep Apnea, Obstructive / therapy*
  • Treatment Outcome


  • Adipokines
  • Oxyhemoglobins
  • Carbon Dioxide
  • C-Reactive Protein

Associated data