New Guidelines on Obesity Hypoventilation Syndrome Released

By Kelly Young

The American Thoracic Society has issued new guidelines on evaluating and managing patients with obesity hypoventilation syndrome (OHS), defined as obesity in the presence of sleep disordered breathing and awake daytime hypercapnia after other causes of hypoventilation are ruled out.

The guidelines, published in the American Journal of Respiratory and Critical Care Medicine, include the following conditional recommendations:

• For obese patients with sleep-disordered breathing who have a high pretest probability of an OHS diagnosis, the authors suggest using PaCO2 to diagnose OHS. For patients with less than a 20% likelihood of having OHS, those with a serum bicarbonate level of less than 27 mmol/L might forego PaCO2.
• Stable, ambulatory patients with OHS may be treated with positive airway pressure during sleep.
• Those with both OHS and severe obstructive sleep apnea may start treatment with continuous positive airway pressure.
• For hospitalized patients with respiratory failure who are suspected of having OHS, the guidelines suggest starting noninvasive ventilation before hospital discharge until outpatient evaluation is arranged.

The guideline also includes a flowchart showing how a patient with suspected obesity hypoventilation syndrome should be managed.