Obesity-Hypoventilation Syndrome

Key Features

• Hypoventilation resulting from blunted ventilatory drive and increased mechanical load imposed on the chest

• Obstructive sleep apnea in most

• Patients with obesity-hypoventilation syndrome have a higher risk of complications in the perioperative period, including respiratory failure, intubation, and heart failure

Clinical Findings

• Obesity

• Lethargy, headache, hypersomnolence

• Loud snoring if accompanied by obstructive sleep apnea

• Dyspnea often absent

• Signs of cyanosis and cor pulmonale may be found

• Many patients have erythrocytosis

Diagnosis

• Diagnostic criteria

  • BMI > 30

  • Arterial partial pressure of carbon dioxide > 45 mm Hg

  • Exclusion of other causes of alveolar hypoventilation

• Arterial blood gas measurements confirm daytime hypoxemia and hypercapnia, which improve with voluntary hyperventilation

• Nocturnal sleep study helpful to evaluate for obstructive sleep apnea

Treatment

• Weight loss is key

• Noninvasive positive pressure ventilation is helpful in many patients

• Sedative hypnotics, opioids, and alcohol should be avoided

• If present, obstructive sleep apnea must be treated aggressively (eg, nasal CPAP)

• Treatment of comorbid conditions