Apnea

Obesity Hypoventilation Syndrome

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Obesity Hypoventilation Syndrome, Obesity-Hypoventilation Syndrome, Pickwickian syndrome

  • See Also
  1. Central Sleep Apnea
  2. Obstructive Sleep Apnea
  • Definitions
  1. Obesity-Hypoventilation Syndrome (OHS, Pickwickian syndrome)
    1. Central Sleep Apnea in morbidly obese patients
    2. Results from Chemoreceptor hyporesponsiveness
    3. Charactized by chronic hypercarbia, Hypoxia and polycythemia, as well as Hypersomnolence
  • Epidemiology
  1. Prevalence: 0.4% of adults in U.S.
  2. Age of diagnosis (typically delayed): 40 to 60 years old
  • Findings
  1. Morbid Obesity (BMI >40 kg/m2)
  2. Sleep disordered breathing
  3. Daytime arterial hypercapnia (PaCO2>=45 mmHg)
    1. Commonly presents with adute on chronic hypercapni Respiratory Failure
  4. Sleep Study with apnea/hypopnea index
    1. Moderate Obstructive Sleep Apnea (>=5 events/hour): 90% of OHS patients
    2. Severe Obstructive Sleep Apnea (>=15 events/hour): 70% of OHS patients
  • Associated Conditions
  1. Obstructive Sleep Apnea
    1. Obstructive Sleep Apnea (OSA) is comorbid in 90% of Obesity-Hypoventilation Syndrome patients (severe in 70%)
    2. However, only 10 to 20% of patients with OSA have Obesity-Hypoventilation Syndrome
  2. Cardiopulmonary Disease (see complications below)
    1. Heart Failure
    2. Coronary Artery Disease
    3. Pulmonary Hypertension
  • Management
  1. Positive Airways Pressure (CPAP or BiPAP)
    1. Use BiPap for patients with Central Sleep Apnea (by Sleep Study)
    2. Paradoxically, nighttime Central Sleep Apnea is less common in OHS
      1. Most OHS patients are treated with CPAP for Obstructive Sleep Apnea
  2. Weight loss
    1. Bariatric Surgery is often indicated
  • Complications
  1. Heart Failure
  2. Pulmonary Hypertension
  3. Increased mortality
  • References
  1. Masa (2019) Eur Respir Rev 28(151): 180097 +PMID: 30872398 [PubMed]