Obesity Hypoventilation Syndrome

摘要

Obesity hypoventilation (OHS) or Pickwickian syndrome are terms used to describe the clinical syndrome characterised by extreme obesity, somnolence, cor pulmonale and awake hypercapnic respiratory failure. These patients have marked depression of both their hypercapnic and hypoxic respiratory drives manifesting with abnormal breathing during both sleep and wakefulness (Rochester and Enson, 1974). Inspiratory muscle weakness (Pankow et al 1997), concomitant lung disease (Bradley et al 1986 ) and impaired load compensation (Lopata and Onal 1982) have all, at various times, been put forward to explain why patients with this syndrome develop awake hypercapnia. Until relatively recently, the role that upper airway obstruction during sleep plays in this syndrome was not fully appreciated. However, once it was identified that severe upper airway obstruction could, in its own right, cause respiratory failure, it became necessary to re-evaluate both the mechanisms underlying the development of awake hypercapnia, as well as the appropriate treatment approaches.