Pulmonary and Sleep Disorders Unit, St. Vincent's University Hospital, Dublin, Ireland.
Curr Opin Pulm Med. 2011 Mar;17(2):79-83. doi: 10.1097/MCP.0b013e32834317bb.
Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) represent two of the most prevalent chronic respiratory disorders and cardiovascular diseases are major co-morbidities in both. Co-existence of both disorders (overlap syndrome) occurs in 1% of adults and overlap patients have worse nocturnal hypoxemia and hypercapnia than COPD and OSA patients alone. The present review discusses recent data concerning the pathophysiological and clinical significance of the overlap syndrome.
The severity of obstructive ventilatory impairment and hyperinflation, especially the inspiratory capacity to total lung capacity (TLC) ratio, correlates with the severity of sleep-related breathing disturbances. Early treatment with continuous positive airway pressure (CPAP) improves survival, reduces hospitalization and pulmonary hypertension, and also reduces hypoxemia. Evidence of systemic inflammation and oxidative stress in COPD and sleep apnea provides insight into potential interactions between both disorders that may predispose to cardiovascular disease. Long-term outcome studies of overlap patients currently underway should provide further evidence of the clinical significance of the overlap syndrome.
Studies of overlap syndrome patients at a clinical, physiological and molecular level should provide insight into disease mechanisms and consequences of COPD and sleep apnea, in addition to identifying potential relationships with cardiovascular disease.
慢性阻塞性肺疾病（COPD）和阻塞性睡眠呼吸暂停（OSA）是两种最常见的慢性呼吸系统疾病，心血管疾病是两者的主要合并症。两种疾病并存（重叠综合征）在成年人中占 1%，重叠综合征患者的夜间低氧血症和高碳酸血症比 COPD 和 OSA 患者更为严重。本综述讨论了关于重叠综合征的病理生理学和临床意义的最新数据。
阻塞性通气障碍和过度充气的严重程度，尤其是吸气量与肺总量（TLC）的比值，与睡眠相关呼吸障碍的严重程度相关。早期使用持续气道正压通气（CPAP）治疗可提高生存率、降低住院率和肺动脉高压，还可降低低氧血症。COPD 和睡眠呼吸暂停中存在的全身炎症和氧化应激证据，为这两种疾病之间可能存在的相互作用提供了深入了解，这些相互作用可能导致心血管疾病。目前正在进行的重叠综合征患者的长期预后研究，应该能进一步证明重叠综合征的临床意义。
对重叠综合征患者进行临床、生理和分子水平的研究，除了确定与心血管疾病的潜在关系外，还应深入了解 COPD 和睡眠呼吸暂停的发病机制和后果。
