Sleep and Sleep-disordered Breathing in Adults with Predominantly Mild Obstructive Airway Disease

Abstract

Predictors of oxyhemoglobin desaturation during sleep in persons both conditions, previously termed an "overlap syndrome" having OAD with and without SAH. Polysomnography and spirome- (11). Chaouat and coworkers have suggested that the preva- try results from 5,954 participants in the Sleep Heart Health Study lence of OAD in patients with SAH exceeds the prevalence were analyzed. OAD was defined by a FEV1/FVC value less than of OAD in the general population (12). Conversely, an unex- 70%. Assessment of SAH prevalence in OAD was performed using pectedly high prevalence of SAH has also been reported in thresholds of respiratory disturbance index (RDI) greater than 10 patients with OAD (13). and greater than 15. A total of 1,132 participants had OAD that A putative association between OAD and SAH could be was predominantly mild (FEV1/FVC 63.81 6.56%, mean SD). due to the role of tobacco smoking. Some, but not all, studies SAH was not more prevalent in participants with OAD than in those have suggested that tobacco use is a risk factor for both without OAD (22.32 versus 28.86%, with and without OAD, respec- entities (14-20). In addition, OAD has been associated with tively, at RDI threshold values greater than 10; and 13.97 versus nocturnal hypoxemia, poor sleep quality, and insufficient or 18.63%, with and without OAD, respectively, at RDI threshold value disrupted sleep (21-25). The sleep-related physiologic distur- greater than 15). In the absence of SAH, the adjusted odds ratio for bances in patients with OAD may be relevant to the patho- sleep desaturation ( 5% total sleep time with saturation 90%) genesis of SAH. Some investigations have implied that these was greater than 1.9 when FEV1/FVC was less than 65%. Participants disturbances may be associated with abnormal ventilatory with both OAD and SAH had greater sleep perturbation and desatu- control and upper airway instability during sleep (26-31). A ration than those with one disorder. Generally mild OAD alone was number of studies have suggested that the presence of both associated with minimally altered sleep quality. We conclude that OAD and SAH leads to greater blood gas and pulmonary (1 ) there is no association between generally mild OAD and SAH; hemodynamic perturbations than found in individuals with (2 ) exclusive of SAH and after adjusting for demographic factors OAD or SAH alone (12, 32-35), thereby increasing risk for and awake oxyhemoglobin saturation, an FEV1/FVC value less than cor pulmonale. On the basis of these studies as well as data 65% is associated with increased risk of sleep desaturation; (3 ) suggesting a specific association between OAD and SAH, desaturation is greater in persons with both OAD and SAH com- some authors have suggested that a diagnostic evaluation for pared with each of these alone; and (4 ) individuals with generally OAD should be conducted in all SAH patients (12). mild OAD and without SAH in the community have minimally per- Prior studies of breathing during sleep and objectively turbed sleep. assessed sleep quality in patients with OAD have evaluated relatively small samples, have focused on patients with severe