VANCOUVER, British Columbia (EGMN) – A significant number of hospitalized patients are at high risk for obstructive sleep apnea, but few have been evaluated for OSA, Dr. Sunita Kumar reported at the annual meeting of the American College of Chest Physicians.
Because OSA has been shown to increase the risk of adverse outcomes such as stroke and heart failure, screening inpatients might help prevent complications. However, Dr. Kumar noted, the diagnosis and treatment of OSA in hospitalized patients have not been shown to affect outcomes.
Of 195 inpatients surveyed over a 24-hour period at Loyola University Medical Center in Maywood, Illinois, 157 (81%) were found to be at high risk for OSA. Of those, 41 had undergone a previous sleep study, and of the 41 patients who had been evaluated, 31 were found to have OSA, said Dr. Kumar of the Division of Pulmonary and Critical Care Medicine at Loyola.
In comparison, 5% of the general population is estimated to have sleep apnea.
The patients had a mean age of 62 years, and 82% were older than 50 years. Their mean body mass index was 28 kg/m2, with 14% having a BMI over 35. More than half (59%) were men. Of the 31 patients with a previous diagnosis of OSA, 17 were using continuous positive airway pressure (CPAP), 1 had undergone surgery, and 13 were not receiving treatment, generally because of nontolerance of CPAP.
The patients were screened using the STOP-BANG questionnaire, which has high sensitivity for detecting a high risk of sleep apnea but is not very specific, Dr. Kumar reported. It has also not been validated in inpatients, she said, which was a limitation of the study. However, the STOP-BANG (snoring, tiredness, observed apnea, high blood pressure, body mass index, age, neck circumference, and gender) questionnaire has been reported to be of high quality for predicting OSA (Can. J. Anaesth. 2010;57:423-38). When these patients were evaluated using only the STOP portion of the survey, 65% were found to be at high risk.
The few previous studies that looked at OSA in hospitalized patients found the prevalence to be as high as 77% (J. Clin. Sleep Med. 2008;4:105-10; Sleep Breath. 2008;12:229-34).
The take-home point of the recent study might be that it is safer to make a presumptive diagnosis of OSA in inpatients, commented session moderator Dr. Rochelle Goldberg, president and chief medical officer of the American Sleep Apnea Association.
Also at the session, Dr. Dennis Auckley presented his study on the frequency of complications in 217 hospitalized patients divided into three groups: those with known OSA (36 patients, 17%), those determined to be at high risk using the STOP and Berlin questionnaires (106 patients, 49%), and those at low risk (75 patients, 35%) based on the questionnaires.
The patients’ mean age was 50 years. Those with known OSA had a mean BMI of 44, the high-risk patients had a mean BMI of 32, and the low-risk patients had a mean BMI of 28.
Dr. Auckley of Case Western Reserve University in Cleveland and his colleagues undertook their 4-month, prospective observational study to further explore earlier findings that patients with OSA experience more adverse outcomes in the perioperative setting (Chest 2008;133:1128-34).
In their study, 38% of those with diagnosed OSA, 22% of those at high risk, and 14% of the low-risk patients experienced complications. Hypoxemia was the most frequent complication. The difference in complication rate between the known OSA patients and the low-risk patients was significant, even after researchers controlled for age, diagnosis, and comorbidities.
Patients with sleep apnea more commonly experience complications, especially hypoxemia, while hospitalized, Dr. Auckley concluded. The questionnaires have not been validated in hospitalized patients, and the patients were not monitored by oximetry, which were two limitations of the study, he noted.
Dr. Kumar reported that she had no relevant financial conflicts. Dr. Auckley disclosed support from ResMed Corp., and Cephalon Inc., and has received equipment from Cleveland Medical Devices Inc. His current study received no funding.
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(EGMN)——在美国胸科医师学会2010年年会上，美国洛约拉大学肺病学与重症医学系的Sunita Kumar博士报告称，有相当数量的住院患者出现阻塞性呼吸睡眠暂停(OSA)的风险很高，但少有患者接受过OSA的评价。
鉴于现已证实OSA会增加患者出现不良结局的风险，如卒中和心衰，因此对住院患者进行OSA筛查可能有助于并发症的预防。不过，研究表明在住院患者中是否诊治OSA对于患者的转归并无影响。
研究者对位于美国伊利诺州梅伍德的洛约拉大学医学中心的195例住院患者进行了为期24 h的调查。患者平均年龄62岁，82%都在50岁以上。平均体重指数(BMI)为28 kg/m2，BMI大于35 kg/m2者占14%。男性受试者占59%。在之前已确诊患有OSA的31例患者中，17例接受了连续气道正压通气(CPAP)，1例接受了手术治疗，13例没有接受任何治疗，大多是因为不能耐受CPAP。
结果发现157例(81%)都存在OSA高风险。其中41例过去曾接受过睡眠检查，在接受过OSA评价的41例患者中，有31例都被证实患有OSA，而一般人群中估计只有5%患有睡眠呼吸暂停。
研究者采用STOP-BANG问卷对患者进行筛查，该问卷检测睡眠呼吸暂停高危患者的敏感性较高，但特异性不高，而且也没有在住院患者中进行过确证，这是这项研究的局限性之一。这项研究给我们的启示是对住院患者进行OSA的初步诊断可能更为安全。
会上，美国克利夫兰凯斯西储大学的Dennis Auckley博士也报告了一项4个月前瞻性观察研究的结果，其受试者为217例平均年龄为50岁的住院患者。研究者将受试者分成3组：已知患有OSA (36例，17%)、根据STOP和Berlin问卷判定为OSA高风险(106例，49%)、根据问卷判定为OSA低风险(75例，35%)。已知患有OSA组的平均BMI为44 kg/m2，高风险组为32 kg/m2，低风险组为28 kg/m2。研究者对这3组患者并发症的发生频率进行了评价，目的是进一步探讨之前的研究发现，即OSA患者围手术期不良结局的发生率更高 (Chest 2008;133:1128-34) 。
结果显示，已知患有OSA组、高风险组和低风险组分别有38%、22%和14%的患者出现了并发症。低氧血症是出现频率最高的并发症。即便是经年龄、诊断和合并症等因素校正之后，已知患有OSA组与低风险组在并发症发生率上的差异也具有统计学意义。
该研究表明，睡眠呼吸暂停患者在住院期间更容易出现并发症，尤其是低氧血症。不过，这项研究也存在两方面的局限性：其一是研究所采用的问卷没有在住院患者中进行过确证，其二是没有采用血氧计对患者进行监测。
Kumar博士声明无相关经济利益冲突。Auckley博士声明接受了ResMed Corp.和Cephalon Inc.的经费支持，并接受了Cleveland Medical Devices Inc.提供的设备。但这项研究没有接受任何资助。
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