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【科普】双水平PAP提高合并心力衰竭睡眠呼吸暂
NEW YORK (Reuters Health) Dec 31 - In patients with sleep apnea and heart failure, bilevel positive airway pressure (PAP) may be better than continuous positive airway pressure (CPAP) at improving left ventricular function.
In the December issue of Chest, researchers at The Ohio State University in Columbus report on a randomized controlled trial in which 24 patients with stable systolic dysfunction and newly recognized sleep apnea were treated for 3 months with either CPAP or bilevel PAP. As its name indicates, bilevel PAP delivers higher pressure during inspiration and lower during expiration.
According to lead author Dr. Rami N. Khayat and colleagues, both approaches effectively improved patients' apnea-hypopnea index, but the improvement in ejection fraction was 7.9% greater with bilevel PAP than with CPAP. The authors note that the mean 8.5% increase in ejection fraction in the 13 patients treated with bilevel PAP was statistically significant, while ejection fraction did not change significantly in the 11-patient CPAP group.
The difference in ejection fraction improvement was still significant after adjustment for body mass index, pressure level, adherence, and apnea severity, the investigators found.
"This study does not provide a specific mechanism for the superior cardiac effect of bilevel PAP," the authors acknowledge. They posit several theories, including the possibilities that CPAP may have a negative effect on stroke volume in patients with low filling pressures, or that bilevel PAP may prevent a reduction in stroke volume in such patients, or that bilevel PAP may be superior at "unloading the respiratory muscles and improving the work of breathing."
"This is the first study to compare the intermediate cardiovascular impact of bilevel PAP and CPAP in the treatment of obstructive sleep apnea in patients with systolic dysfunction, and so must be considered a first-stage (pilot) study," Dr. Khayat and colleagues conclude. "Larger studies with longer follow-up and more hemodynamic measurements are required to arrive at a strong conclusion about the superiority of bilevel PAP."
双水平PAP提高合并心力衰竭睡眠呼吸暂停患者射血分数
（纽约路透电）12月31日-在睡眠呼吸暂停合并心力衰竭患者，双水平气道正压通气(PAP)改善左室功能可能优于持续气道正压通气(CPAP)。
在Chest第12期，美国哥伦布俄亥俄州立大学研究人员进行了一项随机对照试验，24例收缩功能稳定的新发睡眠呼吸暂停病人给予为期3个月CPAP或bi-PAP；正如其名称所示，bi-PAP提供更高的吸气压、较低的呼气压。
据领导此项研究的Khayat和其同事介绍，这两种方法均有效地改善患者的呼吸暂停低通气指数，但bi-PAP改善射血分数优于CPAP 7.9％。作者指出，13个施行bi-PAP患者射血分数平均增幅为8.5％，具有统计学意义，而11例CPAP患者射血分数改变不明显。
研究人员发现，调整体重指数、压力水平、依从性和呼吸暂停严重性后，射血分数改善差异仍然显著。
作者承认，“这项研究并没有提供bi-PAP心脏卓越效果的一个具体机制”，他们提出几种理论，包括CPAP可能负面影响低灌注压患者心搏量，也可能bi-PAP会阻止心搏量下降，或bi-PAP在“减轻呼吸肌负荷、增进呼吸肌力”方面存在优势。
Khayat博士和同事总结，“这是首次进行比较研究bi-PAP和CPAP治疗收缩功能障碍阻塞性睡眠呼吸暂停患者心血管中间影响, 因此必须被视为第一阶段（试点）的研究，需要更多的研究与更长随访和更多的血流动力学测量才能达成bi-PAP优越性的一个强有力结论。”
Chest 2008;134:1162-1168. [标签:content1][标签:content2]
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作者:admin@医学,生命科学 2011-07-27 05:36
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