呼气负压技术检测呼气流速受限在慢性阻塞性肺疾病中的应用

目的:应用呼气负压技术(NEP)检测慢性阻塞性肺疾病(COPD)患者的呼气流速受限(EFL)。方法:94例COPD患者在坐位及卧位时应用NEP方法检测EFL,即在患者潮气呼吸时于患者口部施加一个-5cmH2O的负压,通过比较施加负压前后的潮气流速-容积曲线来检测EFL。采用EFL五分法与经典的一秒钟用力呼气量(FEV1)方法进行比较。结果:55例COPD患者在坐位及卧位时均存在EFL;23例患者仅于卧位时存在EFL;16例患者坐位及卧位均无EFL。EFL五分法与经典FEV1方法判断肺功能损害程度较一致。EFL五分法与COPD患者的主观呼吸困难分级有更好的相关性。结论:①COPD患者在平静呼吸时EFL普遍存在;②NEP提供了一种简便、快速、无创的方法来检测EFL;③EFL五分法与COPD患者的呼吸困难分级有很好的相关性。

Detection of expiratory flow limitation by expiratory negative pressure technique in chronic obstructive pulmonary disease

Objective To detect the expiratory flow limitation (EFL) with a new simple technique, expiratory negative pressure technique (NEP) in patients with chronic obstructive pulmonary disease (COPD). Methods EFL was assessed by applying -5 cmH2O negative pressure at the mouth during the tidal expiration. The flow-volume loops were recorded during a control breath, followed by a test breath during which the negative pressure was applied at the onset of expiration and maintained throughout the expiration. The flow-volume loops during the test breath with NEP were compared with the control breath. And five-point EFL was compared with the criteria forced expiratory volume in one second (FEV1) method. Using this technique, 94 patients with COPD were studied at the sitting and supine position. Results Fifty-five patients were flow-limited both at the sitting and at the supine position. Twenty-three cases were flow-limited only at the supine position. And sixteen patients were not flow-limited either seated or supine. The results obtained from this new technique and the criteria based on FEV1 were similar for judging the lung dysfunction degree. And there lied better consistency between EFL and subjective dyspnea grade in COPD patients. Conclusions There is a high prevalence of expiratory flow limitation in COPD patients at rest, particularly at the supine position. The NEP technique provides a simple, rapid and reliable method for the detection of expiratory flow limitation. And there is good consistency between EFL and subjective dyspnea grade in COPD patients.