呼吸疾病研究所呼气相气道内负压法检测呼气流速受限在支气管哮喘患者中的应用

目的 探讨支气管哮喘(简称哮喘)患者呼气流速受限(EFL)与呼吸困难严重程度的相关性,观察吸入支气管扩张剂对哮喘患者EFL的影响.方法 采用呼气相气道内负压法(NEP)检测65例哮喘患者支气管扩张试验前、后(吸入沙丁胺醇400 μg)EFL情况.结果 65例哮喘患者中有26例(40%)出现EFL,其中11 例仅仰卧位时出现,15例仰卧位及坐位均出现.EFL和无EFL者(N-EFL)第一秒用力呼气容积占预计值百分比(FEV1占预计值%)分别为(52±15)%、( 77±18)%,两组比较差异有统计学意义(t＝5.822,P＜0.01).仅仰卧位有EFL(S-EFL)者和仰卧位、坐位均有EFL(SS-EFL)者FEV1占预计值%分别为(64±10)%、(43±12)%,两组比较差异有统计学意义(t值分别为2.283、6.694,P分别＜0.01、＜0.05).3分法和5分法EFL均与FEV1占预计值%呈负相关(r值分别为-0.637、-0.630,P均＜0.01).第一秒用力呼气容积(FEV1)与加拿大医学研究委员会推荐的呼吸困难严重程度分级标准(MRC评分)呈负相关(r=-0.501,P＜0.01),3分法和5分法EFL均与MRC评分呈正相关(r值分别为0.627、0.636,P均＜0.01).17例FEV1占预计值%＜70%并存在EFL的患者吸入沙丁胺醇后,9例EFL完全消失,5例从SS-EFL变为S-EFL,吸入沙丁胺醇后3分法和5分法EFL评分均较吸入前差异有统计学意义(t值分别为6.769、6.010,P均＜0.01).结论 与FEV1比较,EFL与哮喘患者呼吸困难严重程度相关性更强,可作为评价患者呼吸困难严重程度更可靠的客观指标.哮喘患者EFL可被吸入支气管扩张剂逆转,即表现为可逆性EFL.

Expiratory flow limitation detected by negative expiratory pressure in patients with bronchial asthma

OBJECTIVE: To evaluate the relationship between expiratory flow limitation (EFL) and chronic dyspnea and the effect of bronchodilator on EFL in patients with bronchial asthma. METHODS: Sixty-five patients with bronchial asthma were treated for pre- and post-bronchodilation of 400 microg salbutamol. RESULTS: EFL was detected in 26 (40%) of the 65 bronchial asthma patients, 11 only in supine position and 15 in both sitting and supine positions. There was a significant difference in FEV(1) percentage of the predicted value (FEV(1)% pred) between patients with and without EFL (t = 5.822, P < 0.01); the mean values of FEV(1)% pred in non-EFL group and EFL group was (77 +/- 18)% and (52 +/- 15)% respectively, and the value was lowest in patients who showed EFL both in seated and supine positions (43 +/- 12)%]; the mean values of FEV(1)% pred in those showing EFL only in sitting position (S-EFL) and both in sitting and supine position (SS-EFL) were (64 +/- 10)% and (43 +/- 12)% respectively (t = 2.283, 6.694 respectively, P < 0.01, < 0.05). Both three-point EFL and five-point EFL were significantly correlated with FEV(1) (r = -0.637, -0.630 respectively, all P < 0.01). There was a significant negative correlation between as proposed by the Canadian Medical Research Council (MRC) dyspnea scale and FEV(1) (r = -0.501, P < 0.01), and a significant positive correlation between dyspnea scale and 3-point EFL and five-point EFL (r = 0.627, 0.636 respectively, all P < 0.01). After salbutamol, of the 17 patients having EFL and < 70% pre FEV(1) at baseline, EFL completely reversed in 9, and changed from SS-EFL to S-EFL in 5, with significant improvements in 3-point and 5-point EFL as compared with before salbutamol (t = 6.769, 6.010 respectively, all P < 0.01). CONCLUSIONS: EFL as measured by NEP (negative expiratory pressure) technique may be more useful in the evaluation of dyspnea in bronchial asthma patients than routine lung function measurements. The EFL in bronchial asthma patients is reversible after bronchodilator administration.