呼吸过滤器对肺通气功能检查结果的影响

Effect of respiratory filters on measurements of pulmonary ventilatory function

目的探讨呼吸过滤器对肺通气功能检查结果的影响。方法采用随机交叉对照的方法,对50例常规功能检查的受试者进行试验,比较应用与不应用呼吸过滤器测定肺通气功能的差异。结果应用Cosmed过滤器后,FVC、FEV1、PEF的测定值均比不用过滤器时有所下降,其平均差异分别为(-75.42±134.20)ml(P=0.011)、(-66.67±99.11)ml(P=0.003)和(-260.42±319.76)ml/s(P=0.001),其余指标均无明显变化。应用Microgard过滤器后,FVC、PEF、FEF200-1200的测定值较不用过滤器时下降,其平均差异分别为(-72.31±157.84)ml(P=0.028)、(-425.38±488.81)ml/s(P=0.0001)和(-193.08±371.5)ml/s(P=0.014),其余指标均无明显变化。应用Cosmed和Microgard过滤器对肺通气功能指标无显著影响。结论Cosmed和Microgard呼吸过滤器均引起呼气流速与容量的减小,然而这种差异很小,在通气功能指标的个体重复性变化范围内,并不会影响临床肺功能的诊断与评级。

Objective To determine the effect of Respiratory filters on clinical measurements of ventilatory function. Methods Random Cross-control Trial was used. Fifty randomly selected subjects referred to our laboratory for routine functional evaluation were performed Forced Vital Capacity tests to compare the difference between with filters and without. Results The addition of Cosmed filters to the pulmonary function testing equiptment caused significant decreases in FVC（-75.42±134.20ml, P=0.011）、FEV1（-66.67±99.11ml,P=0.003） and PEF（-260.42±319.76ml/s, P=0.001）, and significant decreases in FVC（-72.31±157.84ml, P=0.028）, FEF200-1200（-193.08±371.5ml/s, P=0.014）and PEF（-425.38±488.81ml/s, P=0.0001） were caused with Microgard filters. Both filters did not affect other indices of lung function. There is no significant difference between the impacts of Cosmed and Microgard filters on ventilatory function. Conclusions The Cosmed and Microgard filters caused significant reductions in expiratory flow and volume measurements,however, the changes were within the intraindividual variability of repeated measurements for the spirometric indices and no appreciable classification error was found in diagnosis and interpretation of pulmonary ventilatory function.