Flow‐pressure looping during plethysmography in wheezy infants
Flow‐pressure looping during plethysmography in wheezy infants
复制标题
喘息婴儿体积描记术中的流量-压力循环
作者：
C. Beardsmore;C. Maayan;E. Bar‐Yishay;Simon Godfrey
当呼吸的空气保持在体温和湿度时，在全身容积描记仪测量气道阻力时，在一些婴儿中注意到流量-压力关系的呼气部分有明显的循环。对13例不同程度气道阻塞婴儿的调查显示，环的严重程度与特定气道导度（SGaw）呈负相关（r = 0.72）。在流量和压力之间的相位滞后角（θ）的正切与从部分强制呼气流量-容积曲线获得的强制呼气时间常数(t)之间发现了更强的相关性（r = 0.85）。这种关系可以从肺在呼气过程中表现为一个简单的电阻-电容网络的模型中预测出来。这表明，循环是喘息婴儿呼气时小气道关闭的结果，随之而来的是肺阻力增加和时间常数延长。
Marked looping of the expiratory portion of the flow‐pressure relationship was noted in some infants during measurements of airway resistance in a whole‐body plethysmograph while the respired air was maintained at body temperature and humidity. An investigation of 13 infants who had varying degrees of airway obstruction showed that there was a negative correlation (r = 0.72) between the severity of the looping and specific airway conductance (SGaw). An even stronger correlation (r = 0.85) was found between the tangent of the angle of phase lag between flow and pressure (θ) and the forced expiratory time constant (t) obtained from the partial forced expiratory flow‐volume curve. Such a relationship would be predicted from a model in which the lung behaved as a simple electrical resistance‐capacitance network during expiration. It is suggested that the looping is the result of small airway closure during expiration in wheezy infants, with a consequent rise in resistance and prolongation of the time constant of the lung.