Dimitriou G, Greenough A, Kavadia V
Department of Child Health, King's College Hospital, London, UK.
Physiol Meas. 1996 Feb;17(1):37-42. doi: 10.1088/0967-3334/17/1/004.
Respiratory distress syndrome (RDS) is characterized by lungs having collapsed alveoli (atelectasis) which reduces the volume of the gas-containing spaces of the lung. It seems likely, therefore, that measurement of lung volume might discriminate between infants with severe respiratory failure due to RDS and those with minimal respiratory distress. To test this hypothesis, lung volume was measured at end expiration, that is functional residual capacity (FRC), in 40 infants (median gestational age 29 weeks, range 24-35) all mechanically ventilated from birth. FRC was measured using a helium gas dilution technique at a median of 3 h of age. The infants were divided into two groups according to their FRC results: group A (n = 29) low FRC (FRC < 24 ml kg-1) and group B (n = 11) normal FRC (FRC > or = 24 ml kg-1). The clinicians were unaware of the FRC results. There was no significant difference in the gestational age or birthweight of the two groups, but group A were characterized by a significantly greater proportion requiring surfactant replacement therapy (p < 0.01), a higher maximum peak inspiratory pressure (p < 0.01) and inspired oxygen requirement (p < 0.01). A low FRC had 79% sensitivity and 91% specificity in predicting a requirement for surfactant replacement therapy. We conclude that measurement of FRC in the first hours of life does allow discrimination of disease severity.
呼吸窘迫综合征（RDS）的特征是肺部出现肺泡萎陷（肺不张），这会减少肺内含气空间的容积。因此，测量肺容积似乎有可能区分因RDS导致严重呼吸衰竭的婴儿和呼吸窘迫轻微的婴儿。为了验证这一假设，对40名（中位胎龄29周，范围24 - 35周）出生后均接受机械通气的婴儿在呼气末测量肺容积，即功能残气量（FRC）。FRC在中位年龄3小时时采用氦气稀释技术进行测量。根据FRC结果将婴儿分为两组：A组（n = 29）FRC低（FRC < 24 ml/kg），B组（n = 11）FRC正常（FRC ≥ 24 ml/kg）。临床医生不知道FRC结果。两组的胎龄或出生体重无显著差异，但A组的特点是需要表面活性剂替代治疗的比例显著更高（p < 0.01）、最大吸气峰压更高（p < 0.01）以及吸氧需求更高（p < 0.01）。低FRC在预测表面活性剂替代治疗需求方面的敏感性为79%，特异性为91%。我们得出结论，在出生后的最初几个小时测量FRC确实能够区分疾病的严重程度。
