Richardson P, Wyman M L, Jung A L
Crit Care Med. 1980 Nov;8(11):637-40. doi: 10.1097/00003246-198011000-00008.
Infants with respiratory distress syndrome (RDS) have insufficient surfactant systems and decreased functional residual capacity (FRC). This study attempts to relate FRC with severity of disease course. Measurements were made on 36 newborn infants with clinically diagnosed RDS. All infants were intubated and breathing on continuous positive airway pressure (CPAP) at the time studied. Infant CPAP levels were adjusted to 10 cm H2O; then FRC and arterial blood gas measurements were made. The infants were grouped according to their FRC per birth weight (BW). Volumes larger than or equal to 2 SD (larger than or equal to 42 ml/kg) of normal term infants not on CPAP were placed in the "large FRC" group. Volumes within +/- 2 SD (15-41 ml/kg) were in the "medium FRC: group, and infants smaller than or equal to 2 SD (< 14 ml/kg) of normal were in the "small FRC" group. The severity of RDS disease course was judged by the time duration the infants were managed on CPAP and FIO2 > 0.21 and by the maximum CPAP and FIO2 levels used. Twelve infants (33%) had small FRC, 18 (50%) medium FRC, and 6 (17%) large FRC. The time duration the infants with large FRC were on CPAP was significantly less than infants with medium FRC and the medium FRC group time was less than the small FRC group. The time duration on increased FIO2 and maximum FIO2 level used on the large FRC group was less than the medium and small FRC groups. Thus, FRC/BW appears related to the severity of RDS disease course. It is possible that the infants with FRC/BW larger than or equal to 42 ml/kg had pneumonia and were misdiagnosed as RDS. If so, FRC monitoring could have assisted in their diagnosis. BW and gestational ages of the groups were not different. Thus, variables other than these two play an important role in the degree of atelectasis occurring in infants with RDS. In patient management, where frequent changes in airway pressure and FIO2 are made, knowing the FRC/BW as well as blood gas values could aid the clinician in his choice of CPAP and FIO2 levels.
患有呼吸窘迫综合征（RDS）的婴儿肺表面活性物质系统不足，功能残气量（FRC）降低。本研究试图将功能残气量与病程严重程度联系起来。对36例临床诊断为RDS的新生儿进行了测量。在研究时，所有婴儿均已插管并通过持续气道正压通气（CPAP）进行呼吸。将婴儿的CPAP水平调整至10 cm H₂O；然后测量功能残气量和动脉血气。根据每出生体重（BW）的功能残气量对婴儿进行分组。未使用CPAP的足月儿功能残气量大于或等于正常均值2个标准差（大于或等于42 ml/kg）的婴儿被归入“大功能残气量”组。在正常均值±2个标准差（15 - 41 ml/kg）范围内的婴儿被归入“中功能残气量”组，小于或等于正常均值2个标准差（<14 ml/kg）的婴儿被归入“小功能残气量”组。根据婴儿使用CPAP和吸入氧浓度（FIO₂）>0.21的持续时间以及所使用的最大CPAP和FIO₂水平来判断RDS病程的严重程度。12例婴儿（33%）功能残气量小，18例（50%）功能残气量中等，6例（17%）功能残气量大。功能残气量大的婴儿使用CPAP的持续时间显著短于功能残气量中等的婴儿，而功能残气量中等组的时间又短于功能残气量小的组。功能残气量大的组使用高FIO₂的持续时间和所使用的最大FIO₂水平均低于功能残气量中等和小的组。因此，功能残气量/出生体重似乎与RDS病程的严重程度相关。有可能功能残气量/出生体重≥42 ml/kg的婴儿患有肺炎而被误诊为RDS。如果是这样，功能残气量监测可能有助于诊断。各组的出生体重和胎龄无差异。因此，除这两个因素外的其他变量在RDS婴儿发生肺不张的程度中起重要作用。在患者管理中，当频繁改变气道压力和FIO₂时，了解功能残气量/出生体重以及血气值有助于临床医生选择CPAP和FIO₂水平。
