Heldt G P, Peters R M
Chest. 1978 Nov;74(5):492-6. doi: 10.1378/chest.74.5.492.
We describe a nonrecirculating helium-rebreathing method providing rapid and simple measurement of the functional residual capacity (FRC) in spontaneously breathing subjects and patients receiving mechanical ventilation. Results of triplicate determinations in 24 normal subjects revealed a repeatability of +/- 5.2 percent of the measured FRC, results similar to those predicted for these subjects. Results in six additional subjects were not significantly different from those obtained with a standard method using helium equilibration in the pulmonary function laboratory. Triplicate determinations in eight patients after cardiac surgery demonstrated similar repeatability. In 22 other patients studied after open-heart surgery, the FRC fell more in those who could not be weaned than in those who could be weaned from the respirator. Since an increase in FRC is the goal of therapy with positive end-expiratory pressure, this method should be useful in determining the efficacy of a particular level of positive end-expiratory pressure.
我们描述了一种非循环式氦气再呼吸法，可快速、简便地测量自主呼吸受试者和接受机械通气患者的功能残气量（FRC）。对24名正常受试者进行的三次重复测定结果显示，测量的FRC的重复性为±5.2%，结果与这些受试者的预测结果相似。另外六名受试者的结果与在肺功能实验室使用氦气平衡的标准方法所获得的结果无显著差异。对八名心脏手术后患者进行的三次重复测定显示出相似的重复性。在另外22名接受心脏直视手术后研究的患者中，无法脱机的患者的FRC下降幅度比能够脱机的患者更大。由于功能残气量增加是呼气末正压治疗的目标，因此该方法应有助于确定特定水平呼气末正压的疗效。
