Macnaughton P D, Morgan C J, Denison D M, Evans T W
Dept of Clinical Physiology, Royal Brompton National Heart and Lung Hospital, London, UK.
Eur Respir J. 1993 Feb;6(2):231-6.
A simple method for measuring lung volume and carbon monoxide transfer factor (TLCO) by a rebreathing technique was assessed in nine healthy volunteers undergoing intermittent positive pressure ventilation (IPPV). Measurements of TLCO, alveolar volume (VA) and carbon monoxide transfer coefficient (KCO) made at three inspired oxygen concentrations (21, 35 and 70%) during IPPV were compared to those obtained during spontaneous breathing. The effects of 10 cmH2O positive end expiratory pressure (PEEP) were also studied. Pulmonary capillary blood volume (Vc) and the diffusing capacity of the alveolar capillary membrane (Dm) were derived. There was a close correlation between measurements of TLCO during IPPV (TLCOIPPV) and spontaneous breathing (TLCOSV) (r = 0.92). Ventilated TLCO was 64 +/- 8% of spontaneously breathing TLCO. There was a close agreement between ventilated and spontaneously breathing measurements of KCO (r = 0.95; mean difference 0.14, 95% limits of agreement +0.37 to -0.09 mmol.min-1 x kPa-1 x l-1). Vc was 92 +/- 23 ml during spontaneous breathing and 72 +/- 21 ml during IPPV (p < 0.05). PEEP of 10 cmH2O significantly increased functional residual capacity (2.3 +/- 0.5 to 3.5 +/- 0.6 l) and decreased TLCO (5.9 +/- 1.0 to 5.3 +/- 1.2 mmol.min-1 x kPa-1), KCO (1.7 +/- 0.2 to 1.1 +/- 0.3 mmol.min-1 x kPa-1 x l-1) and Vc (82 +/- 22 to 56 +/- 20 ml). Dm did not change with PEEP. This simple method may be a useful means of assessing gas exchange and lung volume in ventilated subjects. It showed that PEEP increased lung volume but reduced TLCO and that this reduction appeared to be due to a reduction in capillary blood volume.
一种通过重复呼吸技术测量肺容积和一氧化碳转运因子（TLCO）的简单方法，在9名接受间歇性正压通气（IPPV）的健康志愿者中进行了评估。将IPPV期间在三种吸入氧浓度（21%、35%和70%）下测量的TLCO、肺泡容积（VA）和一氧化碳转运系数（KCO）与自主呼吸期间获得的测量值进行比较。还研究了10 cmH2O呼气末正压（PEEP）的影响。推导了肺毛细血管血容量（Vc）和肺泡毛细血管膜弥散能力（Dm）。IPPV期间的TLCO测量值（TLCOIPPV）与自主呼吸期间的TLCO测量值（TLCOSV）之间存在密切相关性（r = 0.92）。通气时的TLCO为自主呼吸时TLCO的64±8%。通气和自主呼吸时KCO的测量值之间存在密切一致性（r = 0.95；平均差异0.14，95%一致性界限为+0.37至-0.09 mmol·min-1·kPa-1·l-1）。自主呼吸时Vc为92±23 ml，IPPV期间为72±21 ml（p < 0.05）。10 cmH2O的PEEP显著增加功能残气量（从2.3±0.5升至3.5±0.6升），并降低TLCO（从5.9±1.0降至5.3±1.2 mmol·min-1·kPa-1）、KCO（从1.7±0.2降至1.1±0.3 mmol·min-1·kPa-1·l-1）和Vc（从82±22降至56±20 ml）。Dm不随PEEP变化。这种简单方法可能是评估通气受试者气体交换和肺容积的有用手段。结果表明，PEEP增加了肺容积，但降低了TLCO，且这种降低似乎是由于毛细血管血容量减少所致。
