Carroll G C
Department of Anesthesiology, Rush-Presbyterian-St Luke's Medical Center, Chicago, IL.
J Clin Monit. 1992 Apr;8(2):101-6. doi: 10.1007/BF01617426.
To evaluate the potential of trend monitoring of end-tidal PCO2 (PETCO2) to detect pulmonary embolization, the capnograms of 24 mechanically ventilated patients were monitored during simulation of 1-ml pulmonary embolization by inflation of the balloons of their pulmonary artery catheters. Within 1 minute of balloon inflation, PETCO2 showed an exponential decrease to a new equilibrium. This response is characteristic of a CO2 wash-out curve produced by a step increase in dead space. Because of a steady baseline, the depression of the trend line during balloon inflation was apparent to a naive reader repeatedly in 20 of the 24 patients (sensitivity, 85%; specificity, 94%; positive predictive value, 98%; negative predictive value, 89%), despite a small mean decrease in PETCO2 (2 +/- 1.97 mm Hg). The PETCO2 trend curve did not reliably allow detection of balloon inflation in 4 patients whose capnograms were poorly formed. In conclusion, during constant ventilation, PETCO2 trend curve monitoring might provide clinically useful "on line" information regarding pulmonary embolization.
为评估呼气末二氧化碳分压（PETCO2）趋势监测检测肺栓塞的潜力，在通过肺动脉导管球囊充气模拟1毫升肺栓塞过程中，对24例机械通气患者的二氧化碳波形图进行了监测。球囊充气后1分钟内，PETCO2呈指数下降至新的平衡状态。这种反应是由死腔量突然增加产生的二氧化碳洗脱曲线的特征。由于基线稳定，在24例患者中的20例中，球囊充气期间趋势线的下降对未经培训的观察者来说是明显的（敏感性为85%；特异性为94%；阳性预测值为98%；阴性预测值为89%），尽管PETCO2平均下降幅度较小（2±1.97毫米汞柱）。在4例二氧化碳波形图形态不佳的患者中，PETCO2趋势曲线不能可靠地检测到球囊充气。总之，在持续通气期间，PETCO2趋势曲线监测可能为肺栓塞提供临床上有用的“在线”信息。
