Gazmuri R J, von Planta M, Weil M H, Rackow E C
Department of Medicine, UHS, Chicago Medical School, IL 60064.
Crit Care Med. 1989 Mar;17(3):237-40. doi: 10.1097/00003246-198903000-00007.
End-tidal PCO2 (PetCO2) is a quantitative indicator of pulmonary blood flow generated by precordial compression and therefore predicts resuscitability during CPR. A striking increase in PetCO2 follows return of spontaneous circulation. Since PaCO2 is closely related to alveolar PCO2 (PACO2) and therefore PetCO2, we hypothesized that PaCO2 may itself serve as an indicator of the blood flow generated during CPR. In a porcine model of cardiac arrest, PaCO2 during precordial compression was highly correlated with PetCO2 (r = .89), cardiac output (r = .72), and coronary perfusion pressure (CPP) (r = .74). In 14 successfully resuscitated animals, PaCO2, PetCO2, and CPP during precordial compression were significantly higher than in nine nonresuscitated animals. After restoration of spontaneous circulation, there was a marked increase in PaCO2 to levels exceeding control values, which corresponded to the sharp increase in PetCO2 that is characteristic of successful resuscitation. We therefore confirm that both PetCO2 and PaCO2 correspond to the pulmonary blood flow and therefore cardiac output which is generated by precordial compression during CPR. Moreover, both serve as prognosticators of cardiac resuscitability and early indicators that spontaneous circulation has been restored.
呼气末二氧化碳分压（PetCO2）是胸外按压产生的肺血流量的定量指标，因此可预测心肺复苏期间的可复苏性。自主循环恢复后，PetCO2会显著升高。由于动脉血二氧化碳分压（PaCO2）与肺泡二氧化碳分压（PACO2）密切相关，进而与PetCO2密切相关，我们推测PaCO2本身可能是心肺复苏期间产生的血流的指标。在猪心脏骤停模型中，胸外按压期间的PaCO2与PetCO2（r = 0.89）、心输出量（r = 0.72）和冠状动脉灌注压（CPP）（r = 0.74）高度相关。在14只成功复苏的动物中，胸外按压期间的PaCO2、PetCO2和CPP显著高于9只未复苏的动物。自主循环恢复后，PaCO2显著升高至超过对照值的水平，这与成功复苏特有的PetCO2急剧升高相对应。因此，我们证实PetCO2和PaCO2均与肺血流量相对应，因此也与心肺复苏期间胸外按压产生的心输出量相对应。此外，两者均可作为心脏可复苏性的预后指标以及自主循环已恢复的早期指标。
