Van der Linden P, Rausin I, Deltell A, Bekrar Y, Gilbart E, Bakker J, Vincent J L
Department of Anesthesiology, Erasme University Hospital, Brussels, Belgium.
Anesth Analg. 1995 Feb;80(2):269-75. doi: 10.1097/00000539-199502000-00012.
The present study tested the hypothesis that, during acute bleeding, the development of tissue hypoxia might be reflected by an abrupt widening in arteriovenous gradient for PCO2 (AV PCO2) and for pH (AV pH) as accurately as by an increase in blood lactate levels. Twenty-four anesthetized (isoflurane 1.4% end-tidal), paralyzed, and mechanically ventilated dogs submitted to progressive hemorrhage were studied. Oxygen uptake (VO2) was derived from expired gas analysis and oxygen delivery (DO2) was calculated by the product of the thermodilution cardiac index and the arterial O2 content. During the first part of the protocol, VO2 remained stable as the progressive reduction in DO2 was associated with a corresponding increase in O2 extraction (O2ER). Blood lactate increased slightly but not significantly. AV PCO2 and AV pH increased significantly, essentially related to venous respiratory acidosis. The critical value of DO2 below which VO2 decreased was 8.95 +/- 1.60 mL.min-1.kg-1. Below this value, there was a marked increase in blood lactate and an abrupt widening in AV PCO2 and AV pH gradients. The critical value of DO2 obtained from blood lactate, AV PCO2 and AV pH were similar to those obtained from VO2 (8.60 +/- 1.12; 8.73 +/- 1.40; 8.78 +/- 1.37, respectively; P = not significant). A significant correlation was found, during the hemorrhage protocol, between blood lactate and AV PCO2 (r = 0.84; P < 0.001) or AV pH (r = 0.78; P < 0.001). Therefore, AV PCO2 and AV pH represent simple but reliable indicators of tissue hypoxia during hemorrhagic shock.
在急性出血期间，组织缺氧的发展可能通过动脉血与静脉血二氧化碳分压梯度（AV PCO2）和pH值梯度（AV pH）的突然增大来准确反映，其反映程度与血乳酸水平升高相当。对24只接受异氟烷（呼气末浓度1.4%）麻醉、肌肉松弛并进行机械通气的犬进行了研究，使其逐渐出血。氧摄取量（VO2）通过呼出气体分析得出，氧输送量（DO2）通过热稀释法心指数与动脉血氧含量的乘积计算得出。在实验方案的第一阶段，随着DO2的逐渐降低与氧摄取率（O2ER）的相应增加，VO2保持稳定。血乳酸略有升高但无显著变化。AV PCO2和AV pH显著升高，主要与静脉呼吸性酸中毒有关。VO2开始下降时的DO2临界值为8.95±1.60 mL·min-1·kg-1。低于此值时，血乳酸显著升高，AV PCO2和AV pH梯度突然增大。由血乳酸、AV PCO2和AV pH得出的DO2临界值与由VO2得出的临界值相似（分别为8.60±1.12；8.73±1.40；8.78±1.37；P = 无显著差异）。在出血实验过程中，发现血乳酸与AV PCO2（r = 0.84；P < 0.001）或AV pH（r = 0.78；P < 0.001）之间存在显著相关性。因此，AV PCO2和AV pH是失血性休克期间组织缺氧的简单但可靠的指标。
