The Acute Clinic, Department of Anesthesiology and Critical Care Medicine, Oslo University Hospital, Norway.
Acta Anaesthesiol Scand. 2012 Feb;56(2):200-9. doi: 10.1111/j.1399-6576.2011.02572.x. Epub 2011 Nov 21.
The aim of this study was to evaluate how tissue gas tensions and tissue metabolites measured in situ can detect hypoperfusion and differentiate between aerobic and anaerobic conditions during hemorrhagic shock. We hypothesized that tissue PCO(2) (PtCO(2)) would detect hypoperfusion also under aerobic conditions and detect anaerobic metabolism concomitantly with or earlier than other markers.
Prospective experimental animal study with eight anesthetized pigs subjected to a continuous blood loss ∼8% of total blood volume per hour until death. We measured cardiac index, organ blood flows, and tissue levels of PO(2), PCO(2), glucose, pyruvate, lactate, and glycerol in intestine, liver, kidney, and skeletal muscle.
With reduction in blood flow to the organs under aerobic conditions, PtCO(2) increased ∼1-4 kPa from baseline. With the onset of tissue hypoxia there was a pronounced increase of PtCO(2), lactate, lactate-pyruvate (LP) ratio, and glycerol. Tissue pH and bicarbonate decreased significantly, indicating that metabolic acid was buffered by bicarbonate to generate CO(2).
Moderate tissue hypoperfusion under aerobic conditions is associated with increased PtCO(2), in contrast to metabolic parameters of ischemia (lactate, LP ratio, and glycerol) which remain low. From the onset of ischemia there is a much more rapid and pronounced increase in PtCO(2), lactate, and LP ratio. PtCO(2) can be used as a marker of hypoperfusion under both aerobic and anaerobic conditions; it gives an earlier warning of hypoperfusion than metabolic markers and increases concomitantly with or earlier than other markers at the onset of tissue anaerobiosis.
本研究旨在评估组织气体张力和原位测量的组织代谢物如何检测出血性休克期间的低灌注并区分有氧和无氧条件。我们假设组织 PCO2（PtCO2）在有氧条件下也能检测到低灌注，并与其他标志物同时或更早地检测到无氧代谢。
对 8 头麻醉猪进行前瞻性实验性动物研究，每小时持续失血约 8%总血容量，直至死亡。我们测量了心指数、器官血流量以及肠、肝、肾和骨骼肌中的 PO2、PCO2、葡萄糖、丙酮酸、乳酸和甘油水平。
在有氧条件下器官血流量减少时，PtCO2 从基线增加了约 1-4 kPa。随着组织缺氧的发生，PtCO2、乳酸、乳酸-丙酮酸（LP）比值和甘油显著增加。组织 pH 和碳酸氢盐显著下降，表明代谢性酸中毒通过碳酸氢盐缓冲生成 CO2。
有氧条件下的中度组织低灌注与 PtCO2 增加相关，而缺血的代谢参数（乳酸、LP 比值和甘油）仍然较低。从缺血开始，PtCO2、乳酸和 LP 比值的增加更快、更明显。PtCO2 可作为有氧和无氧条件下低灌注的标志物；它比代谢标志物更早地发出低灌注警告，并且在组织无氧发生时与其他标志物同时或更早地增加。
