Garlick R, Bihari D
Department Intensive Care, Middlesex Hospital, London.
Scand J Clin Lab Invest Suppl. 1987;188:47-52.
Monitoring clinical signs in unconscious patients provides only late information about cerebral deterioration. Ischaemia and hypoxia are the mechanisms of much of the damage. Cerebral blood flow (CBF) measurements provide direct evidence of ischaemia but are intermittent values for what may be an unstable situation. Continuous recordings of CBF and oxygenation are more likely to reveal harmful tendencies to ischaemia and hypoxia at an early stage than intermittent readings. We report our experience with intermittent and also continuous recording of the jugular venous bulb oxygen saturation (JVO2Sat) obtained by fibreoptic oximetry in a group of 10 head injured and 7 septic patients. Simultaneous measurements of CBF by an isotopic xenon clearance method were also made. The JVO2Sat has been suggested to be a reliable indicator of cerebral oxygenation, a low value being indicative of ischaemia. We discuss whether our findings support this statement. There are also variations in JVO2Sat with mean arterial blood pressure and intracranial pressure. These variations have important implications in the interpretation that can be made of one single value of JVO2Sat.
监测昏迷患者的临床体征只能提供关于脑功能恶化的滞后信息。缺血和缺氧是造成大部分损伤的机制。脑血流量（CBF）测量能提供缺血的直接证据，但对于可能不稳定的情况而言，这些测量值是间歇性的。与间歇性读数相比，连续记录CBF和氧合情况更有可能在早期发现缺血和缺氧的有害趋势。我们报告了在一组10例头部受伤患者和7例脓毒症患者中，通过光纤血氧测定法间歇性及连续记录颈静脉球血氧饱和度（JVO2Sat）的经验。同时还采用同位素氙清除法对CBF进行了测量。有人提出JVO2Sat是脑氧合的可靠指标，其值较低表明存在缺血。我们讨论了我们的研究结果是否支持这一说法。JVO2Sat还会随平均动脉血压和颅内压而变化。这些变化对于解释单个JVO2Sat值具有重要意义。
