Hannemann L, Meier-Hellmann A, Specht M, Spies C, Reinhart K
Klinik für Anaesthesiologie und operative Intensivmedizin, Freie Universität Berlin.
Anaesthesist. 1993 Jan;42(1):11-4.
The lack of a rise in global O2 consumption (VO2) after increased O2 supply (DO2) (negative O2-flux test) is an indication of adequate tissue oxygenation. We were interested in whether a negative O2-flux test precludes an improvement in regional tissue oxygenation. The pH of the gastric mucosa (pHi) is considered a sensitive marker for tissue hypoxia. Method. The study was approved by the ethics committee of our hospital. In 12 intensive-care patients with septic shock, gastric pHi was determined (Trip'TGS catheter, Tonometrics) in addition to measuring O2-transport-related parameters via invasive haemodynamic monitoring. Following the initial measurement, a further increase in the O2 supply via volume substitution was attempted in all already hyperdynamic patients with DO2 in the upper-normal range. Results. Volume substitution with 1.246 +/- 594 ml colloid resulted in an increase in pulmonary capillary wedge pressure from 14 +/- 2 mm Hg to 17 +/- 1 mm Hg (P < 0.01). All patients had an increase in DO2 from 755 +/- 192 ml/min.m2 to 846 +/- 236 ml/min.m2 (P < 0.05). There was no significant change in VO2, at 153 +/- 28 ml/min.m2 before and 156 +/- 35 ml/min.m2 after volume administration. However, pHi increased from 7.19 +/- 0.08 to 7.24 +/- 0.08 (P < 0.01). DISCUSSION AND CONCLUSION. The low pHi at the time of the initial measurement shows that regional tissue hypoxia may be present even in patients with an above-normal O2 supply > 600 ml/min.m2. Apparently, the lack of rise in global O2 consumption after increased O2 supply does not exclude a regional improvement in tissue oxygenation. The less invasive pHi measurement is an additional useful monitoring procedure for the optimisation of regional tissue oxygenation in critically ill patients.
在增加氧气供应（DO2）后全球氧气消耗（VO2）未升高（负氧通量试验）表明组织氧合充足。我们感兴趣的是负氧通量试验是否排除了局部组织氧合的改善。胃黏膜pH值（pHi）被认为是组织缺氧的敏感标志物。方法。本研究经我院伦理委员会批准。在12例感染性休克的重症监护患者中，除了通过有创血流动力学监测测量与氧输送相关的参数外，还测定了胃pHi（Trip'TGS导管，Tonometrics）。在初始测量后，对所有DO2处于正常上限范围的高动力患者尝试通过容量替代进一步增加氧气供应。结果。用1.246±594ml胶体进行容量替代导致肺毛细血管楔压从14±2mmHg增加到17±1mmHg（P<0.01）。所有患者的DO2从755±192ml/min·m2增加到846±236ml/min·m2（P<0.05）。容量输注前后VO2无显著变化，分别为153±28ml/min·m2和156±35ml/min·m2。然而，pHi从7.19±0.08增加到7.24±0.08（P<0.01）。讨论与结论。初始测量时的低pHi表明，即使在氧气供应高于正常>600ml/min·m2的患者中也可能存在局部组织缺氧。显然，增加氧气供应后全球氧气消耗未升高并不排除局部组织氧合的改善。侵入性较小的pHi测量是优化重症患者局部组织氧合的另一种有用的监测方法。
