Increased inspired oxygen concentration as a factor in improved brain tissue oxygenation and tissue lactate levels after severe human head injury
Increased inspired oxygen concentration as a factor in improved brain tissue oxygenation and tissue lactate levels after severe human head injury
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DOI：
10.3171/jns.1999.91.1.0001
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发表时间：
1999-07-01
影响因子：
4.1
通讯作者：
Bullock, R
中科院分区：
文献类型：
--
作者：
Menzel, M;Doppenberg, EMR;Bullock, R
Object.重型颅脑损伤患者早期脑血流障碍与脑组织氧供应不足有关，可能是缺血性脑损伤的重要原因。本研究的目的是测定重型颅脑损伤患者脑组织的PO 2、乳酸和葡萄糖，以确定通过增加吸入氧分数（FiO（2））来增加组织O-2的效果。除了对颅内压和脑灌注压进行标准监测外，作者还连续测量了22名重型颅脑损伤患者的脑组织PO 2、PCO 2、pH和温度。进行微透析以分析乳酸和葡萄糖水平。在一组12名患者中，通过分两个阶段将FiO（2）从35 +/- 5%提高到100%，PaO 2在6小时内升高到441 +/- 88 mmHg。对结果进行分析，并与12例接受标准呼吸治疗的对照组进行比较（平均PaO 2 136.4 +/- 22.1 mm Hg）。在6小时FiO（2）增强期间，接受O-2治疗的患者的平均脑PO 2水平增加至基线水平的359 +/- 39%，而平均透析液乳酸水平降低了40%（P < 0.05）。在此期间，脑组织中的葡萄糖水平表现出异质性过程，在整个观察期间，对照队列中的监测参数均未显示出显著变化。严重脑损伤后脑组织中乳酸水平显著升高是常见的。如在O-2治疗队列中所进行的那样，将PaO 2增加到高于血红蛋白饱和所需的水平，似乎可以改善脑组织中的O-2供应。在重型颅脑损伤后的早期，脑组织中增加的乳酸水平通过增加FiO（2）而降低。这可能意味着向有氧代谢的转变。
Object. Early impairment of cerebral blood flow in patients with severe head injury correlates with poor brain tissue O-2 delivery and may be an important cause of ischemic brain damage. The purpose of this study was to measure cerebral tissue PO2, lactate, and glucose in patients after severe head injury to determine the effect of increased tissue O-2 achieved by increasing the fraction of inspired oxygen (FiO(2)).Methods. In addition to standard monitoring of intracranial pressure and cerebral perfusion pressure, the authors continuously measured brain tissue PO2, PCO2, pH, and temperature in 22 patients with severe head injury. Microdialysis was performed to analyze lactate and glucose levels. In one cohort of 12 patients, the PaO2 was increased to 441 +/- 88 mm Hg over a period of 6 hours by raising the FiO(2) from 35 +/- 5% to 100% in two stages. The results were analyzed and compared with the findings in a control cohort of 12 patients who received standard respiratory therapy (mean PaO2 136.4 +/- 22.1 mm Hg).The mean brain PO2 levels increased in the O-2-treated patients up to 359 +/- 39% of the baseline level during the 6-hour FiO(2) enhancement period, whereas the mean dialysate lactate levels decreased by 40% (p < 0.05). During this O-2 enhancement period, glucose levels in brain tissue demonstrated a heterogeneous course, None of the monitored parameters in the control cohort showed significant variations during the entire observation period.Conclusions. Markedly elevated lactate levels in brain tissue are common after severe head injury. Increasing PaO2 to higher levels than necessary to saturate hemoglobin, as performed in the O-2-treated cohort, appears to improve the O-2 supply in brain tissue. During the early period after severe head injury, increased lactate levers in brain tissue were reduced by increasing FiO(2). This may imply a shift to aerobic metabolism.