Drenger B, Parker S D, Frank S M, Beattie C
Department of Anesthesiology, Hadassah University Hospital, Jerusalem, Israel.
Anesthesiology. 1997 Jan;86(1):41-7. doi: 10.1097/00000542-199701000-00007.
Although ischemic injury to the spinal cord is a well-known complication of aortic surgery, no metabolic markers have been identified as predictors of an adverse outcome. This study evaluated the effect of cerebrospinal fluid (CSF) drainage, with and without distal femoral perfusion or moderate hypothermia on blood and CSF lactate concentrations and CSF pressure during thoracoabdominal aortic aneurysm surgery.
Three nonconcurrent groups of patients were studied prospectively: patients with normal body temperature (35 degrees C) but without distal femoral bypass (n = 6), patients with normal body temperature with bypass (n = 7), and patients with hypothermia (30 degrees C) and bypass (n = 8). In all patients, CSF pressure was recorded before, during, and after aortic cross-clamping. During the surgical repair, CSF drainage was performed using a 4-Fr intrathecal silicone catheter. Blood and CSF lactate concentrations were measured throughout the operation.
Significant increases in blood (490%) and CSF (173%) lactate concentrations were observed during and after thoracic aortic occlusion in patients with normothermia and no bypass (P < 0.02 and 0.05, respectively). Distal perfusion attenuated the increase in both blood and CSF lactate (P < 0.01), and a further reduction was achieved with hypothermia of 30 degrees C (P < 0.001). Patients who became paraplegic showed a greater increase in CSF lactate concentrations after aortic clamp release compared with those who suffered no neurological damage (275% vs. 123% of baseline; P < 0.05). Increased CSF pressure of 42-60% (P < 0.005) was noted soon after thoracic aortic occlusion, both with and without distal femoral bypass.
Incremental reductions in CSF lactate concentrations were achieved using distal femoral bypass and hypothermia. The reduction in CSF lactate correlated with the methods used to protect the spinal cord during thoracoabdominal aortic aneurysm surgery and was associated with better outcome. Decompression by distal bypass of the hemodynamic overload caused by aortic occlusion was insufficient to eliminate the acute increase in CSF pressure. Cerebrospinal fluid lactate measurements during high aortic surgery may accurately represent the spinal cord metabolic balance.
尽管脊髓缺血损伤是主动脉手术的一种常见并发症，但尚未发现代谢标志物可作为不良预后的预测指标。本研究评估了脑脊液（CSF）引流联合或不联合股动脉远端灌注或中度低温对胸腹主动脉瘤手术期间血液和脑脊液乳酸浓度及脑脊液压力的影响。
前瞻性研究了三组非同期患者：体温正常（35摄氏度）但无股动脉远端旁路的患者（n = 6）、体温正常且有旁路的患者（n = 7）以及低温（30摄氏度）且有旁路的患者（n = 8）。在所有患者中，记录主动脉交叉钳夹前、期间和后的脑脊液压力。手术修复期间，使用4Fr鞘内硅胶导管进行脑脊液引流。在整个手术过程中测量血液和脑脊液乳酸浓度。
在体温正常且无旁路的患者中，胸主动脉阻断期间及之后观察到血液（490%）和脑脊液（173%）乳酸浓度显著升高（分别为P < 0.02和0.05）。远端灌注减轻了血液和脑脊液乳酸的升高（P < 0.01），30摄氏度的低温进一步降低了乳酸水平（P < 0.001）。与未发生神经损伤的患者相比，发生截瘫的患者在主动脉钳夹松开后脑脊液乳酸浓度升高幅度更大（分别为基线的275%和123%；P < 0.05）。在胸主动脉阻断后不久，无论有无股动脉远端旁路，脑脊液压力均升高42 - 60%（P < 0.005）。
使用股动脉远端旁路和低温可逐步降低脑脊液乳酸浓度。脑脊液乳酸的降低与胸腹主动脉瘤手术期间保护脊髓的方法相关，且与更好的预后相关。通过远端旁路减轻主动脉阻断引起的血流动力学过载减压不足以消除脑脊液压力的急性升高。在高位主动脉手术期间测量脑脊液乳酸可能准确反映脊髓代谢平衡。
