Intrathecal lactate to predict spinal cord ischemia in major abdominal surgery

Introduction

The aim was to evaluate the role of intrathecal lactate as an early predictor of spinal cord injury during thoracoabdominal aortic aneurysmectomy. Forty-four consecutive patients were scheduled to undergo thoracoabdominal aortic aneurysmectomy. Two patients had a type B dissecting aneurysm; all other 42 patients suffered from degenerative aneurysm.

Methods

During surgery, samples of cerebrospinal fluid and arterial blood were simultaneously withdrawn to evaluate lactate concentration. Samples were collected at five fixed times during and after surgery: T1 (beginning of the intervention), T2 (15 minutes after aortic cross-clamping), T3 (just before unclamping), T4 (end of surgery), and T5 (4 hours after the end of surgery).

Results

Mean lactate levels in cerebrospinal fluid rose consistently from the beginning of the intervention steadily until after surgery (T1 = 1.83 mmol/l, T2 = 2.10 mmol/l, T3 = 2.72 mmol/l, T4 = 3.70 mmol/l, T5 = 4.31 mmol/l). Seven patients developed spinal cord injury; two of them had delayed injury occurring 24 hours after the end of surgery; the remaining five had early onset. In this group of five patients, preoperative cerebrospinal fluid lactate levels were significantly (P = 0.04) higher than those of the other 40 patients preoperatively (2.12 ± 0.35 vs. 1.79 ± 0.29 mmol/l).

Conclusion

The preoperative cerebrospinal lactate concentration is elevated in patients who will develop early-onset spinal cord injury after thoracoabdominal aortic aneurysmectomy. This may allow a better stratification of these patients, suggesting a more aggressive strategy of spinal cord function preservation and possibly guaranteeing them a better outcome.