Intrathecal lactate concentration and spinal cord injury in thoracoabdominal aortic surgery.

Objective: The aim of this study was to evaluate the role of lactate as an early predictor of spinal cord injury during thoracoabdominal aortic aneurysm repair.

Design: Observational study.

Setting: University hospital.

Participants: Sixteen consecutive patients (10 men and 6 women) scheduled to undergo thoracoabdominal aortic aneurysm repair were enrolled in the study. All patients were affected by atherosclerotic aneurysmal pathology.

Interventions: None.

Measurements And Main Results: During surgery, the authors simultaneously withdrew samples of cerebrospinal fluid and arterial blood to evaluate pO(2), pCO(2), pH, and lactate concentration. Samples were collected at 5 fixed times during and after surgery: T1 (before aortic cross-clamping), T2 (15 minutes after clamping), T3 (just before unclamping), T4 (end of surgery), and T5 (4 hours after the end of surgery). Lactate levels in cerebrospinal fluid rose consistently during aortic cross-clamping (T1 = 1.89 mmol/L, T2 = 2.21 mmol/L, T3 = 2.88 mmol/L, T4 = 3.655 mmol/L, and T5 = 3.16 mmol/L). Lactate concentrations in the cerebrospinal fluid were significantly higher in the 4 patients who developed neurologic injury, even at T1 (before surgery), than in those who did not end in spinal cord injury with the 4 highest values belonging to the 4 patients who later developed spinal cord injury.

Conclusions: This study has the potential to elucidate the time course of early lactate level elevation during thoracoabdominal aortic aneurysm repair and its clinical use in predicting the development of postoperative spinal cord injury.