Perioperative changes in cerebral ischemic markers in the cerebrospinal fluid after preoperative nimodipine treatment.

Abstract

Elderly patients with previous organ damage are at risk for minor neurologic deficits after major surgery. Spinal catheter analgesia is used whenever possible in this group and enables regular cerebrospinal fluid (CSF) sampling. Nimodipine, a calcium blocker, may have neuroprotective effects. We examined whether preoperative treatment with nimodipine affects ischemic markers in the CSF during extracranial surgery. We performed a prospective, randomized, placebo-controlled, double-blind study in patients (ASA III or IV, 65-85 years) that underwent elective implantation surgery of the hip joint with intrathecal catheter anesthesia. Starting 15 h before surgery, patients received either 30 microg x kg(-1) h(-1) of nimodipine (n = 20) or 0.9% saline solution (placebo, n = 23) as a central venous infusion. The concentrations of neuron-specific enolase, hypoxanthine, creatine-kinase, lactate and pH in the CSF were determined before and immediately after surgery as well as 6 and 24 h after surgery. Before surgery, the baseline CSF pH was normal in all patients. Immediately after surgery it fell significantly to 7.08 +/- 0.29 in the placebo group and non-significantly to 7.27 +/- 0.38 in the treatment group; all values were normalized at 6 and 24 h after surgery in both groups. In the placebo group, lactate levels rose significantly from 1.48 +/- 0.28 mmol l(-1) before surgery to 1.77 +/- 0.27 mmol l(-1) immediately after surgery, and to 2.03 +/- 0.32 mmol l(-1) 24 h after surgery. In the treatment group, lactate concentrations remained stable up to 6 h after surgery (1.55-1.62 mmol l-1), while an increase to 2.10 +/- 0.48 mmol l(-1) was observed 24 h after the operation. Neuron-specific enolase, hypo-xanthine and creatine-kinase showed no change in either group. In conclusion, preoperative nimodipine treatment reduced intraoperative CSF acidosis and delayed surgery-related increases in lactate concentration in the CSF by several hours in elderly, comorbid patients at risk for minor postoperative neurologic deficits.