Hypotensive epidural anaesthesia in patients with preoperative renal dysfunction undergoing total hip replacement.

BACKGROUND: Hypotensive anaesthesia does not impair renal function after surgery in normal patients but there are no reports of hypotensive anaesthesia in patients with chronic renal dysfunction (CRD). METHODS: From a database of 1893 consecutive patients undergoing total hip replacement (THR) under hypotensive epidural anaesthesia (HEA) from 1999 to 2004, 54 patients were identified with CRD (preoperative serum creatinine > or =124 micromol litre(-1)). Fifty matched pairs were identified for patients with normal renal function who have hypertension (n=50) or no hypertension (n=50). Changes in serum creatinine and blood urea nitrogen (BUN) were recorded daily for 3 days. Acute renal failure was defined as an increase in serum creatinine of 44 micromol litre(-1). RESULTS: The mean duration of hypotension (MAP<55 mm Hg) was 94 min (range 35-305 min). The mean age was 71 yr. All patients with a creatinine level of 124 micromol litre(-1) had a creatinine clearance of <40 ml min(-1) 1.73 m(-2) (range: 13-56). Patients with CRD received more crystalloid during surgery (1755 ml) than the other two groups (1435 ml) (P<0.001). Otherwise, all three groups were similar. No patients developed evidence of acute renal dysfunction immediately after or by 24 h after surgery. Three patients with CRD had an increase in creatinine of >44 micromol litre(-1) at 48 and 72 h after surgery in the setting of volume depletion (acute blood loss in two patients and early ileus in one). Renal function subsequently improved. CONCLUSION: HEA, per se, when carefully managed does not appear to predispose patients with CRD to acute renal failure after THR.