The effect of dexmedetomidine on renal function in patients undergoing cardiac valve replacement under cardiopulmonary bypass: A double-blind randomized controlled trial.

Study Objective: We attempted to explore the effect of Dex on renal function in patients with cardiac valve replacement under cardiopulmonary bypass (CPB).

Design: We designed a prospective, randomized, placebo-controlled, single-center, parallel-arm double-blind trial.

Setting: Operating room.

Patients: Seven-two eligible patients were randomly divided into Dex group and placebo group.

Interventions: Dexmedetomidine (Dex) (0.6μg·kg) was administered in patients of Dex group at 15min before anesthesia induction, followed by a treatment of 0.2μg·kg·h Dex until the end of operation. Patients in placebo group were treated with normal saline equally.

Measurements: The levels of serum urea nitrogen (BUN), creatinine (Cr), neutrophil gelatinase-associated lipocalin (NGAL), urine interleukin-8 (IL-18) and superoxide dismutase (SOD) activity were tested before anesthesia induction (T1) and after operation at 0, 12h, 24h and 72h (T2-5). The urine output during operation and the post-operative complication of acute kidney injury (AKI) were recorded.

Main Results: The levels of BUN and Cr were significantly increased at T5, and similar findings were found in the levels of NGAL and urine IL-18 at T3 and T4. The SOD activity was significantly declined at T2 and T3 in the two groups. The levels of BUN and Cr at T5 and the NGAL level at T3 and T4 were significantly lower in Dex group, comparable to placebo group. The intraoperative urine output was significantly increased and the postoperative incidence of AKI was significantly lower in Dex group.

Conclusions: Dex may attenuate the renal injury and decrease the incidence of AKI in patients undergoing cardiac valve replacement under CPB.