Nicardipine versus nitroprusside for deliberate hypotension during idiopathic scoliosis repair.

Study Objective: To compare coagulation, blood loss, and transfusion requirements between patients receiving nicardipine and nitroprusside for deliberate hypotension during idiopathic scoliosis repair.

Design: Prospective, randomized study.

Setting: University hospital.

Patients: 51 ASA physical status I patients presenting for spine fusion for idiopathic adolescent scoliosis.

Interventions: Patients were randomized to two groups to receive nicardipine or nitroprusside to maintain mean arterial pressure (MAP) between 55 and 65 mmHg.

Measurements: Blood loss, blood transfusions, and coagulation studies (thromboelastogram and platelet aggregation) before starting vasodilator, 30 minutes and 90 minutes after starting vasodilator, and 30 minutes after stopping vasodilator, were all recorded.

Main Results: There was no difference between the groups in blood loss [nicardipine = 1,129 cc (893 to 1,480), nitroprusside = 960 cc (704 to 1,473)] and only one patient required a nonautologous transfusion. There were no differences in prothrombin time (pT, partial thromboplastin time (pTT), platelet count, or platelet aggregation between groups. There were more episodes of severe hypotension (MAP <45 mmHg) in the nitroprusside group (0% vs. 28%, p = 0.0175). On average, patients in the nicardipine group spent 21 minutes less in the recovery room than did the nitroprusside group (p = 0.043).

Conclusions: Nitroprusside's effect on platelet aggregation produces no increase in blood loss compared with nicardipine. Nicardipine causes less transient severe hypotension than nitroprusside, although both drugs are acceptable choices for obtaining the goals of deliberate hypotension.