The effect of milrinone on induced hypotension in elderly patients during spinal surgery: a randomized controlled trial

Background contextInduced hypotension is widely used intraoperatively to reduce blood loss and to improve the surgical field during spinal surgery.PurposeTo determine the effect of milrinone on induced hypotension during spinal surgery in elderly patients.Study design/settingProspective randomized clinical trial.Patient sampleForty patients, 60 to 70 years old, ASA I-II, who underwent elective lumbar fusion surgery.Outcome measuresIntraoperative hemodynamics, blood loss, hourly urine output, and grade of surgical field.MethodsAll patients were randomized to group M or N. The study drug was infused after perivertebral muscle retraction until complete interbody fusion. In group M, 50 μg/kg/min of milrinone was infused over 10 minutes as a loading dose followed by 0.6 μg/kg/min of milrinone as a continuous dose. In group N, an identical volume of normal saline was infused in the same fashion. This study was not funded by commercial or other sponsorship and the authors confirm no conflicts of interest, financial or otherwise.ResultsDuring infusion of the study drug, the systolic and mean blood pressures were maintained within adequate limits of induced hypotension in group M. Intraoperative blood loss was 445.0±226.5 mL in group M and 765.0±339.2 mL in group N (p=.001). Hourly urine output was 1.4±0.6 mL in group M and 0.8±0.2 mL in group N (p<.001). The grade of the surgical field was better in group M than in group N (p=.004).ConclusionsWe conclude that milrinone is useful for induced hypotension in elderly patients during spinal surgery.