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

BACKGROUND CONTEXT: Induced hypotension is widely used intraoperatively to reduce blood loss and to improve the surgical field during spinal surgery.

PURPOSE: To determine the effect of milrinone on induced hypotension during spinal surgery in elderly patients.

STUDY DESIGN/

SETTING

Prospective randomized clinical trial.

PATIENT SAMPLE: Forty patients, 60 to 70 years old, ASA I-II, who underwent elective lumbar fusion surgery.

OUTCOME MEASURES: Intraoperative hemodynamics, blood loss, hourly urine output, and grade of surgical field.

METHODS

All 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.

RESULTS

During 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).

CONCLUSIONS

We conclude that milrinone is useful for induced hypotension in elderly patients during spinal surgery.