Implementation of an intraoperative glycemic control protocol for cardiac surgery in a high-acuity academic medical center: an observational study.

STUDY OBJECTIVE

To examine the effect on morbidity and mortality of an established intraoperative insulin protocol in cardiac surgical patients.

DESIGN

Retrospective observational study.

SETTING

Single-center, 782 bed, metropolitan academic hospital.

PATIENTS

1,616 adult patients undergoing cardiac surgical procedures with cardiopulmonary bypass (CPB).

INTERVENTIONS

An intraoperative, intravenous (IV) insulin protocol designed to maintain blood glucose values less than 150 mg/dL was implemented.

MEASUREMENTS

Blood glucose was evaluated on entry to the operating room, every 30 minutes during CPB, and at least once after discontinuation of CPB. Blood glucose values were followed postoperatively, as dictated by institutional policy.

MAIN RESULTS

Intraoperative predictors of 30-day mortality using multivariate logistic regression included hyperglycemia on initiation of CPB (OR 1.0, P = 0.05). The strongest predictor of 30-day mortality was the development of postoperative renal failure requiring hemodialysis (OR 3.26, P = 0.001).

CONCLUSIONS

Implementation of an intraoperative IV insulin protocol, while associated with improved glycemic control, was not associated with improved outcomes. While improved glycemic control on initiating CPB was associated with decreased 30-day mortality, the effect was small. Implementation of our insulin protocol was highly associated with decreased renal failure postoperatively. Further prospective studies are warranted to better establish causality.