Prospective Study of Postoperative Glycemic Control with a Standardized Insulin Infusion Protocol after Infrainguinal Bypass and Open Abdominal Aortic Aneurysm Repair

Abstract

Background: The aim of this study is to examine the effect of moderate postoperative glycemic control in diabetic and nondiabetic patients undergoing infrainguinal bypass (INFRA) or open abdominal aortic aneurysm (OAAA) repair.

Methods: In a single center prospective study, we investigated postoperative glycemic control using a standardized insulin infusion protocol after elective INFRA bypass (n = 53, 62%) and OAAA repair (n = 33, 38%) between January 2013 and March 2015. The primary end point was optimal glycemic control, defined as having ≥85% of blood glucose values within the 80-150 mg/dL target range. Suboptimal glycemic control was defined as <85% of blood glucose values within the blood glucose target range. Secondary end points included in-hospital and 30-day surgical site infection (SSI) rates, composite adverse events, length of stay (LOS), and hospital cost.

Results: Optimal glycemic control was achieved more commonly after OAAA repair than INFRA bypass (85% vs. 64%, P = 0.04). Moderate hypoglycemia (<70 mg/dL) was observed in 32 (37%) patients, while severe hypoglycemia (<50 mg/dL) was observed in 6 (7%) patients. SSI at 30 days was more common after INFRA bypass (n = 15, 29%) than OAAA repair (n = 2, 6%) (P = 0.01). In-hospital (6% vs. 6%, P = 1.0) and 30-day (24% vs. 22%, P = 1.0) SSI rates were similar for optimal versus suboptimal glycemic control patients after INFRA bypass. In-hospital (4% vs. 0%, P = 1.0) and 30-day (4% vs. 0%, P = 1.0) SSI rates were similar for optimal versus suboptimal glycemic control patients after OAAA repair. The percentage of blood glucose > 250 mg/dL was similar for patients with and without SSI (3% vs. 2%, P = 0.36). Adverse cardiac and pulmonary events after INFRA bypass were similar between groups (9% vs. 21%, P = 0.23; 0% vs. 5%, P = 0.36, respectively). Adverse cardiac and pulmonary events after OAAA repair were similar between groups (2% vs. 0%, P = 1.0; 4% vs. 0%, P = 1.0, respectively). Mean LOS was significantly lower in patients with optimal glycemic control after INFRA bypass (4.2 vs. 7.3 days, P = 0.02). Mean LOS was similar after OAAA repair for patients with optimal and suboptimal control (5.8 vs. 6.4 days, P = 0.46). Inpatient hospital costs after INFRA bypass were lower for the group with optimal (median $25,012, interquartile range [IQ] range $21,726-28,331) versus suboptimal glycemic control (median $28,944, IQ range 24,773-41,270, P = 0.02).

Conclusions: Postoperative hyperglycemia is common after INFRA bypass and OAAA repair and can be effectively ameliorated with an insulin infusion protocol. The protocol was low risk with reduced LOS and cost after INFRA bypass. Complications including SSI were not reduced in patients with optimal perioperative glycemic control.