Validation of an insulin infusion nomogram for intensive glucose control in critically ill patients

To evaluate the effectiveness, safety, and associated patient outcomes of a simplified, nurse-directed insulin nomogram designed to achieve intensive blood glucose level control (target range 90-144 mg/dl).

Prospective study with a retrospective control group.

A medical-surgical intensive care unit (ICU) in a quaternary care, university-affiliated hospital in an urban center.

Eighty-six critically ill adult patients (aged>or=18 yrs) requiring blood glucose control, with 42 in the retrospective control group and 44 in the prospective nomogram group.

Control patients received insulin subcutaneously or intravenously based on ad hoc insulin sliding scales; nomogram patients received intravenous insulin at a rate specified by the nomogram, based on capillary blood glucose levels measured at the bedside.

Insulin infusion in the prospective patient group was titrated by the bedside nurse based on a predefined nomogram to attain the target blood glucose level. The retrospective control group was used as a comparison to assess the safety and effectiveness of the nomogram. Fewer patients in the nomogram (32%) than control (67%) group had a diagnosis of diabetes mellitus on admission. Overall, blood glucose levels in the nomogram group were within the target range 52% of the time versus 20% in the control group (p<0.001). Morning blood glucose levels were significantly lower compared with the control group (mean+/-SD 128+/-32 vs 176+/-50 mg/dl, p<0.001). Nomogram patients achieved target blood glucose levels faster than control patients (median 15 vs 66 hrs, p<0.0001). This improved blood glucose control remained statistically significant after adjusting for baseline differences in diabetes status. Hyperglycemia occurred less often in the nomogram than the control group (14% vs 53%, p<0.0001), and hypoglycemia occurred more often (3.8% vs 2.2%, p=0.004). The frequency of severe hypoglycemia was similar in both groups (0.2% vs 0.4%, p=NS). Such control required slightly more blood glucose checks/day in the nomogram group (7.1+/-1.5 vs 5.8+/-1.1, p<0.001). No significant reduction was observed in duration of vasopressor or antibiotic therapy or in length of stay in the ICU.

This study demonstrated that intensive blood glucose control is achievable using a nurse-directed nomogram. This improved control was achieved, regardless of diabetes status of the patient, without substantially compromising safety or increasing resource use.