Evaluation of intensive insulin therapy

Introduction

Intensive insulin therapy has been shown to improve outcomes in critically ill patients [1]. We evaluated a protocol aimed at achieving a blood glucose concentration of 4–6 mmol/l [2] in patients in an adult cardiothoracic intensive care unit.

Methods

Records of 552 consecutive patient admissions over a 6-month period were reviewed and compared with 523 patients admitted over a similar time prior to introduction of the protocol.

Results

Age (median 64 years), sex and APACHE II scores (median 12) and reasons for admission were not significantly different between the groups. Use of intravenous insulin infusions increased from 57% to 87% of patients (P < 0.01) and median insulin infusion rate increased from 0.4 to 1.6 units/hour (P < 0.01). The mean glucose concentration decreased from 8.3 to 7.2 mmol/l (P < 0.01) and the hyperglycaemic index [3] decreased from 2.2 to 1.1 mmol/l.

Intensive care length of stay decreased from 1.8 to 1.0 days (median, P < 0.01). Intensive care mortality was not significantly different (4.2% [post] vs 5.2% [pre], P > 0.05). There were no significant differences in requirements for blood transfusion, use of inotropes, haemofiltration or the number of patients with bilirubin concentration > 32 μmol/l. The area under the curve for C-reactive protein concentrations corrected for length of stay was significantly lower in the intensive insulin protocol group (89.6 vs 62.0 mg/l, median, P < 0.01).

Conclusion

The mean glucose concentration was not in the target range despite a significant increase in insulin administration. In this observational study the use of an intensive insulin protocol was associated with decreased C-reactive protein concentrations and shorter intensive care unit length of stay. Tighter control of glucose concentrations may be necessary to achieve other previously described benefits of intensive insulin therapy [4].