The effect of tighter glucose control on outcome

Introduction

Evidence is accumulating that tight glucose control improves outcome in critically ill patients. This study was performed to evaluate the effect of lower blood glucose levels in critically ill patients on outcome.

Patients and methods

The unit is a 10-bed closed-format medical–surgical ICU in a general hospital. Starting in 2003 insulin was prescribed to ICU patients using several nurse-driven computerised protocols, each subsequent protocol aiming for lower glucose levels. From February 2004 until May 2005 protocol 1 was used, aiming for glucose between 5.0 and 9.0 mmol/l; from July 2005 until December 2005 protocol 2 was used, aiming for glucose between 4.5 and 7.5 mmol/l. Serum glucose was measured at 6:00 a.m. in all patients from blood derived from arterial lines or venous puncture. The rest of the day blood glucose was measured either using the Glucotouch (protocol 1) or the AccuCheck (protocol 2) devices. To eliminate differences due to these different methods of measurement, only the 6:00 a.m. glucose measurements done by the central laboratory were studied here. Data were derived from ICU and laboratory databases.

Results

See Table 1. The median morning glucose was reduced from 7.5 mmol/l with protocol 1 to 6.8 mmol/l with protocol 2, resulting in small but nonsignificant improvement in outcome. Subgroup analysis focusing on medical or surgical patients or on patients with specific length of stay in the ICU also revealed nonsignificant differences in outcome.

Table 1 (abstract P139)

Conclusion

A small but significant decrease in serum glucose probably results in a small but statistically nonsignificant decrease in mortality and length of stay.