Should we treat children with hyperglycaemia with insulin after cardiac surgery?

Introduction

Critically ill infants and children often develop hyperglycaemia. In adults it is associated with worsened outcome. No studies have so far investigated the feasibility and outcome of a standardized insulin/glucose protocol in children with congenital heart disease after cardiac surgery.

Methods

We prospectively studied children with congenital heart disease after cardiac surgery, for glucose intake, concomitant blood glucose values and results of insulin treatment. Results are expressed as the median and range, P < 0.05 considered statistically significant.

Results

Eighty-nine children were evaluated (male 56.2%), age 0.9 years (1 day to 17.9 years), length of ICU stay 22 hours (2.5 to 28.0 hours). All children survived. Fifty children were treated with and 39 without insulin. Overall, first blood glucose on admission to the ICU was 5.7 mmol/l (3.1 to 21.6 mmol/l), after 6 hours was 8.2 mmol/l (4.7 to 23.0 mmol/l), highest blood glucose was 9.9 mmol/l (3.4 to 23.7 mmol/l), and 77.5% was hyperglycaemic during admission (>8.0 mmol/l). Fifty out of the 70 children with hyperglycaemia were treated with insulin. Time to reach normoglycaemia in insulin-treated children was 6.4 hours (0.3 to 17.2 hours), total length of insulin treatment was 11.9 hours (2.3 to 23.0 hours) and the length of hyperglycaemia was 6.7 hours (1.2 to 17.0 hours) (Table 1). The duration of hyperglycaemia of treated and untreated children was not significantly different. Hypoglycaemia (<4.0 mmol/l) occurred in 10 children (11.2%); none of them had severe hypoglycaemia (<2.2 mmol/l).

Table 1

Conclusion

This study shows that a majority (77.5%) of children admitted after cardiac surgery develops hyperglycaemia and 72.5% were treated with insulin. The duration of hyperglycaemia was not different between children with or without insulin treatment. It can be questioned whether beneficial effects of insulin therapy can be expected with the short duration of insulin treatment (11.9 hours), which was noticed in this study.