Achieving glycemic control with intensive insulin therapy in the ICU

Introduction

Hyperglycemia is common in critically ill patients and is associated with increased mortality. The aim of our study was to test the efficacy of intensive insulin therapy in maintaining blood glucose levels within the target range.

Methods

During a 2-month period, three patients (mean age: 67.6 years; mean APACHE II score: 13) were included in our study. The goal of the procedure was to maintain blood glucose levels below 150 mg/dl. Insulin intravenous dosages (continuous infusion and push) were adjusted by the ICU nurses based on ABG glucose levels, also according to nutritional support and the glucose levels trend algorithm.

Results

During this period, 547 ABG samples were performed overall for the patients. The number of samples per patient per day was 7.5 ± 1.6 (mean ± SD): minimum 5, maximum 12. The blood glucose value per patient per day was 123.6 ± 25.7 (mean ± SD), minimum 13.5, maximum 196.33. The insulin dosage per patient per day was 86.34 ± 76.86 (mean ± SD) minimum 13.5, maximum 334. We recorded eight episodes of hypoglycemia (1.46% of all measurements), all successfully treated after 30% dextrose infusion. Within the target range were 427 blood glucose levels (78.06%), while the higher glucose values were associated with the initial hyperglycemia correction. The regration between glucose values and insulin dosage was not linear but rather polynomial, while the higher values of insulin dosage correlated with both the higher and the lower glucose levels.

Conclusion

The blood glucose level target is difficult to achieve with intensive insulin therapy in a population of ICU patients with high severity score on admission. In our study, the glycemic control target below 150 mg/dl was achieved in more than two-thirds of measurements using a high insulin dosage. On the other hand, the rate of hypoglycemia was high in our study (1.46%), probably because of application failure of the insulin dosage algorithm during nutritional interruption. We suggest that application of an intensive insulin therapy protocol adjusted to nutritional support and the glucose levels trend will achieve glycemic control in clinical practice, while minimizing the risk of hypoglycemia.