The optimal blood glucose target in critically ill patient: comparison of two intensive insulin therapy protocols

Objective: Recent studies in critically ill patients receiving insulin intravenous therapy (IIT) have shown an increased incidence of severe hypoglycemia, while intermittent subcutaneous insulin «sliding scales» (conventional insulin therapy [CIT]) is associated with hyperglycemia. The objective of this study is to assess whether glycemic control range IIT can affect glucose levels and their variability and to compare it with CIT.

Methods: Prospective comparative cohort study in intensive care unit, with 2 study periods: Period 1, IIT with glycemic target range 110-140 mg/dL, and Period 2, IIT of 140-180 mg/dL. In both periods CIT glycemic target was 110-180 mg/dL. We assessed severe hypoglycemia (< 50 mg/dL), moderate hypoglycemia (51-79 mg/dL), hyperglycemia (> 216 mg/L) and the variability of blood glucose.

Results: We studied 221 patients with 12.825 blood glucose determinations. Twenty-six and 17% of patients required IIT for glycemic control in Period 1 and 2, respectively. Hypoglycemia was associated with a discontinuous nutritional intake, glycemic target 110-140 mg/dL and low body mass index (BMI) (P = .002). Hyperglycemia was exclusively associated with a history of diabetes mellitus (OR 2.6 [95% CI 1.6 to 4.5]). Glycemic variability was associated with a discontinuous nutritional intake, low BMI, CIT insulinization, diabetes mellitus, elderly and high APACHE II (P < .001).

Conclusions: The use of IIT is useful to reduce the variability of blood glucose. Although the 140-180 mg/dL range would be more secure as to presenting greater variability and hyperglycemia, the 110-140 mg/dL range is most suitable.