Aim: To determine whether an insulin algorithm could be used in a similar manner in the setting of diabetes and stress hyperglycaemia following cessation of intravenous (IV) insulin after cardiac surgery.
Methods: Subjects who were clinically stable, requiring ≥1 unit/h of IV insulin 48 h after surgery, were randomized to once daily detemir at 50, 65 or 80% of IV insulin requirements and received aspart according to carbohydrate intake. Diabetes was defined as any history of diabetes or preoperative HbA1c 6.5%.
Results: The morning glucose in patients with diabetes was 143 mg/dl (n = 61) vs. 124 mg/dl in those with stress hyperglycaemia (n = 21,p = 0.05) on day 1 and 127 vs. 110 mg/dl over 72 h (p = 0.01). This was unaffected by adjustment for initial dosing group. At 72 h, 56% of patients with stress hyperglycaemia reached AM (80–130 mg/dl) and 87% reached overall (80–180 mg/dl) glucose targets, compared to 90 and 100% of patients with stress hyperglycaemia, respectively. There was no difference in hypoglycaemia in patients with stress hyperglycaemia or diabetes. The percentage of patients with diabetes receiving insulin was 46% on admission and 77% at discharge, compared to 0 and 42% of patients with stress hyperglycaemia.
Conclusions: Following cardiac surgery, patients with stress hyperglycaemia may be converted from IV insulin to detemir with a 50% conversion factor, while patients with diabetes may require a higher conversion factor. Stress hyperglycaemia may be prolonged; the intensity and duration of insulin therapy required for optimal outcomes warrants further examination.