Evaluation of NPH Insulin Dosing Interval for Critically Ill Hyperglycemic Trauma Patients During Continuous Enteral Nutrition: A Pilot Study

Objective: The aim of this study was to retrospectively evaluate the results of administering subcutaneous neutral protamine Hagedorn (NPH) insulin every 8 h (NPH-8) versus every 12 h (NPH-12) in critically ill, hyperglycemic trauma patients who required continuous enteral nutrition (EN). Methods: Both groups of patients were given concurrent sliding scale regular human insulin (SSI) with NPH therapy. The evaluation of glycemic control continued for 7 days. Results: A total of 15 patients were given NPH every 8 h (NPH-8), and 19 were given NPH every 12 h (NPH-12). Carbohydrate intake was similar between groups (115 ± 35 vs. 108 ± 37 g/d; p = 0.584). There was no significant difference in average blood glucose (BG) concentration (168 ± 18 vs. 166 ± 17 mg/dL; p = 0.803) or time within a BG target range of 70 to 149 mg/dL (7.5 ± 4.7 vs. 8.1 ± 5.0 h/d; p = 0.678) or 70 to 179 mg/dL (14.5 ± 5.0 vs. 16 ± 5.6 h/d; p = 0.419) or the incidence of Level 1 hypoglycemia (2 patients in each group; p = 1.00) or Level 2 hypoglycemia (1 patient vs. 0 patients, p = 0.441) between the NPH-8 and NPH-12 groups, respectively. However, the NPH-8 group required twice as much total (NPH + SSI) insulin (115 ± 52 vs. 58 ± 33 units/d; p = 0.004). Conclusions: These preliminary data suggest no significant difference between the administration of NPH-8 and NPH-12 based on glycemic control metrics in critically ill hyperglycemic trauma patients given EN. However, these results may be confounded by a selection bias as to who received NPH-8 vs. NPH-12. Further research is required.