The Effect of Nutrition on Early Stress-Induced Hyperglycemia, Serum Insulin Levels, and Exogenous Insulin Administration in Critically Ill Patients With Septic Shock: A Prospective Observational Study.

Background: Stress-induced hyperglycemia is common among septic shock patients. Nutritional support influences glucose homeostasis but this effect has never been studied in septic shock. We aimed to determine the course of hyperglycemia and serum insulin levels in critically ill septic shock patients and to address the effects of caloric intake on glycemia, insulin levels, and exogenous insulin requirements.

Methods: A prospective observational study of 24 ventilated septic shock patients during 72 h after ICU admission. Every 4 h nutritional variables, exogenous insulin administration, serum insulin, and glucose levels were recorded.

Results: Stress-induced hyperglycemia was found in 96.2% of patients. Exogenous insulin requirements increased gradually and were most pronounced at 36 h (mean 4.64 IU/h). Total serum insulin levels were lowest at the point of most exogenous insulin requirements (mean 2.75 mIU/L). Total caloric intake and insulin requirements were positively associated (Pearson correlation coefficient 0.210).

Conclusions: In patients with septic shock marked reduced serum insulin levels can be observed during the first 36 h after intensive care unit (ICU) admission that have to be compensated by exogenous insulin administration, a phenomenon gradually improving after 36 h. Feeding is positively associated with exogenous insulin requirements. These results suggest that strategies to manage stress-induced hyperglycemia in patients with septic shock should consider frequent glycemic monitoring, conservative insulin dosing to prevent hypoglycemia when insulin resistance disappears, and slow progressive nutrition support during the early ICU phase as caloric loading may worsen hyperglycemia. This approach may attenuate the risk of glucose variability, hypo- and hyperglycemia and associated poor outcomes.