Hyperglycemia and mortality in high-risk surgical patients

Introduction

Hyperglycemia and insulin resistance are common in critically ill patients, even if they have not previously had diabetes mellitus. Maintenance of normoglycemia with insulin reduces mortality and morbidity of critically ill patients.

Study objective

To investigate the relationship between hyperglycemia and intensive care mortality in a group of surgical critically ill patients.

Methods

We prospectively studied 21 patients (seven females, 14 males, aged 66 ± 14 years old) admitted to a general ICU after high-risk non-cardiac surgery. The exclusion criteria were: known prior diabetes mellitus requiring insulin therapy and hemodynamic instability before or during surgery and during the first hour after admission to the ICU. Demographic data, serum chemistries, type of operation, length of ICU stay (LOS) and mortality were recorded. APACHE II score, blood glucose levels (minimum and maximum levels), PaO₂/FiO₂ ratio, heart rate and mean arterial pressure were recorded upon admission to the ICU.

Results

Non-survivors (n = 4) had higher minimum blood glucose levels (217 ± 69 mg/dl vs 128 ± 46, P < 0.005) and higher maximum blood glucose levels (270 ± 120 mg/dl vs 192 ± 61 mg/dl, P < 0.05) compared with the survivors (n = 17). The ICU LOS (17 ± 11 days vs 4 ± 3 days, P < 0.001) and days of mechanical ventilation (17 ± 11 days vs 3 ± 3 days, P < 0.001) were longer for non-survivors compared with survivors. The APACHE II score on admission was higher for non-survivors than for survivors (22 ± 4 vs 15 ± 9, P < 0.05). Non-survivors (n = 4) had similar PaO₂/FiO₂ ratio levels (202 ± 172 mmHg vs 234 ± 99 mmHg in survivors, P = non-significant). There was no statistically significant difference in mean arterial pressure and heart rate.

Conclusion

Elevated blood glucose levels during the first 24 hours of the ICU stay are associated with a higher mortality rate in stable surgical patients.