Introduction: Experimental and clinical evidences have suggested that hyperglycemia may worsen CNS injury and influence neurological outcome in traumatic brain injury (TBI) patients. It remains unclear whether admission hyperglycemia, an hyperglycemic event, persistent hyperglycemia or blood glucose variability (GV) is predictive of poor outcome.
Methods: We have retrospectively stratified 194 TBI patients admitted to our Intensive Care Unit (ICU) using admission blood glucose (ABG) as grouping variable. Stepwise multiple regression analysis (SMRA) has been used to evaluate the best predictor of outcome among physiological status on admission (APACHE II), head injury severity (AIS) and early factors such as body temperature, hypoxia, hypo and hypercapnia, hyperglycemia, hypotension and anemia. Moreover we have calculated the first two days maximum blood glucose excursion (Delta Blood Glucose, Max BG – Min BG = DBG) as index of early GV. The three groups were analyzed using one-way ANOVA and relative frequencies with Chi-Square test. Outcome measures considered are 30-days mortality, GOS on ICU discharge and 6-months GOS.
Results: No differences were found among the three groups in demographical data, admission status, insulin protocol and 6-months GOS. The ABG >180 mg/dl group had lower ICU-GOS, an higher mortality rate and an increased 24h and 48h DBG (p <.01). SMRA demonstrated ABG as the best predictor of ICU-GOS (p <.01, R2 43), moreover highest ABG values had a very strong correlation with higher DBG. Chi-Square test showed that patients with ABG >180 mg/dl have an higher risk of death (OR 4.49, 95% CI 1.7-11.9).
Conclusions: TBI patients presenting with admission hyperglycemia (ABG >180 mg/dl) are at high risk to develop early higher GV and secondary brain injury leading to worse neurological outcome and death. ABG is a very useful variable to detect patients at high risk among those with similar physiological status and severity of brain injury on admission.
Patient Care: This clinical research highlights how admission hyperglycemia permits a timely recognition of high risk patients. In those cases a more strict insulin therapy is mandatory in order to avoid further uncontrolled glucose variability and secondary brain damage.
Learning Objectives: By the conclusion of this session participants should be able to:
- recognize the importance of early glucose variability (DBG) in TBI patients
- understand the relationship between ABG and clinical outcome