Inpatient hyperglycemia following aneurysmal subarachnoid hemorrhage: relation to cerebral metabolism and outcome.

INTRODUCTION

Despite its clear association with impaired prognosis, it remains controversial whether hyperglycemia after aneurysmal subarachnoid hemorrhage (SAH) actively contributes to neuronal damage. This study aimed to identify a threshold for blood glucose predicting unfavorable outcome, and to evaluate differences in cerebral metabolism in normo and hyperglycemic SAH patients.

METHODS

Prospectively, blood glucose and cerebral metabolism, measured by cerebral microdialysis, were evaluated in 178 patients (WFNS grade I-V; age 51.6 +/- 12.4 years) during days 1-7 after SAH. Patients were classified into groups with mean blood glucose levels <or=/> 6.1 mmol/l (110 mg/dl) and 7.8 mmol/l (140 mg/dl). Glasgow Outcome Score was assessed after 12 months.

RESULTS

Higher inpatient blood glucose was associated with impaired prognosis, with a threshold of 7.5 mmol/l (135 mg/dl) distinguishing best between favorable and unfavorable outcome. Inpatient glucose levels >6.1 mmol/l (110 mg/dl) were associated with higher cerebral lactate and lactate/pyruvate ratio (P < 0.05). Cerebral glucose was elevated only at blood levels >7.8 mmol/l (140 mg/dl). Inpatient glucose levels above 7.8 mmol/l (140 mg/dl) were independent predictors of unfavorable outcome and mortality.

CONCLUSION

Blood glucose levels >7.8 mmol/l (140 mg/dl), but not levels >6.1 mmol/l (110 mg/dl), independently predicted unfavorable outcome. While blood glucose levels >6.1 mmol/l (110 mg/dl) were already associated with slight metabolic derangements, cerebral glucose increased only at blood levels >7.8 mmol/l (140 mg/dl). Considering the risks associated with tight glycemic control, a moderate regimen accepting blood glucose levels up to 7.8 mmol/l (140 mg/dl) might be more reasonable after SAH.