Poor glycemic control is recognized as a risk factor for postoperative infection. For the neurosurgical patient, postoperative infection can lead to devastating complications such as meningitis, encephalitis and death. Neurosurgical patients often receive high doses of medications that increase blood glucose levels such as steroids, placing them at a potentially higher risk for postoperative infection. The purpose of this multisite observational study is to assess the impact of severe intraoperative hyperglycemia as a risk factor for postoperative infection in the neurosurgical patient.

This is a multisite [3 locations] prospective observational study of adult patients (18-89 years old) scheduled for elective intracranial (open or endoscopic) procedures that require general anesthesia and a hospital stay of at least 1 day after the surgery. All sites will follow the standard of care clinical protocol for glycemic management that was developed at Boston Medical Center (BMC). Laboratory tests will be collected at the discretion of the primary clinician. This observational study does not require any change to routine clinical practice.

The following perioperative data (timeframe between Pre-Procedure Clinic visit through Post-Anesthesia Care Unit discharge): blood glucose measurements, total insulin dose, total dexamethasone dose, estimated intraoperative blood loss, antibiotic prophylaxis regimen.

The patient's electronic medical records data will be reviewed 7 days after the neurosurgical procedure to abstract all available culture data (blood, urine, sputum, CSF), available treatment regimen data prescribed for infection (antibiotics), complications from hyperglycemia (diabetic ketoacidosis, hyperglycemic nonketotic coma) or insulin therapy (hypoglycemia episodes). Intensive care unit (ICU) and hospital length of stay will also be obtained form the medical records.

The investigators anticipate finding four groups of patients with regards to intraoperative blood glucose levels and management: 1) patients with no episodes of severe intraoperative hyperglycemia, 2) patients with intraoperative hyperglycemia who received insulin treatment, 3) patients with intraoperative hyperglycemia who did not receive insulin treatment and 4) patients with no available laboratory data.

Inclusion Criteria:

• Adult patients scheduled for elective intracranial (open surgical or endoscopic) intervention
• General anesthesia
• Hospital stay of at least 1 day post-procedure

Exclusion Criteria:

• Diagnosis of infection (local or systemic) in preoperative period
• Emergency procedures

Adult patients (18-89 years at the time of surgery) scheduled for elective intracranial (open surgical or endoscopic) intervention and require general anesthesia and a hospital stay of at least 1 day post-procedure.