Postoperative hyperglycemia after 4- vs 8-10-mg dexamethasone for postoperative nausea and vomiting prophylaxis in patients with type II diabetes mellitus: a retrospective database analysis

• We evaluated blood glucose change with different dexamethasone doses in diabetics.
• There was greater blood glucose increase with dexamethasone 8-10 mg compared to 4 mg.
• Insulin requirements in PACU were also higher with dexamethasone 8-10 mg.
• Dexamethasone dose is one factor determining the magnitude of blood glucose change.

Study objectiveThe study objective is to compare change in postoperative blood glucose from preoperative values in patients with type II diabetes mellitus receiving 4- or 8-10-mg dexamethasone for postoperative nausea and vomiting prophylaxis.DesignThis is a retrospective database study.SettingThe setting is at an academic university medical center.PatientsThere are 1037 adult patients, American Society of Anesthesiologists physical status I-IV, with type II diabetes mellitus, undergoing elective surgery between January 1, 2006, and March 31, 2012, and who were hospitalized for at least 24 hours.InterventionsThe interventions are dexamethasone 4 or 8-10 mg for postoperative nausea and vomiting prophylaxis.MeasurementsAge, sex, American Society of Anesthesiologists class, height, weight, body mass index, surgery date, type and duration of surgery, hemoglobin A1c (HbA1c) within 180 days of surgery, type of anesthesia, preoperative blood glucose in the preoperative holding area, maximum blood glucose in the postanesthesia care unit (PACU) and first 24 hours postoperatively, and insulin requirements intraoperatively and in PACU.Main resultsIn unadjusted analysis, the 8-10-mg dose was associated with greater (mean ± SD) increase in blood glucose compared with the 4-mg dose in PACU (58 ± 50 vs 43 ± 45 mg/dL, P < .0001) and over 24 hours (101 ± 71 vs 67 ± 65 mg/dL, P < .0001). In the multivariable model, predictors of blood glucose increase in PACU included dexamethasone dose (P < .0001), preoperative serum glucose (P < .0001), duration of surgery (P < .0001), and total dose of insulin (P < .0001). Over 24 hours, the significant predictors of glucose increase included dexamethasone dose (P < .0001), preoperative blood glucose level (P < .0001), duration of surgery (P < .0001), year of surgery (P = .04), and neurosurgical procedures (P = .02). This model estimates the increase in postoperative glucose to be 25 mg/dL higher over 24 hours with dexamethasone 8-10 mg than with 4 mg (95% confidence limits, 18-32 mg/dL).ConclusionsDexamethasone 8-10 mg is associated with a significantly greater perioperative increase in blood glucose compared with a 4-mg dose.