Hyperglycemia and insulin resistance in cardiac arrest patients treated with moderate hypothermia.

Abstract

It is unknown whether the hyperglycemia that follows cardiac arrest and during therapeutic hypothermia (TH) is due to the arrest or the TH, whether it is associated with adverse outcomes, or whether its treatment affects outcomes. The objective of the study was to determine the effects of TH on the blood glucose (BG) levels in postcardiac arrest patients and the effects of hyperglycemia on mortality. This was a chart review of 62 patients undergoing TH after cardiac arrest between September 2005 and April 2008. BG levels from 72 hours before the arrest to 48 hours after TH and iv insulin infusion rates were analyzed and correlated with survival to discharge from hospital. The study was conducted at a tertiary, university referral center. PATIENTS undergoing TH after cardiac arrest participated in the study. TH consisted of cooling as rapidly as possible to 33°C, holding that temperature for 24 hours, and then controlled rewarming to 37°C over 8 or 16 hours. Hyperglycemia was managed with iv insulin drip protocols. The relationship of cardiac arrest and hypothermia to hyperglycemia, with a key secondary outcome being the relationship of hyperglycemia to survival to discharge, was measured. Analysis of glucose patterns showed no independent effect of TH on BG levels. Mean BG levels between cardiac arrest and the initiation of hypothermia were higher in nonsurvivors (253 ± 112 mg/dL, n = 48) than in survivors (192 ± 69 mg/dL, n = 24, P = .016). BG, insulin infusion rates, and insulin resistance during hypothermia, during rewarming, and 24-48 hours after hypothermia were not significantly different between the 2 groups. In patients treated with TH, the TH had no independent effect on BG levels. Mortality was associated with increased BG levels after cardiac arrest but before initiation of TH or an insulin drip. Likely, it is the severity of stress from the cardiac arrest that causes the hyperglycemia in these patients.