['To describe the trend of blood glucose immediately after successful resuscitation from out-of-hospital ventricular fibrillation.', 'Data from cardiac arrest registry supplemented with blood glucose data were analyzed in this population-based observational study. Between 2005 and 2009, a total of 170 adult patients survived to hospital admission after resuscitation from bystander-witnessed cardiac arrest of cardiac origin and ventricular fibrillation as an initial rhythm.', 'Sufficient data for analysis were available in 134 (79%) patients, of whom 87 (65% [95% CI 57-73]) survived to hospital discharge in Cerebral Performance Category 1 or 2. Blood glucose did not change significantly between prehospital (10.5 ± 4.1 mmol/L) and admission (10.0 ± 3.7 mmol/L) in survivors (P = 0.3483), whereas in nonsurvivors, blood glucose increased from 11.8 ± 4.6 to 13.8 ± 3.3 mmol/L (P = 0.0025).'] Does early increase in blood glucose in patients resuscitated from out-of-hospital ventricular fibrillation predict poor outcome?