Serum potassium decreases significantly during the induction of TH (p=0.005). Potassium levels were not found to be different in patients with and without VF/VT in this study, perhaps due to the low number of patients, as a difference has been seen in other studies. It is recommended that an infusion of supplementary potassium be initiated during the early cooling phase in order to avoid severe hypokalemia (serum potassium <3.0 mmol/L) and terminated in due time before normothermia is reached during rewarming in order to avoid severe hyperkalemia (serum potassium >5.5 mmol/L), as serum potassium increases during rewarming.