ADELSMAYR Gabriel

Effects of Skeletal Muscle Paralysis on Metabolic Changes during Therapeutic Hypothermia in Patients after Cardiopulmonary Resuscitation

Mild hypothermia improves outcome after cardiopulmonary resuscitation (CPR). Modes of action for it are manifold, though one way might be reduction of resting energy expenditure (REE). Neuromuscular blockers are in use, together with analgesia and sedation, during the cooling process in many centers to prevent shivering. Since neuromuscular blockers (NMB) are accused to be associated with various side effects causing serious harm and/or leading to prolonged ICU stay, use of NMB is controversial. Therapeutic hypothermia was able to reduce REE in patients with traumatic brain injury and critically ill patients with fever. Effect of neuromuscular blockers on REE during cooling is unknown as well as effect of cooling itself on REE after successful CPR. Moreover we have collected indices that neurological status of patients after CPR might influence substrate metabolism (unpublished data). Since these findings could be shown in a small group of patients, confirmation of these results in a larger cohort of patients after successful CPR is necessary.

60 patients after CPR will be treated with therapeutic hypothermia (33C°) for 24 hours and subsequently rewarmed with a rate of 0.4C°per hour until 36C° is reached. Patients will be randomized to receive and neuromuscular blockers or standardized sedoanalgetic medication alone during cooling. Indirect calorimetry assessing REE and substrate metabolism will be performed at 33C°, 34,5C°and 36C°, as well as between 36.5-37.5C° and 48-72 hours after CPR. Dose of administered medications will be documented at all measurement points. Outcome parameters will be REE at different temperatures, fat, protein and glucose oxidation rates at different temperatures stratified according to neurological outcome assessed at 12 month using the Cerebral Performance Category (CPC) scoring system (CPC 1 and 2 = good neurological outcome, CPC 3-5 = bad neurological outcome). For statistical analysis repeated measures ANOVA, linear and logistic regression will be used.