Abstract 183: Appropriate Prolongation of Therapeutic Hypothermia Reduces Myocardial Damage After Prolong Cardiac Arrest
Background: Therapeutic hypothermia improves myocardial dysfunction and survival in cardiac arrest survivors. However, whether the duration of hypothermia should be prolonged in according to the duration of cardiac arrest to mitigate excess myocardial damage has not been clarified.
Hypothesis: Appropriate prolongation of therapeutic hypothermia can mitigates excess myocardial damage after prolong cardiac arrest.
Methods: The animals were equally randomized to NormoT(normothermia), 5H1, 5H2, 7H1, 7H2 and 7H4 groups. VF was induced and untreated for 5 minutes (NormoT, 5H1, 5H2) or 7 minutes (7H1, 7H2, 7H4), followed by 1 minutes of CPR, and then one electric shock of 5 J. Therapeutic hypothermia was initiated at simultaneously at the start of CPR with intravenous administration of 4°C saline and fan. After ROSC, hypothermia was maintained for 1hour (5H1, 7H1), 2 hours (5H2, 7H2) and 4 hours (7H4), respectively.
Results: The plasma Troponin-I and FABP concentration at 2nd hour following ROSC was significantly lower in the 5H2 and 7H4 groups than in the other groups (except the 7H2 group) (Figure). At 4th hour after ROSC, The 5H2 and 7H4 groups showed less myocytolysis and apoptosis (Tunel staining) in the myocardium when compared with the other groups. Six out of 12 animals in both the 5H2 and 7H4 groups survived 72 hours after ROSC, whereas only 3 out of 12 animals in the 5H1 and 7H2 groups, and only 1 out of 12 animals in the 7H1 and NormoT groups. At the 72nd hour, the 5H2 and 7H4 groups showed less myocardial fibrosis when compared with the groups.
Conclusion: Appropriate prolongation of therapeutic hypothermia can mitigates excess myocardial damage in prolong cardiac arrest.
- © 2013 by American Heart Association, Inc.