Emergency preservation and resuscitation improve survival after 15 minutes of normovolemic cardiac arrest in pigs.
OBJECTIVE
Outcome after prolonged normovolemic cardiac arrest is poor, and new resuscitation strategies have to be found. We hypothesized that the induction of deep hypothermia for emergency preservation and resuscitation (EPR) during prolonged cardiac arrest, before the start of reperfusion, will mitigate the deleterious cascades leading to neuronal death and will thus improve outcome.


METHODS
Prospective experimental study.


METHODS
University research laboratory.


METHODS
Thirteen pigs, Large White breed (27-37 kg).


METHODS
After 15 mins of ventricular fibrillation, pigs were subjected to 1) EPR (n = 6), 20 mins of hypothermic stasis induced with a cold saline aortic flush; or 2) 20 mins of conventional resuscitation (n = 7). Then cardiopulmonary bypass was initiated in both groups, followed by defibrillation. Controlled ventilation and mild hypothermia were continued for 20 hrs; survival was for 9 days. For neurologic evaluation, neurologic deficit score (100% = brain dead, 0-10% = normal), overall performance category (1 = normal, 5 = dead or brain dead), and brain histologic damage score were used.


RESULTS
In the EPR group, brain temperature decreased from 38.5 degrees C +/- 0.2 degrees C to 16.7 degrees C +/- 2.5 degrees C within 235 +/- 27 secs. Five animals achieved restoration of spontaneous circulation and survived to 9 days: two pigs with overall performance category 2 and three pigs with overall performance category 3. Their neurologic deficit score was 45% (interquartile range 35, 50) and histologic damage score was 142 (interquartile range 109, 159). In the control group, four pigs achieved restoration of spontaneous circulation: one survived to 9 days with overall performance category 3, neurologic deficit score 45%, and histologic damage score 226 (restoration of spontaneous circulation, p = .6; survival, p = .03; overall performance category, p = .02).


CONCLUSIONS
EPR is feasible in an experimental pig model and improves survival after prolonged cardiac arrest in pigs. Further experimental studies are needed before this concept can be brought into clinical practice.
Janata
Andreas
A
Department of Emergency Medicine, Medical University of Vienna, Austria.
Bayegan
Keywan
K
Weihs
Wolfgang
W
Schratter
Alexandra
A
Holzer
Michael
M
Frossard
Martin
M
Sipos
Wolfgang
W
Springler
Gregor
G
Schmidt
Peter
P
Sterz
Fritz
F
Losert
Udo M
UM
Laggner
Anton N
AN
Kochanek
Patrick M
PM
Behringer
Wilhelm
W
D000818:Animals; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004632:Emergency Medical Services; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D007036:Hypothermia, Induced; D020925:Hypoxia-Ischemia, Brain / Q000517:prevention & control*; D011446:Prospective Studies; D013552:Swine; D013997:Time Factors