Use of a cardiocerebral-protective drug cocktail prior to countershock in a porcine model of prolonged ventricular fibrillation.
OBJECTIVE
This was the third study in a series exploring whether the use of combination pharmacotherapy with delayed countershock would produce higher rates of return of spontaneous circulation (ROSC) and one-hour survival when compared with standard advanced cardiac life support (ACLS) therapy in prolonged ventricular fibrillation (VF).


METHODS
Twenty-four female, mixed-breed, domestic swine (ranging in mass from 22 to 25 kg) were used in this prospective, blinded, randomized, experimental trial. Animals were sedated (ketamine/xylazine), anesthetized (alpha-chloralose), paralyzed (pancuronium), mechanically ventilated with room air, and monitored with electrocardiography, arterial pressure, and Swan-Ganz catheters. VF was induced with a 3 s, 60 Hz, 100 mA transthoracic shock, and remained untreated for 8 min. One minute of basic life support followed (standardized by use of a mechanical device). At 9 min, animals were treated with one of three regimes: Group 1, cardiocerebral-protective cocktail (antioxidant U-74389G (3.0 mg/kg), epinephrine (0.2 mg/kg), lidocaine (1.0 mg/kg), bretylium (5.0 mg/kg), magnesium (2.0 g), and propranolol (1.0 mg)); Group 2, magnesium (2.0 g); and Group 3, standard ACLS. Groups 1 and 2 received drugs at minute nine (first countershock at minute 11), while Group 3 received first countershock at minute nine. Data were analyzed with two-tailed Fisher's exact tests.


RESULTS
ROSC was achieved in Group 1, 7/7 (100%); Group 2, 3/9 (33%, P versus Group 1=0.01); and Group 3, 3/8 (38%; P versus Group 1=0.02). One-hour survival was attained in Group 1, 7/7 (100%); Group 2, 3/9 (33%; P versus Group 1=0.01), and Group 3, 1/8 (13%; P versus Group 1=0.001).


CONCLUSIONS
Combination pharmacotherapy with a cardiocerebral-protective drug cocktail prior to countershock produced superior rates of ROSC and one-hour survival when compared with singular drug therapy (Group 2) and standard ACLS (Group 3) in this porcine model of prolonged VF.
Seaberg
D C
DC
Department of Emergency Medicine, University of Florida Health Sciences Center, PO Box 100186, Gainesville, FL 32610-0186, USA. seaberg@emergency.ufl.edu
Menegazzi
J J
JJ
Check
B
B
MacLeod
B A
BA
Yealy
D M
DM
D022561:Advanced Cardiac Life Support; D000818:Animals; D002316:Cardiotonic Agents / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D004554:Electric Countershock; D005260:Female; D008274:Magnesium / Q000627:therapeutic use; D011446:Prospective Studies; D013552:Swine; D014693:Ventricular Fibrillation / Q000628:therapy*
D002316:Cardiotonic Agents; D008274:Magnesium