title: Combination pharmacotherapy with delayed countershock vs standard advanced cardiac life support after prolonged ventricular fibrillation.
abstract: OBJECTIVE
  To test the hypothesis that 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.
  
  
  METHODS
  A prospective, block-randomized, blinded, laboratory experiment was conducted in an established swine model of prolonged ventricular fibrillation (VF). Fifty-six female domestic swine were anesthetized, instrumented, and shocked into VF with a bipolar pacing catheter. The VF was untreated for 8 minutes, then basic CPR was done mechanically for 1 minute. At 9 minutes of VF, the animals were randomized to treatment with one of seven therapies: group 1, combination pharmacotherapy with epinephrine (0.20 mg/kg), lidocaine (1.0 mg/kg), bretylium (5.0 mg/kg), propranolol (1.0 mg), and U-74389G (3.0 mg/kg); group 2, epinephrine (0.20 mg/kg); group 3, lidocaine (1.0 mg/kg) and bretylium (5.0 mg/kg); group 4, propranolol (1.0 mg); group 5, U-74389G (3.0 mg/kg); group 6, normal saline solution (volume equal to that for group 1); and group 7, standard ACLS (first countershock at 9 minutes of VF). Initial countershocks for groups 1-6 were given after 11 minutes of VF. Data were analyzed with two-tailed Fisher's exact test, with alpha set at 0.05.
  
  
  RESULTS
  Return of spontaneous circulation occurred in group 1 = 8/8 (100%); group 2 = 7/8 (88%); group 3 = 3/8 (38%); group 4 = 3/8 (38%); group 5 = 5/8 (63%); group 6 = 4/8 (50%); and group 7 = 3/8 (38%). One-hour survival occurred in group 1 = 8/8 (100%); group 2 = 5/8 (63%); group 3 = 2/8 (25%); group 4 = 2/8 (25%); group 5 = 3/8 (38%); group 6 = 2/8 (25%); and group 7 = 1/8 (13%).
  
  
  CONCLUSIONS
  Combination pharmacotherapy with delayed countershock (group 1) produced significantly higher rates of ROSC (p = 0.03) and one-hour survival (p = 0.001) when compared with standard ACLS in this porcine model of prolonged VF.
authors.affiliation: Department of Emergency Medicine, University of Pittsburgh School of Medicine, Pennsylvania, USA. menegazz+@pitt.edu
authors.forename: J J
authors.initials: JJ
authors.lastname: Menegazzi
authors.forename: D C
authors.initials: DC
authors.lastname: Seaberg
authors.forename: D M
authors.initials: DM
authors.lastname: Yealy
authors.forename: E A
authors.initials: EA
authors.lastname: Davis
authors.forename: B A
authors.initials: BA
authors.lastname: MacLeod
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D000975:Antioxidants / Q000737:chemistry / Q000627:therapeutic use; D001949:Bretylium Compounds / Q000627:therapeutic use; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D003131:Combined Modality Therapy; D004359:Drug Therapy, Combination; D004554:Electric Countershock; D004837:Epinephrine / Q000627:therapeutic use; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D008012:Lidocaine / Q000627:therapeutic use; D011281:Pregnatrienes / Q000737:chemistry / Q000627:therapeutic use; D011433:Propranolol / Q000627:therapeutic use; D011897:Random Allocation; D016019:Survival Analysis; D013552:Swine; D013566:Sympathomimetics / Q000627:therapeutic use; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000628:therapy*
chemical_list: D000889:Anti-Arrhythmia Agents; D000975:Antioxidants; D001949:Bretylium Compounds; D011281:Pregnatrienes; D013566:Sympathomimetics; C074965:U 74389F; D008012:Lidocaine; D011433:Propranolol; C045166:bretylium; D004837:Epinephrine