title: Combination of cardiac pacing and epinephrine does not always improve outcome of cardiopulmonary resuscitation.
abstract: We hypothesized that the combination of cardiac pacing and epinephrine would yield a better efficacy for cardiopulmonary resuscitation (CPR) and the combination of 2 therapies at different opportunity would achieve the same results of CPR. Cardiac arrest was induced by clamping the tracheal tubes in 60 Sprague-Dawley rats. At 10 minutes of asphyxia, the animals were prospectively randomized into 5 groups (n = 12/group), and received saline (Sal-gro, 1 mL, intravenous [i.v.]), epinephrine (Epi-gro, 0.4 mg/kg, i.v.), pacing (Pac-gro, transesophageal cardiac pacing combined with saline 1 mL, i.v.), pacing + epinephrine group 1 (PE-gro1, transesophageal cardiac pacing combined with epinephrine 0.4 mg/kg, i.v.), or pacing + epinephrine group 2 (PE-gro2, transesophageal cardiac pacing combined with epinephrine 0.4 mg/kg, i.v., 4 minutes after the transesophageal cardiac pacing initiating and failing to resuscitate the animals), followed by initiation of CPR. Restoration of spontaneous circulation in Sal-gro was lower than in Epi-gro, Pac-gro, PE-gro1, and PE-gro2 (16.67% vs 66.67%, 66.67%, 100%, and 100%; P < .05 or P < .001, respectively). The proportions of withdrawing ventilator and 2-hour survival proportions in Pac-gro and PE-gro2 were higher than in Epi-gro and PE-gro1 (8/8, 10/12 vs 1/8, 2/12, respectively, P < .01, and 7/8, 8/12 vs 1/8, 2/12, respectively, P < .05 or P < .01). Mean survival time in Pac-gro and PE-gro2 were longer than in Epi-gro and PE-gro1 (P < .05 or P < .01). Therefore, the combination of 2 therapies does not always improve outcome of CPR. It is obvious that the combination of transesophageal cardiac pacing with delayed administration of epinephrine yields a better outcome compared to the combination of 2 therapies at the same time during CPR in a rat asphyxia cardiac arrest model.
authors.affiliation: Institute of Cardiovascular Diseases, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China. cmhnn@sina.com
authors.forename: Meng-Hua
authors.initials: MH
authors.lastname: Chen
authors.forename: Tang-Wei
authors.initials: TW
authors.lastname: Liu
authors.forename: Zhi-Yu
authors.initials: ZY
authors.lastname: Zeng
authors.forename: Lu
authors.initials: L
authors.lastname: Xie
authors.forename: Feng-Qing
authors.initials: FQ
authors.lastname: Song
authors.forename: Tao
authors.initials: T
authors.lastname: He
authors.forename: Shu-Rong
authors.initials: SR
authors.lastname: Mo
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002304:Cardiac Pacing, Artificial; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D003131:Combined Modality Therapy; D004837:Epinephrine / Q000627:therapeutic use*; D011446:Prospective Studies; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
chemical_list: D004837:Epinephrine