Supplement of Lipid Emulsion to Epinephrine Improves Resuscitation Outcomes of Asphyxia-Induced Cardiac Arrest in Aged Rats

OBJECTIVE: The goal of the study was to investigate the efficacy of lipid supplement to epinephrine-based therapy in resuscitation of asphyxia-induced cardiac arrest in aged rats. METHODS: The study included two parts: in experiment A, rats underwent asphyxial cardiac arrest and cardiopulmonary resuscitation, randomized to receive epinephrine and normal saline (control group, n=22), epinephrine and intralipid 20% (long-chain triglycerides (LCT) group, n=22) or epinephrine and lipovenoes 20% (LCT/medium-chain triglcerides (MCT) group, n=22). Return of spontaneous circulation, recurrence of asystole after resuscitation, hemodynamic metrics, arterial blood gas values, neurological assessment score and indexes of pulmonary transudation were recorded. In experiment B, rats using the same model and resuscitation protocol were randomly divided into 21 groups: Control (0), Control (20), Control (40), Control (60), Control (80), Control (100), Control (120), LCT (0), LCT (20), LCT (40), LCT (60), LCT (80), LCT (100), LCT (120), LCT/MCT (0), LCT/MCT (20), LCT/MCT (40), LCT/MCT (60), LCT/MCT (80), LCT/MCT (100) and LCT (120) (n=10, the subscripts represent respective endpoint of observation in minutes). Myocardial bioenergetics were determined. RESULTS: In experiment A, the LCT and LCT/MCT groups had a shorter time to return of spontaneous circulation (ROSC) (P=0.001and P<0.001, respectively) and higher survival rate (P=0.033 and P=0.014, respectively) compared with the Control group. The LCT/MCT group had higher MAP (P<0.001 and P=0.001, respectively), HR (P<0.001 and P=0.004, respectively) and RPP (P<0.001 and P<0.001, respectively) compared with the Control and LCT groups, respectively. In experiment B, the LCT/MCT group had a higher energy charge compared with the control group at 20 (P<0.001) and 40 (P<0.001) minutes. The LCT group had higher energy charge compared with the Control group at 40 (P<0.001) and 60 (P<0.001) minutes. CONCLUSION: The supplement of lipid emulsion to epinephrine improves resuscitation outcomes of asphyxia-induced cardiac arrest than epinephrine alone in our in vivo model of aged rat. LCT/MCT emulsion may be superior to LCT emulsion in epinephrine-based resuscitation.