Effects of Oxygen Concentrations on Postresuscitation Myocardial Oxidative Stress and Myocardial Function in a Rat Model of Cardiopulmonary Resuscitation.
OBJECTIVE
Lipid peroxidation induced by free-radical species plays a prominent role in myocardial injury following ischemia and reperfusion. However, there is a lack of data in different oxygen concentrations on myocardial lipid peroxidation during the early phase of reperfusion. In this study, we investigated whether ventilation with medium or normal concentration of oxygen would decrease the severity of myocardial lipid peroxidation and postresuscitation myocardial dysfunction.


METHODS
Prospective, randomized, controlled experimental study.


METHODS
University-affiliated animal research institution.


METHODS
Sixty-three healthy male Sprague-Dawley rats.


METHODS
Animals were randomized into three groups: 1) 100% group, 2) 50% group, and 3) 21% group. Ventricular fibrillation was induced and untreated for 8 minutes, and defibrillation was attempted after 8 minutes of cardiopulmonary resuscitation. Ventilation with 100%, 50%, or 21% oxygen was initiated in all groups during cardiopulmonary resuscitation and 1 hour following the return of spontaneous circulation. Normoxic ventilation was maintained thereafter.


RESULTS
Myocardial function, including ejection fraction and myocardial performance index, were measured at baseline, 4, or 72 hours after resuscitation. Blood samples were drawn at baseline, 15 minutes, 1, 4, or 72 hours after resuscitation for the measurements of blood gas or biomarkers. Significantly better myocardial function and longer duration of survival were observed in the 50% group. Compared with the 21% and 100% groups, a mild hyperoxia and greater oxygen extraction with lower 8-iso-prostaglandin F2α were observed in the 50% group. Pearson correlation analysis confirmed that 8-iso-prostaglandin F2α was positively correlated with myocardial performance index at 4 hours postresuscitation.


CONCLUSIONS
In a rat model of cardiac arrest and resuscitation, ventilation with 50% inspired oxygen during early postischemic reperfusion phase contributed to a decreased lipid peroxidation and a better myocardial function and duration of survival.
1Weil Institute of Critical Care Medicine, Rancho Mirage, CA. 2Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China. 3Keck School of Medicine of the University of Southern California, Los Angeles, CA.
Shen
S
Zhao
Jie
J
Qian
Jiangang
J
Wang
Ping
P
Gong
Zhengfei
Z
Yang
Jena
J
Cahoon
Xiaobo
X
Wu
Neil
N
Duggal
Caijing
C
Lin
Wanchun
W
Tang
D000818:Animals; D015415:Biomarkers; D001784:Blood Gas Analysis; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D006323:Heart Arrest / Q000503:physiopathology* / Q000628:therapy*; D006334:Heart Function Tests; D015227:Lipid Peroxidation / Q000187:drug effects; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control; D009206:Myocardium / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects*; D010100:Oxygen / Q000008:administration & dosage*; D011446:Prospective Studies; D051381:Rats; D017207:Rats, Sprague-Dawley; D012121:Respiration, Artificial / Q000379:methods*; D013997:Time Factors; D019210:Troponin I / Q000097:blood
D015415:Biomarkers; D019210:Troponin I; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D010100:Oxygen