Emulsified Isoflurane Produces Cardioprotection against Severe Burn-Induced Cardiac Shock

Abstract

Background: Cardiac shock, occurring at the early stage of severe burns, causes cardiac insufficiency. Cardiac dysfunction after severe burn is associated with myocardial injury. Emulsified isoflurane (EIso) has been demonstrated to have cardioprotective effect against ischemia and reperfusion injury. Whether burn-induced cardiac dysfunction is influenced by EIso is currently unknown. We tested the hypothesis that EIso decreases myocardial damage in rat model with severe burn.Methods: In an in vivo study, sprague dawley rats, weighting 250-300 g, were randomized into four groups: 1) sham-burn group (sham, saline), 2) burn group (CON, saline, 30% total body surface area [TBSA] full-thickness burn), 3) burn+30% intralipid (IL, vehicle for EIso) group, and 4) burn+8% EIso of 1.5 ml/kg (EIso) group. Lactated ringers solution was immediately injected intraperitoneally to all rats after burn injury according to Parkland formula (4.0 ml/kg/1%TBSA), followed by continuous intravenous infusion of isovolumetric saline, intralipid and EIso for 30 minutes in each group. Hemodynamic parameters were constantly monitored throughout the experiment. 3 hours post-burn, hearts were excised for determination of enzyme activity and apoptosis.Results: Under baseline conditions, no significant differences in systemic hemodynamics were observed among the groups. Heart rate decreased after burn injury in the CON, EIso and IL groups. Compared with the sham group, burn injury was accompanied by a reduction of systolic function in left ventricular systolic pressure (LVSP) and maximum rate of increase in left ventricular pressure (dP/dtmax), and an increase in maximum rate of decrease in left ventricular pressure (-dP/dtmax). 2 to 3 hours after burn, EIso attenuated decreases in LVSP and dP/dtmax. Malondialdehyde (MDA) was reduced from 2.55±0.29 mmol/mg prot in CON group and 2.21±0.23 in IL group to 1.79±0.28 in EIso group (P<0.01 vs. CON and P<0.05 vs. IL). EIso also increased the level of superoxide dismutase (SOD) (162.5±10.5 U/mg prot), compared with CON group (140.4 ±12.1, P<0.01). However, there was no difference regarding the changes of apoptotic protein (Bcl-2 and Bax) expression among groups. Meanwhile, no apoptotic cells were detected throughout the experiment in any groups.Conclusions: EIso could protect hearts against severe burns during the early stage post-burn, which may be independent from the involvement of apoptosis. Citation: Zhao-Yang Hu, Ya-Dong Fang, Ze-Gang Yin, Bai-Xing Li, Yue-Sheng Huang, Jin Liu. Emulsified isoflurane produces cardioprotection against severe burn-induced cardiac shock. J Anesth Perioper Med 2016; 3: 11-17. doi: 10.24015/JAPM.2016.0002This is an open-access article, published by Evidence Based Communications (EBC). This work is licensed under the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium or format for any lawful purpose. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.