Impact Of Postmortem Blood Flow On Postmortem Redistribution Of Ketamine

ObjectiveOur early studies found that postmortem redistribution of ketamine really happened in rats body via intragastric administration of ketamine. The aim of the study is to establish an animal model of acute poisoning rabbits via intravenous injection of ketamine to rabbits, to study the impact of postmortem blood flow on postmortem redistribution of ketamine in the rabbits and explore the mechanism on postmortem redistribution of ketamine in animals.MethodsAnalysis method for ketamine in body fluids and tissues:After internal standard SKF525A was added, the alkalization samples of body fluids and tissues were extracted by ether. Ketamine in extracts was qualitative analyzed using GC/MS based on retention time in the chromatographic system coupled with the ion fragmentation spectrum in the mass spectrometer and quantitative analyzed using GC-NPD equipped with internal standard method and working curve.Impact of postmortem blood flow on postmortem redistribution of ketamine:Forty eight rabbits received40mg·kg-1ketamine, slowly infused via the right ear vein(experiment group), and8rabbits received a comparable amount of saline and were used as blanks (controls group). The experiment group rabbits were divided into two groups according to whether or not immediate postmortem ligation was carried out on part of the large vessels around the heart. The experiment and controls group rabbits were left in a supine position at temperature of19℃-24℃. From each rabbit, cardiac blood, peripheral blood, urine, bile and the following tissues such as cardiac muscle, liver, spleen, lungs kidney and stomach wall were sampled at Oh,3h,6h,12h,24h,48h,72h and96h postmortem. Ketamine level were detected using GC/MS and GC-NPD.Resultsl.The linear range for ketamine in blood and liver were0.5～80μg·ml-1and0.5～80μg·g-1respectively. The limit of detection was0.25μg. The analytical recovery were from91.55%to134.37%and inter-day and intra-day relative standard deviation of precision were less than6.0%. The rabbits in experimental group were could not death soon via intravenous injection of ketamine with a dose of40mg·kg-1and the ketamine could be detected in body fluids and tissue of rabbits body.2. The rabbits executed by hypoxia method after being given intravenous injection of ketamine with a dose of40mg·kg-1for1.5hours later. The ketamine lever in rabbits was as follow:urine> bile> stomach wall> cardiac muscle, lungs, kidney, peripheral blood> liver spleen,cardiac blood.3. Whether ligating part of rabbits’large blood vessels around the heart (the aorta) or not, the concentration of ketamine in cardiac muscle, liver, spleen, lungs, kidney, cardiac blood, peripheral blood and bile of rabbits which were executed by hypoxia method after being given intravenous injection of ketamine had no significant difference from Oh to96h (P>0.05). There was no significant difference of ketamine lever between ligating part of rabbits’large blood vessels around the heart (the aorta) group and not ligating group (P>0.05)Conclusions1. Established an animal model of acute poisoning rabbits via intravenous injection of ketamine and analysis method of ketamine in biological samples by GC. The methods can be used in forensic medicine study for ketamine poisoning via intravenous injection.2. Ketamine wide distribution in rabbits body and ketamine lever is high in urine when rabbits received40mg·kg-1ketamine via the right ear vein1.5hour.3. There is no significant difference of ketamine lever in tissue and body fluid of rabbits during96h between ligating part of rabbits’large blood vessels around the heart (the aorta) group or not ligating group. The result indicate that postmortem blood flow may be not a main influencing factor on postmortem redistribution of ketamine in animal body.