Study On The Postmortem Redistribution Of Bupivacaine In Anesthesia Accident Death Dogs

Objective1.To establish the bupivacaine epidural administration,the subarachonid anesthesia and the intravenous injection death models.2.To establish the models of postmortem redistribution in dogs with an epidural administration of bupivacaine hydrochloride.3.To investigate the distribution of bupivacaine in epidural anesthesia accident death dogs.4.To investigate the postmortem redistribution of bupivacaine in epidural anesthesia accident death dogs.Methods1.Animal models1.1 The models of postmortem distribution1.1.1 The epidural anesthesia modelFifteen male dogs were randomly allocated to three groups.The first group(six dogs)was given a dose of 5mg/kg weight of bupivacaine hydrochloride by the epidural anesthesia tube at an even speed in five minutes;the second group(six dogs)was given a dose of 15mg/kg;the third group(control,three dogs)was given the same volume of physiological salt solution as the second group.1.2 The subarachonid anesthesia modelNine male dogs were randomly allocated to two groups.The experimental group(six dogs) was given a dose of 5mg/kg weight of bupivacaine hydrochloride by the subarachonid anesthesia tube at an even speed in five minutes;the other group(three dogs)was given the same volume of physiological salt solution as the experimental group.1.3 The intravenous injection modelNine male dogs were randomly allocated to two groups.The experimental group(six dogs) was given an intravenous injection of bupivacaine hydrochloride with the dose of 15mg/kg weight at an even speed in five minutes;the other group was given the same volume of physiological salt solution as the experimental group.2.The models of postmortem redistributionEighteen male dogs were given a dose of 5mg/kg weight of bupivacaine hydrochloride by the eoidural anesthesia tube.The epidural anesthesia death dogs were allocated to three groups, each group had six dogs.The three groups were respectively stored at -20℃,4℃or the room temperature.3.Records of vital signsBy a biological function system,the vital signs such as electro cardia,blood pressure and respiration from beginning of the administration to the death of dogs were recorded.4.Collection of samples4.1 The models of postmortem distributionA dog died from the anesthesia was dissected as soon as its vital signs disappeared,and then its specimens--the cerebrum,cerebrospinal fluid(CSF)in lateral ventricle,spinal cord(cervical spinal cord,thoracic spinal cord,lumbar spinal cord and sacrum spinal cord),heart,lung,liver, spleen,kidney,bile,urine,heart blood,peripheral blood,muscle in injection location and muscle in no injection location -- were collected and analyzed immediately.4.2 The models of postmortem redistributionA dog died from anesthesia was placed at the corresponding temperature,the heart blood, peripheral blood,liver and cerebrum were collected in 0,2,4,8,24,48,72,96,120 hours after the death and were analyzed.5.AnalysisThese obtained samples were extracted by ethyl ether.Analysis was performed with a GC equipped with a NPD and a GC/MS.The qualitative analysis was based on retention time in the chromatographic system coupled with the ion fragmentation spectrum in the mass spectrometer. The quantitative analysis was on an intemal standard method.Results1.SymptomThe symptoms observed in the three models were similar.After having been given a lower dose of bupivacaine,the dogs showed pupil decreased,salivated,difficultly breathed,fidgeted, foamed at the mouth,muscle trembled after the abdominal breathing.After having been given a higher dose of bupivacaine,the dogs showed the emotional state lost,analgesia,breathe frequency stepped down,costal breathing decrescendo,crease,muscle relaxation,pain reaction lost,and then dead.The epidural anesthesia dogs with 5mg/kg were all died in 11 minutes,the dogs with 15mg/kg were in 7 minutes.The subarachonid anesthesia clogs were all died in 6 minutes,two of them died immediately.Four dogs in the intravenous injection model group were died immediately,and the other two showed poisoning symptom,but the symptom disappeared in 2 hours.The experimented dogs showed the pathology of the sudden death.The dogs in the three control groups didn't show the similar symptom.2.The postmortem distribution group In the epidural anesthesia with 15mg/kg group,the ratios of bupivacaine concentrations detected in the sacrum spinal cord,cervical spinal cord,thoracic spinal cord,lumbar spinal cord, kidney,cerebrum,cerebrospinal fluid(CSF)to in peripheral blood were 51.62±15.65, 35.49±8.03,20.51±14.68,15.34±3.25,4.09±0.67,2.93±1.7,1.60±1.67:In the 5mg/kg group, ratios of bupivacaine concentrations detected in cervical spinal cord,thoracic spinal cord,lumbar spinal cord,sacrum spinal cord,CSF to in peripheral blood were 70.71±29.11,53.17±59.46, 48.17±50.15,37.22±56.96,6.24±5.27.In the subarachonid anesthesia model,the bupivacaine concentrations detected in organs or body fluid were all higher than in peripheral blood except in muscle of no injection location,the ratios of bupivacaine concentrations detected in lumbar spinal cord,thoracic spinal cord,sacrum spinal cord,cervical spinal cord,CSF,kidney,liver,spleen,cerebrum to in peripheral blood were 4868.49±8173.9,3300.70±4539.2,812.89±1140.3,634.34±681.02,97.55±105.53,42.98±64.76, 8.71±1.58,7.57±1.07,7.12±1.72.In the intravenous injection group,the bupivacaine concentrations detected in bile,liver, spleen,spinal cord and urine were higher,the ratios of them to peripheral blood were 4.52±0.83, 2.62±1.12,2.61±0.18,2.71±0.38,1.55±0.96,1.24±0.61.3.The postmortem redistribution groupEpidural anesthesia accident dogs showed different changes of bupivacaine concentrations detected in cardiac blood,peripheral blood,liver and cerebrum at -20℃,4℃and room temperature.At -20℃,concentrations of bupivacaine detected in cardiac blood,peripheral blood, liver and cerebrum began to step up after death,and decreased in 4～8 hours,in 72 hours showed another wave crest then stabled.The change of concentration detected in peripheral blood was so large that it fluctuated from 1.82±1.89μg/ml(in 0 hour)to 11.18±12.97μg/ml(in 72 hours). There was significant difference betwewn them in statistics(P＜0.05).The varying tendency of bupivacaine detected in peripheral blood deposited at 4℃was similar to at -20℃.The first crest-time of bupivacaine detected in heart blood at 4℃was lasting longer than at -20℃.There was no significant postmortem redistribution in liver at 4℃(P＞0.05). The concentration detected in cerebrum was affected so largely that it fluctuated from 3.48±0.51μg/g(in 0 hour)to 24.64±3.62μg/ml(in 72 hours),and there was significant difference betwewn them in statistics(P＜0.01).The postmortem redistribution of heart blood and peripheral blood at room temperature were more complicated.There was a little postmortem redistribution in liver,but there was no significant difference betwewn them in statistics(P＞0.05).The postmortem redistribution in cerebrum at room temperature was similar to at 4℃,but their fluctuated extents were different. Conclution1.The study established the epidural administration,the subarachonid anesthesia and the intravenous injection death models,established epidural administration anesthesia models with two doses,established the postmortem redistribution models of bupivacaine in epidural administration death dogs at -20℃,4℃and room temperature.The models established were available for the forensic toxicokinetics study on bupivacaine epidural anesthesia accident.2.The study showed the symptom of bupivacaine epidural anesthesia accident was related to the administration route,dose and the individual.The lower dose group showed excited,the higher group showed repressed.The preliminary experiment showed the order of intoxicating dose were intravenous injection,epidural anesthesia,subarachonid anesthesia.The experimented dogs showed the pathology of the sudden death.The dogs in the three control groups didn't show the similar symptom.The details such as case history,administration dose,sings and symptoms,death time,should provide some reference for the forensic investigation.3.The administration route and dose affected the postmortem distribution of bupivacaine in anesthesia accident dogs.The concentration detected in spinal cord and CSF was higher after epidural administration,but detected in bile,liver,spleen was higher after intravenous injection. The concentrations detected in sacrum spinal cord and cervical spinal cord was higher than in thoracic spinal cord and lumbar spinal cord when dogs were epidural anesthetized,the results detected in subarachonid anesthesia group were reversed.So collecting all samples and comparing their concentration may provide some evidence for the investigation of suspected epidural anesthesia accident case.4.There was postmortem redistribution of bupivacaine in epidural anesthesia accident death dogs.Deposited temperature affected the postmortem redistribution of bupivacaine.The changes and varying tendency in different organs or body fluid were different.The change in heart blood, peripheral blood and cerebrum were more significant than in the liver.The effect on blood was more remarkable and complicated than on other samples(P＜0.05).So the postmortem redistribution should be considered in the forensic identification of the epidural anesthesia accident.5.Although both lidocaine and bupivacaine were local anesthetics of amide derivative,their poisoning symptom,postmortem distribution and postmortem redistribution were different.So their dynamic distribution should be further studied.6.The study indicated that deposited temperature was an effective factor of postmortem redistribution.It was presumed that deposited temperature affected microbic multiply,the tissue autopepsia and disaggregation,which caused postmortem diffusion.Postmortem diffusion may be one important mechanism of postmortem redistribution.