case report: an unusual case of carbon monomde poisoning

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The b l d was a cherry-red coiour which could indicate carbon monoxide poisoning. Samples of blood and stomach contents were taken for toxicobgical analysis ...

McAuley, F. and Wigmore, J.G. Can. SOG.Forensic Sci. J. 1987.20(2):83-86.

CASE REPORT: AN UNUSUAL CASE OF CARBON MONOMDE POISONING F. M C A U L E Y ~ N DJ.G. WIGMORE' An eighteen year old woman who went missing the previous day was found dead in &e closed trunk of an automobile in a residential garage. The ignition of the automobile was off and the engine was not running. The automobile keys were inside the nunk beside the body. No suicide note was found.

Some of the deceased's fingernailswere broken and the inside of the trunk was heavily scratched as if in an attempt to get out of the closed trunk. A large amount of brown stomach contents was present in her mouth, nose, both ears and on the nsck of her sweater.

The woman who had a history of emotional problems and depression pmia3ly amriuted to her obesity, was under the care of a psychiatrist. A year earlier, she had attempted suicide by taking a drug overdose.

AUTOPSY FIM)INGS Autopsy showed no obvious sign of violence. The stomach was distended with a large meal. The b l d was a cherry-red coiour which could indicate carbon monoxide poisoning. Samples of blood and stomach contents were taken for toxicobgical analysis. Orat, vaginaI, and rectal swabs were collected for determination of the presence of semen. The cause of death was listed as "Asphyxia due to aspiration of stomach content and carbon monoxide poisoning'".

TOXICOLOGICAL AND BIOLOGICAL FIWDINGS No semen was detected on the oral, vaginal, or anal swabs. Although the deceased had not had any medication prescribed and no medication was missing from the home, a drug screen was conducted on the blood and stomach contents. There were no significant findings.

The blood was anaiysed for w b o n monoxide by gas chromatography using a modified method of Glantz et al.(l). The blood contained 55% saturation of carboxyhemoglobin, a concentration which can be fatal(2,3). One problem this death presented was how could a fatal carboxyhemoglobinconcentration be obtained in the closed trunk of an automobile which was not runing. The police investigators could find no evidence that another person was involved 4the sole source of carbon monoxide appeared to be the automobile. Therefore rn aaempt at a reconstruction of the events immediately prior to death was

made. RECONSTRUCTION OF EVENTS The reconstruction was conducted in the same garage using the same automobile. The gmge was a two car garage measuring 6. lm by 5.5m by 2.7m high. At the time of the investigation only the one automobiIe was in it. It contained no windows and the door, which w a s automatic, sealed tightly. The automobile was found to emit a high concentration of carbon monoxide in (5% v/v>.

'. Centre of Forensic Sciences, Toronto, Ontario M7A 2G8

exhaust

McAuley, F. and Wigmore, J.G. Can. Soc. Forensic Sci. J. 1987. 20(2):83-86, Two remote sampling sites were selected, one inside the trunk and the other inside the automob'de in the dri\ier7s position at approximately head height. The driver's window was left partially open so that this site could also indicate the carbon monoxide concentration in ttte garage. The tests were conducted with the garage door closed. The carbon monoxide concentration in the air was measured with Drager tubes(4)

RESULTS ANI) DfSCUSSION The first test was conducted with the trunk dosed. The results are shown in Table 1 The concentration of carbon monoxide was found to be lower in the trunk than in the garage, This indicated that there were no leaks of the exhaust system into the tntnk which was therefore relatively air tight. The automobile was then run for 20 minutes with the trunk open. The results are shown in Table 2. Since the trunk is close to the exhaust in this test there was a higher carbon monoxide concentration in the trunk than in the garage. To test how long the carbon monoxide would remain in the trunk, the automobile was turned off, the trunk was closed and the carbon monoxide concentration was monitored in the trunk and garage for 25 minutes. The results are shown in Table 3. After 25 minutes the trunk still contained a high concentration of carbon monoxide, although the coacentration of carbon momxide in the garage decreased rapidly. From alf the evidence, it was postulated that the deceased had started the automobile in the closed garage. After a period of time, she turned it off, entered the trunk with the automobile keys in her possession and dosed the lid. Once the trunk was closed it could not be opened from the inside. While some carboxyhemogtobin buildup would occur outside the trunk, it could not be much more than approximately 30% in order for her to be able to enter the tru~lkand close it. The rest of the carbon monoxide exposure would then have to occur in the trunk until a carboxyhemoglobin concentration of 55% was obtained.

At a carbon monoxide concentration of 0.3%,it would take approximately 24 minutes for the carboxyhemoglobin concentration to reach 30%(5). If the deceased then entered the trunk and closed it, the toxic carbon monoxide gas would be trapped in the trunk and in less than 30 minutes a carboxyhemoglobin concentration of 55% could be obtained

CONCLUSIONS While the exact sequence of events leading to this death could not be determined, the reconstruction showed that the trunk could retain a potentidly lethal concentration of carbon monoxide for a considerable time. Death from carbon monoxide poisoning coufd there fore occur in the trunk of the automobile without the automobile running.

McAuley, F. and Wigmore, J.G. Can. Soc. Forensic Sci. J. 1987.20(2):83-86. T

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TBE CONCENTRATION OF W AT TBE TWO SAlVLPLMG LOCATIONS mTRE~GPIEI3UPIIMPIGANDTBETRUNg~

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THE CONCENTRATION OF CO A T THE TWO SAMfWNG LOeATIONS WITH THE ENGINE RZJNNING AND THE TRUNK OPE%

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TfiE CONCENTRATION OF CO RETAENED AT TWO SAMPLING UHJAmNS llUFFER THE ENGINE WAS SfOPPED

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hicAuley, F. and Wigmore, J.G. Can. Soc. Forensic Sci. J. 1987.20(2):83-86.

I.

2.

Glana,W.M.,~tembtidg~.V.A.,~ez,A.M.,GoMbaurn,L.R..~~n,H.F.,Lovell . . in Airrmft Aa5kn.t Fatal F.W.,~T.L.,andTo~,FM.~Monoxidef)etcrmurstion Sties. Aerospace Med. 1959; W7I 1-715. Stewart, R.D. The Effect of Carbon Monoxide on Hum?m. 3. &up. Med. 1976; 18:309-309

3.

T i e , B., Lundevail, 3.. and FIeixber, E. ~rboxyhemoglobinConcentrations on Fire Victims and in Cases of Fatai CO biisonings. Z. Reehtmadz, 1977; m17-21.

4.

Leichnitz,

5.

Qilintiere, f .G.,Biriry, M., Mixdonaid, F., and Smith,G . An Analysis ofSmoldering Fires in Closed Compartments and Their Hazards Due to CO. Fire and Materials 1982; 6:99-110

K. Detector Tube Handbook. (4th ed.) 1979; 52-59, Lubeck, Germany.

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