d
* * - Sci. Law ( 1 9 7 8 ) V o l . 1 8 , N o . 2
117
Printed in Great Britain
An Unusual Case of Carbon Monoxide Poisoning N. G. F L A N A G A N , Consultant
in
M B , C h B , M R C Path, M R C P , D C P ,
D- G. W O O T T O N , Medical Technical
G. S M I T H , Senior Specialist
CChem, M R I C ,
FIMLS
Officer M B , ChB, FFARCS in
Anaesthetics
D- K. GOFF,
M B , BS,
Senior Specialist
in
Pathology
Royal Air Force
Institute
MRCPath
of Pathology
and Tropical
SUMMARY A case o f suicidal carbon m o n o x i d e poisoning b y car xhaust inhalation is described. It is unusual in that "·« subject at t h e beginning of the incident switched ° a cassette tape recorder and recorded his dying °unds. The circumstances of the death were recon nected experimentally and a correlation between 'he recorded sounds and experimental concentrations °f carbon m o n o x i d e in t h e vehicle has been obtained. e
n
s
C
ASE
DMJ
Pathology
REPORT
Medicine,
Halton,
Aylesbury,
Bucks.
A few seconds later he was heard t o settle in his seat and start the car engine. For the next 17 minutes a variety of sounds were heard which are described in detail below. After this time there were n o other sounds although the tape remained live. N o spoken words were heard at any time. Examination of his medical records s h o w e d him t o have been in excellent physical condition during his 13 years in the Services.
POST M O R T E M
FINDINGS
Tl
>e subject was a 3 6 year o l d married British Service man w h o was separated from his wife and was serving Germany. He had started an association with a girl ^ m e 16 years his junior about o n e m o n t h previously and apparently had b e c o m e deeply involved. A t U p m ° the evening in question the girl told him that she Wanted t o end the relationship. He was seen shortly afterwards b y a friend of the girl w h o described him ^ being in a highly emotional state. He stayed with this '"end until l a m and left saying that he was going t o ° m m i t suicide. His c o m m e n t s were n o t taken seriou |y_ l n
n
c
The
gross
findings
were
typical
of
classical
carbon m o n o x i d e poisoning and the histology supported a diagnosis of asphyxia due t o this. There
were
no
other
abnormal features.
No
evidence of vomiting was f o u n d on t h e clothing, on gross autopsy examination or o n histology. The c a r b o x y h a e m o g l o b i n level was 7 0 per cent saturation. A full toxicological screen for drugs and alcohol was negative.
s
At 5am on t h e following morning he was found "ead b y a game warden in his car in a nearby w o o d . £* was in the driver's seat, sitting upright, with his " a d leaning backwards. The engine was still running, A rubber hose-pipe was attached t o the exhaust and passed through the nearside rear w i n d o w of the . The o p e n end o f this pipe was in t h e centre o f the a r seat. A tape recorder had been placed o n the front Passenger seat and was switched o n . A note indicating . intention t o c o m m i t suicide and a will were found ' his jacket pocket. The tape was played through and lasted for 6 0 ""nutes. T h e first sounds heard o n t h e tape were 'hose made b y the subject switching on the recorder. e
e
C a r
te
l s
RECONSTRUCTION OF INCIDENT In view of the unusual information from
the
tape
obtained
recording a reconstruction
of
the incident was performed. A l t h o u g h the actual car used could n o t be tested for administrative reasons, a car o f the same make and m o d e l and comparable state of tune was obtained. A test
n
was carried o u t w h e n the air temperature and weather c o n d i t i o n s were similar t o that of the night in question.
118
Med. Sci. Law (1978) Vol. 18, No. 2
Per cent saturation 3 CO
2
5
10
15
20
Time in minutes Fig. 1: Levels of carbon m o n o x i d e found in test vehicle over a period of 2 0 minutes.
A Mark II Austin 8 5 0 c c motor car was warmed up by running for several minutes before the start of the test. A rubber hose was fastened to the exhaust pipe with towels and the open end passed through the nearside rear window. The w i n d o w was plugged with towels and tape in a similar manner to that found in the original vehicle. The inner end of the tube was placed in the centre of the rear seat. LABORATORY
INVESTIGATIONS
A sample tube was positioned at head height above the driver's seat and passed o u t between the car body and the door. The outer end of the sample tube was fitted with a rubber septum s o that the gas mixture inside of the vehicle could be sampled with the aid of a large disposable syringe fitted with a narrow gauge needle. Samples were taken before the car was started and at 30 second intervals over the next
20 minutes. After fully ventilating the car the experiment was repeated several hours later, this time sampling at minute intervals. A'' samples were obtained with a 2 0 ml syringe which was twice filled, the first volume which was equal to that of the dead space in the sample tube was discarded. The syringe W* sealed by inserting the needle into a rubber bung. The samples were analyzed on a Perkin Elme' F l l gas chromotagraph fitted with a hot Wir< detector. A t w o metre column packed w i ^ molecular sieve 5A was used at an over temperature of 100°C with helium as th< carrier gas at 30 mis per minute. s
FINDINGS n
The concentration of carbon m o n o x i d e i ' creased steadily with time reaching 5 per een' saturation at 2 0 minutes. Figure I shows th