FORENSIC TOXICOLOGY - Bio Medical Forensics

standard deviation of the mean value. Using this approach, the limit of
detection was calculated to be a peak area of 3.13 × 10 5 . Samples of lung
and brain from cases in which the cause of death was not related to
helium or any other inhalants were also analyzed and found to be
negative. Confirmatory analyses are being conducted using gas
chromatography/mass spectrometry (GC/MS) in order to verify
GC/TCD identification of helium.
In conclusion, this analysis provides a method for detection of
helium that is easily conducted, both in the acquiring of the specimen
and the toxicological analysis.
Helium, Gas Chromatography, Postmortem
K49 In Vitro Adsorption of Carbon Monoxide
and Hydrogen Cyanide in Pooled Blood
Patrick S. Cardona, BA*, Federal Aviation Administration, AAM-610,
CAMI Building, 6500 South MacArthur Boulevard, Oklahoma City, OK
73169-6901
After attending this presentation, attendees will be able to apply the
findings of this study to the interpretation of results of blood
carboxyhemoglobin (COHb) and cyanide (CN¯) analyses.
This presentation will impact the forensic science community by
informing those who investigate accidents associated with fires of the
effect that an atmosphere containing primary combustion gases—that is,
carbon monoxide (CO) and hydrogen cyanide (HCN)—will have on
postmortem blood from open wounds of victims.
The Federal Aviation Administration’s Civil Aerospace Medical
Institute (CAMI) assists in the investigation of fatal aircraft accidents by
conducting toxicological analyses of specimens received from victims of
the accidents. One aspect of the analyses is the determination for the
presence of primary combustion gases in blood specimens. Combined
with the crash site investigation, autopsy and pathology findings, and
toxicological results, the investigators could determine whether the crew
members were incapacitated by engine CO leaks into the cabin area,
whether they survived the crash and were overcome by inhaling CO and
HCN from aircraft fires, whether and/or the victims died on impact or
came to a rapid death from the intense heat of the fire without inhaling
these gases.
Because of the violent impacts involved in crashes, victims quite
often suffer large open wounds near sites on the body from where
autopsy whole blood is collected. Many aircraft crashes result in fire,
which in turn, fill the atmosphere of the victims with smoke (CO and
HCN). It is important to determine whether pooled blood in those open
wounds may have adsorbed CO and HCN after death and could
erroneously lead investigators to determine that the presence of COHb
and CN ¯ in whole blood was the result of breathing in primary
combustion gases.
A chamber was set up in the CAMI laboratory to determine whether
CO and HCN may be adsorbed in undisturbed, pooled whole blood. To
determine in vitro CO adsorption, a large laboratory desiccator was used
as the chamber. A light film of silicone grease was applied to the valve
and the rim of the lid and chamber. A female Luer-Lok fitting was
affixed to the arm of the valve by use of a small piece of Tygon tubing.
To facilitate air movement in the chamber, a large cross-shaped magnetic
stirring bar was placed at the bottom of the chamber, which was rotated
with a magnetic stirring plate. A ceramic plate with numerous rows of
holes was placed above the stirring bar. Setting on it was a shallow open
dish containing 4 mL of whole human blood that had been treated with
sodium heparin. A 100-cc valved Luer gas syringe was used to evacuate
air from the chamber and introduce pure CO into it to achieve desired
concentrations. Prior to the setup, the volume of the chamber was
determined by measuring the amount of water required to displace all the
air in the chamber and lid, after taking into account the volumes of the
blood sample and the items used in the desiccator. The chamber volume
was determined to be 9038 cc. Various concentrations and lengths of CO
exposure to the pooled blood were conducted. COHb concentrations
were determined spectrophotometrically.
The apparatus was modified slightly for the determination of in
vitro HCN adsorption by using an additional open dish containing a 5mL
beaker having a weighed amount of sodium cyanide (NaCN). The
Ideal Gas Law was used to determine the amount of NaCN required to
achieve the desired concentrations of HCN in the chamber. To conduct
the experiment, 4 mL of heparin-treated, whole human blood was used
in the second dish. With the lid of the chamber partially opened, 1 mL
of concentrated sulfuric acid was added to the beaker containing the
NaCN; then the chamber lid was immediately closed. The volume of the
chamber was determined to be 8981 cc, after taking into account the
volumes of the blood sample, sulfuric acid, and the items used in the
desiccator. Two concentrations and various lengths of HCN exposure to
the pooled blood were conducted. CN¯ concentrations were determined
colorometrically by microdiffusion; then, positives were quantitated
spectrophotometrically.
No significant amount of COHb was detected in the whole blood of
the experiment after exposure to CO at 5532, 8298, 11064, 22129, and
33193 ppm for 30- and 60-minute exposure times. However, CN¯
concentrations in whole blood increased with exposure to an atmosphere
containing HCN at 100 and 200 ppm each at 15, 30, 45, and 60 minutes
of exposure times. The CN¯ concentration in blood ranged from 1.55 to
5.01 µg/mL.
Therefore, there is a potential for blood CN¯ levels to increase by
the adsorption of atmospheric HCN present in the smoke. This study
also demonstrated that the COHb in pooled blood exposed to an
atmosphere containing CO within the parameters of this experiment
would not alter the integrity of postmortem blood at an aircraft crash site.
This selective adsorption is consistent with the solubility of HCN and
insolubility of CO in water. These findings suggest that the COHb and
CN¯ levels should be carefully interpreted in view of the potential for
selective presence of these primary combustion gases in blood.
Carbon Monoxide, Hydrogen Cyanide, Blood
K50 Levetiracetam (Keppra®) and Suicide
Sandra C. Bishop-Freeman, PhD*, North Carolina Office of the Chief
Medical Examiner, 1001 Brinkhous Bullitt Building, Campus Box 7580,
Chapel Hill, NC 27599-7580; and Ruth E. Winecker, PhD, North
Carolina Office of the Chief Medical Examiner, Campus Box 7580,
Chapel Hill, NC 27599-7580
After attending this presentation attendees will be educated on the
effects of the drug levetiracetam (Keppra®) and will have explored its
potential risk for suicide.
This presentation will impact the forensic science community by
providing a detailed description of an anticonvulsant drug with relatively
unknown toxicity. Only one case of drug overdose has been presented in
the literature where the individual recovered with respiratory support.
The North Carolina Office of the Chief Medical Examiner has two
deaths from 2010 that are noted to have suicidal drug concentrations
of levetiracetam.
Levetiracetam (Keppra ® ) is among the new anticonvulsant drugs
that are replacing drugs such as carbamazepine, phenytoin,
Phenobarbital, and valproic acid. Along with drugs such as topiramate,
lamotrigene, and oxcarbazepine, the new drugs have been reported to
have a more tolerable side-effect profile, better efficacy and an easier
therapeutic maintenance. While the side-effect profile for levetiracetam
has been good overall in comparison to classical anticonvulsants, there
have been recognized psychiatric effects. The FDA revised the labeling
of this drug in 2007 to include warnings regarding these potential
behaviors. Individuals with prior psychiatric difficulties may be most at
risk for possible mood changes, agitation, and thoughts of suicide.
27 * Presenting Author