FORENSIC TOXICOLOGY - Bio Medical Forensics

Celebrating
60 years
K1 Gas Chromatography of Postmortem
Blood Revealing Sevoflurane in a
Patient Six Hours Post-Op
Diane C. Peterson, MD*, and Susan Kloda, MT, University of Alabama at
Birmingham, Department of Pathology, 619 South 19th Street,
Birmingham, AL 35233; Gary T. Simmons, MD, and Robert M. Brissie,
MD, Jefferson County Medical Examiner’s Office, 1515 South 6th Avenue,
Birmingham, AL 35233; and C. Andrew Robinson, PhD, University of
Alabama, Department of Pathology, 619 South 19th Street, Birmingham,
AL 35233
Attendees will understand basic physiology and properties of sevoflurane,
a general anesthetic used in same-day surgeries. Attendees will also
learn that sevoflurane may interfere with an ethanol peak with a certain
method of gas chromatography.
This poster will impact the forensic science community by alerting the
community to the possibility of the presence of “ethanol” peaks on gas
chromatography due to sevoflurane in post-operative patients.
A 54-year-old female patient underwent facelift surgery which lasted
approximately six hours. During surgery, sevoflurane was used for induction
and maintenance of anesthesia. There were no intraoperative complications.
The patient was discharged home about one hour and forty-five minutes postop
at 1645 hours. Her only post-op complaint was of a migraine headache,
which was treated with topiramate (Topamax®). Patient history as detailed
by her family, stated that the patient consumed only ginger ale and yogurt
prior to going to sleep after surgery. At 2100 hours, she was sleeping soundly.
At 2115 hours, she was not breathing and unresponsive. Postmortem examination
revealed focal moderate calcific atherosclerotic narrowing of the
proximal left anterior descending coronary artery, microscopic fibrosis of
the superior interventricular septum of the heart near the atrioventricular
node, and mild to moderate microvesicular steatosis of the liver. Postmortem
toxicology revealed the presence of citalopram (Celexa®), lidocaine, morphine,
and fentanyl. Gas chromatography (GC) of postmortem blood revealed
a peak at 2.496 seconds retention time, consistent with ethanol
(retention time 2.3 ± 0.1 sec). The concentration of ethanol was calculated
to be 0.05 g/dL. Antemortem blood also revealed ethanol by GC at a
concentration of 0.04 g/dL. However, the vitreous fluid was negative for
ethanol.
Due to the family’s insistence that the patient had not consumed ethanol,
possible interferences were sought. Of the medications the patient received,
sevoflurane was the best possible medication to cause interference. Sevoflurane
[fluoromethyl 2,2,2,-trifluoro-1-(trifluoromethyl) ethyl ether] is a four
carbon molecule that exists as a liquid and is used for induction and maintenance
of anesthesia. A review of the literature revealed two manuscripts
which reported ethanol and sevoflurane peaks to be within 0.1 and 0.15
seconds of each other (Biomed Chromatogr 2004; 18: 714-18 and Clin
Chem 2001; 47: 281-91, respectively). Ethanol-negative blood was spiked
with varying dilutions of sevoflurane, which co-eluted with ethanol. For
example, the retention time of the 1:20,000 dilution was 2.483 seconds.
Volatile analysis was performed with a head space procedure, using
n-propanol as the internal standard. The column was a 6 foot Porapak-S at
a temperature of 180°C. Instrumentation was Shimadzu GC-I 4A, Kyoto,
Japan. Due to the high volatility of sevoflurane, a linear concentration curve
could not be produced.
A study by Kharasch et al. of sevoflurane’s metabolism and pharmacokinetics
shows that it can still be detected in a patient’s blood several hours
after an administration of three to five hours (Anesthesiology 1995; 82:
1369-78). The average half-life of sevoflurane in that study was 2.8 ± 1.0
hours. The above patient died approximately six hours after the end of
TOXICOLOGY
1948 ~ 2008
anesthetic administration. The long detection time may be partially due to
the high partition coefficient for adipose tissue. Adipose tissue dominates the
pharmacokinetics past three hours post-administration (BMC Clin Pharmacol
2007; 7:1-21). The above patient had a body mass index of 28.6 kg/m2 ,
indicating a possible increase in body fat percentage over normal.
Therefore, although ethanol cannot be completely excluded, it is likely
that the above patient did have sevoflurane in her blood, causing an interfering
peak on gas chromatography. An interfering peak was obtained when
ethanol-negative blood was spiked with sevoflurane. However, due to the
high volatility of sevoflurane, consistent data points could not be obtained to
determine the concentration of sevoflurane in the patient’s blood.
Gas Chromatography, Sevoflurane, Ethanol
K2 Signature Analysis of 25 Illicit Cocaine
Samples and a Comparison to Analysis
by AccuTOF DART
Jeri D. Ropero-Miller, PhD*, Peter R. Stout, PhD, Edward J. Minden
Jr., BS, and Nichole D. Bynum, MS, RTI International, Center for Forensic
Sciences, 3040 Cornwallis Road, Building 3, Research Triangle Park, NC
27709; John F. Casale, BS, Drug Enforcement Administration, Special
Testing Laboratory, 22624 Dulles Summit Court, Dulles, VA 20166;
Insook Kim, PhD, Jennifer Runkle, BS, Marilyn Past, PhD, and Buddha D.
Paul, PhD, Armed Forces Institute of Pathology, 1413 Research
Boulevard, Building 102, Rockville, MD 20850
After attending this presentation, attendees will gain an enhanced
understanding of multiple techniques for characterization of illicit cocaine
and their ability to assess purity, level of performance, and their ability to
determine specific compounds of interest.
This presentation will impact the forensic science community by
providing a comparison of established quantitative, chromatographic method
to a novel qualitative time-of flight mass spectrometric method to determine
the purity of illicit cocaine and its relative abundance of signature
compounds.
Introduction: Characterization of 25 illicit cocaine samples was
undertaken in support of a research project funded in part by the National
Institute of Justice (NIJ Award # 2006-DN-BX-K019) examining the ratios
of cocaine-related compounds in hair samples contaminated with cocaine.
Various coca-related compounds, isotope ratios and solvent determinations
among other parameters are used to determine the manufacturing process
and geographical origin of cocaine exhibits. Furthermore, this information
is a useful tool to answer questions related to cocaine distribution and
trafficking.
A novel application of direct analysis in real time (DART) sample
introduction coupled with time-of-flight (TOF) mass spectrometry was
evaluated for analyzing 25 samples of bulk powdered illicit cocaine hydrochloride
salt seized by the Drug Enforcement Administration (DEA). The
cocaine samples were analyzed by the DEA to determine their “signature”
including their purity and the presence of specific compounds including
products of manufacture, adulterants, and other cocaine analytes including
oxidation products. The results of the analysis were then compared to data
obtained by CFS to assess the AccuTOF-DART’s level of performance.
Methods: Analysis was conducted in positive mode using AccuTOF-
DART mass spectrometry. After analysis of the cocaine samples, each data
set was examined for the presence of cocaine analytes (e.g., cocaine,
benzoylecgonine, ecgonine ethyl ester, cocaethylene, norcocaine,
anhydroecgonine methyl ester, truxillines, other ethyl esters) and a number
87 * Presenting Author