Dennis V. Canfield

Postmortem Alcohol Production in Fatal Aircraft Accidents

During 1989 and 1990, the Civil Aeromedical Institute received specimens from 975 victims of fatal aircraft accidents. The maximum concentration of ethanol allowed under FAA regulations (0.04%, 40 mg/dL) was exceeded in 79 of these cases (8%). It was determined based on the distribution of ethanol in urine, vitreous humor, blood, and tissue that 21 of the positive cases (27%) were from postmortem alcohol production. Twenty-two of the positive cases (28%) were found to be from the ingestion of ethanol. In 36 cases (45%), no determination could be made regarding the origin of the ethanol. In two cases, postmortem alcohol production exceeded 0.15% (150 mg/dL). The opinion held by some toxicologists that postmortem alcohol production can be inferred from the presence of acetaldehyde, acetone, butanol, and other volatiles was found to be incorrect. Several cases with postmortem ethanol had no other volatiles. Volatile compounds were found in several cases where no ethanol was present. In addition a case was found in which the relative ethanol concentrations in blood, bile, and vitreous humor were solely consistent with the ingestion of ethanol, but acetaldehyde, acetone, and 2-butanol were also found in blood. This clearly indicates that the presence or absence of other volatiles does not establish postmortem ethanol production.

Genotyping for DQA1 and PM loci in urine using PCR-based amplification: Effects of sample volume, storage temperature, preservatives, and aging on DNA extraction and typing

Urine is often the sample of choice for drug screening in aviation/general forensic toxicology and in workplace drug testing. In some instances, the origin of the submitted samples may be challenged because of the medicolegal and socioeconomic consequences of a positive drug test. Methods for individualization of biological samples have reached a new boundary with the application of the polymerase chain reaction (PCR) in DNA profiling, but a successful characterization of the urine specimens depends on the quantity and quality of DNA present in the samples. Therefore, the present study investigated the influence of storage conditions, sample volume, concentration modes, extraction procedures, and chemical preservations on the quantity of DNA recovered, as well as the success rate of PCR-based genotyping for DQA1 and PM loci in urine. Urine specimens from male and female volunteers were divided and stored at various temperatures for up to 30 days. The results suggested that sample purification by dialfiltration, using 3000-100,000 molecular weight cut-off filters, did not enhance DNA recovery and typing rate as compared with simple centrifugation procedures. Extraction of urinary DNA by the organic method and by the resin method gave comparable typing results. Larger sample volume yielded a higher amount of DNA, but the typing rates were not affected for sample volumes between 1 and 5 ml. The quantifiable amounts of DNA present were found to be greater in female (14-200 ng/ml) than in male (4-60 ng/ml) samples and decreased with the elapsed time under both room temperature (RT) and frozen storage. Typing of the male samples also demonstrated that RT storage samples produced significantly higher success rates than that of frozen samples, while there was only marginal difference in the DNA typing rates among the conditions tested using female samples. Successful assignment of DQA1 + PM genotype was achieved for all samples of fresh urine, independent of gender, starting sample volume, or concentration method. Preservation by 0.25% sodium azide was acceptable for sample storage at 4 degrees C during a period of 30 days. For longer storage duration, freezing at -70 degrees C may be more appropriate. Thus, the applicability of the DQA1 + PM typing was clearly demonstrated for individualization of urine samples.

Blood carbon monoxide and hydrogen cyanide concentrations in the fatalities of fire and non-fire associated civil aviation accidents, 1991–1998 ☆

Blood samples submitted to the Civil Aeromedical Institute (CAMI) from aviation accident fatalities are analyzed for carbon monoxide (CO), as carboxyhemoglobin (COHb), and hydrogen cyanide, as cyanide (CN(-)). These analyses are performed to establish possible exposure of victims to smoke from in-flight/post-crash fires or to CO from faulty exhaust/heating systems. The presence of both gases in blood would suggest that the victim was alive and inhaled smoke. If only COHb is elevated, the accident (or a death) could be the result of CO contamination of the interior. Information pertaining to blood levels of these gases in aviation fatalities, in relation to the associated accidents, is scattered or not available, particularly with regard to toxicity. Therefore, considering that COHb> or =10% and CN(-)> or =0.25 microg/ml are sufficient to produce some degree of toxicological effects, the necessary information was extracted from the CAMI database. Samples from 3857 fatalities of 2837 aviation accidents, occurring during 1991-1998, were received; 1012 accidents, encompassing 1571 (41%) fatalities, were fire associated, whereas 1820 accidents were non-fire related. The remaining five accidents were of unknown fire status. There were fewer fire related fatalities and associated accidents in the (COHb> or =10% and CN(-)> or =0.25 microg/ml) category than that in the (COHb<10% and CN(-)<0.25 microg/ml) category. No in-flight fire was documented in the former category, but in-flight fires were reported in 14 accidents (18 fatalities) in the latter category. No non-fire accident fatality was found wherein levels of both gases were determined to be at or above the stated levels. There were 15 non-fire accidents with 17 fatalities wherein only COHb (10-69%) was elevated. The present study suggests that aviation fire accidents/fatalities were fewer than aviation non-fire accidents/fatalities and confirms that aviation accidents related to in-flight fires and CO-contaminated interiors are rare.

Utilizing the Urinary 5-HTOL/5-HIAA Ratio to Determine Ethanol Origin in Civil Aviation Accident Victims

Specimens from fatal aviation accident victims are submitted to the FAA Civil Aerospace Medical Institute for toxicological analysis. During toxicological evaluations, ethanol analysis is performed on all cases. Care must be taken when interpreting a positive ethanol result due to the potential for postmortem ethanol formation. Several indicators of postmortem ethanol formation exist; however, none are completely reliable. The consumption of ethanol has been shown to alter the concentration of two major serotonin metabolites, 5-hydroxytryptophol (5-HTOL) and 5-hydroxyindole-3-acetic acid (5-HIAA). While the 5-HTOL/5-HIAA ratio is normally very low, previous studies using living subjects have demonstrated that the urinary 5-HTOL/5-HIAA ratio is significantly elevated for 11-19 h after acute ethanol ingestion. Recently, our laboratory developed and validated an analytical method for the simultaneous determination of both 5-HTOL and 5-HIAA in forensic urine samples using a simple liquid/liquid extraction and LC/MS/MS and LC/MS/MS/MS. In this previous work a 15 pmol/nmol serotonin metabolite ratio cutoff was established in postmortem urine, below which it could be conclusively determined that no recent antemortem ethanol consumption had occurred. In the current study this newly validated analytical method was applied to five ethanol-positive aviation fatalities where the origin of the ethanol present could not previously be conclusively determined. In four of the five cases examined the detected ethanol was demonstrated to be present due to postmortem microbial formation, and not consumption, even though some indication of ethanol consumption may have been present.

PCR-Based Identification of Postmortem Microbial Contaminants—A Preliminary Study

Investigation of postmortem blood can reveal the presence of significant ethanol levels. However, in some instances it cannot easily be determined if the source of ethanol is from ingestion or from postmortem endogenous fermentation by contaminating microbes. Described here is a robust polymerase chain reaction (PCR)-based method for detecting the presence of common ethanol producing microbial contaminants in human blood. A set of DNA primers were designed for use in PCR to amplify and detect the genomic DNA from humans and three test microorganisms Escherichia coli, Proteus vulgaris, and Candida albicans. A rapid and reproducible protocol was developed for isolating genomic DNA from mixed human blood-microorganism samples that yields a suitable template for PCR. The organism-specific primer pairs can detect the presence of the target microorganisms in human blood at concentrations as low as 10 colony forming units/mL. The PCR products readily can be detected after agarose gel electrophoresis. This method provides an additional means of rapidly identifying microbial contaminants in postmortem blood samples.

Vitreous fluid and/or urine glucose concentrations in 1335 civil aviation accident pilot fatalities.

Abstract:u2002 During aviation accident investigations, vitreous fluid and urine samples from pilot fatalities are analyzed for glucose and blood for hemoglobin A1c (HbA1c) to monitor diabetic pilots and to discover other pilots with undiagnosed/unreported diabetes. The prevalence of elevated glucose concentrations in fatally injured pilots was evaluated by searching the Civil Aerospace Medical Institute’s Toxicology Database for the period 1998–2005. Out of 1335 pilots involving 363 vitreous fluid, 365 urine, and 607 vitreous fluid and urine analyses, 43 pilots had elevated glucose in vitreous fluid (>125u2003mg/dL) and/or in urine (>100u2003mg/dL). Of the 20 pilots whose blood samples were analyzed, nine had >6% HbA1c—four were known diabetics, and five were unknown diabetics. Urinary glucose levels were elevated in all 13 known hyperglycemic pilots. A considerable number of pilots (30 of 43) had elevated glucose and HbA1c (5 of 20), suggesting undiagnosed/unreported diabetic conditions.

Drugs and alcohol in civil aviation accident pilot fatalities from 2004-2008.

INTRODUCTIONnThe Federal Aviation Administration (FAA) Office of Aerospace Medicine sets medical standards needed to protect the public and pilots from death or injury due to incapacitation of the pilot. As a part of this process, toxicology testing is performed by the FAA on almost every pilot who is fatally injured in an aviation accident to determine the medical condition of the pilot, medications used by the pilot at the time of the accident, and the extent of impairment, if any.nnnMETHODnThe data were extracted from the FAA toxicology database for all pilots who died from 2004 to 2008 in aviation accidents.nnnRESULTSnThe laboratory received and tested specimens from 1353 pilots who died in aviation accidents between 2004 and 2008; 507 of these pilots were found to be taking drugs and 92 had ethanol in excess of 0.04 g x dl(-1).nnnDISCUSSIONnThis study was conducted to determine the extent of drug use in pilots who have died in aviation accidents from 2004 to 2008 and to determine the types of drugs most commonly found. A comparison of previously published reports with this studys report was made to determine trends in drug use by pilots who have died in aviation accidents over the past 20 yr. Factors were discussed that could influence drug trends. Diphenhydramine, an H1 antihistamine with impairing properties, is the most commonly found drug in pilots who died in an aviation accident.

DISTRIBUTION AND OPTICAL PURITY OF METHAMPHETAMINE FOUND IN TOXIC CONCENTRATION IN A CIVIL AVIATION ACCIDENT PILOT FATALITY

Toxicological evaluation of postmortem samples collected from a pilot involved in a unique fatal civil aircraft accident is described in this paper. A one-occupant airplane was substantially damaged upon colliding with terrain in poor visibility. Remains of the pilot were found outside the aircraft. Pathological examination revealed multiple blunt force injuries and vascular congestion. The fluorescence polarization immunoassay disclosed 8.0 microg/mL amphetamines in urine. Gas chromatographic/mass spectrometric analyses determined the presence of methamphetamine (1.13 microg/mL in blood and 59.2 microg/mL in urine) and amphetamine (0.022 microg/mL in blood and 1.50 microg/mL in urine). Methamphetamine was distributed throughout the body, including the brain. The amount of methamphetamine in gastric contents was 575-fold higher than that of amphetamine. The (+)- and (-)-forms of methamphetamine were present in equal proportions in gastric contents. The methamphetamine concentration found in blood was in the range sufficient to produce toxic effects, causing performance impairment.

Effects of fluid load on human urine characteristics related to workplace drug testing.

During workplace drug testing, urine is tested for dilution, substitution and adulteration. Donors argue that these findings are due to medical, health or working conditions or diet and genetic differences. There is a paucity of data correlating changes in urine characteristics after a fluid load to various body parameters. Therefore, five urine specimens (one in the morning, one prior to drinking 800 mL of a beverage, and three time intervals thereafter) from 12 males and 12 females were tested for four different beverages on separate occasions. Of the 480 samples, 376 were in sufficient amounts. Of these 376, 36 (10%) had creatinine <20 mg/dL but ≥2 mg/dL; 27 (75%) of 36 had specific gravity <1.0030 but >1.0010. Thus, these 27 samples can be considered to be dilute; 20 (74%) of 27 were from females. For males with at least one dilute sample, body fat was 11% less and resting metabolic rate (RMR) was 29% more than males with no dilute samples (p > 0.05); for females with at least one dilute sample, height was 8% less and weight 20% less than females with no dilute samples (p > 0.05). Individuals with a higher RMR appear to have a greater potential for producing dilute urine specimens than those with a lower RMR. Thus, a dilute sample does not necessarily indicate that it was intentionally diluted. Such samples must be carefully evaluated in consideration with recent consumption of liquid by donors to avoid false accusations.

Medical histories of 61 aviation accident pilots with postmortem SSRI antidepressant residues

INTRODUCTIONnSelective serotonin reuptake inhibitor (SSRI) antidepressants are popularly prescribed, but these drugs are not currently approved for use by U.S. civilian aviators. In a 2003 study, the presence of 4 SSRIs--citalopram, fluoxetine, paroxetine, and sertraline-was reported in 61 pilot fatalities of civil aviation accidents that occurred during 1990-2001. However, it was not known whether these pilots had disqualifying psychological conditions, including depression, and had properly reported the use of the antidepressants.nnnMETHODSnThe aeromedical history of the pilots was retrieved from the Federal Aviation Administrations (FAAs) Aerospace Medical Certification Database; additional pilot medical information and the cause/factor of the accidents were obtained from the National Transportation Safety Boards (NTSBs) Aviation Accident Database.nnnRESULTSnThere were 59 pilots who had medical records in the FAAs Certification Database. Disqualifying psychological conditions were self-reported in the past examinations of only 7 (12%) of the 59 pilots, and the use of an SSRI was reported by 3 of the 7 pilots. In later examinations, 6 of the 7 indicated that they were free from the conditions and not taking SSRIs; thus, they were reissued medical certificates. Such conditions and/or drug use were not self-reported in the aeromedical records of the remaining 52 (88%) pilots. Nevertheless, the NTSB investigations revealed that 12 (20%) of the 61 pilots had a history of a psychological condition and/or an SSRI use, as suggested by their personal medical records.nnnCONCLUSIONSnThese findings reconfirm that SSRIs were used by the aviators but were not reported in their last aeromedical examinations.