Kristi J. Craft

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.

Ethanol and Drugs Found in Civil Aviation Accident Pilot Fatalities, 1989-2013.

BACKGROUND Biological specimens from pilots fatally injured in civil aviation accidents are analyzed for ethanol and drugs at the Civil Aerospace Medical Institute (CAMI). Prevalence of these substances in the pilots has been evaluated at 5-yr intervals since 1989. In continuation, a fifth 5-yr study (2009-2013) was conducted. METHODS The CAMI toxicology/medical certification and National Transportation Safety Board (NTSB) aviation accident databases were searched. RESULTS During 2009-2013, samples from 1169 pilots were analyzed. Aircraft involved in the accidents were primarily operating under general aviation. Most airmen were private pilots and held third-class medical certificates. In relation to the first 5-yr (1989-1993) period, the pilot fatality cases decreased by 37% and the presence of ethanol and/or drugs in the pilots increased by 239% in the fifth 5-yr period. The ethanol usage was unchanged, but increases were 267% and 583% with illicit and prescription drugs, respectively. The use of ethanol and/or drugs by aviators, along with underlying medical conditions, was determined by the NTSB to be cause/factors in 5% of the accidents. CONCLUSION The observed decrease in the fatality cases does not necessarily suggest the decrease in aviation accidents, as active airmen numbers also declined. The increase in the drug positive cases is primarily attributed to the continuous rise in the use of prescription drugs. Although prevalence of ethanol and drugs has been evaluated in fatally injured aviators, such evaluation has not been performed in active pilots not involved in accidents. This type of comparative study would be crucial in assessing aviation safety.

Toxicological findings in fatally injured pilots of 979 amateur-built aircraft accidents.

BACKGROUND Specimens from aviation accident pilot fatalities are submitted to the Civil Aerospace Medical Institute (CAMI) for toxicological analyses. Trends of fatal amateur-built aircraft accidents and toxicological findings in the associated pilot fatalities have not been examined. METHODS Fatal amateur-built aircraft accidents that occurred during 1990-2009 were evaluated by retrieving information from the CAMI toxicology database. Probable cause/factor in the amateur-built aircraft mishaps were obtained from the National Transportation Safety Boards (NTSBs) aviation accident database. RESULTS Of 6309 fatal aviation accidents from which CAMI received postmortem samples, 979 (16%) were related to amateur-built aircraft. There was a decreasing trend in non-amateur-built aircraft accidents, but an increasing trend in amateur-built aircraft accidents. In the 979 accidents, 392 pilots (40%) were positive for ethanol and/or drugs. In these 392 accidents also, the review showed a decreasing trend with non-amateur-built aircraft and an increasing trend with amateur-built aircraft. Percentages of pilots with prescription drugs were 26% for amateur-built aircraft, 16% for non-amateur-built aircraft, and 18% for all aircraft. Ethanol/drug use and medical condition were determined to be a cause/factor in 42 (11%) of the 385 ethanol/ drug-positive amateur-built aircraft accidents investigated by the NTSB. DISCUSSION Drugs found in the pilots were consistent with commonly used medications in the general population. The contributory role of mechanical malfunction of home-built aircraft cannot be ruled out in the observed increasing trends in their accidents, with or without ethanol and/or drugs. Regardless, the increasing trends of such accidents are of significant concern.

Resolution of aviation forensic toxicology findings with the aid of DNA profiling

Body components of aviation accident fatalities are often scattered, disintegrated, commingled, contaminated, and/or putrefied at accident scenes. These situations may impose difficulties in victim identification/tissue matching. The prevalence of misidentification in relation to aviation accident forensic toxicology has not been well established. Therefore, the Civil Aerospace Medical Institute (CAMI) toxicology database was searched for the 1998-2008 period for those cases wherein DNA profiling was performed to resolve identity issue of the samples submitted to CAMI for toxicological evaluation. During this period, biological samples from the casualties of a total of 3523 accidents were submitted to CAMI. The submitted samples were primarily from pilots. Out of the 3523 accidents, at least, one fatality had occurred in 3366 (≈ 96%) accidents; thus, these accidents were considered fatal accidents. Accordingly, biological samples from 3319 pilots (3319 of the 3366 accidents) were received at CAMI for toxicological testing. Of these 3319 pilots, 3275 (≈ 99%) were fatally injured. DNA profiling was performed in 15 (≈ 0.5%) of the 3319 accidents. The profiling was conducted upon the requests of families in two accidents, accident investigators in three, and pathologists in four. In six accidents, contradictory toxicological findings led CAMI to initiate DNA profiling. The requests made by families and investigators were primarily triggered by inconsistency between the toxicological results and the history of drug use of the victims, while by pathologists because of commingling of samples. In three (20%) of the 15 accidents, at least one submitted sample was misidentified or mislabeled. The present study demonstrated that the number of aviation accident cases requiring DNA profiling was small and this DNA approach was effectively applied in resolving aviation toxicology findings associated with those accidents.

Tricyclic Antidepressants Found in Pilots Fatally Injured in Civil Aviation Accidents

Prevalence of tricyclic antidepressants (TCAs) has not been explored in pilots. The National Transportation Safety Board (NTSB) aviation accident and the Federal Aviation Administrations Civil Aerospace Medical Institute (CAMI) toxicology and medical certification databases were searched for pilots fatally injured in aviation accidents. During 1990–2012, CAMI received bio‐samples of pilots from 7037 aviation accidents. Of these, 2644 cases were positive for drugs. TCAs were present in 31. TCA blood concentrations ranged from therapeutic to toxic levels. The NTSB determined that the use of drugs and ethanol as the probable cause or contributing factor in 35% (11 of 31) of the accidents. None of the 31 pilots reported the use of TCAs during their aviation medical examination. The prevalence of TCAs in aviators was less than 0.5% (31 of 7037 cases). There is a need for aviators to fully disclose the use of medications at the time of their medical examination.