Cannabinoid distribution in fatally-injured pilots' postmortem fluids and tissues

The primary psychoactive component of cannabis, Δ⁹-tetrahydrocannabinol (THC) impairs cognitive function and psychomotor performance, particularly for complex tasks like piloting an aircraft. The Federal Aviation Administration's (FAA) Forensic Sciences Section at the Civil Aerospace Medical Institute (Oklahoma City, OK) performs toxicological analyses on pilots fatally injured in general aviation incidents, permitting cannabinoids measurement in a broad array of postmortem biological specimens. Cannabinoid concentrations in postmortem fluids and tissues from 10 pilots involved in airplane crashes are presented. Median (range) THC blood concentration was 1.6 (1.0-13.7) ng/mL. Phase I metabolites, 11-hydroxy-THC (11-OH-THC) and 11-nor-9-carboxy-THC (THCCOOH) and phase II glucuronide metabolite, THCCOOH-glucuronide, had median (range) blood concentrations of 1.4 (0.5-1.8), 9.9 (2.2-72.6) and 36.6 (7.1-160) ng/mL, respectively. Urine analyses revealed positive results for THCCOOH, THC-glucuronide, THCCOOH-glucuronide and 11-nor-9-carboxy-Δ⁹-tetrahydrocannabivarin (THCVCOOH). THC was readily distributed to lung, brain, kidney, spleen and heart. The psychoactive metabolite, 11-OH-THC, was identified in liver and brain with median (range) concentrations 7.1 (3.5-10.5) and 2.4 (2.0-6.0) ng/g, respectively. Substantial THCCOOH and THCCOOH-glucuronide concentrations were observed in liver, lung, brain, kidney, spleen and heart. These cannabinoid concentrations from multiple types of postmortem specimens add to the limited postmortem cannabinoid research data and suggest useful biological matrices for investigating cannabinoid-related deaths.