Technical Transfer: Cockpit Exposure Reconstruction via Physiologically Based Pharmacokinetic Modeling for HPARS
Abstract
Chemical irritants can pass through the on-board oxygen generation system in high-performance aircraft (HPA), but the level andfurther identification of irritants have not been thoroughly evaluated. The 711th Human Performance Wing recently conducted aHigh-Performance Aircraft Respiratory Study (HPARS) to identify the etiology of reported respiratory pilot symptoms and mitigate a common health complaint in HPA. HPARS sampling included exhaled breath before and after hundreds of sorties to identify volatile organic compounds (VOCs). Typically, VOCs absorbed into the body via inhalation rapidly clear from the bloodstream after cessation of exposure. Thus, it is challenging to accurately reconstruct actual exposure concentrations and blood levels within a pilot's circulatory system and potential toxic chemical levels at the most responsive tissue sites. The current study seeks to overcome these issues by applying physiologically-based pharmacokinetic modeling to the HPARS exhaled breath samples to reconstruct pilot blood and tissue concentrations during each specific sortie. These reconstructions allow for the determination of possible exposure ranges experienced by pilots during flight (some modeled in-flight concentrations exceeded post-sortie breath samples by as much as 1000x),compare modeled exposure to permissible exposure limits and threshold limit values (TLVs) (some modeled in-flight concentrations exceeded TLVs), and compare modeled exposure to exposure levels and symptomology from the literature associated with various chemicals. This approach produced informed knowledge judgment as to the probability that any particular chemical could have both the potential to have achieved high enough in-flight exposure concentrations and have a known level of toxic potency to be of consequence.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2019
- Accession Number
- AD1102406
Entities
People
- Darrin Ott
- Heather Pangburn
- Jeffery Gearhart
- Tammie Covington