Tuesday, November 12, 2013

Decompression Sickness Update

Despite 50 years of research on decompression sickness (DCS) (for divers coming up too fast to aviators going up too fast), the actual mechanisms remain poorly understood. Aviation DCS (important differences from diving DCS) authority James Webb recently indicated that while formation of nitrogen bubbles in body tissues is strongly correlated with DCS, this is unlikely to be the actual cause, and DCS still occurs among pilots despite all usual protocols being taken. Still, DCS mitigation strategies (e.g. prebreathing pure 02 to flush the system of N2) are so strongly inversely correlated with DCS, in 000's of tests, that they are strong predictors of DCS risk for aviators and are 'the best tools we have' for DCS prevention in high-altitude aviation. I've been working on the pressure schedule for the 2015 flight for about a year. This tells what suit pressures I need to maintain at certain altitudes while flying to avoid DCS (planning your own flight? don't copy my table, it is particular to my pressure exposure regime!). I base these estimates on years of research into DCS (32 great papers on it are here in case you're interested: https://search.knodeinc.com/viewProfile.action;jsessionid=11p6vj18liy3v13rp09yutfgl0?profile.profileId=C1869700#.UoL6vHBJPzg).

My DCS mitigation for flight will look something like 60 minutes of breathing 100% oxygen before flight, also 10 min exercise breathing that 100% ox at about 75% cardio capacity, followed by staying on pure ox for entire flight (c.180 minutes) and simple post-flight measures such some supplemental pure ox, air transport to a pressure chamber with flight lower than 1000 feet and a few hours in that pressure chamber (in Copenhagen), essentially like a decompression episode for deep-divers experiencing DCS. Cool stuff!

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