Compression Avascularization / Re-perfusion Syndrome (CARP)
also known as Harness Hang Syndrome.
The origins of awareness of CARP stem from members of the
French Speleological Society suspecting that some caver fatalities previously
attributed to exposure might have in fact been caused by something else. The
group undertook informal experiments where volunteers hung limply in harnesses.
The volunteers very quickly became ill so testing was stopped, in favour of more
scientifically rigorous protocols where the subjects’ vital signs could be
monitored. The testing showed that hanging immobile in a harness caused problems
in as little as ten minutes. The group tested numerous harness designs
and various body positions but the results were all similar. Recently, testing
done by a German industrial safety group (FISAT) showed similar results from
hanging immobile in a full body harness.
CARP Syndrome occurs when a person hangs in a harness and the venous blood in
the legs is unable to return to the torso while arterial blood continues to flow
downward. The result is identical to hypovolemic shock. Even if the
subject is released within ten minutes, there may be additional complications
caused by re-perfusion of the legs. Like shock, CARP Syndrome is difficult to
treat in the field and must be prevented by rescuing anyone hanging immobile on
Download Joe Ivy's full article on CARP.