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IPE is a multifactorial condition, largely a net effect
of increased central blood volume, pressures within the
chest and, for compressed-gas divers, increased breathing
resistance. The squeeze is a primary component, but only
part of the story. Immersion produces a shift in blood
from the periphery to the core, and this effect can be
magnified in cold water or partially replicated by wearing
a tight wetsuit. Excessive fluid intake (hyperhydration)
increases the risk. For compressed-gas divers, respiratory
loading (most important, the effort to inhale) increases
with water immersion, with breathing through a
mouthpiece that adds resistance (particularly as gas
density increases) and with exertion. Using compressed
gas or freediving, if the net effect of the various stressors
is a sufficient increase in the pulmonary artery pressure,
capillary stress failure can produce a shift of blood into
the lungs. Symptoms of IPE can include the perception of
strain or stiffness in breathing, coughing and the coughing
up of small amounts of blood.
While I cannot confirm that this is what you are
experiencing, it may be that the central blood volume
increase magnified by the cold water is the stressor
that takes you over the edge that you skirt in warmer
water exposures. IPE is most likely to appear when
multiple predisposing factors are acting in concert. You
may have found your own threshold.
I encourage you to consult with your medical
monitors, keeping in mind that the classic squeeze is
not the only risk that freedivers face.
— Neal W. Pollock, Ph.D
Q:
A From the Medical Line article in a
previous issue of
Alert Diver
(Summer
2015)
addressed the topic of the new
generation of anticoagulant medications. It
mentioned that there was no way to reverse the
effects of these newer anticoagulants. I recently
heard this is no longer true. Can you verify this?
A:
Indeed, a new medication called idarucizumab
(Praxbind®) can reverse the anticoagulant
effects of dabigatran etexilate (Pradaxa®).
Reversal medications for other next-generation
anticoagulants are still in development. Note that when
traveling outside the U.S., however, idarucizumab may
not be available in an emergency. This should prompt
consideration when planning diving activities.
AD
— Marty McCafferty, EMT-P, DMT
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