Q:
I work as a divemaster on a small island. Last
weekend some of my coworkers went to the
local chamber for “wash-out treatments,”
despite not having any symptoms. We all dive a lot,
but I’d never heard of anything like that before. Is that
something I should do?
A:
There is a misconception among some divers —
particularly recreational dive professionals and
fisherman divers — that a degree of tissue nitrogen
saturation will occur over weeks or months of frequent
diving activity. Some of these divers believe they may benefit
from occasional “wash-out treatments” in a hyperbaric
chamber, but that is a fallacy. Such a concept is completely
at odds with all credible diving and decompression research
and is inconsistent with informed clinical practice standards.
Efforts to determine the origin of this misunderstanding
have thus far proven unsuccessful.
Similarly, there are reports of chamber operators actually
propogating this myth by offering routine “nitrogren
desaturation treatments” — for a price, of course.
Decompression sickness (DCS) can certainly manifest
as musculoskeletal pain, so any such presentation within
24 hours of diving would warrant prompt evaluation and
perhaps treatment in a chamber. However, while chronic
pain has many possible causes, diving-related trapped
nitrogen is not one of them.
Inert gas uptake and elimination during air, nitrox and
heliox diving will obey both Dalton’s and Henry’s gas laws.
Should bubbles be produced upon decompression (whether
there are symptoms of DCS or not), then Boyle’s law also
comes into play. Asymptomatic bubbles may remain in tissues
for a day or so at most.
Throughout the compression phase of a dive and while
at depth, the associated increase in inert gas pressure in
the breathing gas is delivered to the diver’s lungs (Dalton’s
RESEARCH, EDUCATION & MEDICINE
//
F R O M T H E M E D I C A L L I N E
56
|
FALL 2013
The Nitrogen Saturation Myth
DANmedics and researchers answer your questions
about dive medicine.
STEPHEN FRINK
