| Divers Alert Network has had several
inquiries from sport divers who expressed concern about mammary implants
and decompression safety.
This concern extended beyond the final ascent to sea levels after a
dive because diving vacations frequently conclude with air flights home
at reduced atmospheric pressure.
Since there is little pertinent information available in the
literature, an experimental study was conducted to determine if subjecting
mammary implants to a simulated dive followed by exposure at commercial
airline cabin altitudes wound result is bubble formation and volume
changes that might be dangerous for a women with mammary implants.
Studies were also conducted to determine the maximum extent of bubble
formation that might occur should airline cabin pressure be lost at a typical
cruising altitude.
Gel-filled, saline-filled and gel and saline-filled implants were
exposed to pressure or altitude in a pressure-altitude chamber.
The temperature was controlled to 98.6 degrees Fahrenheit, and all
pressure exposures were conducted with nitrogen rather than air to
simulate conditions in the body where there is less oxygen that in the
atmosphere.
The implants were exposed to the desired pressure-time profiles and
then removed from the chamber for observation. The simulated
diving profiles were 72 hours at 20 feet of seawater (FSW), 72 hours at
40 FSW, 72 hours at 60 FSW, 60 minutes at 60 FSW, 30 minutes at 90 FSW,
and 15 minutes at 120 FSW. |
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After the simulated dive, implants were
observed once per hour for eight hours for the number of bubbles present
and their sizes. After 21 hours at sea level, the implants were
subjected to 7,000 feet for two hours, which represents commercial
airline cabin pressure, followed by two hours at 30,000 feet to simulate
loss of aircraft cabin pressure at a typical flight altitude.
Results
Implant volume changes were 1-4 percent at sea level after dives of
200 minutes or less. Volume changes were 0-5 percent at 7,000 feet
of altitude and 4-12 percent at 30,000 feet. For the 72 hour
exposures, changes were 2-4 times greater. Changes were least for
saline and greatest for gel-saline.
Bubbles in the saline implants coalesced into one large bubble.
Between 12 and 50 bubbles formed in the gel implants. These had
diameters ranging from 1/1000 to 2.5 centimeters at sea level.
Volume changes for saline-filled implants were small because saline
absorbs less than silicone gel, since the solubility of nitrogen in
saline is less than in gel.
A surprising result was the greater volume changes in the gel and
saline-filled implant. Most of the bubbles formed within the
saline, and it is postulated that the gel acted as a reservoir from
which nitrogen diffuses into the saline.
Discussion
These laboratory experiments show that bubble formation and volume
expansion can occur in implants that are exposed to pressure similar to
those encountered in diving and flying. However, the volume
changes observed
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in this study exceed those that would occur
in the body because the implants in the simulated dives were
instantaneously exposed to the full nitrogen partial pressure present in
the diver's breathing gas.
This does not occur in living tissue because of the delay in the
transport of nitrogen between lungs and tissue and because metabolism
reduces the oxygen tension in the tissue to below the partial pressure
in the lungs. Also a bubble in tissue or in an implant surrounded by
tissue is eventually absorbed by the same mechanism through which a
collapsed lung is reinflated, a consequence of the metabolic exchange of
oxygen for carbon dioxide, causing the nitrogen partial pressure in the
bubble to exceed the alveolar nitrogen partial pressure.
In summary, bubble formation in mammary implants leading to a volume
increase of several percent might occur after recreational diving and
larger increases could occur after shallow saturation diving, but it is
unlikely that this would result in tissue or implant damage.
The bubbles would be tolerated safely and absorbed naturally.
However, prolonged deep saturation diving followed immediately by flying
in unpressurized aircraft at 30,000 feet, albeit an unrealistic scenario,
should be avoided, since the long diffusion distances within an implant
would make inert gas exchange very slow.
In the worst case, the resulting bubble formation might cause an
increase in the implant volume of sufficient magnitude for implant
tissue trauma to occur.
Excerpted from: "Mammary Implants, Diving and Altitude
Exposure", By R.D. Vann, R. Riefkohl, G.S. Georgiade, and N.G.
Georgiade, Plastic and Reconstructive Surgery, (81(2):200-203), February
1988.
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