Page 86 - AlertDiver_Winter2013

84 | WINTER 2013
Past Achievements
The history of research at DAN goes back 30 years. In that
period, DAN-affiliated researchers have published more than
300 papers in scientific journals as well as dozens of special
reports, scientific workshop proceedings and annual reports.
Collection of data on injuries and fatalities started in
1982 and resulted in the first DAN Annual Diving Report in
1983. After that, research expanded to include studies of risk
factors and causes of injuries such as decompression illness,
toxicity of hyperbaric gases, fatalities and more.
In 1985 DAN started a field study to learn about how
recreational dive patterns affect risk of decompression
sickness (DCS). Volunteer divers were examined with an
ultrasound doppler monitor, which detected bubbles in the
venous blood entering the right side of the heart and flowing
toward the lungs. Doppler-detected bubbles were common
during warm-water recreational dives, but there were no
cases of DCS in the study group. More bubbles were found
in warmer water, in males, in older divers, on deeper and
repetitive dives and on the first day of diving.
At that time dive computers were just appearing on the
market and there were concerns that their use might increase
DCS risk. In 1988 DAN organized a workshop of dive-
physiology experts to address the concerns about computers.
Unlike decompression tables, which prescribed a maximum
of two dives per day, computers enabled divers to do multiple
dives. Again, this caused alarm among dive professionals, and
DAN addressed that issue in a workshop on repetitive diving
in 1989. It became obvious from these two workshops that
the basic ingredient for risk assessment was missing. DAN
was already receiving reports on injuries and fatalities (which,
along with participation in diving, were on the rise), but
there was no data about dive exposure (depth-time profiles,
frequency of diving, total number of dives) that
would enable calculation of accident rates or
estimation of risk.
For that reason, DAN started a prospective
study of dive exposure and outcomes:
Project Dive Exploration (PDE). This study
was possible thanks to dive-computer
manufacturers who implemented modifications
to their computers that would allow DAN
to collect electronic records of dive profiles.
Volunteer divers who participated provided
additional information about their dives, health,
dive history and health status after diving. So
far, with contributions from DAN Europe, DAN has collected
data from more than 250,000 dives. PDE data has provided an
opportunity to study the effects of various dive patterns, dive
environments and diver demographics on the risk of injury.
This data is being analyzed, and publications are pending.
For seven years DAN conducted experimental studies with
volunteer divers resting in a dry hyperbaric chamber at the
Duke Center for Hyperbaric Medicine and Environmental
Physiology to determine a safe time to wait to fly after diving.
This data has been used to update the guidelines for flying
after diving (FAD). The other phase of FAD study — looking
at how the delay is affected by exercise and immersion in
water — concluded in December 2012.
Analysis of diving injuries over the years has shown that
recreational divers often dive in remote places and that
travel time to places where they can receive recompression
treatment may be very long. In 2004 DAN organized the
workshop “Management of Mild or Marginal Decompression
Illness in Remote Locations,” which provided guidance for
optimal treatment in such cases.
The DAN® Medical Research department contributes to DAN’s mission
by monitoring existing and emerging health and safety issues in recreational
diving. It follows trends in diving practices and examines the causes,
risk factors and mechanisms of injuries in diving. Perhaps of greatest
interest to the diving public, DAN Research studies evidence-based
treatment methods and the prevention of diving injuries.
Safer Diving Through Science
DAN
Research
By Petar Denoble, M.D., D.Sc.
Respiratory
function
(spirometry)
is measured
as part of a
physical-fitness
screening
during a field
dive-monitoring
study. Maximum
ventilatory
volumes and
flow rates are
determined.
NEAL POLLOCK