Annual Diving Report - Divers Alert Network

3. DIVE INJURIES
The frequency of dives, by days and number of dives, is given for each diagnostic category in
Table 3.3-2. The median is a better measure of central tendency than the mean because of the
presence of outliers (extreme values).
Table 3.3-2 Days of diving and dives in series.
Diagnosis Days In Dive Series Dives In Series
AGE Mean 2.2 2.8
N 18 18
Median 1 2
DCS Mean 2.5 4.6
N 146 145
Median 1 2
DCI Mean 6.8 11
N 137 132
Median 2 2
NDR Mean 2.3 2.8
N 6 6
Median 2 3
Table 3.3-3 indicates that AGE occurred at shallower depths than DCS. This may be because
AGE can occur at any depth where as DCS requires some degree of inert gas loading, a process
that happens more rapidly with deeper immersions. When dives are examined by gender, males
tended to dive deeper than females (Table 3.3-4).
Table 3.3-3 Maximum depth (fsw) of last dive by diagnosis.
Diagnosis Mean (fsw) N Median (fsw)
AGE 45 18 28
DCS 52 217 36
NDR 19 4 19
DCI 33 149 22
Table 3.3-4 Maximum depth (fsw) of the last dive before injury by gender.
Gender Mean (fsw) N Median (fsw)
Male 46 354 30
Female 39 126 27
Consensus recommendations allow flying within 12 hours of a single no-decompression dive and
within 18 hours of multiple no decompression dives (Sheffield P, Vann RD (eds). Flying After
Recreational Diving: Workshop Proceedings. Durham: Divers Alert Network; 2004.) Divers
appear to heed these warnings because at least 63 percent of the injured divers waited longer
than 24 hours to fly, but from the 2004 data, it was not established if they had symptoms before
or after flight.
36 Annual Diving Report: 2006 Edition