September 1998

Vol. 13, No. 9     What's this?

DCS & the Recovery of TWA Flight 800

from the September, 1998 issue of Undercurrent  

After the crash of TWA Flight 800 off Long Island, Navy and civilian divers recovered the aircraft and the remains of over 100 victims.

Scuba divers made 3,992 nodecompression dives to an average depth of 117 feet. Most were planned within no-decompression limits of either 120 feet for 15 minutes or 130 feet for 10 minutes, though a few employed decompression using computers. One third of the dives involved a 3-5 minute safety stop at 20-25 feet.

These dives were particularly stressful because of the long hours, the hazards (including 67 degree water and 15-foot visibility), and the presence of human remains. Several divers noted that their hearts were "pounding" in anticipation of finding the bodies. The remains of over 100 victims were recovered by divers.

Even so, there were only three cases of DCS, one embolism, and two cases of vascular headache, which can mimic DCS.

In decompression dives of up to 50 minutes, divers used suits heated with hot water. Interestingly, 14 of these resulted in five recompression treatments, so bottom times were reduced and more decompression time was given.

According to a study of the TWA divers, some researchers have come to suspect that "...the use of hot-water suits is a contributory factor both to the overall incidence of DCS and to the proportion of Type 2 cases."

So what about taking a hot shower or jumping in the jacuzzi after a dive? DAN recommends against it. They cite a study published in the Undersea Biomedical Research Journal in September, 1989, which found a higher incidence of DCS cases in divers who went from environmentally cold dive conditions into a hot shower. The test subjects took hot showers approximately 3 hours post-dive and developed symptoms 30 minutes to an hour after the hot shower. Seventyfive percent of the test subjects developed pruritus and shoulder pain.

According to DAN, the physiological relationship between hot showers and DCS is complex. The theoretical supposition is that peripheral blood vessels are occluded by the gas phase and that the temperature increase causes vascular dilation and changes the inert gas solubility of the tissues. Of course, DAN cautions, in the case of divers who go to the resort, take a hot shower, and then get symptoms, it's hard to say that the hot shower was at fault or that it wouldn't have happened anyway. But if a diver called and asked whether to take a hot shower after a dive, DAN says they'd recommend against it.