Breathing device aims to save lives under water

January 22, 2004, vol. 29, no. 2
By Carol Thorbes



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A new type of a breathing system could save dozens of lives lost annually in helicopter crashes in hostile marine environments, such as Canada's North Atlantic Ocean and the Baltic Sea.

They are home to numerous gas and oil drilling operations, which rely on helicopters to ferry workers to and from ocean-bound offshore oil platforms.

Matthew White at Simon Fraser University's school of kinesiology leads three national projects aimed at improving the abysmal survival rate of offshore drilling workers involved in helicopter crashes.

While roughly 80 per cent of such victims survive the initial crash, only about 20 per cent of those survivors escape drowning.

Despite mandatory training on how to escape such incidents and survival suits that provide hours of protection in brutally cold and often freezing waters, survivors are disadvantaged from the moment their helicopter crashes.

They must wait until the rotating blades of their sinking craft have completely stopped before prying open doors and swimming to the surface.

White and his 12 research partners have discovered in experiments that survivors do not have the ability to hold their breath long enough to swim safely to the surface in most cases.

“We've established that, regardless of the water temperature, the average breath-hold time for lightly exercising men is 25 seconds. For women in the same conditions, it is only 15 seconds,” says White. “That's significantly shorter than the estimated time survivors need to escape a submerged helicopter. That time averages about 28 to 92 seconds in calm water in a laboratory. We anticipate these escape times would be prolonged in cold, open ocean conditions.”

White and his partners will assess three types of devices that could enable ditched helicopter survivors to make a successful underwater swim to the surface.

Two of the devices are modelled after the re-breathing capabilities of existing military equipment, which is not adequate for an escape from a submerged helicopter. Rebreathing devices allow the reuse of exhaled air, which has less oxygen and more carbon dioxide, stimulating faster breathing.

One device is a prototype hood developed by Mustang Survival in B.C. It is made out of a micro-porous waterproof membrane that enables the underwater wearer to retain air for rebreathing. The hood seals around the head and provides visibility for underwater escape.

Another device is a miniature oxygen-containing scuba (self-contained underwater breathing apparatus) bottle that has an air regulator and mouthpiece.

The third option would be a hybrid of the hood and the scuba bottle.

There are problems with all three options that still need to be resolved.

“Claustrophobia could be a big concern with the hood and a scuba bottle would have all the challenges associated with scuba diving,” explains White.

“The hood wearer would have the challenge of breathing normally under stress to conserve available air, while use of the scuba bottle requires good diving technique to avoid decompression injuries.”

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