Most holidaying divers are aware of the need to be well decompressed before flying home, to avoid possible complications linked with the reduced pressures experienced when flying.
But while the recommended 24-hour waiting period after the last dive may be enough for single-flight journeys home, it may be insufficient for journeys that involve two or more connected flights.
That's the conclusion of a study carried out by the San Francisco Institute for Hyperbaric Medicine. The theory is that, on first take-off, excess nitrogen still in the body starts bubbling and, on landing, reduces but not to the same level as before.
Subsequent take-offs and landings have the effect of gradually increasing the size of nitrogen bubbles in the body's tissues and blood.
Presenting findings to a meeting of the Undersea Hyperbaric Medical Society, as reported by the US diving newsletter Undercurrent, the San Francisco Institute's director, Frederick Cramer, cited the case of
a diver who, having holidayed in the Cayman Island, made a four-leg trip home.
It involved an unpressurised inter-island plane that rose to just 5000ft; a pressurised plane which rose to 35,000ft, maintaining an 8000ft cabin pressure; another plane that flew similarly to the second but landed at Minneapolis, 1000ft above sea level; and a fourth plane that flew to Spokane, 2400ft above sea level.
The 37-year-old female diver in question, while having dived in conservative fashion on holiday and observed the usual rest-before-flying recommendations, ended up with signs of severe DCI.
Fortunately she recovered fully after reporting at a hospital and being admitted for recompression treatment.
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