How delay to recompression influences treatment and outcome in recreational divers with mild to moderate neurological...

This retrospective review examined the influence of delay to recompression on mild/moderate neurological decompression sickness (DCS) in divers, as a pilot for an abandoned prospective study.

The medical histories of 28 divers treated at a hyperbaric facility in the Maldive Islands in the Indian Ocean were evaluated. The term 'oxygen unit' (OU; 1 OU = 1 bar (ambient pressure) x 1 min x 1.0 (inspiratory oxygen fraction)) was used to enable a quantification of administered hyperbaric oxygen. Visual analog symptom scale (VASS) scores of the worst symptom at presentation (used routinely at the clinic to quantify treatment response) were analysed.

Divers presenting later than 17 hours after surfacing (the median time to treatment after surfacing for the whole group) were likely to have more intense symptoms on VASS (median 100%) than those who presented earlier for treatment (median 30%, P = 0.02). Total OU needed to treat divers presenting within 17 hours did not differ from those treated later (P = 0.11). Divers with ≥ 70% symptom reduction with the first hyperbaric oxygen treatment (HBOT) needed between 260 and 1,463 OU in total, whereas those with less than 70% reduction in VASS needed between 263 and 2,126 OU (P = 0.04).

Neither more HBOT nor a worse outcome of DCS could be related to delay to treatment longer than 17 hours. The amount of oxygen that had to be administered in total during the whole HBOT course was lower in cases that responded better to the initial HBOT.