Analysis of two datasets of divers with actual or suspected decompression illness

(Sayer MDJ, Ross JAS, Wilson CM. Analysis of two datasets of divers with actual or suspected decompression illness. Diving and Hyperbaric Medicine. 2009;39(3):126-32.) Introduction: We examined national and single-centre datasets in Scotland to determine any trends in the treatment of diving-related disease and to assess how the choice of first treatment may be linked to the divers' condition on referral and on discharge. Method: Two datasets were analysed: (1) 300 divers treated for actual or suspected decompression illness by the Dunstaffnage Hyperbaric Unit (Oban) between 1972 and 2007; and (2) 536 divers treated by the Scottish recompression chamber network between 1991 and 2003 (some data were common to both sets). The type and frequency of initial and any subsequent hyperbaric treatment used were examined. Any trends in demographics, reasons for diving, dive series profiles and condition on admission were examined. Results: Ninety to 92 per cent of treated divers received standard or modified Royal Navy treatment table 62 (RN 62) or US Navy table 6 (USN 6) for their primary treatment. Nearly a third of the divers (32%) were rated as having a severe condition on admission; only 4% had a severe condition on discharge. Analysis of outcome versus treatment type was complicated by divers with more severe symptoms on referral tending to have a worse outcome (concomitant with their referral condition) while receiving more prolonged and complex treatments. Conclusions: Shorter and shallower treatment tables (e.g., US Navy table 5, Royal Navy table 61), when used as first treatment, may result in poorer outcomes compared with RN 62/USN 6 treatment. Although subject to ongoing analysis, the shorter and/or shallower treatments have been discouraged as a first treatment in Scotland.