Decompression illness in divers treated in Auckland, New Zealand, 1996-2012

Introduction: The treatment of divers for decompression illness (DCI) in Auckland, New Zealand, has not been described since 1996, and subsequent trends in patient numbers and demographics are unmeasured. Methods: This was a retrospective audit of DCI cases requiring recompression in Auckland between 01 January 1996 and 31 December 2012. Data describing patient demographics, dive characteristics, presentation of DCI and outcomes were extracted from case notes and facility databases. Trends in annual case numbers were evaluated using Spearman's correlation coefficients (rho) and compared with trends in entry-level diver certifications. Trends in patient demographics and delay between diving and recompression were evaluated using regression analyses. Results: There were 520 DCI cases. Annual caseload decreased over the study period (rho = 0.813, P < 0.0001) as did entry-level diving certifications in New Zealand (rho = 0.962, P < 0.0001). Mean diver age was 33.6 (95% confidence limits (CI) 32.7 to 34.5) years and age increased (P < 0.0001) over the study period. Median (range) delay to recompression was 2.06 (95% CI 0.02 to 23.6) days, and delay declined over the study period (P = 0.005). Conclusions: Numbers of DCI cases recompressed in Auckland have declined significantly over the last 17 years. The most plausible explanation is declining diving activity but improvements in diving safety cannot be excluded. The delay between diving and recompression has reduced.