Classification of Decompression Sickness Signs and Symptoms Using Cluster Analysis

The decompression sickness (DCS) is the general name given to the maladies caused by deficient decompression after being exposed to high ambient pressure. The DCS may cause a large spectrum of signs and symptoms that determine the type of the disease and the treatment is performed accordingly. The aim of this study is to investigate different types of DCS using data mining techniques. The data has been collected from more 604 DCS reports from commercial diving operations that cover: 1) Air diving operations from 12 msw to 60 msw, with either air standard decompression, decompression using oxygen or surface decompression into a diving decompression chamber (DDC). These logs refer to dive mostly single dives but also include few repetitive dives. 2) Heliox bounce diving operation from 48 msw to 120 msw, performed either with surface supplied suing a wet bell or with bell diving using transfer under pressure into a DDC for the rest of the decompression. 3) Heliox saturation in the North Sea with both incidents reported during a final decompression of after a bell excursion dive. The information in the reports includes the sign and symptoms of the patients, that constitute the data for the cluster analysis. Two configurations were tested using Two Step Cluster Analysis with Ward’s method: 1) In the first study, the analysis was forced to identify at least two clusters. 2) In the second study, three clusters were forced to further investigate the sub groups. The result of the first study yielded 2 clusters: 1) Pain only and 2) all other symptoms. The clusters of the seconds study can be defined as: 1) Pain in or around articulations, 2) Predominantly vestibular and 3) Predominantly neurological.