[abstract] STATISTICAL ASSOCIATION OF DECOMPRESSION SICKNESS MANIFESTATIONS IN SHEEP AFTER SIMULATED NO-STOP AIR DIVES.

Abstract

Decompression sickness (DCS) involves numerous manifestations, including limb bends, spinal cord DCS, and respiratory (RDCS), known as chokes. DCS manifestations can occur together or separately in clinical cases. We tested whether DCS manifestations occur randomly together by a Pearson chi-square analysis of Des signs that presented in adult sheep after no-stop air dives (2.1-5.2 ATA). When all animal dives were analyzed, limb bends and RDCS as well as spinal DCS and RDCS showed highly significant (P <0.01) positive associations; limb bends and spinal DCS were independently distributed (P >0.05). When only cases of DCS were analyzed, spinal DCS and RDCS were independently distributed (P>0.05); limb bends showed a negative association with both RDCS and spinal DCS (P<0.01). These findings demonstrate that cases of DCS will often present with more than one manifestation. However, spinal DCS and limb bends are less likely to occur with each other in DCS cases. This suggests that dive profiles that provoke spinal DCS are less likely to provoke limb bends, and vice versa, across the wide spectrum of dive pressure and duration tested. Dive profiles would appear to control both the incidence of DCS and the occurrence of specific DCS manifestations.<table> Percentage of DCS manifestations after no-stop air dives; DCS form/Dive duration(h), 1/2, 1, 2, 4, 24; Limb bends, 4.3, 3.8, 25.0, 13.9, 54.7; Spinal, 12.0, 2.9, 0.0, 0.0, 5.3; Resp. DCS, 7.6, 2.9, 0.0, 0.0, 42.7; N animal dives, 92, 104, 8, 72, 75</table> (Supported by the University of Wisconsin Sea Grant Institute)