Spinal cord lipid levels in a porcine model of spinal cord decompression sickness.

Spinal cord lipid content was analyzed in 50 pigs that had experienced a simulated dive known to produce 20-80% incidence of neurologic decompression sickness (DCS). Using air and heliox as breathing mixtures, these animals underwent chamber dives ranging from 200-250 feet of seawater (fsw). These dives were designed to generate spinal cord DCS, which was detected by observing the animals for gross neurologic deficits. Using a standardized method, cylindrical samples of cord were cut from different spinal levels and analyzed for total lipid (TL) content, which produced two cervical, three thoracic, and two lumbar samples. All areas with gross hemorrhage were also sampled. The range of TL (mean) in milligrams per gram from the cervical, thoracic, and lumbar regions were 118-679 (319), 140-635 (366), and 109-658 (307), respectively. Although this implies that TL varies markedly between cords, values within each cord were fairly consistent (+/- 20% from cord mean). The difference in TL values between cord regions with and without hemorrhage was not significant (P > 0.1). This reveals that increased spinal cord TL levels, together with their presumed dissolved inert gas, do not play a major role in the location or incidence of spinal cord hemorrhages in pigs with clinical signs of spinal cord DCS.