Prophylactic high dose methylprednisolone fails to treat severe decompression sickness in swine

• Published in: Aviation, space, and environmental medicine space, and environmental medicine, 2003, Vol.74 (1), p.21-28
• Main Authors: DROMSKY, David M, WEATHERSBY, Paul K, FAHLMAN, Andreas
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animals; Anti-Inflammatory Agents - administration & dosage; Biological and medical sciences; Bones, joints and connective tissue. Antiinflammatory agents; Decompression Sickness - prevention & control; Disease Models, Animal; Dose-Response Relationship, Drug; Hyperbaric Oxygenation; Logistic Models; Male; Medical sciences; Methylprednisolone - administration & dosage; Multivariate Analysis; Pharmacology. Drug treatments; Space life sciences; Swine; Treatment Outcome
• ISSN: 0095-6562; 1943-4448

Controlled decompression from saturation conditions is not always an option, particularly in a disabled submarine scenario. Hypothesis Prophylactic high dose methylprednisolone (MP) would improve outcome in severe cases of decompression sickness (DCS). Littermate pairs of male Yorkshire swine (n = 86, mean weight +/- SE = 19.3 +/- 0.2 kg) were randomized to one of three groups, then compressed on air to 4.3 ATA (33 msw) for 22 h and brought directly to surface pressure (1 ATA) at 0.9 ATA x min(-1). The MP-50 group received i.v. infusion of 50 mg x kg(-1) of MP dissolved in 60 cc normal saline (NS) immediately prior to the hyperbaric exposure. The NS group received 60 cc NS i.v. immediately prior to the hyperbaric exposure. The MP-10 group received i.v. infusion of 10 mg x kg(-1) MP dissolved in 60 cc NS during the hyperbaric exposure, 7 h before the decompression. Outcomes of severe DCS and death were recorded. NS group: 14 DCS, 4 died; MP-50 group: 19 DCS, 12 died; MP-10 group: 19 DCS, 10 died. Compared with the NS group, logistic regression analysis suggested that animals in the MP-10 group were more likely to get severe DCS and to die (p < 0.01) and animals in the MP-50 group were more likely to die from their disease (p < 0.01). Prophylactic high dose MP exerts no protective effect against severe DCS and actually worsens mortality in this model. An earlier group of untreated controls (UC, n = 44, 30 DCS, 11 died, mean weight +/- SE = 19.9 +/- 0.3 kg) exposed to the same profile was also available for analysis. Comparison of the UC and NS animals suggested that pre-dive NS treatment may protect against severe DCS.