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


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Dromsky
David M
DM
Naval Medical Research Center, Bethesda, MD, USA.
Weathersby
Paul K
PK
Fahlman
Andreas
A
D000704:Analysis of Variance; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D003665:Decompression Sickness / Q000517:prevention & control*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006931:Hyperbaric Oxygenation; D016015:Logistic Models; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage*; D015999:Multivariate Analysis; D013552:Swine; D016896:Treatment Outcome
D000893:Anti-Inflammatory Agents; D008775:Methylprednisolone