Short oxygen prebreathing and intravenous perfluorocarbon emulsion reduces morbidity and mortality in a swine saturation model of decompression sickness

Abstract

Disabled submarine (DISSUB) survivors will achieve inert gas tissue saturation within 24 h. Direct ascent to the surface when saturated carries a high risk of decompression sickness (DCS) and death, yet may be necessary during rescue or escape. O(2) has demonstrated benefits in decreasing morbidity and mortality resulting from DCS by enhancing inert gas elimination. Perfluorocarbons (PFCs) also mitigate the effects of DCS by decreasing bubble formation and increasing O(2) delivery. Our hypothesis is that combining O(2) prebreathing (OPB) and PFC administration will reduce the incidence of DCS and death following saturation in an established 20-kg swine model. Yorkshire swine (20 +/- 6.5 kg) were compressed to 5 atmospheres (ATA) in a dry chamber for 22 h before randomization into one of four groups: 1) air and saline, 2) OPB and saline, 3) OPB with PFC given at depth, 4) OPB with PFC given after surfacing. OPB animals received >90% O(2) for 9 min at depth. All animals were returned to the surface (1 ATA) without decompression stops. The incidence of severe DCS < 2 h after surfacing was 96%, 63%, 82%, and 29% for groups 1, 2, 3, and 4, respectively. The incidence of death was 88%, 41%, 54%, and 5% for groups 1, 2, 3, and 4, respectively. OPB combined with PFC administration after surfacing provided the greatest reduction in DCS morbidity and mortality in a saturation swine model. O(2)-related seizure activity before reaching surface did not negatively affect outcome, but further safety studies are warranted.

Impairment of the autonomic nervous function during decompression sickness in swine

“…Thus the PDM method, by tracking the dynamics of the ANS, has the potential to be used as a noninvasive diagnostic measure for DCS. Modalities to prevent DCS have been sought and the results are promising, based on short oxygen prebreathing and administration of perfluorocarbon (6). Although the PDM is not a method to prevent DCS, it could be used in conjunction with such therapy to examine the proper dosage of the perfluorocarbon and the proper duration of oxygen prebreathing by tracking the dynamics of the ANS from DCS to eventual normal condition.…”

Perfluorocarbon‐Based Oxygen Carriers: Review of Products and Trials

“…Decompression sickness. Oxygen prebreathing in combination with Oxygent reduced the morbidity and mortality in a swine model of severe decompression sickness (49).…”

Preconditioning Methods and Mechanisms for Preventing the Risk of Decompression Sickness in Scuba Divers: A Review

“…It is speculated that administration of degassed liquids (ingestion or infusion) also could be involved in prevention of mild DCS (Watenpaugh 2003). In combination with oxygen breathing, PFC might reduce the morbidity and mortality of DCS swine if administered immediately after a saturation dive (Dainer et al 2007, Dromsky et al 2004). More research should be conducted, however, to learn about the potential deleterious effects of these therapeutic agents (e.g., pulmonary hypertension, increased seizure activity under HBO conditions; Dainer et al 2007, Mahon et al 2006) before generalizing them as an alternative nonrecompression DCS treatment.…”