Cardiovascular parameters in a mixed-sex swine study of severe decompression sickness treated with the emulsified perfluorocarbon Oxycyte

Abstract

Intravenous perfluorocarbons (PFC) have reduced the effects of decompression sickness (DCS) and improved mortality rates in animal models. However, concerns for the physiological effects of DCS combined with PFC therapy have not been examined in a balanced mixed-sex population. Thirty-two (16 male, 16 female) instrumented and sedated juvenile Yorkshire swine were exposed to 200 feet of seawater (fsw) for 31 min of hyperbaric air. Pulmonary artery pressure (PAP), cardiac output (CO), and systemic arterial pressure (SAP) were monitored before (control) and after exposure. Animals were randomized to treatment with Oxycyte (5 ml/kg; Oxygen Biotherapeutics, Inc., Morrisville, NC) vs. saline (control) with 100% oxygen administered upon DCS onset; animals were observed for 90 min. Parameters recorded and analyzed included PAP, CO, and SAP. In all animals PAP began to rise prior to cutis marmorata (CM) onset, the first sign of clinical DCS, generally peaking after CM onset. Female swine, compared with castrated males, had a more rapid onset of CM (7.30 vs. 11.46 min postsurfacing) and earlier onset to maximal PAP (6.41 vs. 9.69 min post-CM onset). Oxycyte therapy was associated with a sustained PAP elevation above controls in both sexes (33.41 vs. 25.78 mmHg). Significant pattern differences in PAP, CO, and SAP were noted between sexes and between therapeutic groups. There were no statistically significant differences in survival or paralysis between the PFC and control groups during the 48-h observation period. In conclusion, Oxycyte therapy for DCS is associated with a prolonged PAP increase in swine. These species and sex differences warrant further exploration.

Benefits of Escin for Decompression Sickness in Bama Pigs by Endothelial-Targeting Protection

“…Death is a common and unpredictable outcome in DCS experimental studies (Spiess et al, 2009; Mahon et al, 2014). The death rates were 1/8 and 2/7 in Group 1 and 3/8 and 1/5 in Group 2 for the first and second dive, respectively.…”

Therapeutic oxygen delivery by perfluorocarbon-based colloids

“…Another study with a F-pentane P-SNE found no effectiveness in rodents [392]. An undesirable increase of pulmonary artery pressure and no effect on survival were observed with Oxycyte, also in swine [393]. Further options are being discused [394].…”

Perfluorocarbons for the treatment of decompression illness: how to bridge the gap between theory and practice

“…This observation, for example in sheep, is even more relevant, because severe DCI itself can cause high PAP due to nitrogen-bubble-associated mechanical obstruction or indirectly by endothelial effects with vasoconstriction (Josephson 1970; Sheppard et al 2015). A recent mixed-sex swine study using the emulsified perfluorocarbon Oxycyte™ revealed a prolonged PAP increase in this species (Mahon et al 2015). There is one report of an adverse pulmonary reaction in human use concerning Fluosol™ (Vercellotti et al 1982).…”