Effect of oxygen breathing and perfluorocarbon emulsion treatment on air bubbles in adipose tissue during decompression sickness

Abstract

Decompression sickness (DCS) after air diving has been treated with success by means of combined normobaric oxygen breathing and intravascular perfluorocarbon (PFC) emulsions causing increased survival rate and faster bubble clearance from the intravascular compartment. The beneficial PFC effect has been explained by the increased transport capacity of oxygen and inert gases in blood. However, previous reports have shown that extravascular bubbles in lipid tissue of rats suffering from DCS will initially grow during oxygen breathing at normobaric conditions. We hypothesize that the combined effect of normobaric oxygen breathing and intravascular PFC infusion could lead to either enhanced extravascular bubble growth on decompression due to the increased oxygen supply, or that PFC infusion could lead to faster bubble elimination due to the increased solubility and transport capacity in blood for nitrogen causing faster nitrogen tissue desaturation. In anesthetized rats decompressed from a 60-min hyperbaric exposure breathing air at 385 kPa, we visually followed the resolution of micro-air bubbles injected into abdominal adipose tissue while the rats breathed either air, oxygen, or oxygen breathing combined with PFC infusion. All bubble observations were done at 101.3 kPa pressure. During oxygen breathing with or without combined PFC infusion, bubbles disappeared faster compared with air breathing. Combined oxygen breathing and PFC infusion caused faster bubble disappearance compared with oxygen breathing. The combined effect of oxygen breathing and PFC infusion neither prevented nor increased transient bubble growth time, rate, or growth ratio compared with oxygen breathing alone. We conclude that oxygen breathing in combination with PFC infusion causes faster bubble disappearance and does not exacerbate transient bubble growth. PFC infusion may be a valuable adjunct therapy during the first-aid treatment of DCS at normobaric conditions.

Threshold Altitude for Bubble Decay and Stabilization in Rat Adipose Tissue at Hypobaric Exposures

“…Further, PFC emulsions have been shown to cause faster elimination of extravascular air bubbles in adipose tissue during normobaric oxygen breathing using a model similar to the present experiments ( 17 ). Similarly, nitrogen oxide (NO) donors have proven benefi cial in preventing DCS from air diving, supposedly caused by increased blood fl ow rate or removal of micronuclei precursors ( 29 ).…”

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

“…Despite evidence of adverse hemodynamic effects of PFC emulsion in swine (and sheep), PFCs have a long history in the prevention of DCS as well as improving mortality after DCS onset in animal models (9,27). This improvement could be due to overall higher oxygen content, enhanced nitrogen elimina- tion, or surfactant properties that may limit arterial bubble derangements (12,13,26,31,32). Why female swine manifested earlier onset and less time to peak PAP can only be hypothesized.…”

Liquid Perfluorochemicals as Flexible and Efficient Gas Carriers Applied in Bioprocess Engineering: An Updated Overview and Future Prospects

“…The form of liquid PFC-based emulsions depends on the way of its bioengineering application. Two main lines of research are being actively pursued: (i) PFC-inwater emulsions for in vivo intravascular oxygen delivery (known as perfluorinated temporary blood substitutes) (Krafft et al, 2003;Riess, 2006b;Vasquez et al, 2013), as storage-media during organ transplantation procedures (Bezinover et al, 2014;Maillard et al, 2008;Terai et al, 2010), currently under development for treatment of traumatic brain and spinal cord injury (Spiess, 2009) as well as in decompression sickness therapy (Randsoe and Hyldegaard, 2009), and (ii) water-in-PFC reverse emulsions for pulmonary drug delivery (Courrier et al, 2004;Smoła et al, 2008), targeted emulsions for diagnosis and therapy (Kaufmann and Lindner, 2007;Lanza and Wickline, 2001;Martin and Dayton, 2013), as well as valuable research tool used in polymerisation technology (Chen et al, 2010;Zetterlund et al, 2008).…”