Microvascular gas embolization clearance following perfluorocarbon administration

Abstract

Effective treatment of vascular gas embolism may be possible with emulsified fluorocarbon compounds. We tested the hypothesis that a fluorocarbon emulsion delivered before gas embolization would enhance bubble motion through the vasculature, favoring more rapid clearance. Air microbubbles were injected into the rat cremaster microcirculation in six groups of rats receiving Perftoran, an emulsified fluorocarbon, or saline immediately before, 2 h before, or after bubble injection. Embolism dimensions and dynamics were observed by using intravital microscopy. Surface area at lodging was equal between groups. Bubbles having smaller volume embolized smaller diameter vessels in the Perftoran pretreatment groups. A higher incidence of bubble dislodgement and larger distal displacement occurred in these two groups, with a 36% decrease in the time to bubble clearance and restoration of blood flow. Intravascular emulsified fluorocarbon administration before gas embolization affected initial bubble conformation, increased bubble dislodgement, and resulted in bubble displacement further into the periphery of the microcirculation. These dynamic events did not occur if embolization preceded fluorocarbon administration.

A front tracking method for a deformable intravascular bubble in a tube with soluble surfactant transport

“…Since bubble lodging occurs when bubble diameter is of the same order magnitude as the diameter of the blood vessel, into which it progresses [2,14], the asymmetry is often small and can be ignored. Thus, it is sufficient to set up the problem in an axisymmetric geometry, as shown in Fig.…”

“…(30), a central difference scheme is utilized for all cells except for those that are within one mesh size and adjacent to the interface. For cells adjacent to the interface, special treatment is needed to ensure that the flux boundary condition (14) is identically satisfied. The detailed implementation is addressed in the following section.…”

“…Also, it is noted that a central difference scheme to evaluate the diffusion term is valid only for cells located away from the interface. For cells close to the interface, special treatment is needed to ensure that the boundary condition (14), which is represented as an integral source term in Eq. (30), holds true.…”

“…With the Frumkin isotherm, there is a non-linear term as noted from the left hand side of Eq. (14). The time step, Dt for the Frumkin isotherm case will therefore be different from that for the Langmuir case since the time step has to satisfy the stability criterion in either case.…”

“…The intravascular gas emboli may deposit into organs, like the heart or the brain, and as a result, cause permanent injury. Surfactant based intervention [2,14] is a novel treatment to eliminate such risks, and the present study will enable an evaluation of this process. A suitable, soluble, inert surfactant introduced into the system may adsorb onto the gas-liquid interface and may modify the interfacial tension, and also shield biological moieties in the blood stream from encountering an adsorptive surface.…”