<em></em> <i>In Vitro</i> Investigation of Gas Embolism in Microfluidic Networks Mimicking Microvasculature

Abstract

Gas embolism is a medical condition leading to the blockage of blood flow in the microvasculature by gas bubbles. While reported as rare, gas embolism often has devastating, fatal physiological consequences. Despite this acute importance, the genesis and evolution of air bubbles in blood vessels under different physiological conditions, such as blood viscosity and blood flow rate, is still understudied, largely because of difficult experimentation and in situ visualization. The objective of this work was to study the gas embolism phenomenon in vitro, using a microfluidic system that mimicked the architecture of microvasculature. The microfluidic systems comprised linear channels with two different air inlet types, namely, T- and Y-junctions with three different widths (20 &amp;micro;m, 40 &amp;micro;m, and 60 &amp;micro;m), and a 30 &amp;micro;m width honeycombed network with three bifurcation angles (30&amp;deg;, 60&amp;deg;, and 90&amp;deg;). Three synthetic liquids equivalent to 0%, 20%, and 46% hematocrit that mimicked the physiological blood viscosity and hematocrit concentrations were used. Our results show that: (i) 20 &amp;micro;m and 40 &amp;micro;m width channels had an elevated risk of gas embolism due to wide fluctuations in the total slug sizes; (ii) the resistance to the flow of air bubbles increased with the increase in the equivalent concentration of hematocrit; (iii) gas bubbles causing blockages and dampening of the flow velocity were frequently observed in 20 &amp;micro;m channels, and lastly (iv) increased risk of gas embolism was observed in the honeycomb architecture with 60&amp;deg; and 30&amp;deg; bifurcations. This work suggests that in vitro experimentation using microfluidic devices with microvascular tissue-like structures opens the possibility of studying this medical condition with high reproducibility and impacts the fact-based medical guidelines for preventing or mitigating iatrogenic occurrences.

Investigation of air bubble behaviour after gas embolism events induced in a microfluidic network mimicking microvasculature

“…The median analysis and density maps were generated based on the protocol discussed in previous studies. 48 3 Results and discussion…”