Assessing the Effects of Gas Insufflation on Compromised Blood Vessels Using Vascular Systems-on-Chip

Gas insufflation is a procedure used in many medical interventions, such as laparoscopy. This study investigates the uptake of gas as a result of gas insufflation in the near vicinity of small blood vessels presenting submillimeter, often-invisible fissures. Because gas uptake is entirely a physical process, the microvasculature could be mimicked by an abiotic, polydimethylsiloxane (PDMS) made microfluidics system, comprising microchannels simulating small blood vessels, with widths of $30 \mu \mathrm{~m}, 50 \mu \mathrm{~m}, \mathbf{8 0} \mu \mathrm{~m}$, or $250 \mu \mathrm{~m}$, hosting the flow of synthetic blood at rates similar to those experienced in human body. The artificial blood vessels presented perforations with either $16 \mu \mathrm{~m}, 32 \mu \mathrm{~m}$, or $100 \mu \mathrm{~m}$ widths, positioned between the pressure chamber, where gas insufflation occurs, and the artificial blood vessels. Air was injected into the pressure chamber at rates similar to those used in laparoscopy, i.e., ranging from $10 \mathrm{~mL} / \mathrm{h}$ to $100 \mathrm{~mL} / \mathrm{h}$. The characteristics of bubbles due to gas uptake in the blood stream were correlated with perforation sizes, artificial blood vessel widths, and insufflation rates. Bubble volumes, particularly the maximum bubble volumes, increased proportionally with the width of the artificial blood vessel and the flow rate of the blood. As the artificial blood vessel width increased, the bubbles exhibited increasingly chaotic behavior, indicated by greater variability in bubble volumes. Larger perforations translated in an increased risk of gas embolism phenomena. Finally, higher injection rates intensified the chaotic character and simultaneously increased the total bubble volumes. These findings underscore possible significant risks associated with gas insufflation and similar procedures involving gas introduction, particularly for patients with damaged or compromised vascular systems.