In vivo validation of a miniaturized electrochemical oxygen sensor for measuring intestinal oxygen tension

Abstract

Recent advances in the fields of electronics and microfabrication techniques have led to the development of implantable medical devices for use within the field of precision medicine. Monitoring visceral surface tissue O₂ tension ($\text{P}{\text{T}}_{{\text{o}}_2}$) by means of an implantable sensor is potentially useful in many clinical situations, including the perioperative management of patients undergoing intestinal resection and anastomosis. This concept could provide a means by which treatment could be tailored to individual patients. This study describes the in vivo validation of a novel, miniaturized electrochemical O₂ sensor to provide real-time data on intestinal $\text{P}{\text{T}}_{{\text{o}}_2}$. A single O₂ sensor was placed onto the serosal surface of the small intestine of anesthetized rats that were exposed to ischemic (superior mesenteric artery occlusion) and hypoxemic (alterations in inspired fractional O₂ concentrations) insults. Control experiments demonstrated that the sensors can function and remain stable in an in vivo environment. Intestinal $\text{P}{\text{T}}_{{\text{o}}_2}$ decreased following superior mesenteric artery occlusion and with reductions in inspired O₂ concentrations. These results were reversible after reinstating blood flow or by increasing inspired O₂ concentrations. We have successfully developed an anesthetized rat intestinal ischemic and hypoxic model for validation of a miniaturized O₂ sensor to provide real-time measurement of intestinal $\text{P}{\text{T}}_{{\text{o}}_2}$. Our results support further validation of the sensors in physiological conditions using a large animal model to provide evidence of their use in clinical applications where monitoring visceral surface tissue O₂ tension is important.NEW & NOTEWORTHY This is the first report of real-time continuous measurements of intestinal oxygen tension made using a microfabricated O₂ sensor. Using a developed rodent model, we have validated this sensor's ability to accurately measure dynamic and reversible changes in intestinal oxygenation that occur through ischemic and hypoxemic insults. Continuous monitoring of local intestinal oxygenation could have value in the postoperative monitoring of patients having undergone intestinal surgery.

Keywords: hypoxemia; intestinal resection and anastomosis; intestinal serosal tissue oxygen tension; miniaturized electrochemical oxygen sensor; superior mesenteric artery occlusion.