# Hydrogen Molecule Delivery System to Ischemic Intestine Using Resuscitative Endovascular Balloon Occlusion of Aorta in Hemorrhagic Shock—A Proof-of-Concept Study

## TL;DR

This study shows that hydrogen can be delivered to the intestine during a medical procedure called REBOA in a pig model of hemorrhagic shock.

## Contribution

A novel method for delivering hydrogen molecules to ischemic organs during REBOA use is proposed and tested.

## Key findings

- Hydrogen concentration in the portal vein was significantly higher with hydrogen-dissolved saline irrigation during REBOA.
- Hydrogen delivery varied depending on the type of shock and REBOA inflation level.
- The control model showed minimal hydrogen presence, confirming the effectiveness of the delivery method.

## Abstract

Background: The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) for hemorrhagic shock in the torso has become increasingly common as a bridge to definitive hemostasis. Hydrogen molecules, distributed throughout the bloodstream, alleviate ischemic injury but cannot reach ischemic organs during REBOA use. This study investigates whether intra-aortic irrigation with hydrogen-dissolved saline under REBOA use delivers hydrogen to the intestine in a swine hemorrhagic shock model. Methods: We induced volume-regulated hemorrhagic shock in a 40 kg female swine. Following this, hydrogen-dissolved saline irrigation was initiated through an intra-aortic catheter positioned distal to the REBOA balloon. Hydrogen concentration in the portal vein was determined in four models: controlled hemorrhagic shock with full REBOA inflation during the standard occlusion time, uncontrolled hemorrhagic shock with liver injury and full REBOA inflation during the extended occlusion time, uncontrolled hemorrhagic shock with liver injury and partial REBOA inflation during the extended occlusion time, and as the control model, controlled hemorrhagic shock with full REBOA inflation during the standard occlusion time with normal saline irrigation without hydrogen. Results: Hydrogen concentration in the portal vein was found to be 0.224 mg/L (13.998%) in the controlled hemorrhagic shock model with full REBOA inflation, 0.049 mg/L (3.063%) in the uncontrolled hemorrhagic shock model with liver injury and full REBOA inflation, 0.018 mg/L (1.125%) in the uncontrolled hemorrhagic shock model with liver injury and partial REBOA inflation, and 0.002 mg/L (0.015%) in the control model. These results demonstrate the presence of hydrogen in the portal vein under different REBOA applications. Conclusions: Increased hydrogen concentration in the portal vein indicated that hydrogen was delivered to the intestine. These findings suggest an approach for drug administration during REBOA use. However, further investigations are required to establish its application in clinical settings.