# Real-time organ perfusion monitoring of human kidney transplants using ex vivo normothermic perfusion and reflectance spectroscopy

## TL;DR

This study introduces a non-invasive method to monitor kidney transplant perfusion in real-time using optical reflectance and normothermic perfusion.

## Contribution

A novel, minimally invasive technique for real-time kidney perfusion monitoring using reflectance spectroscopy during ex vivo normothermic perfusion.

## Key findings

- Oxygen saturation estimates before perfusion issues were higher than after.
- Spectroscopic measurements correlated well with renal blood flow index changes.
- The method shows promise for in vivo monitoring of transplanted kidneys.

## Abstract

Transplantation is the standard treatment for end-stage kidney disease but carries with it a non-trivial risk of post-operative complication. There is a need for a continuous, real-time, not additionally invasive method of monitoring organ perfusion. We present an approach to allograft perfusion monitoring using a human kidney model using ex vivo normothermic perfusion (EVNP) and custom spectroscopic optical reflectance probes. Five discarded human kidneys underwent EVNP, spectroscopic measurement and were subjected to perfusion compromising events (rejection, thrombosis or haemorrhage). Oxygenated and deoxygenated haemoglobin spectra were fitted to the spectra acquired from the kidneys in order to estimate the oxygen saturation. Average oxygen saturations before the perfusion compromising events were estimated to be higher than after (or similar in the control cases). Changes in oxygen saturation estimated from measurements made continuously were synchronized well with changes in renal blood flow index measurements. This proof of concept study proves promising in identifying a technique for continuous monitoring of perfusion and oxygenation of a transplanted kidney in vivo with minimal additional invasiveness.