# Role of oxygen reserve index monitoring in patients undergoing robot-assisted radical prostatectomy: a retrospective study

## TL;DR

This study shows that monitoring the oxygen reserve index during prostate surgery can help predict and manage low oxygen levels, especially in patients with higher body mass index.

## Contribution

The study introduces the oxygen reserve index as a predictive tool for intraoperative hypoxia during robot-assisted radical prostatectomy.

## Key findings

- Intraoperative hypoxia occurred in 18.8% of patients undergoing robot-assisted radical prostatectomy.
- An ORi value of less than 0.16 was identified as an independent risk factor for hypoxia.
- Higher body mass index was also found to be an independent risk factor for hypoxia during the procedure.

## Abstract

Robot-assisted radical prostatectomy (RARP) is a common surgical procedure for the treatment of prostate cancer. Although beneficial, it can lead to intraoperative hypoxia due to high-pressure pneumoperitoneum and Trendelenburg position. This study explored the use of oxygen reserve index (ORi) to monitor and predict hypoxia during RARP.

A retrospective analysis was conducted on 329 patients who underwent RARP at the Seoul National University Bundang Hospital between July 2021 and March 2023. Various pre- and intraoperative variables were collected, including ORi values. The relationship between ORi values and hypoxia occurrence was assessed using receiver operating characteristic curves and logistic regression analysis.

Intraoperative hypoxia occurred in 18.8% of the patients. The receiver operating characteristic curve showed a satisfactory area under the curve of 0.762, with the ideal ORi cut-off value for predicting hypoxia set at 0.16. Sensitivity and specificity were 64.5% and 75.7%, respectively. An ORi value of < 0.16 and a higher body mass index were identified as independent risk factors of hypoxia during RARP.

ORi monitoring provides a non-invasive approach to predict intraoperative hypoxia during RARP, enabling early management. Additionally, the significant relationship between a higher body mass index and hypoxia underscores the importance of individualized patient assessment.