Association Between Renal Regional Oxygen Saturation Measured by Near-InfraRed Spectroscopy and Postoperative Renal Failure After Lung Transplantation Surgery: A Pilot Study

Complications after lung transplantation are almost ubiquitous, among which postoperative acute renal failure may represent more than 50% of lung transplant patients and require extrarenal purification in 5 to 13% of cases.

Multiple factors are associated with postoperative acute renal failure. These factors can be classified into preoperative, intraoperative, and postoperative factors. While some postoperative complications are explained by donor and recipient factors, the literature suggests that certain intraoperative events represent modifiable or avoidable risk factors that could be targeted by therapeutic interventions to reduce the risk of postoperative acute renal failure. Some of these factors (intraoperative hemodynamic instability, significant bleeding or hypoxemia) can generate renal hypoxic aggression, alone or in combination. However, to date, there is no validated tool available at the patient's bedside during surgery to detect renal hypoxia or guide interventions to restore renal perfusion during surgery. Yet, as recent recommendations suggest, intraoperative renal protection is an important axis for improving the outcome of lung transplant patients, to the extent that the recommendations of Marczin et al. recommend the establishment of a renal prevention protocol for each patient. Without a tool to guide this plan intraoperatively, anesthesia teams can't establish a renal prevention protocol. This research aims to establish whether renal NIRS is a reliable tool for monitoring intraoperative renal hypoxic aggression predictive of postoperative renal failure.

Near-infrared spectroscopy (NIRS) is an optical technology that allows non-invasive measurement of tissue oxygen saturation. This technique is commonly used for intraoperative monitoring of cerebral perfusion in adults and children. Some studies have shown that regional renal oxygen saturation (renal rSO2) measured by NIRS during aortic-coronary bypass surgery under extracorporeal circulation (ECC) is correlated with renal venous oxygen saturation measured by catheterization. It is also associated with the risk of postoperative acute renal failure in patients undergoing cardiac surgery under ECC. However, there are no equivalent data in lung transplant patients, who frequently present with postoperative acute renal failure. In the available literature, no clear threshold of renal desaturation has been established. Because it is assumed that the depth of renal desaturation can be particularly deleterious, in addition to desaturation time, the investigator have chosen to retain in this project the integral of time and magnitude spent under a renal desaturation threshold, aggregated into a renal hypoxia index, during the intraoperative period.

The primary objective of this research is to demonstrate the usefulness of measuring the intraoperative renal hypoxia index in predicting the risk of early postoperative acute renal failure