Title : Utility of near-infrared spectroscopy in monitoring renal perfusion following adult kidney transplantation
Abstract:
Background: Near-infrared spectroscopy (NIRS) is a continuous, real-time method for evaluating regional oxygen saturation (rSO2) that can detect early declines in renal tissue oxygenation. This study aims to assess the effectiveness of NIRS in monitoring the perfusion of transplanted kidneys in the postoperative period.
Methods: In this prospective observational study, 21 end-stage renal disease (ESRD) patients undergoing living donor renal transplantation were enrolled. Immediately after transplantation, a NIRS monitor was placed on the skin over the upper pole of the kidney, allowing for continuous rSO2 (renal saturation) monitoring. Measurements of rSO2, mean arterial pressure (MAP), and urine output were recorded at baseline. Every 30 minutes for the first 24 hours, followed by hourly intervals until 48 hours, and then every eight hours until 120 hours. Creatinine and arterial lactate levels were measured at baseline and every 24 hours. Patients were followed for five days, with renal perfusion assessed using rSO2 trends and correlations between rSO2 values, urine output, and serum creatinine levels.
Results: Our findings indicated that rSO2 levels increased over time, signaling improved kidney perfusion following transplantation. Consistently, a significant negative correlation was found between rSO2 and serum creatinine levels. A negative correlation was also observed between mean rSO2 and urine output, which was statistically significant at all time points except 48 hours.
Conclusion: NIRS monitoring is an efficient, noninvasive, and valuable tool for assessing renal perfusion in patients after renal transplantation. It allows for the early detection of complications during the postoperative period. The continuous nature of this monitoring method provides real-time insights into renal oxygen saturation, facilitating the early identification of impaired blood flow in renal allografts and potentially leading to timely interventions that increase the success rates of salvage attempts.
