Prognostic value of intraoperative renal tissue oxygenation measurement on early renal transplant function

Abstract

Summary Ischemia time is a prognostic factor in renal transplantation for postoperative graft function and survival. Kidney transplants from living donors have a higher survival rate than deceased donor kidneys probably because of shorter ischemia time. We hypothesized that measurement of intraoperative kidney oxygenation (μHbO2) and microvascular perfusion predicts postoperative graft function. We measured microvascular hemoglobin oxygen saturation by reflectance spectrophotometry and microcirculatory kidney perfusion by laser Doppler flowmetry 5 and 30 min after kidney reperfusion on the organ surface in 53 renal transplant patients including 19 grafts from living donors. These values were related to systemic hemodynamics, cold ischemia time (cit), early postoperative graft function and length of hospital stay. μHbO2 improved 30 min after reperfusion compared to 5 min (from 67% to 71%, P < 0.05). μHbO2 correlated with mean arterial blood pressure and central venous pH (P < 0.01). Most importantly, μHbO2 was significantly higher in kidneys from living compared with deceased donors (74% vs. 63%) and in kidneys without vs. with biopsy‐proven postoperative rejection (71% vs. 45%, P < 0.001). Finally, μHbO2 correlated positively with cit and postoperative creatinine clearance and negatively with postoperative plasma creatinine, need for hemodialysis and length of hospital stay. Our results suggest higher oxygen extraction and thus oxygen demand of the grafts shortly after reperfusion. The intraoperative measurement of tissue oxygenation in kidney transplants is predictive of early postoperative graft function. Future studies should evaluate the potential effect of intraoperative therapeutic maneuvers to improve organ tissue oxygenation in renal transplantation.

Targeting Endogenous Repair Pathways after AKI

“…There have been studies using blood oxygenation level-dependent magnetic resonance imaging in experimental ischemic AKI and clinical settings, including allograft rejection compared with normal functional transplants and transplants with acute tubular necrosis. [9][10][11] Other noninvasive tools that are potential candidates for assessing RBF and tissue oxygenation include positron emission tomography and optical spectroscopy, 12,13 both of which need validation in additional clinical studies.…”

Evidence of a heterogeneous tissue oxygenation: renal ischemia/reperfusion injury in a large animal model

“…Not surprisingly, tissue oxygenation was higher in kidneys from living donors compared with deceased donors and correlated directly with ischemia time. 14 In that study, the authors noted that the tissue oxygenation measurements did not correlate with the surgeon's observations of mottling. The disadvantage of making measurements in a probe format, however, is the loss of regional information unless multiple measurements are made across the tissue.…”

“…13,14 By exploiting the different spectral properties of oxygenated and de-oxygenated hemoglobin, it is possible to quantify the level of oxygenation in the blood by measuring the wavelengths reflected off the kidney. To better understand the dynamics of intraoperative renal ischemia and recovery of renal oxygenation during reperfusion, a visible reflectance imaging system (VRIS) was developed to measure renal oxygenation during renal artery clamping in both cooled and warm kidneys.…”

Untitled

“…6 However, to our knowledge, our study is the first study introducing graft renal vein blood gases as an indicator for graft function. In addition, this study suggests that a low hemoglobin concentration has a negative effect on kidney transplant.…”