CONTINUOUS MEASUREMENT OF PORCINE RENAL-CORTEX MICROCIRCULATION WITH ENHANCED THERMAL-DIFFUSION TECHNOLOGY

Continuous monitoring of renal cortical blood how (RCBF) in the periop erative setting of aortic or renal vascular surgery could faciliate th e early detection of vascular complications, possibly resulting in a r eduction of postoperative renal failure. A new prototype system for me asurement of parenchymous organ perfusion based on the principle of th ermal diffusion (''TD''-Thermal Diffusion Electrode, Thermal Technolog ies Inc., Cambridge, MA, USA) was used for RCBF measurements in the ou ter cortex of the porcine kidney. We validated the sensitivity of the device to detect renal blood flow impairment, comparing TD flow data w ith renal artery blood flow values (RABF), measured by ultrasonic how probes. The hypothesis was tested that acute disturbances of RCBF, ind uced by a variable degree of renal artery stenosis, can be immediately detected and continuously monitored by TD measurements in the porcine renal cortex. Mean baseline RCBF measured by TD electrodes was 68.1 /- 25.0 ml/100 g/min. Mean baseline RABF was 102.1 +/- 26.6 ml/min. Co ntrolled induction of a variable degree of renal arterial occlusion by implanted vascular balloon occluders was always followed by an immedi ate and proportional decline of RCBF, as measured by TD. Flow data obt ained with both methods were significantly correlated by linear regres sion (r = .82, r(2) = .68; P < 0.0001). Dynamic changes of RABF in the time course of renal artery partial/total occlusion and arterial flow release could be continuously followed by detection of corresponding flow changes of RCBF. We conclude that the TD system investigated in t he current study allows a continuous and sensitive determination of po rcine renal cortex perfusion. A clinical evaluation of the method, e.g ., in the perioperative setting of aortic or renal transplantation sur gery, now appears to be justified. (C) 1996 Academic Press, Inc.