Cold Renal Ischemia: Comparison of Efficacy Between Two Techniques of Cooling, in a Swine Model

Abstract

Objectives: In a swine model of renal ischemia, we compared the effectiveness of the transureteral retrograde cold saline perfusion technique to the traditional method of renal cooling with ice slush, in achieving adequate parenchymal temperatures for functional preservation of the organ. Physiological and histological effects were also assessed. Methods: Twenty-four domestic male pigs were sampled into four groups to be submitted to a 60-minute ischemia of the left kidney without cooling, with either one of the two cooling techniques (cold saline retrograde perfusion or ice slush), or sham surgery. All of them had also a concomitant right nephrectomy. Renal cortical and medullary temperatures were recorded throughout the experiment. Urinary output was measured, and serum renal function tests were carried on, pre-and postoperatively. After 5 days, the animals were euthanized and their kidneys were submitted to histological analysis. Results: Mean renal temperature fell in both groups submitted to kidney cooling. With ice slush, a faster drop was observed and a lower minimum temperature was achieved (5.08C in the cortex and 6.38C in the medulla, vs. 25.48C and 24.98C with retrograde cooling). In the other groups, temperature was unchanged. Urinary output and serum creatinine worsened after the experiment, but without significant differences among groups. The histological analysis showed no differences among the four groups, for the studied ischemia time. Conclusions: Ice slush and retrograde perfusion of cold saline are both effective for cooling the kidney during ischemia. Ice slush is faster in doing so, and it allows much lower temperatures to be achieved in the renal parenchyma. With ischemia time of 60 minutes, no significant differences on the occurrence of functional and histological alterations were detected, even for the group without a cooling procedure.

Infrared Thermometer: an accurate tool for temperature measurement during renal surgery

“…If cutoff value was 15ºC, at T5 and T10 70-80% and 80-90% of kidneys were adequately cooled, respectively. We confirmed data from other studies proving ice slush to be an excellent fast and efficient method for renal cooling (10,17,18). Gill et al achieved a nadir renal parenchymal temperature of 5 to 19ºC by using ice slush during laparoscopic partial nephrectomy in humans (21).…”

“…Gill et al achieved a nadir renal parenchymal temperature of 5 to 19ºC by using ice slush during laparoscopic partial nephrectomy in humans (21). Guerra et al recently compared ice slush with retrograde ureteral cold saline perfusion during experimental renal cooling (10). In the ice slush group, they obtained a mean renal temperature decrease rate of 1.37ºC per minute in the medulla and 1.44ºC per minute in renal cortex during the first 20 minutes.…”

“…However, intraoperative assessment of kidney temperature during cooling and/or ischemia procedures are not routinely performed and poorly studied. Even when different renal cooling techniques are compared, whether in animals or humans, there is no standardization for such measurement (3)(4)(5)(6)(7)(8)(9)(10).…”

Comparative study between trimetazidine and ice slush hypothermia in protection against renal ischemia/reperfusion injury in a porcine model

“…Optimum temperature has been shown to be 15ºC in the canine model (21). Surface cooling of the kidney has been the most popular method of in situ hypothermia and has been accomplished by a variety of techniques such as surrounding the kidney with ice slush, immersing the kidney in a cold material, retrograde ureteral infusion of cold solution, or applying an external cooling device to the kidney (20,25,26). The most popular method has been to surround the mobilized kidney with a rubber sheet on which sterile ice slush is placed to completely immerse the kidney.…”

Comparação entre as modalidades de isquemia renal isotérmica seletiva, não-seletiva e intermitente em coelhos

“…Alguns inconvenientes existem nesta técnica como o não resfriamento adequado do córtex renal, permanecendo com uma diferença de temperatura significante em relação à medular, mesmo quando as células mais sensíveis ao agravo isquêmico estão na cortical. Há ainda o fato de poder ocorrer um vazamento da solução de perfusão e perda da hipotermia se houver abertura de via excretora (48) . Outro aspecto a ser considerado é a necessidade de uma abordagem endoscópica adicional para a cateterização ureteral.…”