Evaluation of the ischemic protection efficacy of a laparoscopic renal cooling device using renal transplantation viability assessment criteria in a porcine model.
OBJECTIVE
We assessed the efficacy of a prototype laparoscopic topical cooling device. The aim of regional renal hypothermia in laparoscopic surgery is to limit ischemic injury and extend safe operative time. A reliable model for assessing renal ischemic injury exists in the field of nonheart beating donor renal transplantation. Hypothermic machine perfusion allows calculation of the pressure flow index and measurement of glutathione S-transferase in the perfusate. These parameters allow accurate assessment of the extent of renal damage.


METHODS
The device incorporates a 2-layer cooling bag and coolant circuit. The system achieves hypothermia by circulating coolant across the surface of the kidney. Using 10 pigs individual kidneys were subjected to periods of renal ischemia with or without device in situ cooling. Each kidney was then machine perfused and assessed using nonheart beating donor viability criteria.


RESULTS
The best performance of the device achieved a renal parenchymal temperature of 15C in 11.2 minutes (mean +/- SD 21.4 +/- 8.42). In the warm ischemia groups significant deterioration of pressure flow index compared to controls occurred by 60 minutes (p = 0.0001). In cooled kidneys at 60 minutes the mean pressure flow index was not significantly different from that in controls. Greater mean glutathione S-transferase measurements were associated with the warm ischemia groups.


CONCLUSIONS
Our study reinforces the efficacy of topical renal cooling in the laparoscopic setting. We report the use of assessment techniques capable of accurate quantitative measurement of renal injury in an animal model. Our cooling device is currently undergoing further development to enhance its efficiency.
Navarro
A P
AP
Liver and Renal Transplant Unit, Freeman Hospital, Newcastle-upon-Tyne, United Kingdom. alex@navarro1.wanadoo.co.uk
Sohrabi
S
S
Colechin
E
E
Griffiths
C
C
Talbot
D
D
Soomro
N A
NA
D000818:Animals; D004195:Disease Models, Animal; D007036:Hypothermia, Induced / Q000295:instrumentation*; D007511:Ischemia / Q000517:prevention & control*; D007668:Kidney / Q000098:blood supply* / Q000601:surgery; D016030:Kidney Transplantation; D010535:Laparoscopy; D009392:Nephrectomy; D010477:Perfusion; D013552:Swine; D014022:Tissue Survival; D016896:Treatment Outcome; D052096:Warm Ischemia