Can the kidney function as a lung? Systemic oxygenation and renal preservation during retrograde perfusion of the ischaemic kidney in rabbits.
OBJECTIVE
To investigate renal preservation by a novel method of perfusion using an oxygenated perfluorocarbon (PFC) emulsion via retrograde access to the kidney, as preserving renal function during urological surgery has been elusive, and the recognized technique of nephron-sparing surgery has increased its application and practice in modern urology.


METHODS
After institutional review and approval, 30 New Zealand White rabbits were studied. In a solitary kidney model, each rabbit had the ureter catheterized before 40 min of renal artery occlusion. Each rabbit was randomized to one retrograde perfusion group, i.e. sham, normothermic PFC, chilled PFC, normothermic saline, and chilled saline. The rabbits were maintained for 2 weeks, during which renal function, urine output, systemic blood gases, weight and serum creatinine level were measured. After death, the kidneys were individually examined and graded by one renal pathologist unaware of the treatment.


RESULTS
The rabbits treated with retrograde PFC perfusion (normothermic and chilled) had less change in their creatinine clearance, at 3.6 and 4.0 mL/min per kg, than the sham group, at 7.8 mL/min per kg, while also having significantly higher systemic venous oxygenation, at 26.3 and 10.0 mmHg, than the sham group, at 0.2 mmHg. Normothermic and chilled perfusion with PFC was also associated with less histological evidence of ischaemic damage, with mean (sd) scores of 13.0 (13.5) and 8.7 (4.5), respectively, than in the sham group, at 33.3 (16.8), while favourably matching the contralateral control kidney group, at 5.5 (2.3). The rabbits treated with saline retrograde perfusion also had better outcomes than the sham cohort. There were no adverse effects in any of the study arms or with the use of PFC.


CONCLUSIONS
Retrograde oxygen delivery to the kidney through the urinary collecting system was successful in this pilot study. Renal function, laboratory and histological data indicate a trend towards renal preservation and even systemic oxygenation in the experimental groups compared with the sham rabbits, with no adverse effects attributed to this technique.
Humphreys
Mitchell R
MR
Department of Urology, Mayo Clinic, Rochester, MN, USA. Humphreys.Mitchell@mayo.edu
Ereth
Mark H
MH
Sebo
Thomas J
TJ
Slezak
Jeffrey M
JM
Dong
Yue
Y
Blute
Michael L
ML
Gettman
Matthew T
MT
D000818:Animals; D015687:Cell Hypoxia; D003404:Creatinine / Q000652:urine; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage*; D007511:Ischemia / Q000503:physiopathology*; D007668:Kidney / Q000098:blood supply* / Q000503:physiopathology; D010100:Oxygen / Q000008:administration & dosage* / Q000378:metabolism; D010865:Pilot Projects; D011817:Rabbits; D011897:Random Allocation
D005466:Fluorocarbons; D003404:Creatinine; D010100:Oxygen