A comparison of kidney oxygenation profiles between partial and complete renal artery clamping during nephron sparing surgery in a porcine model.

OBJECTIVE: To compare kidney oxygenation profiles between partial and complete renal artery clamping during nephron sparing surgery (NSS) in a porcine model. MATERIALS AND METHODS: Twelve female farm pigs underwent a laparoscopic nephrectomy. Subsequently, an open partial nephrectomy was performed on the remaining kidney using either total (n = 6, TC) or partial (n = 6, PC) clamping of the renal artery. Real time renal partial oxygen pressure (rPO2) was monitored using a Licox probe (Integra, San Diego, CA). Creatinine levels were measured prior to open partial nephrectomy and on POD #3 and #7. The remaining kidney was harvested for pathologic evaluation. RESULTS: Compared to TC, the PC group demonstrated a more favorable renal oxygenation profile during the NSS. Specifically, rPO2 decreased less from baseline (58% versus 84%, p = 0.03), took a longer interval to nadir (23.1 min versus 8.7 min, p = 0.04), and experienced a more rapid recovery to maximal or baseline values (4.8 min versus 10.4 min, p = 0.03) in the PC group. Furthermore animals undergoing TC had significantly higher creatinine levels at POD #3 (2.2 mg/dl versus 1.6 mg/dl, p = 0.03) and POD #7 (2.5 mg/dl versus 1.7 mg/dl, p = 0.009). Histological analysis demonstrated varying levels of acute inflammation in the two groups. Finally, the intraoperative blood loss was greater in the PC versus TC group (40 cc versus 10 cc, p = 0.04). CONCLUSIONS: In this porcine model, partial clamping of the renal artery during NSS was feasible and demonstrated a favorable renal oxygenation profile. Theoretically, intraoperative rPO2 monitoring may provide a novel means to allow real time assessment and titration of kidney perfusion during partial nephrectomy.