Comparison of Tissue Oxygenation Profiles Using 3 Different Methods of Vascular Control During Porcine Partial Nephrectomy

Objectives: To compare oxygenation profiles and renal function outcomes between 3 methods of vascular control during porcine partial nephrectomy. Methods: To create a solitary kidney model, 18 pigs were subjected to a laparoscopic nephrectomy. Following a 7-day recovery, a contralateral open partial nephrectomy was performed with vascular control by either total renal artery clamping (TRAC, n = 6), partial renal artery clamping (PRAC, n = 6), or selective renal parenchymal clamping (SRPC, n = 6). Renal partial oxygen pressure (rPO₂) was monitored using a Licox probe. Serum creatinine was assessed on day 0 and postoperative days 3 and 7. Pigs were sacrificed on the seventh day and the kidney sent for pathological examination. Results: Intraoperative oxygenation profiles demonstrated a lower percentage decline (P = .01), longer interval to nadir (P = .04), improved percentage recovery of baseline rPO₂ (P = .04), and a shorter duration to recover baseline rPO₂ (P = .03) in the PRAC and SRPC groups than in the TRAC. Despite not occluding the renal vasculature, the SRPC group experienced declines in rPO₂ profiles of almost 50% from baseline. Serum creatinine levels increased significantly more in the TRAC group at days 3 and 7 (P = .04 and .01, respectively). Histological examination demonstrated patchy inflammation of parenchyma in all groups. Conclusions: The rPO₂ monitoring may provide a novel means to allow real-time assessment and titration of kidney perfusion during partial nephrectomy. PRAC and SRPC demonstrate favorable renal oxygenation profiles compared with TRAC. Interestingly, SRPC kidneys experienced a significant decline in tissue oxygenation profiles. Further work is necessary to better delineate the mechanism underlying this decline.