Microparticulate ICE slurry for renal hypothermia: Laparoscopic partial nephrectomy in a porcine model

OBJECTIVES: Previously, we described the feasibility of renal hypothermia using microparticulate ice slurry during laparoscopy. In the present study, we compared surface cooling with the ice slurry versus near-frozen saline or warm ischemia (WI) during laparoscopic partial nephrectomy (LPN) in a porcine model. METHODS: We used a single-kidney porcine model. Animals in 5 equal groups (n = 6 each) underwent right laparoscopic complete nephrectomy. In Phase I, left LPN was performed under 90 minutes of ischemia and 90-minute renal cooling with either slurry (Slurry group 1) or saline (Saline group 1). No cooling was applied in the WI group. In Phase II, to simulate more extreme condition, ischemia time was extended to 120 minutes and cooling shortened to 10 minutes (Slurry group 2 and Saline group 2). The study endpoints were renal and core temperature during the surgery and serum creatinine at baseline and days 1, 3, 7, and 14 after the procedure. RESULTS: The ice slurry was easily produced and delivered. Nadir renal temperature (mean ± SD) was 8 ± 4 °C in Slurry group 1 vs. 22.5 ± 3 °C in Saline group 1 (P < .0001). Renal rewarming to 30 °C occurred after 61 ± 7 minutes in Slurry group 2 vs. 24 ± 6 minutes in Saline group 2 (P < .0001). Core temperature decreased on average to 35 °C in the Saline groups compared with 37 °C in the Slurry groups (P < .0001). Serum creatinine did not differ between the Saline and Slurry groups in Phases I and II at any time point. CONCLUSIONS: Ice slurry provides superior renal cooling compared with near-frozen saline during LPN without associated core hypothermia.