Philip J Dorsey

Tulane University, New Orleans, Louisiana, United States

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Publications (4)5.4 Total impact

  • Journal of Biomedical Optics 10/2014; 19(10):107001. · 2.75 Impact Factor
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    ABSTRACT: PURPOSE: Renal hypothermia is commonly utilized during nephron sparing surgery to minimize ischemic tissue damage. We propose a method to induce renal hypothermia using continuous retrograde irrigation of iced saline via dual-lumen ureteral catheter. We will report results in an ex vivo porcine model followed by clinical outcomes in a series of patients with solitary kidney undergoing robotic-assisted laparoscopic partial nephrectomy (RALPN). MATERIALS AND METHODS: First, we performed temperature measurements during retrograde renal cooling in a porcine model before investigating the technique in humans. In porcine experiments, renal cortical temperature measurements (n = 270) were recorded during retrograde infusion of ice-cold saline via a 10-Fr dual-lumen ureteral catheter placed in ureter. Subsequently, a series of patients (n = 10) undergoing RALPN with a solitary kidney had concomitant intra-operative retrograde renal cooling. A 10-Fr dual-lumen ureteral catheter was placed at initiation of anesthesia and cold saline initiated prior to renal artery clamping. RESULTS: Porcine cortical temperature reached the target temperature (≤20 °C) within an average of 203 s of retrograde irrigation. In the clinical series, patients' mean preoperative creatinine was 1.16 mg/dL (GFR = 60). At a median follow-up of 10 months (range 1-27 months), postoperative creatinine was 1.50 mg/dL (GFR = 41.28). Average clamp time was 19.4 min. All patients had negative surgical margins. CONCLUSIONS: Retrograde irrigation is a technically feasible method to induce cold ischemia, which may provide an additional protective effect of renal function in patients who have a solitary kidney undergoing surgery via a minimally invasive approach.
    International Urology and Nephrology 02/2013; · 1.33 Impact Factor
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    ABSTRACT: Objective: During partial nephrectomy, renal hypothermia has been shown to decrease ischemia induced renal damage which occurs from renal hilar clamping. In this study we investigate the infusion rate required to safely cool the entire renal unit in a porcine model using retrograde irrigation of iced saline via dual-lumen ureteral catheter. Materials and Methods: Renal cortical, renal medullary, bowel and rectal temperatures during retrograde cooling in a laparoscopic porcine model were monitored in six renal units. Iced normal saline was infused at 300 cc/hour, 600 cc/hour, 1000 cc/hour and gravity (800 cc/hour) for 600 seconds with and without hilar clamping. Results: Retrograde cooling with hilar clamping provided rapid medullary renal cooling and significant hypothermia of the medulla and cortex at infusion rates ≥ 600 cc/hour. With hilar clamping, cortical temperatures decreased at -0.90 C/min. reaching a threshold temperature of 26.90 C, and medullary temperatures decreased at -0.90 C/min. reaching a temperature of 26.10 C over 600 seconds on average for combined data at infusion rates = 600 cc/hour. The lowest renal temperatures were achieved with gravity infusion. Without renal hilum clamping, retrograde cooling was minimal at all infusion rates. Conclusions: Significant renal cooling by gravity infusion of iced cold saline via a duel lumen catheter with a clamped renal hilum was achieved in a porcine model. Continuous retrograde irrigation with iced saline via a two way ureteral catheter may be an effective method to induce renal hypothermia in patients undergoing robotic assisted and/or laparoscopic partial nephrectomy.
    International braz j urol: official journal of the Brazilian Society of Urology 01/2013; 39(1):37-45.
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    ABSTRACT: To determine whether placement of a 10 French dual lumen catheter produces a low-pressure collecting system during retrograde irrigation to induce renal hypothermia. Indication for the study is as a potential adjunct for partial nephrectomy. Ex vivo porcine kidneys underwent harvest, and a ureteral catheter (either single lumen or dual lumen) was placed in the ureter within the renal pelvis. Pressure measurements (n = 1,080) were recorded at 1-s intervals. Irrigant flow rates were initiated at gravity and subsequently increased at 10 cc/min increments to a maximum of 100 cc/min. During retrograde infusion without a dual lumen catheter, every 10 cc/min rate increase resulted in an 8 cm H(2)O rise in intrarenal pressure. The maximum flow rate obtained was 20 cc/min before urinary extravasation or intrarenal drainage occurred. Maximum pressure obtained before urinary extravasation or collecting system perforation was 16 cm H(2)O. Placement of a dual lumen catheter within the renal pelvis allowed intrarenal pressures to remain less than 5 cm H(2)O (when infusion rates <80 cc/min). The maximum flow rate while maintaining pressures <20 cm H(2)O was 90 cc/min. Flow rates above 100 cc/min resulted in urinary extravasation. The maximal flow rate that is safe for collecting systems with a dual lumen catheter is 80 cc/min, and without a dual lumen catheter rates greater than 20 cc/min resulted in collecting system perforations. Using an ex vivo porcine model, application of a 10 French ureteral dual lumen catheter produced adequate retrograde drainage that resulted in low intrarenal pressures at high infusion rates (up to 80 cc/min).
    International Urology and Nephrology 05/2012; 44(5):1425-9. · 1.33 Impact Factor