Assessment of Perioperative Variables That Predict the Need for Surgical Drains Following Robotic Partial Nephrectomy Utilizing Quantitative Drain Creatinine Analysis.

Abstract

To utilize body fluid creatinine analysis to determine which patients will require a surgical drain following robotic-assisted partial nephrectomy (RAPN). One hundred fifty consecutive RAPN performed by a single surgeon were reviewed. Postoperative day (POD) 1 drain creatinine was compared to serum creatinine to calculate the drain to serum creatinine ratio (D/S ratio). Elevated D/S ratio was defined as any value >1.2. From February 2008 to April 2015, 140 patients underwent RAPN and had a drain placed (124 had D/S ratio available on POD 1). In the 103 patients with a D/S ratio of <1.2 and the 21 with D/S ratio of >1.2, the mean tumor size was 3.0 and 3.9 cm (P = .001) and mean RENAL score was 7.6 and 8.1 (P = .270), respectively. Collecting system entry occurred in 68.2% of patients with a D/S ratio of <1.2 and 71.4% of patients with a D/S ratio of >1.2. Mean drain time was 2.4 and 4.2 days (P = .001), hospital stay was 2.7 and 3.3 days (P = .036) for the D/S ratio <1.2 and D/S ratio >1.2 groups, respectively. Those with renal mass size of 4-7 cm had increased likelihood of D/S ratio >1.2 (OR 2.78; P = .041). Most RAPN do not require a surgical drain. A POD 1 elevated D/S ratio is more likely to occur with larger masses (those approaching or greater than 4 cm) and can be associated with prolonged drain time and hospital stay.