Evaluation of Routine Postoperative Labs Following Robotic Assisted Partial Nephrectomy in Patients With Normal Preoperative Renal Function

To evaluate predictors of abnormal routine postoperative day 1 (POD1) labs in patients with normal pre-operative renal function following robotic assisted partial nephrectomy (RAPN) and the associated clinical outcomes of these lab results.We analyzed 500 consecutive RAPN from a single surgeon series. Patients with chronic kidney disease (CKD) III or greater were excluded from the study. Three hundred ninty-three RAPN were included in the analysis. Routine POD1 lab tests including hemoglobin (Hgb), creatinine, potassium, and sodium were evaluated to determine rates of abnormal values and rates of clinical intervention. Abnormal Hgb at POD1 was defined as8 g/dL or ≥3 g/dL decrease from the preoperative (baseline) value. Abnormal sodium (Na) preoperatively and postoperatively was defined as135 mEq/L or145 mEq/L. Abnormal potassium (K) was defined preoperatively and POD1 as3.5 mEq/L or5 mEq/L.Of 37.4% (147/393) had one or more abnormal labs at POD1. Of the 101 patients with abnormal Hgb, 15 patients required blood transfusion. Twenty-six patients had abnormal sodium for which two were treated with IV fluids. Twenty-seven patients had potassium abnormalities (12/25 were hypokalemia). Acute kidney injury stage I was seen in 27 patients (6.9%) and stage II in 3 (0.8%). Patients with abnormal labs were more likely to have larger renal mass, higher R.E.N.A.L. scores, intraoperative complications, longer operative times, and higher EBL on multivariate analysis.POD1 serum laboratory tests appear to be necessary following RAPN in patients with normal pre-operative renal function.