P1.187. No Correlation Between Conduit Perfusion and Peri-Anastomotic Drainage pH After Esophagectomy

Topic Esophageal Cancer: Surgical Treatment of Esophageal Cancer Background Fluid pH and electroconductivity are emerging biomarkers for early detection of anastomotic leak after bowel anastomoses. Lower cervical drain pH and poor conduit perfusion are associated with anastomotic leak. We hypothesized that impaired conduit perfusion would be associated with lower pH levels in cervical postoperative drain fluid. Methods A prospective pilot study of patients undergoing esophagectomy with cervical anastomosis at a single academic institution was performed. A portable, non-invasive biosensor system was attached in line to a closed-suction cervical drain. The sensor continuously monitored drainage fluid characteristics, including pH. The sensor was initiated on postoperative day (POD) 0/1 and remained attached until the clinical removal of the drain (POD 5). Conduit perfusion ingress slope and peak values were collected intraoperatively using ICG green dye and the SPY Elite system ©. Patients were stratified by perfusion ingress slope using the cohort median threshold (19.1). Additional analyses focused on postoperative days 2-3, when differences between complication groups are most pronounced. Results Eighteen patients were included with a mean age of 66, of whom 67% (12/18) were male. Patients were divided into two groups based on conduit perfusion: “high perfusion” (n=9) patients had an average ingress of 222 and an ingress rate of 28; while the “low perfusion” group (n=9) had an average ingress of 128 and an ingress rate of 11 (p<0.001). Demographics and preoperative factors did not differ between the two groups. Two patients (11%) had diagnosed postoperative leak, both within the high conduit perfusion group. Perfusion ingress slope demonstrated moderate negative correlation with drainage pH overall (r = −0.583). When analysis was restricted to patients without a leak, stratification by perfusion slope did not meaningfully separate postoperative pH trajectories (Figure). Mean pH trends remained overlapping between perfusion groups across postoperative time points. Conclusion Conduit perfusion does not appear to correlate with pH measurements in drain fluid following esophagectomy. The two patients with leaks had high perfusion, resulting in an inverse relationship between factors, that we feel is erroneous. If these two factors are independent, drainage pH is potentially a distinct postoperative physiologic marker that could be used in conjunction with conduit perfusion to identify patients at high (or low) risk of leak after esophageal anastomosis.