Background: Ascites is a common complication of cancer. Symptomatic ascites contributes to cancer-related morbidity and is distressing for patients (pts). Therapeutic abdominal paracentesis (TAP) provides symptom relief but requires specialized procedural knowledge and is usually performed in the inpatient setting with several days of hospitalization. Additionally, high hospital bed occupancy during the COVID-19 pandemic prevented timely admission for TAP. An Advanced Practice Nurse (APN)-led ambulatory TAP service was introduced at our center, with the aim of improving access to TAP and reducing hospital bed occupancy. Methods: A multidisciplinary team developed workflows and safety guidelines for TAP to enable right-siting of pts in a cancer day care unit. Pts were scheduled for radiologically guided insertion of abdominal drains in the morning before 10am to allow adequate time for drainage. Pre-procedure clinical examination and safety checks were performed by APNs in the day unit. Following the procedure, abdominal fluid was drained with concurrent administration of 20% IV albumin. Drains were removed by the APN and pts were examined before discharge on the same day. Data for all cancer pts requiring TAP in the day unit and hospital from 1 Jan to 30 Nov 2020 were extracted from the electronic medical record system. The primary outcome was length-of-stay (LOS). The primary safety outcome was adverse events in the day unit. Continuous data were compared using the t-test. Data analysis was done in SPSS version 22. Results: The number of TAPs performed in the day unit and general ward requiring hospitalization were 102 and 133, respectively. There was a significant reduction in average LOS with TAPs performed in the day unit vs. hospitalization (1.48 vs. 5.82 days, p<0.001) (Table). The mean difference was 4.34 (95% confidence interval 3.33 - 5.34) days saved per pt, or a saving of 443 inpatient bed days. The TAP day unit service encountered 10 adverse events (AEs) requiring admission to the ward for continued drainage. AEs were borderline baseline blood pressure, pt frailty and inability to care for an indwelling catheter. There were no infective or bleeding complications. The majority of TAPs (86.8%) were performed in one day, with the remainder over 2-days with the abdominal drain left in-situ and reattendance at the day unit the next day for further drainage. Differences in average length-of-stay with TAP in the hospital vs. day unit. Conclusions: An APN-led ambulatory abdominal paracentesis service is a safe alternative to inpatient paracentesis. Optimal utilization of a day unit enabled reduced LOS for pts with advanced cancer. This reduction in LOS was critical during a pandemic where bed demand was high. This was possible from advanced scheduling and control over the day unit capacity.