Does Point-of-Care Ultrasound Change the Needle Insertion Location During Routine Bedside Paracentesis?

BACKGROUND: Paracentesis is a bedside procedure to obtain ascitic fluid from the peritoneum. Point-of-care ultrasound (POCUS) improves the safety of some medical procedures. However, the evidence supporting its utility in paracentesis is limited.

OBJECTIVE: We aimed to assess if POCUS would yield a user-preferred site for needle insertion compared to conventional landmarking, defined as a ≥ 5 cm change in location.

DESIGN: This was a prospective non-randomized trial comparing a POCUS-guided site to the conventional anatomic site in the same patient.

PARTICIPANTS: Adult patients at Kingston Health Sciences Centre undergoing paracentesis were included.

INTERVENTIONS: Physicians landmarked using conventional technique and compared this to a POCUS-guided site. The paracentesis was performed at whatever site was deemed optimal, if safe to do so.

MAIN MEASURES: Data collected included the distance from the two sites, depth of fluid pockets, and anatomic considerations.

KEY RESULTS: Forty-five procedures were performed among 30 patients and by 24 physicians, who were primarily in their PGY 1 and 2 years of training (33% and 31% respectively). Patients' ascites was mostly due to cirrhosis (84%) predominantly due to alcohol (47%) and NAFLD (34%). Users preferred the POCUS-guided site which resulted in a change in needle insertion ≥ 5 cm from the conventional anatomic site in 69% of cases. The average depth of fluid was greater at the POCUS site vs. the anatomic site (5.4±2.8 cm vs. 3.0±2.5 cm, p < 0.005). POCUS deflected the needle insertion site superiorly and laterally to the anatomic site. The POCUS site was chosen (1) to avoid adjacent organs, (2) to optimize the fluid pocket, and (3) due to abdominal wall considerations, such as pannus. Six cases landmarked anatomically were aborted when POCUS revealed inadequate ascites.

CONCLUSIONS: POCUS changes the needle insertion site from the conventional anatomic site for most procedures, due to optimizing the fluid pocket and safety concerns, and helped avoid cases where an unsafe volume of ascites was present.