Analysis of irrigation pressure according to flow rate in syringe-based wound irrigation using computational fluid dynamics: a pilot study

Wound irrigation applies constant pressure of an irrigating fluid to the wound bed to remove bacteria, necrotic tissue, and debris. The recommended pressure is 8–15 psi, but syringe-based irrigation studies have shown wide variations among practitioners. Clear guidance is needed. This pilot study used Computational Fluid Dynamics simulations to provide foundational data on optimal pressure under different conditions. Pressure and flow dynamics were analyzed using a 19G needle. Variables included irrigating solution (0.9% sodium chloride, 10% povidone-iodine), syringe-to-wound distance (2 or 10 cm), and angle (45° or 90°). Flow rates of 0.5–5.0 cc/sec were tested with Ansys CFX software. The computational domain consisted of a free-jet region between the syringe outlet and wound surface, with lateral boundaries defined as openings to allow fluid and air exchange. The wound bed was idealized as a flat, rigid circular surface 50 mm in diameter (19.6 cm 2 ), with a 1-mm-high cylindrical domain above the surface to simulate jet–wound interaction. For 0.9% sodium chloride, a 4.0–5.0 cc/sec flow rate maintained 8–15 psi at 90°, both at 2 cm and 10 cm. For 10% povidone-iodine, optimal rates varied: 5.0 cc/sec at 2 cm/45°, and 4.0–5.0 cc/sec at 2 cm/90° or 10 cm/90°. This pilot study provides guidance for syringe-based wound irrigation, showing that irrigation pressure depends on multiple factors and that optimal flow rates vary with angle and distance.