Functional Impact of Needle Gauge (14G vs. 15G) on High-Flux Hemodialysis Efficiency.

Abstract

Introduction: Effective blood flow (Qbe) is the critical determinant of uremic toxin clearance in hemodialysis (HD). This study analyzes the clinical impact of increasing the gauge of needles used for autologous arteriovenous fistulas (AVF)—from 15G to 14G—on high-flux hemodialysis efficiency and short-term complication rates.

Materials and Methods: A multicenter, controlled, quasi-experimental study was conducted in Ecuador (2025) involving 83 adult patients undergoing high-flux hemodialysis (HF-HD). Each subject completed 12 consecutive sessions (6 using 15G needles and 6 using 14G needles). Kinetic flow rates, circuit pressures (arterial, venous, and transmembrane), recirculation rates, dialysis dose (Kt/V, Kt), hemostasis time, and pain levels (measured via the Visual Analog Scale, VAS) were analyzed.

Results: The use of 14G needles resulted in a statistically significant increase (p=0.00) in pump flow (444.8 vs. 381.3 mL/min) and effective flow (419.2 vs. 352.9 mL/min), thereby increasing the dialysis dose (Kt/V: 1.99 vs. 1.84; Kt: 70.8 vs. 66.2 L). Recirculation decreased significantly with 14G needles (6.95% vs. 8.42%; p=0.01). Pre-pump arterial pressures (–148.7 vs. –187.0 mmHg) and venous pressures (154.0 vs. 174.6 mmHg) were substantially less extreme with the larger-gauge needles. Perceived pain was lower with 14G needles (1.81 vs. 2.05; p=0.00), although hemostasis times were slightly longer (6.0 vs. 5.3 min; p=0.00).

Conclusions: In high-flux hemodialysis (HF-HD), 14G needles increase blood flow rate (Qbe)—and consequently Kt/V—and reduce physical stress on the extracorporeal circuit. This promotes safe arterial and venous pressures that positively impact arteriovenous fistula (AVF) survival and patient quality of life, without increasing pain and with only a slight increase in hemostasis time.