To investigate the influence of needle insertion angle on pain during venipuncture. We enrolled 50 patients and assigned them to large-angle (30–45 degrees) or small-angle (15–30 degrees) needle insertion for venous puncture in random order. Pain was measured by Numerical Rating Scale (NRS), Verbal Rating Scale (VRS), and Wong–Baker Faces Pain Scale Revision (FPS-R) as the primary endpoint. The secondary endpoints were puncture failure and complications. All 50 enrolled patients completed the crossover trial. Wilcoxon signed-rank tests confirmed significantly lower pain scores with large-angle (30–45°) versus small-angle (15–30°) insertion across all scales (all P < 0.001). The large-angle group demonstrated median reductions of 1.0 point for NRS (95% CI: 1.0–2.0) and VRS (95% CI: 1.0–2.0), and 2.0 points for FPS-R (95% CI: 2.0–4.0). Zero pain was reported by 34–42% of patients in the large-angle group across scales, compared to none in the small-angle group. Puncture failure and complication rates did not differ between conditions. This randomized crossover clinical study demonstrated that needle insertion at a large angle could significantly reduce pain during venipuncture, irrespective of BMI. Trial Registration: This trial was retrospectively registered at Chinese Clinical Trial Registry identifier: ChiCTR2300075257, Registration Date 2023/08/01. Venipuncture is a common medical procedure often associated with patient discomfort and pain. The study was undertaken to investigate whether the angle of needle insertion during venipuncture influences pain levels, aiming to identify a less painful technique to improve patient experience. The study found that needle insertion at a larger angle (30–45 degrees) resulted in significantly lower pain scores across all measurement scales compared to a smaller angle (15–30 degrees), without increasing the risk of puncture failure or complications. Our study suggests that adopting a larger needle insertion angle during venipuncture could reduce patient pain, enhancing procedural comfort and potentially improving compliance with medical interventions requiring blood sampling or intravenous access.
Zhou et al. (Mon,) studied this question.