Needle sharpness is minimally affected by vaccine vial puncture

To survey the commonality of needle-changing practices among veterinarians and measure whether 1 or 2 passages through a vaccine vial septum affects needle sharpness.

An anonymous online survey of needle-changing behaviors by veterinary professionals was conducted from April to May 2023. Subsequently, a blinded randomized controlled bench trial assessed the impact of septum passage on needle sharpness between June and August 2023 at Midwestern University. Veterinary hypodermic needles of 3 brands and 4 gauges were tested after passing through a septum 0, 1, or 2 times. The primary outcome was the peak penetration force (PF) required to puncture standardized material. Secondary analysis involved visual examination of needles with the use of an optical 3-D surface roughness measurement instrument.

Of 482 survey respondents, 76% routinely changed needles due to concerns about dulling. Experimental results showed a minor increase in PF after 1 (9%) and 2 (18%) septum passages. Needle gauge and brand impacted PF more than septum passage, with differences of 6% to 58% and 9% to 10%, respectively. Visual inspection revealed a 40% incidence of gross defects after 1 passage and 52% after 2 passages, with PF through the vial septum being the strongest damage predictor.

While septum passage slightly increased the PF, brand and gauge had a more substantial impact.

This study suggests that changing needles may not be necessary for maintaining sharpness if proper technique is used, potentially reducing the risk of needlestick injuries and medical waste.