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Background and Aims NRFit connectors are 20% smaller and 3mm longer than standard Luer connectors [1]. Does switching to NRFit connectors from Luer connectors of the same manufacturer increase the perceived resistance to flow during aspiration and injection when performing spinal block? This study compares the flow resistance to water between: (a) Pajunk® NRFit versus Pajunk® Luer of the Sprotte® 24G x 90mm spinal needles. (b) Vygon® NRFit versus Vygon® Luer of the Whitacre® 25G x 90mm spinal needles.

Methods Thirty ward nurses who had never used these needles volunteered to test these spinal needles in a simulated practice. Each needle was primed with water and then attached to a 5 ml syringe containing 3 ml water. Using the same hand, each nurse was asked to aspirate 1ml from a glass filled with 10 ml water and then inject 3 ml under the water in the same glass. Unlimited attempts were permitted until they could determine the needle with the lowest resistance or if they felt that there was no difference in resistance between the two needles from the same manufacturer.

Conclusions Within the measure parameters, volunteers perceived a lower resistance to injection using the NRFit connectors. In contrast, they perceived lower resistance to aspiration using the leur connectors.