Coolsense® versus EMLA® for peripheral venous cannulation in adult volunteers: A randomised crossover trial

Peripheral venous cannulation (PVC) is a commonly performed invasive medical procedure. Topical treatments such as the eutectic mixture of local anaesthetics (EMLA®, Aspen Pharmacare Australia Pty Ltd, St Leonards, NSW) attenuate the associated pain, but are limited by requiring up to one hour of application before becoming effective. The Coolsense® (Coolsense Medical Ltd., Tel Aviv, Israel) pain numbing applicator is a new device using a cryoanalgesic means to anaesthetise skin within seconds. Coolsense is being increasingly used for cannulation, but comparative studies are lacking. We recruited 64 healthy adult volunteers to this open-label two sequence, two period randomised crossover trial. Participants had two 20 gauge venous cannulae inserted, one on the dorsum of each hand. Each cannulation attempt was preceded by treatment with Coolsense or an EMLA patch containing 2.5% lidocaine and 2.5% prilocaine. The primary outcome was participant pain using the 0-10 numerical pain rating scale. Secondary outcomes were participant satisfaction scores on a 0-10 scale, treatment preference, and failed cannulation attempts. Participants were randomly assigned to either the Coolsense EMLA (n = 32) or EMLA Coolsense (n = 32) sequence. All participants completed the trial. The pooled mean paired difference of the numerical pain rating scale was -1.84 (95% confidence intervals -1.28 to -2.41; P < 0.001) in favour of EMLA. The pooled mean paired difference for satisfaction score was 2.26 (95% confidence intervals 1.46 to 3.07; P < 0.001) higher with EMLA. Most participants preferred EMLA over Coolsense (P < 0.001). There was no significant difference regarding failed cannulation between the two treatments (P = 0.14). Among healthy individuals undergoing elective PVC, EMLA was associated with reduced pain, increased satisfaction, and was the preferred treatment compared to Coolsense.