Given that vapocoolant is effective immediately, compared to EMLA cream which is recommended to be applied 60 minutes beforehand, the study suggests that in dogs at least, vapocoolant may be the better option in practice.
For the study, researchers from the Royal Veterinary College assessed 83 dogs and 18 cats requiring intravenous catheterisation for either blood donation collection or as oncology patients.
Patients were randomly assigned to receive either EMLA cream or a swab saturated with vapocoolant spray (Ethycalm / Invicta Animal Health) applied before catheterisation, and their reactions were assessed during initial restraint, limb handling, swab application and skin puncture.
Overall, there was no significant difference between vapocoolant spray and EMLA cream, and neither method appeared better at improving patient tolerance of intravenous catheter placement.
Vapocoolant spray was less effective than EMLA cream in reducing adverse reactions to skin puncture during catheterisation in cats, suggesting that EMLA may be preferable for feline patients.
Dogs that received vapocoolant spray showed a greater adverse response during swab application compared to those receiving EMLA, possibly due to the coldness of the swab.
Success of intravenous catheter placement was identical for both anaesthetics.
Dr Richie Trinder, lead author of the study, said: “The study is the first of its kind comparing vapocoolant spray and EMLA, and suggests in this context that the use of vapocoolant spray provides a similar degree of relief as EMLA, but with the added advantage of being instantaneous, instead of needing to wait the recommended 60 minutes for EMLA.”
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