Effectiveness of vapocoolant spray compared to eutectic lidocaine/prilocaine cream to enhance tolerance during intravenous catheterisation: a randomised controlled trial
Effectiveness of vapocoolant spray compared to eutectic lidocaine/prilocaine cream to enhance tolerance during intravenous catheterisation: a randomised controlled trial
Open access
In our edition of: Apr 2025
In our categories of: small animals
our summary:
Trinder, R, et al. (2025) Effectiveness of vapocoolant spray compared to eutectic lidocaine/prilocaine cream to enhance tolerance during intravenous catheterisation: a randomised controlled trial. Journal of Small Animal Practice, 66 (4), pp. 236-242.
The aim of this randomised, blinded and controlled trial was to investigate if tolerance of intravenous catheterisation (IC) in cats and dogs differed following the application of vapocoolant spray (VS) compared to EMLA cream (a topical anaesthetic containing 2.5% lidocaine and 2.5% prilocaine).
Dogs and cats attending a referral hospital for either blood donation or as oncology patients were prospectively enrolled into the study with client consent. Prior to IC patients were randomly allocated to receive either VS or EMLA cream, patients could only be enrolled once with treatment outcome only recorded on their first catheterisation attempt.
Preparation for the IC site was the same for both groups, patients randomised to receive EMLA having 1.5 g of the cream applied topically to the area 60 minutes prior to IC attempt and patients in the VS group having a swab saturated with vapocoolant spray applied immediately prior to the IC. The size of catheter used was determined by the placer based on the principle of selecting the largest gauge catheter that could be placed safely and confidently in the prepared vein. The IC process was video recorded from point of initial patient restraint to placement of the catheter, patient restraint and IC placement followed a standardised protocol.
Video recordings were reviewed for reactions by a single observer, blinded to the treatment group. Reaction scores were assigned on a scale of 0-3 (no reaction-aggressive behaviour) at four timepoints (initial restraint, limb handling for IC site preparation, application of treatment or control swab, and skin punctured by the catheter).
The total study population was 101 patients (18 cats, 83 dogs) of which 13 cats attending were attending for blood donation and 88 dogs and cats as oncology patients. There were 56 patients in the VS group and 45 in the EMLA group.
The overall results revealed no significant differences in the reaction scores between patients receiving VS and EMLA cream at restraint, limb handling or skin puncture. Patients receiving VS had greater than six and a half times increased odds of showing an increased reaction during swab application compared to EMLA. No adverse skin reactions were reported in any patient.
When considering dogs only those receiving VS had increased odds of showing an increased response during swab application compared to those receiving EMLA, there was no similar difference in cats. For cats only VS spray was significantly less effective in reducing adverse reaction to skin puncture than lidocaine/prilocaine cream.
There was no significant difference in rate of success of first time IC observed when comparing the use of VS or EMLA cream.
Limitations of the study include the use of a non-validated reaction scoring system, the small number of cats, of which a significant number were blood donors and a high proportion of these were in the EMLA group, which may have affected the results , the block randomisation for all species rather than each species, the smaller number receiving EMLA cream, and the lack of a control group that did not receive any treatment.
The study provides some evidence that neither application of VS or EMLA cream was superior in improving tolerance to IC placement. However, while the use of vapocoolant spray enables immediate catheterisation it may be less effective than EMLA cream in reducing adverse response to skin puncture during catheterisation in cats.
The following may be of interest
Oostrom, H. van and Knowles, T.G. (2018) The efficacy of EMLA cream for intravenous catheter placement in client-owned dogs. Veterinary Anaesthesia and Analgesia, 45 (5), pp. 604-608. https://doi.org/10.1016/j.vaa.2018.03.009
An inFOCUS summary available
Leask, E. (2021) Efficacy of EMLA™ cream for reducing pain associated with venepuncture in felines. Veterinary Evidence, 6 (3), https://doi.org/10.18849/ve.v6i3.456
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