Introduction

Intravenous (IV) catheterisation is a common and sometimes uncomfortable procedure. Topical local anaesthetic cream reduces discomfort associated with IV catheterisation if applied 45–60 minutes prior to venepuncture, but this limits its utility in emergency departments. A vapocoolant spray (VS - EthyCalm^TM, Invicta) is an alternative with the advantage of almost instantaneous effect. This study aimed to determine if dogs and cats had improved tolerance of IV catheterisation following the application of VS.

Method

A prospective study of client-owned dogs and cats presenting as an emergency and requiring IV catheterisation was performed. All animals had their age, breed, sex and mentation score recorded. The animals were restrained and fur clipped over the catheterisation site. They were then randomly allocated to either have a swab saturated with VS or a swab saturated with saline applied to the clipped area, followed by placement of the IV catheter. The procedure was video recorded from the point of restraint until placement of the catheter. A single blinded observer reviewed the recordings and assigned behavioural scores (0–3) at 4 time points (initial restraint, limb handling, swab application and skin puncture). A Mann-Whitney U Test was used to compare the scores between the groups. A sample size calculation revealed 50 animals per group were required to detect a four-fold decrease in odds ratio of response to catheterisation in the VS group compared to control group, with 90% power and 5% type I error rate. This study was approved by the RVC Ethics and Welfare Committee

Results

Between October 2020 and January 2021, a total of 100 patients were enrolled (79 dogs and 21 cats). No significant difference in species, age, breed, sex or mentation score was detected between the two groups. There was no significant difference in behavioural scores between the groups at any time point with the exception of a significantly increased swab application reaction score in the VS group compared to the saline group (p<0.001).

Conclusion

The application of VS via a swab prior to catheterisation does not significantly reduce the reaction of dogs and cats to IV catheterisation in the emergency department.

Disclosures

Disclosures to report: The vapocoolant spray (EthyCalm^TM) used in the study was provided from the manufacturer free of charge. They were not involved in study design, patient recruitment or data assessment.