Vapocoolant Spray Versus Lidocaine Infiltration for Radial Artery Cannulation: A Prospective, Randomized, Controlled Clinical Trial

Objectives: Local infiltration with lidocaine is a frequently used measure to prevent pain during arterial cannulation. Its administration is associated with pain. Vapocoolants like ethyl chloride or alkanes also affect rapid-onset anesthesia. However, their administration causes less discomfort compared with administration of lidocaine. The effectiveness of vapocoolants in mitigating discomfort associated with arterial cannulation never has been studied. The authors therefore compared vapocoolant with lidocaine for reducing discomfort caused by arterial cannulation.

Design: Prospective, randomized, controlled study.

Setting: University hospital, single center.

Participants: One hundred sixty adult patients requiring arterial cannulation before induction of general anesthesia for cardiac surgery or carotid endarterectomy.

Interventions: Patients received either lidocaine infiltration or vapocoolant spray prior to arterial cannulation. Overall discomfort resulting from the whole procedure (applying local/topical anesthesia followed by arterial puncture) was rated on a 0 to 10 numerical rating scale. Puncture failure rate and time required for the intervention also were recorded.

Measurements and main results: One hundred forty-three patients were included in the per-protocol analysis. Mean pain scores in the vapocoolant group were 3.4 (±1.58) compared with 4.5 (±2.29) in the lidocaine group (difference 1.1±0.33; p = 0.032; Mann-Whitney U-test). The higher puncture failure rate in the lidocaine group (n = 11 v 4) was not significant (p = 0.06; Fisher's exact test). The time required for the intervention was longer in the lidocaine group (138±44 s v 128±44 s; p = 0.019; Mann-Whitney U-test).

Conclusions: Vapocoolant spray is an alternative to lidocaine infiltration to mitigate discomfort associated with arterial cannulation.