Vapocoolant spray vs subcutaneous lidocaine injection for reducing the pain of intravenous cannulation: a randomized, controlled, clinical trial.

BACKGROUND

We compared the efficacy, acceptability, and safety of a topical vapocoolant alkane spray and 1% plain s.c. lidocaine in reducing pain from i.v. cannulation.

METHODS

This was a non-blinded, randomized, controlled trial, in a large emergency department. Adult patients requiring i.v. cannulation were enrolled. The vapocoolant was administered from a pressure pack, at a distance of 12 cm for 2 s, and cannulation was undertaken within 15 s. Alternatively, 1% plain lidocaine 0.2 ml was administered s.c. using a 27 G needle, and cannulation was undertaken after a minimum of 30 s. The primary outcomes were anaesthetic administration and cannulation pain (0-100 mm visual analogue scale). Convenience of anaesthetic use and patient satisfaction were measured using a five-point Likert scale.

RESULTS

One hundred and ten patients were enrolled in each group. The groups did not differ in age, gender, cannulation anxiety, cannulator experience, cannulation indication or site, or cannula size. Median anaesthetic administration pain scores were 0 and 11 mm in the vapocoolant and lidocaine groups, respectively (P<0.001). Median cannulation pain scores were 9 and 0 mm, respectively (P<0.001). Vapocoolant was associated with greater cannulation success (83.6% vs 67.3%, P=0.005), less time to administer (median 9.0 vs 84.5 s, P<0.001), and more staff convenience (median 5 vs 4, P<0.001). Median patient satisfaction was 4 in both groups. Unexpected events were rare and minor.

CONCLUSIONS

Although vapocoolant reduces cannulation pain less than lidocaine, it has a number of important advantages. Vapocoolant offers a useful alternative in the emergency department setting.