Lidocaine/tetracaine patch (Rapydan) for topical anaesthesia before arterial
access: a double-blind, randomized trial.
Author(s): Ruetzler K, Sima B, Mayer L, Golescu A, Dunkler D, Jaeger W, Hoeferl M, You J,
Sessler DI, Grubhofer G, Hutschala D.
Affiliation(s): Department of Cardiothoracic and Vascular Anaesthesia and Intensive Care
Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna,
Austria.
Publication date & source: 2012, Br J Anaesth. , 109(5):790-6
BACKGROUND: Arterial catheterization is painful and is associated with patient
stress and anxiety. Analgesia is usually provided by subcutaneous injection of
local anaesthetic. An alternative is topical anaesthesia, such as Rapydan which
is a novel topical anaesthetic patch containing 70 mg each of lidocaine and
tetracaine. We therefore tested the hypothesis that Rapydan patch analgesia is
non-inferior to subcutaneous local anaesthetic.
METHODS: Ninety patients undergoing elective major cardiac surgery were included
in this prospective, double-blind clinical trial. Patients were randomly assigned
to receive either a lidocaine/tetracaine patch, followed by subcutaneous
injection 0.5 ml of normal saline solution, or placebo patch with subsequent
subcutaneous injection of 0.5 ml of lidocaine 1%. Pain during arterial
catheterization using 100-mm-long visual analogue scale (VAS) was the primary
outcome. Other outcomes were pain during anaesthetic/saline injection and plasma
tetracaine concentrations.
RESULTS: VAS pain scores during arterial puncture were comparable in both groups
and Rapydan was non-inferior to subcutaneous lidocaine. Pain scores at the time
of subcutaneous injection were significantly lower (better) in patients assigned
to the lidocaine/tetracaine patch than to lidocaine (P=0.001). Plasma tetracaine
concentrations never exceeded the detection limit of 25 ng ml(-1) at any time in
any patient.
CONCLUSIONS: Both the lidocaine/tetracaine patch and subcutaneous injection of
lidocaine provided comparable pain control during arterial catheter insertion.
Subcutaneous lidocaine caused discomfort during injection, whereas the
lidocaine/tetracaine patch required placement 20 min before the procedure. Given
adequate time, the patch provided better overall analgesia by obviating the need
for subcutaneous infiltration.
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