Rapydan Topical Anaesthesia for Arterial Cannulation
Condition: Arterial Catheterization
Study type: Interventional
Phase: Phase 4

Summary: 
      Arterial catheterization is painful and is associated with patient stress and anxiety.
      Analgesia is usually provided by subcutaneous injection of local anesthetic. An alternative
      is topical anaesthesia, such as Rapydan which is a novel topical anesthetic patch containing
      70 mg each of lidocaine and tetracaine. We therefore tested the hypothesis that Rapydan patch
      analgesia is non-inferior to subcutaneous local anesthetic.
    

Detailed description: 
      Many clinical procedures including arterial and venous punctures, percutaneous venous
      catheter insertion, lumbar puncture, and dermatological procedures are associated with pain
      and consequent patient discomfort.1-2 With the exception of venopuncture, arterial puncture
      is the most common invasive procedure performed on critically ill patients. Also, it is often
      necessary before induction of anaesthesia for invasive measurements of blood pressure and
      collection of arterial blood samples in patients undergoing major cardiac surgery. Injection
      of local anesthetics before insertion causes intra-dermal turgor and can trigger local
      vasoconstriction, both of which reduce puncture success rate.

      An alternative approach is to use topical anesthesia for percutaneous procedures. However,
      intact skin presents a significant barrier to topical anesthetic preparations. Therefore,
      topical anesthetic preparations typically must be applied under occlusive dressings for 45-60
      minutes before vascular access - which is often longer than is clinically practical.

      Rapydan (also known as Synera in the United States) is a novel topical anesthetic patch that
      contains 70 mg each of lidocaine and tetracaine. The central area of each Rapydan patch
      consists of a Controlled Heat Assisted Drug Delivery pod which is designed to allow for
      application just 20 minutes before percutaneous procedures. However, the efficacy of Rapydan
      topical analgesia has yet to be quantified for the more intense pain resulting from arterial
      puncture. We thus compared routine analgesia (subcutaneous injection with 0.5 ml of 1%
      lidocaine) with heated lidocaine/tetracaine patches. Specifically, we tested the hypothesis
      that lidocaine/tetracaine patch analgesia is non-inferior to that provided by subcutaneous
      lidocaine injection for insertion of arterial catheters.

      Ninty 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, looking identically to the Rapydan patch and subsequent
      subcutaneous injection of 0.5 ml of lidocaine 1%. Pain during arterial catheterization using
      100-mm-long visual analog scale (VAS) was the primary outcome. Other outcomes were pain
      during anesthetic/saline injection and plasma tetracaine concentrations.

      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 at any time in any patient.

      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
      minutes before the procedure. Given adequate time, the patch provided better overall
      analgesia by obviating the need for subcutaneous infiltration.
    

Intervention name(s): Lidocaine/tetracaine patch; Placebo Patch; Subcutaneous injection of 0.5 ml Lidocain 1%; Subcutaneous injection of saline
Intervention type(s): Drug; Drug; Drug; Drug
Intervention description(s): The lidocaine/tetracaine patch topical anesthetic patch contains 70 mg each of lidocaine and tetracaine. The central area of each patch consists of a Controlled Heat Assisted Drug Delivery pod which is designed to warm the skin to 26-34°C, theoretically enhancing drug absorption and allowing application just 20 minutes before percutaneous procedures. A active or placebo patch was placed on each patient's wrist in the region of the maximum radial artery pulsation. After 20 minutes, the patch was removed.; A placebo patch was placed on each patient's wrist in the region of the maximum radial artery pulsation. After 20 minutes, the patch was removed.; After removing the patch, a blinded investigator injected 0.5 ml of 1% lidocaine solution. Three minutes after injection, an attempt was made to cannulate the radial artery with a 20-gauge catheter.; After removing the patch, a blinded investigator injected 0.5 ml saline solution. Three minutes after injection, an attempt was made to cannulate the radial artery with a 20-gauge catheter.
Other intervention name(s): Rapydan; Synera, 76667213
Intervention MeSH terms: Lidocaine; Tetracaine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Supportive Care
Keywords: Arterial catheter; arterial cannula; Rapydan; lidocaine/tetracaine patch; topical anaesthesia