Radial artery blood gas sampling: a randomized controlled trial of lidocaine local anesthesia

Radial artery puncture is a common procedure and yet the role of local anesthesia for reducing the pain of this procedure continues to be debated. Clinical practice is variable and there is potential for substantial financial savings. This is the first randomized trial to investigate the effectiveness of subcutaneously injected lidocaine anesthesia on the perceived pain of radial artery puncture and the financial impact.

Between December 2012 and April 2013, 43 patients in the Emergency Department were randomized into the intervention group to receive lidocaine 1% 1 mL subcutaneously or the control group (to receive no local anesthesia) prior to radial artery puncture for blood gas sampling. Pain was rated on a 10 cm visual analogue scale and procedural variables collected for between group analyses.

Overall, 41 participants were included. Subcutaneously injected lidocaine anesthesia did not reduce the median pain of radial artery puncture (control 1.8 vs. intervention 1.6 cm, P = 0.938). Those patients who had other systemically acting analgesia appeared to report reduced pain for radial artery puncture (0.60 vs. 2.30 cm, P = 0.105) as did those where a smaller 25-gauge needle was used compared to the standard 22-gauge (1.40 vs. 4.35 cm, P = 0.150), although these were not statistically significant. Anxious patients and those requesting local anesthesia experienced relatively higher levels of pain.

Local anesthesia did not reduce the perceived pain of radial artery puncture.