| Tran NQ et al, 2002, Australia | Topical use of 4% amethocaine gel applied for 30 mins prior to arterial puncture for blood gas analysis | RCT | Primary outcome was pain experienced (measured on a visual analogue scale, 0–100) | Amethocaine group-mean score 16.0 (SD 23.3). Placebo group-mean score 20.7 (SD 18.5) | Amethocaine can cause blanching to the skin, which may affect blinding by introducing bias, though this was not commented on in the paper as one of the reported side effects |
| | | Number of passes through the skin | These differences were not statistically significant | Women of “child bearing potential” were excluded from the study. Does this mean that all pre-menopausal women were not included, and if so why? |
| 81 adult patients. 42 received amethocaine gel and 39 received a placebo gel | | Heart rate before, during and after arterial puncture | These differences were not statistically significant | |
| | | Side effects of the gel | Small number of minor irritations reported in both groups | |
| Aaron AD, et al, 2003, Canada | Fifty patients randomised, 24 to receive tetracaine and 26 placebo, 45 minutes prior to elective radial arterial puncture | RCT | Patient’s perception of pain (visual analogue scale, 0–100) | Tetracaine group-mean score 26.2+/−32.6 The placebo group-mean score 23.8+/−27.4 (p = 0.78) | |
| | | Mean time from skin puncture to procurement of 1 ml of arterial blood | Tetracaine group-mean time 70+/−103 seconds. Placebo group-mean time 49+/−48 seconds. (p = 0.40) | |
| | | Difficulty performing the test (graded scale) | Identical for both groups (p = 0.86) | |