The use of pre-cannulation local anaesthetic and factors affecting pain perception in the emergency department setting.

STUDY OBJECTIVE To determine whether the use of subcutaneous local anaesthetic (lignocaine) is associated with a reduction in cannulation pain in the emergency department setting. METHODS Patients over 18 with a Glasgow Coma Score (GCS) of 15 and conversational English were allocated into one of three groups: Group 1 were cannulated after routine skin preparation; Group 2 received 1% lignocaine 0.1 ml via a 27 gauge needle and diabetic syringe before cannulation; Group 3 were injected as for Group 2 but saline was substituted for lignocaine. The cannulator and subject were blinded to the ampoule. The pain was measured using a 100 mm visual analogue scale. SETTING A large urban university hospital emergency department. RESULTS 366 patients were recruited and the data on 322 analysed. Those receiving lignocaine before cannulation reported lower pain scores (1.9 cm) than the saline (4.1 cm) or immediate cannulation (3.6 cm) groups, p<0.0001. Other factors such as the experience of cannulator, patient characteristics, the presence of a painful underlying condition and cannula size did not effect pain scores. CONCLUSION The use of lignocaine before cannulation reduced cannulation pain in the emergency department setting. Other factors examined did not influence pain perception.