Eutectic mixture of local anaesthetics (EMLA®) as a primary dressing on painful chronic leg ulcers: a pilot randomised controlled trial

Anne Purcell, Thomas Buckley, Jennie King, Wendy Moyle, Andrea P. Marshall

The physical, occupational, social and psychological impact of chronic leg ulcers (CLUs) on an individual is considerable. Wound-related pain (WRP), the most common symptom, is frequently reported as moderate to severe and mostly occurs at dressing change. WRP pain may not be alleviated by oral analgesics alone. Persistent poorly controlled leg ulcer pain can negatively impact wound healing and health-related quality of life (HRQoL). A pilot, parallel group, non-blinded, randomised controlled trial was conducted in six procedure clinics located in a public community nursing service in New South Wales, Australia to evaluate eutectic mixture of local anaesthetics (EMLA®) on painful CLUs when used as a primary dressing. The primary objective was to assess feasibility by using pre-determined criteria: at least 80% recruitment rate, 80% retention rate and 80% adherence to the study protocol. Key eligibility criteria were that participants had a painful CLU no larger than 100 cm2, a numerical rating scale (NRS) wound-related pain intensity score equal to or greater than 4, low to moderate exudate, no contraindications to EMLA® and capacity to consent. One hundred and seven patients with painful CLUs were screened for eligibility; 56% (n = 60) were eligible and consented to participate in the study. Participants were randomly assigned to the intervention (n = 30) or control (n = 30) groups. The intervention group received a measured dose of the topical anaesthetic EMLA® 5% cream daily as a primary dressing for 4 weeks followed by usual wound management for a further 8 weeks. The control group received usual wound management. Participants and investigators were not blinded to the treatment. WRP was measured at every dressing change. Wound healing and HRQoL were measured at baseline, 4 and 12 weeks. Recruitment rate was lower than expected which likely meant patients were missed. Study retention rate was 90% (n = 54). Intervention fidelity was impacted by availability of resources and patient factors such as increased WRP. This study identified that a larger randomised controlled trial investigating EMLA® applied as a primary dressing on painful chronic leg ulcers is feasible with modifications to the study protocol. Australian New Zealand Clinical Trials Register: Registered 16 December, 2009.