Eutectic mixture of local anaesthetics (EMLA) 5% cream as a primary dressing on a painful lower leg ulcer

Innovative pain management solutions in animals may provide improved wound pain reduction during debridement in humans: An opinion informed by veterinary literature

Painful animal husbandry procedures are routinely performed in a range of livestock species without analgesia. Recently, innovative strategies have been developed to address wound pain in these animals. In particular, a farmer-applied "spray and stay" approach that is administered directly to open wounds was developed (Tri-Solfen® Medical Ethics Pty Ltd., Melbourne, Victoria, Australia). This strategy anaesthetises the wounds immediately upon their formation, with long-lasting effect. This development, described as a "pain management revolution," has become firmly established in the Australian livestock industries and has global potential. The positive outcomes of this approach provide insights and highlight potential benefits that may be accrued from its use in human wound care, providing rapid-onset wound analgesia and/or anaesthetising wounds prior to cleansing and debridement procedures. If these benefits are realised from a clinician and patient perspective for wound debridement as an initial indication, it could provide new horizons in pain management for a spectrum of wound-related procedures. Evidence from use in animal husbandry does support the concept that multimodal anaesthesia holds great potential in the field of wound management across many procedures.

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

BACKGROUND

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).

METHODS

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.

RESULTS

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.

CONCLUSION

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.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Register: Registered 16 December, 2009.

The Effectiveness of EMLA as a Primary Dressing on Painful Chronic Leg Ulcers: Effects on Wound Healing and Health-Related Quality of Life

This study aimed to evaluate the effect of EMLA 5% cream applied to painful chronic leg ulcers (CLUs) as a primary dressing on wound healing and health-related quality of life (HRQoL). A pilot, parallel-group, nonblinded, randomized controlled trial was conducted in 6 community nursing procedure clinics in New South Wales, Australia. A total of 60 participants with painful CLUs of varied etiology were randomly assigned to the intervention (EMLA daily for 4 weeks as a primary dressing, followed by usual care) or usual care only. Wound size and HRQoL were measured at baseline, end of the intervention period (week 4), and week 12. At baseline, wound sizes were similar for both the intervention and control groups. During the intervention period, there was no significant difference in wound sizes between groups (intervention group: median (cm²) = 2.4, IQR = 1.3-12.7; control group: median (cm²) = 5.0, IQR = 2.5-9.9; P = .05). Mean HRQoL scores for all subscales at baseline and weeks 4 and 12 were similar between groups except for Wellbeing, which was significantly higher in the intervention group at the end of the 4-week intervention period (intervention group: mean = 52.41, SD = 24.50; control group: mean = 38.15, SD = 21.25; P = .03; d = 0.62). The trial findings suggest that daily applications of EMLA as a primary dressing do not inhibit wound healing and may improve patient well-being. Studies with larger samples are required to more comprehensively evaluate the impact of this treatment on wound healing and HRQoL.

Analgesic efficacy of equimolar 50% nitrous oxide/oxygen gas premix (Kalinox®) as compared with a 5% eutectic mixture of lidocaine/prilocaine (EMLA®) in chronic leg ulcer debridement

Chronic foot and leg ulcers are a common health problem worldwide. A mainstay of chronic ulcer therapy is sharp mechanical wound debridement requiring potent analgesia. In this prospective, controlled, single-centre, crossover design study, patients were assigned to either the administration of topical analgesia with 5% lidocaine/prilocaine cream or the inhalation of an analgesic 50% N₂ O/O₂ gas premix. Primary outcome parameter was level of pain at maximum wound depth during debridement as measured by a visual analogue scale. Secondary outcomes included level of pain after debridement, overall duration of treatment session, duration and completeness of debridement, and the patient's subjective perception of analgesic quality during debridement. Pain level increased from 0·60/0·94 (first/second debridement; baseline) to 1·76/2·50 (debridement) with 5% lidocaine/prilocaine and from 1·00/1·35 (baseline) to 3·95/3·29 (debridement) with 50% N₂ O/O₂ gas premix. Patient satisfaction was 90·48%/94·44% (first/second debridement) with topical 5% lidocaine/prilocaine analgesia and 90·48%/76·47% with the inhalation of 50% N₂ O/O₂ gas premix. Debridement was completed in a significantly higher percentage of 85·71%/88·89% (first/second debridement) with 5% lidocaine/prilocaine than with 50% N₂ O/O₂ gas premix (42·86%/58·82%) (odds ratio 6·7; P = 0·001). This study provides sound evidence that analgesia with topically administered 5% lidocaine/prilocaine cream is superior to the use of inhaled 50% N₂ O/O₂ gas premix in chronic leg ulcer debridement.