3.1
Full details of all clinical outcomes considered by the committee are available in the assessment report overview.
Guidance
3 Clinical evidence
Summary of clinical evidence
3.2
The key clinical outcomes for the Mega Soft Patient Return Electrode presented in the decision problem were:
-
incidence of patient return electrode site burns
-
incidence of alternative site burns
-
incidence of post-operative pressure ulcers
-
use of the device in certain patient subgroups.
3.3
The clinical evidence for the Mega Soft Patient Return Electrode was based on 2 published studies and 4 unpublished documents. The published studies were 1 technical evaluation (ECRI 2000) and 1 observational study (Sheridan 2003). Both studies evaluated the earlier version of the Mega Soft Patient Return Electrode, the Mega 2000. The unpublished evidence was 1 technical evaluation from the sponsor, testimonials from 2 USA hospitals about the Mega 2000 and the Mega Soft Patient Return Electrode, and 1 questionnaire from 3 London hospitals on the Mega Soft Patient Return Electrode.
3.4
ECRI (2000) was a laboratory study that examined the safety, efficacy and cost consequences of the Mega 2000 compared with standard disposable single-use patient return electrodes, in relation to relevant American and international technical standards. The tests were performed on 1 adult volunteer and on a piece of meat (tests that assessed the occurrence of burns). No statistical tests were reported. Mega 2000 was rated 'acceptable (with conditions)'. All the test results were rated as good except the results for the test of alternative current pathways, which were rated as fair. The Mega 2000 is the immediate predecessor product to the Mega Soft Patient Return Electrode and differs in not having a gel layer. Although the results cannot therefore be extrapolated between products, the external assessment centre considered that any observed differences between Mega 2000 and standard electrodes would be relevant to the Mega Soft Patient Return Electrode.
3.5
Sheridan (2003) reported an observational study of 17 children with extensive burns in a tertiary hospital in the USA. The children had only a few areas of the body suitable for placing the electrode and grounding the current. No statistical tests were reported. The results showed that Mega 2000 did not cause any burns, was convenient to use, and enabled effective patient grounding despite the presence of extensive burns.
3.6
A laboratory-based comparative technical study comparing the Mega Soft Patient Return Electrode with a disposable single-use split patient return electrode was submitted by the sponsor. The study has not been peer-reviewed. The tests were carried out on anaesthetised pigs. The main outcome was whether or not electrode site burns were observed (recorded as, yes or no). No statistical tests were reported. There was a rise in temperature of 9.7°C with the disposable split electrode compared with 1.2°C with the Mega Soft Patient Return Electrode. The IEC 60601-2-2-2006 standards for electrosurgery allow a maximum temperature increase of 6°C to minimise the risk of electrode site burns.
3.7
The sponsor provided 2 testimonial reports from Christus St Joseph's Hospital, USA in 2011. These were not clinical studies and no statistical tests were reported. There were no pre-defined outcomes. These hospitals initially used Mega 2000 and then switched to using Mega 2000 Soft (the US equivalent of the Mega Soft Patient Return Electrode) when it came onto the market. In both reports, Mega 2000 and Mega 2000 Soft was compared indirectly with standard disposable single-use patient return electrodes for patient comfort and cost savings. Both hospitals issued statements saying that the Mega Soft Patient Return Electrode improved patient comfort and provided cost savings.
3.8
An evaluation report was based on the use of the Mega Soft Patient Return Electrode at 3 London hospitals. Over a period of 2 weeks, theatre nurses completed a questionnaire after surgery to rate the use of the Mega Soft Patient Return Electrode. No information was provided about the selection criteria of patients, the total sample size or the number of non-responders. Data were obtained after procedures were completed on 18 paediatric patients at 1 hospital and on 12 and 24 adult patients respectively at the other 2. Mean scores were provided, together with raw data submitted for each question. Scores were from 0 to 5, with a higher score indicating a better outcome, and were averaged. Overall, a rating of 4.7 was recorded for the Mega Soft Patient Return Electrode. The highest scores were for skin irritation and power settings (4.9) and the lowest score was for positioning (4.2).
Committee considerations
3.9
The committee noted that patient return electrode site burns are rare. It was advised that, on average, 117 electrosurgery burns are reported to the MHRA each year. Of these, approximately one-third are patient return electrode site burns and about two-thirds are alternative site burns. Expert advisers stated that, in their experience, patient return electrode site burns are very uncommon indeed, are not severe and can be treated with topical cream only. The committee was advised that all types of burn can usually be avoided by good operating theatre practice.
3.10
The committee noted that the published clinical evidence comparing the Mega Soft Patient Return Electrode against disposable single-use patient return electrodes for use during monopolar electrosurgery is limited and did not provide evidence of whether or not the device reduced the incidence of patient return electrode site burns in practice. The committee accepted that there have been no reports of burns as a result of its use in the UK, and it acknowledged, therefore, that it is plausible that using the Mega Soft Patient Return Electrode reduces the risk of patient return electrode site burns, based on theoretical considerations. The committee concluded that technical testing had shown that the Mega Soft Patient Return Electrode was safe in the normal circumstances of UK practice. It noted that no adverse incidents (and specifically no burns of any kind) had been reported from use of the Mega Soft Patient Return Electrode in the UK.
3.11
The committee noted that the type of electrical circuit formed by the Mega Soft Patient Return Electrode can be associated, if good operating theatre practice is not adhered to, with an increased risk of alternative site burns compared with standard disposable single-use patient return electrodes. In the absence of evidence of this, and balancing the plausible reduction in patient return electrode site burns against the possible increase in alternative site burns if good operating theatre practice is not adhered to, the committee judged that there was likely to be a similar overall risk of burns with the Mega Soft Patient Return Electrode compared with current practice. Any reduction in the overall risk of burns using the Mega Soft Patient Return Electrode would depend on good standards of operating theatre practice to minimise the incidence of alternative site burns. Therefore, clinicians and managers considering the adoption of the Mega Soft Patient Return Electrode should take into account current practice in their operating theatres with regard to prevention of alternative site burns.
3.12
The committee accepted it was likely that the Mega Soft Patient Return Electrode may have practical advantages in selected patient groups, but despite a limited number of positive user feedback reports, there was a lack of clinical studies to support these claims. Examples are patients with fragile or damaged skin, and patients who would need shaving before application of standard disposable single-use patient return electrodes. The committee noted estimates from clinical experts that between 20% and 30% of patients need to be shaved before the use of standard disposable single-use patient return electrodes. The committee noted that adipose tissue, bony prominences, tattoos and scar tissue need to be considered, as well as body hair, when placing single-use patient return electrodes but not when using the Mega Soft Patient Return Electrode.