MTG2 MoorLDI2-BI laser doppler blood flow imager for burn wound assessment - No.2 Practical considerations
Mrs Sarah Pape, Consultant Plastic Surgeon at Newcastle Upon Tyne Hospitals NHS Foundation Trust discusses her experience of using the MoorLDI2-BI laser doppler blood flow imager for burn wound assessment and practical advice for those implementing the NICE Medical Technology guidance on this device. We recommend that you listen to podcast No. 1 before this second extended discussion.
This podcast was added on 15 Apr 2011
Podcast 2 with Mrs Sarah Pape: NICE medical technology guidance on the moorLDI2-BI
Interviewer: Hello and welcome to this second NICE podcast about the NICE medical technology guidance on the moorLDI2-BI laser doppler blood flow imager for burn wound assessment. In particular this podcast will be focusing on the practical issues of using the device.
This second extended podcast should be listened to after you have listened to the first podcast.
For the purpose of this podcast we will shorten the name of the device to the moorLDI.
I am Katie Worrall, implementation lead for this guidance and with me is Mrs Sarah Pape, Consultant Plastic Surgeon at Newcastle Upon Tyne Hospitals NHS Foundation Trust. Mrs Pape has published research using this technology and provided expert advice to the medical technologies advisory committee who developed the recommendations on the moorLDI.
SP: With the moorLDI we can confidently examine the images, compare them with the patient make a decision about the treatment and then we know that we are giving the patient the best outcome.
The advantage of the moorLDI is that it seems to see things that we can't see with our naked eyes and it quantifies them. So if the increase in the blood flow is only moderate it will detect that and it will give me a different picture from a burn where the increase in flow is extremely high and it displays it in a colour coded format that, because of the way the technology is now set up, absolutely correlates to the expected healing time. So an area that shows in red or bright pink correlates to a healing potential of within 14 days, areas of the burn with only a more modest increase in blood flow are shown in yellow and green and those areas correlate to burns that will heal within 14-21 days. (and) The areas that remain blue or navy blue are those that have very low blood flow and are therefore expected to take longer than 21 days to heal and in all situations unless they are very very small or the patient is extremely unfit those are areas that you would expect to have a better outcome with surgery.
Q1 Interviewer:I wanted to ask some practical questions about using the device. When should the device be use post injury and how long does it take to do a scan?
SP: In the guidance we (NICE) suggest that the best time for imaging is between 48 and 72 hours after the burn injury but in fact it can be used up until 5 days after injury. Now that is not because of any particular feature of the technology, that simply relates to what is happening in the burn wound. In any burn there will be areas of skin that are killed immediately by the heat or chemical or whatever has caused the burn and those areas will be dead from the time of the injury and will never change until it has healed or it has been operated on. But there are areas that are particularly common in intermediate depth burns where there has been a significant insult to the skin where the circulation may have become rather sluggish, there may be tiny thrombi in the blood vessels so the delivery of oxygen and nutrients to the damaged skin is less than good and that may evolve and deteriorate over a period of time. So it would be untrue to say the technology is not stable until 48-72 hours after the burn; it is the burn that is not stable until 48-72 hours after the injury. So if you look at a burn sooner than 48 hours you may believe it to be completely superficial but then you look at it around 72 hours and you may find that things have changed in the mean time and your initial assessment now appears to be wrong. It was not wrong it is just you are looking at a different situation.
Q2 Interviewer:If the best time for imaging is 48 - 72 hours after the injury, might there be delays in treating the injury, while you were waiting to be able to scan it?
SP: The difficulty is where people believe that the patient would benefit from extremely early surgery such as on the day of injury. It is not possible to use the LDI to make a clear assessment of the burn depth, but then to be perfectly honest there is no method of assessment on the first day neither by clinical examination nor by any other technology that has ever been suggested that will give you an accurate assessment of burn depth on the first day, because it is likely to change. The risk of making a decision very early is that we tend to err on the side of caution and the area of burn that looks a little bit deeper you may think well, if this is going to progress over the next two days, then perhaps I should just remove that area as well. That is a natural human temptation. We want to do a good job and we want do a good job first time around so unfortunately, and I know that in the past I have been guilty of doing that, that one may end up removing more skin on the first day than was actually required. So there is always a balance to be made if a clinician feels that, in that particular clinical situation, that patient must have their burn excised on the day then no technology is going to be able to assist in that decision, but if there is no clear benefit to the patient to have the burn excised sooner than 48 hours then the scan can be delayed until 48 hours and the surgery can follow. Frequently where we feel the need for early surgery we can even perform the scan in the operating theatre just before the operation starts and then we have the image in front of us. We have a map of the burn, we can see which areas clearly can be left, which areas clearly require surgery and then we can confidently proceed with that surgery. There are some other situations where we might want to apply dressings to the wound and I am thinking here of extensive superficial burns particularly in children but increasingly we use this in adults as well. So these are patients who would not require surgery for skin graft but whose burn is extremely painful because of its extent and of course superficial burns are more painful than deep burns. They have a high requirement for pain killers, their burn is leaking fluid so they have a high requirement for fluid and generally they feel absolutely awful. We can take those patients to the operating theatre on day 1 or day 2 and we can remove the loose blistered skin, we can mop away any leakage that has come from their capillaries and we can replace the surface of the wound with semi biological dressings. The one that we use most commonly is a stretchy polyester dressing that fits snugly around the wound and on the under surface it's impregnated with collagen. Collagen stimulates the clotting process and forms a fibrin mesh which helps to adhere the dressing to the surface of the wound and we have found and this has been confirmed by many people around the world that if you apply this dressing in the early stages, the amount of pain the patient suffers is dramatically reduced, their analgesia requirement is reduced, the amount of leakage from their fluid surface is reduced and they generally start to feel better very very quickly, and where they may have been kept in hospital for 5 days recovering from this very superficial burn we can usually get them home 48-72 hours after injury. (and) I have seen in children who have gone through this procedure in the morning and I have gone back to see them at tea time and this child who was previously in bed on a drip looking really very poorly is now running up and down the corridor and playing and laughing and clearly quite a different child and that is just within a few hours of the surgery. In those situations what we would do is we would perform the LDI in theatre before applying the biological dressings, or if we were doing the dressings at a much earlier stage so the wound was not sufficiently stable to have a good and accurate scan, you can actually scan through the dressings and I have got many patients now where we have done that. The dressing is so thin that the laser beam from the scanner is able to penetrate through the skin and the reading is completely accurate and so it does not in any way prevent you from doing a later assessment of the burn depth. From the point of view of how long the scan takes it depends on how we set it up. It is possible to set up a relatively low resolution scan that will scan a fairly large area in about 15 seconds. So if the patient finds it uncomfortable to keep still or if it is a young patient then we can set it to the lowest resolution and the smallest areas to be scanned, we can just look at the very area that we are most concerned about and that can literally be done in just a few seconds. If we want more extensive scans performed over larger areas of the body, or we want more detail, then we can set up higher resolution scans that take a few minutes to be done but most of the scans can be done within about 30 seconds to 2 minutes and then there is a pause before the next area is scanned. If the patient wishes to move their position then they are able to do so in between the scan then they are able to do so. It is however, important that they keep still during the scan because movement of the body parts will be picked up by the scanner.
Q3 Interviewer: Where would the device be routinely used and by who?
SP: It would be lovely to suggest that every patient who ever had a burn would be able to have a scan to confirm the depth but in reality that is impractical. The vast majority of patients with minor burns are managed in accident and emergency departments and that may be in a hospital where there is no burns expert on hand to interpret the scans and it is no doubt it does require a degree of training and experience to be able to make the most accurate assessment. I think where this really comes to the front is in the assessment of patients with intermediate depth burns and the majority of those patients are going to be referred by the accident and emergency departments, by the general practitioners to a burns service for assessment. In the united kingdom we are in the process of designating burns services according to the level of burn patients that they will be dealing with. So we have burn facilities which are usually plastic surgery units that would manage a number of small but possibly deep burns in the course of a year. We also have burn units which would manage patients with the larger burns requiring a little more intensive management and then we have the burns centres, many of which will be in association with the major trauma centres, and these would be managing all burns from the very small burns right through to the very large burns, and they would be taking in the large burns from the wider area. In my opinion all of the burns services from facility right through to centre will be able to offer a better service to their patients, make better use of their time and their costs and be more productive if they use the moorLDI to scan all of those patients who have intermediate depth burns or areas of intermediate depth burn in areas of superficial burns.
Q4 Interviewer: Brilliant thank you. What advice do you have for clinicians who are looking to using this technology in practice?
SP: Clearly the most important thing is to receive some training so that they become familiar both with setting up the device, how to use it, how to reduce the possibility of any artifactual elements being introduced into the scan. There are some very simple things like making sure the patient is comfortable so that they are not going to fidget and move during the scan, making sure that loose blistered skin has been removed because loose skin lying on top of the skin will prevent the laser from penetrating and giving an accurate result, making sure that all the margins of the burn have been included possibly by repeating the scan from a different angle. There are a number of practical things that can be done to improve the accuracy of the scan and therefore the interpretation of it. It is also important that people have experience of looking at a wide range of scans, looking at scans in different parts of the body, looking at scans in patients from different age groups, looking at scans in people with different skin types, particularly in darker skin types and intermediate colour skin types, and this can be obtained by training. Really attending training given by somebody who is experienced in using the scan, setting it up and interpreting it. We are probably really only talking about a few hours of training for those who are already experienced in looking after patients with burns.
Q5 Interviewer: Brilliant thank you. Do you have any advice for managers on how best to support this change in practice?
SP: Yes, I think that managers should ensure that their staff are fully trained and comfortable in the practical use of the scan. It is important to make sure that there is time every day for scans to be performed because there are always days where it is appropriate for that patient. If that patient comes in late at night it may be that the scan needs to be done during the later part of the day, 2 days after the injury, and we need to be sure that whatever the time of day there are staff around who can do the scan. I am not saying in the middle of the night that clearly would be unnecessary, but if the scan needs to be done late on a Friday afternoon we need to make sure that we have enough staff around who can perform the scan. It is also important to make sure that the service is backed up with experienced clinicians who are available to look at the scans. They do not necessarily have to see the patients right in front of their eyes with the scan. If a good quality medical photograph is available then that is sufficient, provided that it covers the same areas as the scan that is sufficient for them to be able to look at and there are other issues around availability of theatre. In my opinion there should be the ability to take a patient with a burn to theatre every day of the week. Not necessarily in the middle of the night. There are some instances where that is necessary but there should be provision for access to burn lists 9-5 seven days a week and these are the sorts of things that managers are able to influence and make sure that we have the standards of care that will give us best quality for the patients. It is also important that the device itself is kept up to date. From time to time there are software upgrades and it is important that managers ensure that the staff are able to upload these. It is important that the data is able to be stored safely so we need to have facilities for that to be carried out. It is also important that the devices are serviced from time to time and the easiest way to make sure that this happens is to set up a service contract and then routine service takes place, the devices are checked over, the sensors are checked, the alignments. Everything can be checked over on a regular basis and then one doesn't have the worry that some technical issue with the machine or the quality of the scan is going to interfere with the process of determining the burn depth and determining the best treatment for the patient.
Interviewer:Thank you very much Mrs Pape. We hope that you will find the information in this podcast useful in helping you implement this NICE guidance in practice. For more information about the NICE medical technology guidance on the moorLDI2-BI blood flow imager for burn wound assessment, and access to the NICE implementation tools which can all be adapted for local use, please visit our website, www.nice.org.uk/MT.
This resource should be used alongside the published guidance. The information does not supersede or replace the guidance itself.
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This page was last updated: 19 September 2012