NEW INVESTIGATIONS INTO THE MEASUREMENT AND PREVENTION OF MUSCLE WASTAGE

Interview with Danielle Bear R.D. by Meg Marquardt, Nestlé Health Science.

From the Metabolic and Nutritional Issues in the ICU Workshop – 29-30 May 2018, Brussels, Belgium.

MB: I am here with Ms Danni Bear who is a critical care dietitian. She is the lead dietitian at Guy’s and St Thomas’ Hospital in London and she is also part of the Health Education England National Institute for health research where she is a clinical doctorate fellow. Now, what’s your PhD in Danni?

DB: My PhD is currently investigating the measurement and prevention of skeletal muscle wasting in critical illness. So there’s actually currently three parts to that. So one of them is looking at which body composition analysis techniques we can use to both measure muscle wasting in ICU patients, but also look at the effectiveness of nutrition interventions. So I’m specifically looking at CT scans and muscle ultrasound. I’ve also undertaken a systematic review and meta-analyses looking at the effect of HMB in clinical populations, not just in ICU patients, and also my trial. So the main part of my PhD is investigating the effect of HMB on muscle wasting in critically ill patients.

MB: On that you presented a very elegantly on body composition here at this congress. Why is this topic important for this audience?

DB: So the topic of body composition is really important at the moment in the area of critical care, not just in regards to nutrition but also in regards to physical and functional recovery, because we know that a lot of patients in the ICU experience significant muscle wasting and that then goes on to influence how weak those patients are and how prolonged their recovery might be. So being able to measure body composition and the changes in muscle and fat components of the body will allow us to then think about interventions to target the reduction in the change in that body composition, but also to look at recovery and how we might be able to start to rebuild muscle after the patients leave ICU.

MB: And what proportion of ICU patients suffer from this?

DB: So I don’t know the proportion of patients that suffer from muscle wasting per say, but if, you know, on average patients are losing around 20% of their muscle mass, so rectus femoris cross sectional area specifically I’m talking about here, over the first 10 days of ICU stay and that…

MB: All patients?

DB: That’s patients with multi…sorry, patients with a SOFA score of more than 2, but those with multi-organ failure, so the sickest patients, can loose up to 25% of their muscle mass over 10 days. So the sicker you are the more you waste away.

MB: And how well adopted is measurement in the ICU?

DB: So I don’t think that body composition measurement is very well adopted in the ICU at all, I think there are several reasons for that. I think one is…so for example if we’re using muscle ultrasound there isn’t a very good standardised protocol to use for that yet, so muscle ultrasound isn’t really a technique that I think should be adopted into clinical practice yet. It should be used for research purposes only. You have the option of using CT scans, but you can only use CT scans if you already have one because we don’t tend to send patients to a CT scan just for body composition analysis, so that makes things difficult. It’s also more difficult to look at change over time with CT scans. Other options are tricep skin folds, mid-arm muscle circumference or using the subjective global assessment. And again, tricep skin folds and mid-arm muscle circumference can be influenced by fluid shifts and they’re quite difficult in a really sedated patient. And the SGA had some conflicting data on whether or not it is useful in ICU patients, but in my opinion I think any measurement is better than no measurement. So if you don’t have the availability of the equipment or the expertise then I think that at least doing the SGA is something that should be done. The other option is bilateral impedance analysis. Again, very controversial in terms of whether or not it’s useful in ICU because of these significant fluid shifts, but there are some data to say that using phase angle, so rather than the actual measurement of fat free mass using phase angle instead, can be more useful because it’s not as influenced by fluid shifts.

MB: So even though there’s a lack of standardisation across these different tools you categorically would say do something rather than nothing?

DB: I think doing something rather than nothing. I don’t think doing muscle ultrasound is included in that statement, but I definitely think doing something like the SGA or at least measuring some sort of circumference is better than nothing because if you can’t track how your patient is doing then you don’t know whether or not your interventions or your treatments are having an effect. So I think definitely something’s better than nothing.

MB: And whose role is it, do you think, to measure and to apply the results?

DB: I think the role is dependent on who the nutrition specialist is in that ICU and that varies from country to country, so I’m learning. So in the UK for example, that role would really fall to the dietician because we are the ones who are developing and implementing the nutrition plans for those patients, but in other units it’s the nurse or it’s the pharmacist or it’s the medical team that do it. So it’s really very dependent, but I would say whoever is the person who’s responsible for implementing a plan and is responsible for that should be the one doing the body composition measurements, and in my opinion there should be at least someone on the unit who is an advocate for nutrition. So someone who is encouraging and teaching people to use these techniques and how to reassess and monitor the patients.

MB: What evidence is there that measurement improves management?

DB: In ICU patients at the moment there is no evidence to say that measuring body composition analysis is going to improve what we do or is going to improve outcome, but in other populations you can’t implement a plan unless you have all of the information and I think that’s where we kind of lack information in ICU patients because we’re not really doing a full assessment.

MB: What is the most realistic way do you think of increasing adoption?

DB: I think increasing adoption is going to be the most difficult part of this, for many reasons. One because it, you know change is difficult, everyone finds change a little bit hard, but I think increasing knowledge and awareness is probably the number one factor. There are people who still don’t really understand the implications of a loss of muscle mass or a change in body composition on patient outcomes. So I think once we have increase in knowledge and awareness around that then people will start to adopt some of these techniques. I think, you know, we need to have some way of training people to do that. So whether that’s a web based tool that allows people to understand more about the difficulties and limitations of these techniques in ICU patients, because they are different to, you know, your more mobile patient, I think that that will also be helpful. So I think it’s a lack of awareness and a lack of knowledge that we need to change before these types of things are going to be adopted into clinical practice. Also I think there’s a reluctance because we don’t really know which interventions can change body composition in ICU. So people think, well, I don’t know what I’m going to do when I get that number so why am I going to do anything about it, but at least it allows you to track and see whether or not you’re interventions are being effective. So even if we don’t know the best thing to do yet, I still think it forms a very important part of our assessment within the ICU patients and also post ICU.

MB: As increasing evidence has shown the interventions in our ICUs have a longterm impact, so perhaps this is an area that we could expand the knowledge on so people see it in a more quality of life result rather than an acute result?

DB: Yes, absolutely, and I think change is in nutrition and you’re never going to see an acute change from a nutrition intervention unless you’re looking specifically at the muscle maybe in terms of muscle biopsy or protein signalling pathways, you’ll see that very quickly, but you may not see changes in muscle mass or quality very quickly. So we need to look over the longterm, definitely.

MB: Thanks a lot Danni, and good luck with your PhD.

DB: My pleasure, thank you very much.

END.