Muscle wasting in critically ill patients: a major breakthrough

Patients in intensive care often develop severe muscle wasting and problems with muscle function. This delays recovery and can affect survivors’ exercise capacity (the amount of physical exertion that a person can sustain) and quality of life for up to five years.

In healthy people, muscle mass is maintained through a balance between the rate at which muscle protein is synthesised and the rate at which it is broken down. Until now, doctors and scientists have been unclear how critical illness affects this balance, limiting the available treatment options.

“We found that muscle protein is significantly broken down in the first week of critical illness, with patients losing 2% of muscle mass per day,” says Dr Zudin Puthucheary, who led the research. “Muscle protein synthesis levels were reduced at the start of illness but were recovering by the end of the first week, which was a surprise. This is an exciting discovery because we now know more about how and why people waste away when they’re critically ill.” Dr Puthucheary is a National Institute for Health Research (NIHR) Fellow at University College London and King's College Hospital NHS Foundation Trust.

“Whilst this study doesn’t yet offer a treatment, it does tell us we need to develop strategies to both block muscle breakdown and increase its growth. We doubt that one, on its own, is the answer.”

Also surprising was the finding that feeding via a tube inserted through the nose into the stomach was associated with greater muscle wasting. This suggests that, contrary to current thinking, more feeding is unlikely to help.

Collaborative effort

“This was a demanding study to undertake because the patients were acutely unwell and unstable,” says Dr Nicholas Hart, consultant in respiratory and critical care medicine, NIHR Biomedical Research Centre at Guy’s and St Thomas’ and King’s College London, who is presenting the research today (Wednesday 9 October) at the European Society of Intensive Care Medicine’s 26th Annual Congress in Paris.

“This work extended from the Intensive Care Unit to the laboratory and this kind of discovery is only possible when clinicians and scientists work closely together.”

Four NHS hospital trusts (Guy’s and St Thomas’, University College London Hospitals, King’s College Hospital, and Whittington) and four universities (King’s College London, University College London, Nottingham, and Imperial College) collaborated on this work.