Can we do a better job of preserving and promoting muscle strength in critically ill patients?
As advancements have been made in the care of critically ill patients, we have had a growth in the number of ICU survivors, and this patient population has its own set of challenges, including a high incidence of ICU-acquired weakness or ICUAW. There is currently no standard protocol for care of this condition, but a review article in a recent issue of the journal Respiratory Care, which followed a national symposium dedicated to the care of the chronically critically ill patients, examined the current state of diagnosis and treatment of this condition and suggested some potential strategies for better management and prevention in the future.
ICUAW can be caused by immobility and resulting muscle atrophy; prolonged bed rest can cause the muscles to synthesize protein ineffectively and to break down at the molecular level, which can lead to decreased muscle mass. Some studies show that muscle atrophy beings within hours of immobility. According to this article, four to five percent of muscle strength can be lost for each week of bed rest.
A condition called critical illness neuromyopathy (CINM), in which muscle weakens due to a host of metabolic, inflammatory or bio-energetic changes, can also be to blame for ICUAW.
There is also conflicting evidence regarding the role that the use of corticosteroids and neuromuscular blocking agents – often given to patients in the ICU – might play.
The current question is: how can we prevent ICUAW and better treat it if it does develop? Depending on what we find out about their role, minimizing exposure to corticosteroids and neuromuscular blocking agents when possible might be prudent. But there may be some new options that are worth considering.
Rehabilitation and mobilization of patients in the ICU may reduce muscle atrophy and may make a great deal of sense in targeting ICUAW. To date, there have been a limited number of studies but the evidence we do have from them is encouraging:
- One study of early rehabilitation in chronically critically ill patients in a respiratory ICU showed that the rehab group made greater improvements in their 6-minute walk distance and their inspiratory pressure and dyspnea (shortness of breath) scores were also better
- One study showed that early mobilization is safe and feasible and can decrease the length of the ICU stay
- One study showed a speedier return to functional status at hospital discharge
We need further studies to corroborate this early evidence, and we also need to encourage an ICU environment supportive of this rehab intervention. Also exciting is the development of novel rehabilitation technology such as neuromuscular electrical stimulators and bedside cycle technology that can be used on awake or sedated patients.