A new study is to examine the sketetal muscle metabolic phenotype during early critical illness. The muscles of people in intensive care are less able to use fats for energy, contributing to the extensive loss of muscle mass. The study was published in Thorax.

Intensive Care Patients

Intensive care patients can lose 20% of their muscle mass in just 10 days, which can contribute to long-term disability. Nutrition and exercise programmes designed to prevent this muscle loss have largely been unsuccessful. They already knew that our patients have difficulty using glucose to generate energy. Our new data suggests they also find it hard to use fats in the feed we give them to generate energy.

The findings suggest the inability to generate energy is likely a result of the widespread muscle inflammation experienced by patients in the early days of intensive care. The research team took leg muscle biopsies and blood samples from 62 patients on their first and seventh days in intensive care, and tested them for key proteins that are involved in energy conversion.

Muscle Quality

They found that the quantity of fat in a patient's tube feed was unrelated to the amount of energy in the muscle and to changes in quantity of muscle, instead finding a close and direct relationship between impaired energy conversion and loss of muscle quantity.

Previous studies into increasing nutrition for intensive care patients have shown conflicting results; our findings help clarify why our patients aren't benefiting from higher-calorie feeds as fats are an ineffective source of energy in the first few days of intensive care.

The researchers are now investigating whether different types of nutrition that use alternative energy sources, such as ketones, could be more effective, and perhaps treating muscle inflammation before exercise interventions could help maintain.

ICU And Moratlity

Muscle wasting is associated with increased length of intensive care unit stay and with mortality, so it's vital that we find better ways to ensure that nutrition and rehabilitation programmes are effective at preventing muscle wasting.

Exercise and rehabilitation in this group is going to be difficult if our patients' muscles lack energy to work and grow. Our patients may need a coordinated nutrition and exercise regime to recover just like athletes do not just one or the other. This needs to be put in place once the muscle inflammation has subsided.