Muscle Protein Metabolism in Critically Illness

Most patients experience a considerable amount of muscle wasting during critical care. A decrease in muscle mass causes weakness which inevitably leads to delayed recovery. Since muscle also plays an important role in protein metabolism, metabolic instability increases as muscle mass decreases. Accordingly, various treatments have been attempted to maintain muscle mass and function in critically ill patients; however, it is still difficult to prevent muscle loss. It is known that muscle wasting in critical illness is primarily due to increased muscle protein breakdown rather than a decrease in muscle protein synthesis. Nutritional therapy and rehabilitation are fundamentally important, but additional anabolic agents may be needed to overcome anabolic resistance. In this review, we will learn about muscle protein metabolism in critically ill patients and how various treatments affect muscle protein metabolism.