Transcutaneous Functional Magnetic Muscle Stimulation in Critically Ill

1. Introduction

ICU-Acquired weakness (ICU-AW) is a significant complication of critical illness. ICU-AW is common in patients with sepsis, systemic inflammatory response, and mechanically ventilated. It is estimated that around 50% of patients recovering from the primary illness remain in intensive care with characteristic muscle weakness. This leads to dependence on mechanical ventilation, prolonging costly intensive care hospitalization. The resulting myopathy causes persistent functional impairment, endangering patients long after hospital discharge.

1.1 Pathophysiological basis of development of Critical illness myopathy The pathophysiological mechanisms of ICU-AW are poorly understood, leading to the absence of specifically targeted treatments for its prevention. In most patients, skeletal muscle atrophy is observed, particularly the loss of fast-twitch muscle fibers (type II) and decreased levels of myosin heavy chains (MyHC). The loss of MyHC is a consequence of disrupted balance between its synthesis and degradation. The most significant contributors to the development of ICU-AW include systemic inflammation, sepsis, immobilization, sedation, hyperglycemia, exposure to neuromuscular blocking agents and corticosteroids, resulting in decreased muscle mass and strength. The principal intracellular system for protein degradation in skeletal muscles is the ubiquitin-proteasome system, which also regulates MyHC degradation.

1.2 Physiotherapy and Transcutaneous Electrical Muscle Stimulation Therapeutic activity in the intensive care unit often begins with passive mobilization, especially in inactive and unconscious patients. In the treatment of critically ill patients is aimed to reduce sedation, providing appropriate analgesia, thus promoting faster awakening and cooperation, and encouraging active movement even in patients on mechanical ventilation.

For muscle strengthening and reducing atrophy, physiotherapy is often combined with peripheral transcutaneous electrical stimulation of skeletal muscles. With electrical stimulation muscle strength can be increase in non-critically ill patients by using stimulation protocols that do not induce muscle fatigue.