Bioelectric Impedance Analysis (BIA) Assessment of Polymyoneuropathy in Critically Ill Patients as a Part of Post-ICU Syndrome

Intensive medicine keeps pushing its borders, and enables survival of critical illnesses, including the substitution of organ functions in patients with multiple organ dysfunction (MODS). Despite the improvements in short-term outcomes, the long-term prognosis and quality of life (long-term outcomes) in patients, who survived a critical condition at ICU, remain unfavorable. The long-term consequences may persist for months or even years.

Post-intensive care syndrome (PICS) represents a significantly limiting impairment in three areas: physical (polyneuromyopathy of critically-ill patients), cognitive (delirium), and mental (development of depressions and PTSD - post-traumatic stress disorder). It is especially the rapid deterioration of muscles caused with the catabolic effect of the illness itself during accentuated proteolysis, very negatively affects the muscle strength, inability to discontinue artificial ventilation in the patient, increase of infections, and prolongation of the ICU stay. It often results in the inability to discharge the patient into home care. Polyneuromyopathy affects up to 40% of critically-ill patients; at the greatest risk are especially patients in a serious catabolic state, with activated systemic inflammatory response, with microvascular ischemia, on corticosteroids, immobilized, and on long-term artificial ventilation. The prevention is difficult, as well as monitoring of the lean body mass (LBM), especially in the muscle mass of critically ill patients, who are further affected with changes in hydration and fluid leak.

BIA - bioelectric impedance is a non-invasive technique, which is able, on the basis of impedance, to evaluate body composition (muscles, fat, total body fluid), determine hydration (ratio of extracellular and intracellular fluid, fluid retention); another prognostic marker is also the phase angle. It helps to evaluate markers of nutrition, basal energetic metabolism.

The BIS Multiscan 5000 device measures 50 frequencies, which are used to create a Cole Plot, using a mathematical model. It enables obtaining data from bed-ridden critically-ill patients, using tetrapolar bioelectric impedance.