ICU acquired weakness in patients with respiratory failure

Background: Most patients with severe respiratory failure in intensive care unit (ICU) require bed rest. The limitation of physical activity leads to some adverse consequences such as ICU Acquired Weakness (ICUAW). Progression of respiratory failure, including that caused by the new coronavirus infection (COVID-19), can lead to the development of acute respiratory distress syndrome, the treatment of which contributes to a combination of risk factors for the development of ICUAW. Traditional diagnostic methods have certain limitations. Muscle ultrasonography is a modern tool for early detection of muscle mass loss. Aims: To compare different methods of early ICUAW screening and to estimate the incidence and peculiarities of ICUAW in patients with respiratory failure of infectious genesis. Methods: 31 patients with severe coronavirus pneumonia (COVID-19 “+”) and 13 patients with viral and/or bacterial lung infection (COVID-19 “-”) were included in the study. The muscle mass loss percent from day 1 to day 7 was higher in the COVID-19 “-” group (p=0.022). These patients also had longer durations of the ICU and hospital stay but a significantly lower mortality (2.5 times). Results: The analysis of the parameters of deceased and living patients regardless of the lung damage etiology showed a correlation between the indices of hand grip strength dynamometry (handgrip test) and ultrasonography of the thigh muscles: F1 and D1 (rho=0.6, p=0.003), F1 and S1 (rho=0.6, p=0.005), D1 and F7 (rho=0.9, p=0.001). In addition, the examined levels of the ICUAW markers were associated with age - F1 (rho=-0.6, p=0.001), D1 (rho=-0.4, p=0.003), S1 (rho=-0.4, p=0.004). Conclusions: During the critical illness, ICUAW develops by the 3d day of bed rest in two thirds of patients with respiratory failure of different infectious genesis. The correlation between the investigated markers of ICUAW and age indicates that elderly patients are the most vulnerable category in respect to the formation and progression of muscle weakness in the ICU. The handgrip test can serve as a reliable and simple method of ICUAW screening. Early identification of patients with ICUAW should provide the improvement of nutritional support and individualization of rehabilitation.