Variation of muscles thickness and strength in critically ill patients: preliminary results

<bold>Background:</bold> Mechanical ventilation (MV) is associated with adverse outcomes in ventilated patients, and impact of MV-induced diaphragm changes are still unclear. <bold>Aim:</bold> i) to assess the association between diaphragm and quadriceps thickness changes in intensive-care unit (ICU); ii) to identify factors influencing muscle variations. <bold>Methods:</bold> We enrolled adults expected to undergo MV for at least 48 hours. Quadriceps strength changes over the ICU stay period were assessed by rectus femoris cross-sectional area (CSA), Medical Research Council (MRC) sum-score, and dynamometer measurement. <bold>Results:</bold> So far, we included 21/38 (55%) patients (females 28.6%), aged 55.9(16.9) years, spending 11.7(6.7) days on MV during 14.9(9.4) days of ICU stay. Preliminary results showed several strong positive correlations: rectus femoris CSA and quadriceps thickness (ρ=0.77, p<0.001), respiratory muscle strength and MRC (ρ=0.84, p<0.001), respiratory muscle strength and quadriceps extensor right (ρ=0.84, p<0.001) and MRC and quadriceps extensor right (ρ=0.87, p<0.001). At ICU discharge, 20/21 (94.7%) scored <48 on the MRC scale. In patients with preserved diaphragm function, median time to sitting position was 6 (interquartile range (IQR): 5-15) days, compared to 17 days (IQR=9-25) in patients with impaired diaphragm function. <bold>Conclusions:</bold> The current findings deliver promising evidence on the feasibility of ultrasound and dynamometer alongside the MRC scale for evaluating peripheral muscle strength in ICU and for planning timely rehabilitation interventions.