Dynamic tibialis anterior ultrasound monitoring reveals a multimodal ultrasound signature for intensive care unit-acquired weakness: A prospective cohort study

Objective To validate a serial multimodal ultrasound (MMUS) protocol for assessing dynamic tibialis anterior changes in detecting intensive care unit-acquired weakness (ICUAW) and to develop a diagnostic algorithm. Methods In a prospective cohort of 97 high-risk adults (mean age 60.7±13.7 years; 73.2% male; SOFA score ≥8 for ≥3 days), MMUS quantified structural (thickness, echogenicity), hemodynamic (perfusion grade, peak systolic velocity [PSV]), and mechanical (elastic modulus) parameters of the tibialis anterior at ICU admission (Day 1) and Day 7. ICUAW was diagnosed per American Thoracic Society guidelines. Serum biomarkers (IL-6, PCT, CRP) were correlated with sonographic changes. Diagnostic models were constructed using binary logistic regression and evaluated by ROC analysis. Results 31 patients (32.0%) developed ICUAW. By Day 7, the ICUAW group showed greater structural deterioration (echogenicity progression: 54.8% vs. 16.7%, P < 0.001), hemodynamic changes (PSV: 7.60 ± 1.72 vs. 6.35 ± 1.78 cm/s, P < 0.001), and faster stiffness increase (elastic modulus rate: 14.1±12.3% vs. 5.4±6.0%, P < 0.001). Day 7 PSV correlated with IL-6 ( r = 0.59), PCT ( r = 0.50), and CRP ( r = 0.68) (all P < 0.05). A 7-parameter model achieved an AUC of 0.917 (95%CI: 0.857-0.978) with an NPV of 92.4%. Conclusion Dynamic MMUS captures ICUAW pathophysiology. The proposed algorithm shows potential as a non-invasive bedside tool for early risk stratification, pending multicenter validation.