The mediating effect of psychological capital in the relationship between stress and college adjustment among nursing students in South Korea: a cross-sectional study.

Intensive care unit-acquired weakness (ICUAW) is a frequent complication in critically ill adults, particularly among patients with acute respiratory failure, shock, and other severe conditions [, ]. Systematic reviews indicate that ICUAW affects approximately 25%–75% of critically ill patients [, ] and may increase to 33%–82% among those requiring mechanical ventilation for more than four days [, ]. Despite advances in critical care, ICUAW remains a major contributor to poor short- and long-term outcomes, including impaired recovery and reduced quality of life [, ]. Notably, a substantial proportion of patients continue to have ICUAW after hospital discharge [], and ICUAW has been reported as an independent predictor of mortality in ICU populations [, ]. Currently, no specific pharmacological therapy has proven effective for ICUAW, prevention and early rehabilitation strategies are central to reducing its burden [, ]. However, ICUAW diagnosis relies on the Medical Research Council (MRC) score, which requires patient consciousness and cooperation, rendering it inapplicable to sedated patients—a critical barrier to early detection. To address the limitations of using MRC scores for early ICUAW prediction, we aimed to develop an early ICUAW prediction model through a prospective multicentre investigation. Although several ICUAW prediction models have been proposed, most were developed using traditional logistic regression and retrospective or small single-centre datasets, with limited external validation and consequent concerns about generalisability [, ]. Furthermore, most models focus on basic demographic factors (e.g., age and gender), duration of mechanical ventilation, length of ICU stay, and laboratory parameters such as albumin (ALB) and lactate, while failing to adequately integrate bedside ultrasound-derived metrics. Pathophysiological changes related to sepsis and systemic inflammatory response syndrome (SIRS), together with protein hypercatabolism and anabolic resistance induced by prolonged immobilisation, drive muscle atrophy and weakness—the core pathological mechanisms of ICUAW []. Studies demonstrate that bedside ultrasound-measured muscle thickness (MT), cross-sectional area (CSA), and echo intensity (EI) serve as reliable indicators of muscle atrophy and ICUAW in critically ill patients [, ]. Thus, incorporating muscle ultrasound metrics into predictive models may enhance the precision of ICUAW prediction.