The effect of self-directed learning ability on core competence in undergraduate nursing students: the mediating role of professional self-concept.

Over the past two decades, advances in critical care medicine have substantially improved short-term survival among intensive care unit (ICU) patients, transforming many previously fatal conditions into survivable illnesses. As survival rates have risen, the priority of critical care has shifted beyond mere life support to optimising long-term functional recovery and health-related quality of life. A large and growing body of evidence demonstrates that ICU survivors frequently develop persistent physical, cognitive, and psychological impairments collectively termed post-intensive care syndrome (PICS). Systematic reviews indicate that PICS affects approximately 60% of patients at 3 months post-ICU discharge and 40% at 12 months, with manifestations including ICU-acquired weakness (ICU-AW), executive dysfunction, anxiety, depression, and post-traumatic stress disorder that may persist for years after hospital discharge (). These impairments not only reduce patients' ability to return to independent living and employment but also drive substantial increases in post-discharge healthcare utilisation and long-term societal costs. Early rehabilitation (ER) is a multidisciplinary, patient-centred intervention delivered by collaborative teams including intensivists, critical care nurses, respiratory therapists, physiotherapists, occupational therapists, and psychologists. For the purpose of this review, ER is explicitly defined as structured rehabilitation initiated within 72 h of ICU admission or 24 h of haemodynamic stabilisation (), encompassing four core domains: physical rehabilitation, respiratory rehabilitation, cognitive rehabilitation, and psychological rehabilitation, aligned with international multimodal rehabilitation frameworks (, ). International clinical practice guidelines, including the 2018 Pain, Agitation/Sedation, Delirium, Immobility, and Sleep (PADIS) guidelines from the American College of Critical Care Medicine (ACCM), endorse early rehabilitation as a standard component of high-quality ICU care for haemodynamically stable patients, with initiation recommended as soon as clinically feasible within the first 72 h of admission (, ). Accumulating evidence from primary studies and systematic reviews confirms that ER can improve physical function, reduce delirium duration, shorten mechanical ventilation time and ICU length of stay, and enhance long-term quality of life (–). Despite these established benefits, the existing evidence base for ER in critical illness has important limitations. First, there is marked heterogeneity across studies in ER protocols, including wide variation in initiation timing, intervention intensity, session duration, and component modalities, which limits comparability of findings and clinical generalisability. Second, most available systematic reviews (SRs) have focused predominantly on physical mobilisation in general ICU populations, while evidence regarding the efficacy and safety of ER in high-risk subgroups—such as patients receiving extracorporeal membrane oxygenation (ECMO), those with severe neurological injury, or older adults with pre-existing frailty—remains sparse and inconsistent. Third, adverse event reporting across primary trials and SRs is highly variable and incomplete, leaving the safety profile of ER insufficiently characterised. Fourth, methodological quality assessments of published systematic reviews in this field consistently demonstrate widespread shortcomings in study conduct and reporting, with fewer than 30% of available reviews meeting high-quality standards when evaluated using the AMSTAR 2 tool (). Finally, overlapping primary study samples across published SRs may introduce bias and distort effect estimates, further weakening the reliability of available conclusions.