Respiratory muscle dysfunction in older critically ill patients: Implications for rehabilitation

Older patients represent a rapidly expanding and clinically vulnerable population within intensive care units (ICUs), often presenting with complex, multifactorial health challenges. The physiological changes associated with aging, when compounded by critical illness, result in significant dysfunction of both peripheral and respiratory musculature. These alterations are further aggravated by clinical frailty, a multidimensional syndrome now recognized as a key determinant of adverse outcomes in critically ill patients. Respiratory muscle dysfunction in this population contributes to prolonged weaning from mechanical ventilation, diminished physical resilience, and delayed functional recovery. Converging factors such as age-related sarcopenia, diaphragmatic atrophy, impaired neuromuscular transmission, and systemic inflammation impair respiratory mechanics and ventilatory efficiency. The interplay between frailty and respiratory muscle weakness highlights the urgent need for early identification and targeted interventions. This review synthesizes current evidence on the pathophysiological changes affecting respiratory and peripheral muscles in older ICU patients and explores their impact on clinical outcomes. It emphasizes the essential role of clinicians in developing and implementing early, individualized rehabilitation strategies tailored to the needs of this population. Multidisciplinary approaches aimed at improving respiratory muscle performance, accelerating functional recovery, and reducing the burden of ICU-acquired weakness and ventilator dependence are also discussed. Recognizing the unique physiological and functional needs of older critically ill patients is imperative for optimizing rehabilitation trajectories and improving both short- and long-term outcomes in this increasingly prevalent patient group.