Applying lessons from limb muscle disuse and ageing to better understand ventilator-induced diaphragm dysfunction

Mechanical ventilation (MV) is a life-saving intervention applied to critically ill patients. A common consequence of MV is ventilator-induced diaphragm dysfunction (VIDD), which is characterized by significant diaphragm atrophy and reduced contractile function. Older patients who receive MV are more likely to develop VIDD, have worse recovery, and higher mortality rates compared to younger adults. Despite the greater susceptibility of older adults to develop VIDD and lower survival rates compared to young adults, studies investigating the effects of ageing on VIDD and the recovery from MV are scarce. The field of limb skeletal muscle disuse has extensively shown that compared to adult limb muscles, aged limb muscles respond differently and have blunted recovery after disuse. This review summarizes the literature on the effects of MV on the diaphragm, discussing the available data on the effects of ageing and the recovery process after MV. We also provide an overview of the effects of ageing and the recovery of limb muscle from periods of disuse. We conclude with recommendations for future studies to apply lessons learned from the field of limb muscle disuse to the field of MV and VIDD.