Unstable alveoli may collapse during one part of the breathing cycle and reopen during another. Repeated movement creates shear stress at the alveolar surfaces, adding mechanical damage even when the primary problem is respiratory failure. This process can disrupt the alveolar-capillary barrier, promoting edema and worsening gas exchange. Preventing excessive cycling is therefore a central lung-protective goal.
Excessive tidal volume stretches lung units beyond a tolerable range, causing overdistension, while excessive airway pressure adds mechanical stress to the ventilated lung. Together, these forces can injure alveolar structures and disrupt the alveolar-capillary barrier. The resulting edema can impair gas exchange, making control of both volume and pressure clinically important.
Mechanical injury can activate inflammation within the lung, rather than remaining a purely local mechanical problem. Inflammatory signaling may increase pulmonary damage and contribute to disruption of the alveolar-capillary barrier. Mediators associated with this response can also produce systemic inflammatory effects, which helps explain why severe ventilation-related injury may affect organs beyond the lungs.
Positive end-expiratory pressure must be selected for the individual patient because unstable alveoli are vulnerable to repeated collapse and reopening. An appropriate individualized level can help limit that cycle while supporting adequate oxygenation. The goal is not simply to apply pressure, but to coordinate end-expiratory support with controlled ventilation, alveolar stability, and the patient’s oxygenation needs.
A lung-protective approach begins by choosing an appropriate tidal volume, controlling airway pressures, and setting positive end-expiratory pressure for the individual patient. These elements address different contributors to injury: volume limits overdistension, pressure control reduces excessive mechanical stress, and individualized end-expiratory support helps address unstable alveoli. Adequate oxygenation remains an essential outcome during this process.
Clinicians should consider ventilation-induced lung injury when mechanically ventilated patients with respiratory failure develop or risk worsening pulmonary injury. The concern is especially relevant when ventilation exposes the lung to excessive pressure or volume, or when unstable alveoli repeatedly open and close. Applying protective settings in this context aims to reduce additional damage while preserving adequate oxygenation.
Treatment success cannot be judged only by whether a patient remains connected to a ventilator. Clinicians also need to consider whether ventilation is maintaining adequate oxygenation without promoting edema, worsening gas exchange, or amplifying systemic inflammation. These outcomes connect ventilator management with the patient’s broader clinical course and with potential effects on other organs.