Cyclic recruitment of atelectasis – Are there implications for our clinical practice?

SummaryAtelectrauma refers to lung injury due to recruitment of collapsed lung with each inspiration and de-recruitment with each exhalation. Atelectrauma has long been hypothesized to be a mechanism of ventilator-associated lung injury, but only recently have experimental tools become available to study this phenomenon. Cyclical recruitment of atelectasis has now been clearly demonstrated in specific animal models of lung injury. These animal studies have also shown that recruitment and collapse are time-dependent processes and cannot be predicted solely on the basis of end-inspiratory and end-expiratory pressures. To determine if this is a concern in patients, we need to know the incidence of cyclical recruitment, and we need to know if it injures the lung. Definitive answers are not currently available for either question, and will await the application of new high temporal resolution methods for measuring cyclical recruitment in patients. Recent animal studies suggest that cyclical recruitment, when present, can be very damaging to the lung. Avoiding cyclical recruitment may therefore become an important consideration in clinical ventilator management.