"Tailored" vs. "one-size-fits-all": current knowledge of individualized PEEP and constant PEEP strategy during the perioperative period.

Postoperative pulmonary complications (PPCs) are dramatically associated with prolonged hospitalization and increased mortality rates in surgical patients. Positive end-expiratory pressure (PEEP), a standardized lung-protective strategy, has been proven to effectively improve perioperative oxygenation and pulmonary compliance. However, constant high PEEP may induce alveolar hyperventilation and elevate pulmonary vascular resistance, while fixed low PEEP may not prevent atelectasis and even cause PPCs. Currently, an individualized PEEP (iPEEP) approach is found to be superior to the constant PEEP strategy during surgery. This review highlights that iPEEP reduces PPCs, decreases the risk of atelectasis, improves arterial oxygenation, prevents end-expiratory lung collapse, and reduces ventilator-induced lung injury during gastrointestinal, urologic, cardiac, abdominal, and other surgeries under general anesthesia. Besides, iPEEP can also attenuate local lung inflammatory responses, counterbalance intraabdominal pressure, improve postoperative cognitive function, elevate cardiopulmonary exercise capacity, and reduce hospitalization time. Therefore, it is recommended to apply iPEEP against a constant low or high PEEP strategy during surgery under general anesthesia. Further studies are still warranted to define the best ventilation setting and reach a consensus on the ventilatory management of surgical patients.