Fig. 6.
Algorithm for intraoperative management of pulmonary atelectasis. A standard ventilatory strategy targeting surgical patients is implemented after anesthesia induction (positive end-expiratory pressure [PEEP] 2 to 5 cm H2O, no recruitment maneuvers, tidal volume 6 to 10 ml/kg of predicted body weight). In patients presenting intraoperative respiratory compromise consistent with pulmonary atelectasis, fixed higher PEEP is set after a recruitment maneuver. Attention is given to basic maneuvers to eliminate additional causes, e.g., secretions and bronchoconstriction, and maintain safety (transient increase in fractional inspired oxygen tension [Fio2]). If the respiratory dysfunction persists despite empiric alveolar expansion, an individualized strategy can be considered in high-risk conditions for atelectasis: PEEP titration targeting optimization of usually available (e.g., compliance, driving pressure) or advanced respiratory measurements (transpulmonary pressure, ultrasound, electrical impedance tomography). If individualization of lung recruitment fails to improve lung function or in patients without specific risk for intraoperative atelectasis, a specific diagnostic approach should be implemented without delay using lung imaging or bronchoscopy. *Hypoxemia may be defined by oxygen saturation measured by pulse oximetry drop by more than 5% or Fio2 increase by more than 30% to maintain oxygenation with PEEP of 5 cm H2O (presuming other causes such as airway, ventilator, or hemodynamic issues have been excluded). **Significant respiratory mechanics change may be defined by a compliance of the respiratory system drop by more than 20%, or a driving pressure 15 cm H2O or greater with PEEP of 5 cm H2O and tidal volume of 6 ml/kg predicted body weight. ‡Attend to hemodynamic stability during recruitment maneuvers. §Body mass index 35 kg/m2 or greater, pneumoperitoneum, Trendelenburg position, upper abdominal surgery with diaphragmatic surgical retractors, diaphragmatic injury, intraoperative lung injury, or pulmonary edema.