Lung protective strategies in anaesthesia

Abstract

Patients are at risk for several types of lung injury in the perioperative period including atelectasis, pneumonia, pneumothorax, acute lung injury, and acute respiratory distress syndrome. Anaesthetic management can cause, exacerbate, or ameliorate these injuries. This review examines the effects of perioperative mechanical ventilation and its role in ventilator-induced lung injury. Lung protective ventilatory strategies to specific clinical situations such as cardiopulmonary bypass and one-lung ventilation along with newer novel lung protective strategies are discussed.

Fig 1

(a) An inspiratory compliance curve (lung volume vs airway pressure) during OLV as the lung is slowly inflated by 100 ml increments in a patient with mild COPD. The lower inflection point of the curve (thought to represent FRC) is at 7 cm H₂O. During OLV, this patient developed intrinsic PEEP (measured by the end-expiratory airway occlusion plateau pressure ‘auto-PEEP’) of 6 cm H₂O. The addition of 5 cm H₂O of PEEP in this patient raised the end-expiratory lung volume above FRC, thus raising pulmonary vascular resistance in the ventilated lung and caused a deterioration in oxygenation. (b) The inspiratory compliance curve during OLV in a patient with normal pulmonary function. The lower inflection point of the curve is at 6 cm H₂O. During OLV, this patient developed intrinsic PEEP of 2 cm H₂O. The addition of 5 cm H₂O of PEEP raised the end-expiratory lung volume to FRC, thus decreasing pulmonary vascular resistance in the ventilated lung and caused an improvement in oxygenation. Based on data from Slinger and colleagues.

Fig 2

Impact of intraoperative lung protective strategies in lung cancer surgery. Comparison of historical control group vs lung protective ventilation group in patients undergoing OLV for lung cancer surgery showed significant benefits in terms of reduced ALI, atelectasis, and ICU admissions.