Extrapulmonary Lung Protection Strategy for Patients With Mechanical Ventilation

As an important life sustaining support , mechanical ventilation has greatly promoted the development of modern intensive care units. However, mechanical ventilation can lead to ventilator-induced lung injury, including barotrauma, volutrauma, atelectrauma and biotrauma. All patients undergoing mechanical ventilation are at risk of barotrauma. A multicenter prospective cohort study of 5183 patients with mechanical ventilation showed that the incidence of pulmonary barotrauma was 3%. The incidence of pulmonary barotrauma varied according to the causes of mechanical ventilation: chronic obstructive pulmonary disease (3%), asthma (6%), chronic interstitial lung disease (10%), acute respiratory distress syndrome (7%) and pneumonia (4%). At present, it is considered that one of the main causes of barotrauma is the increasing of transpulmonary pressure. Transpulmonary pressure is the difference between alveolar pressure and intrapleural pressure. The commonly adopted lung protective ventilation methods include: limiting plateau pressure less than or equal to 30 cmH2O, using small tidal volume ventilation (6-8 mL/kg ideal body weight) . All the above methods are to reduce trans-pulmonary pressure by reducing alveolar pressure. In addition to reducing alveolar pressure, increasing pleural pressure is another important way to reduce transpulmonary pressure and the incidence of barotrauma. At present, the main method is the use of neuromuscular blockade. However, there are many shortcomings in of neuromuscular blockade: 1. Time limit, generally not more than 48 hours; 2. Long-term use of neuromuscular blockade causes adverse reactions such as myopathy; 3. Neuromuscular blockade are only suitable for invasive mechanical ventilation patients, but not for non-invasive mechanical ventilation or high flow oxygen inhalation patients. Therefore, it is urgent to find other methods to reduce trans-pulmonary pressure and lung injury. The investigators drew inspiration from the early