Driving Pressure-guided Lung Protective Ventilation

The study, named as "The Efficacy of Driving Pressure-guided Lung Protective Ventilation in Surgical Repair of Acute Type A Aortic Dissection: an open-label, randomized control clinical trial", aims to investigate whether driving pressure-guided lung protective ventilation can reduce postoperative oxygenation function in patients who have undergone surgical repair of acute type A aortic dissection. The primary outcomes is the incidence of postoperative hypoxemia (a partial pressure of arterial oxygen to inspiratory oxygen fraction ratio less than 300 mm Hg or a peripheral blood oxygen saturation less than 93% at any concentration of inspiratory oxygen) within 7 days after the surgery.

Postoperative hypoxemia is defined as a partial pressure of arterial oxygen to inspiratory oxygen fraction ratio less than 300 mm Hg or a peripheral blood oxygen saturation less than 93% at any concentration of inspiratory oxygen. Acute type A aortic dissection is a lethal disease requiring emergency surgery. Compared with non-cardiac surgery, hypoxemia frequently occurs after surgical repair for acute type A aortic dissection which has been reported to be 52%-67.6%, and the possible mechanisms are as followed: (1) systemic inflammatory reaction induced by massive thrombosis formation and long duration of extracorporeal circulation; (2) ischemia-perfusion injury in lung; and (3) a massive perioperative transfusion. Postoperative hypoxemia has been reported to be associated with prolonged duration of extubation, length of stay in ICU and respiratory failure, which contributes a high mortality of 20% to 44%.

Driving pressure, defined as the difference between platform airway pressure and positive end-expiratory pressure, was first introduced by Amato and his colleagues in their meta-analysis study on acute respiratory distress syndrome in 2015, demonstrating that driving pressure was most strongly associated with survival among various ventilation parameters. A lower driving pressure has been verified to be closely relative to an ameliorative prognosis after surgery. However, controversy persists regarding whether driving pressure-guided ventilation can decrease the incidences of postoperative hypoxemia and other pulmonary complications in the patients underwent surgical repair of acute type A aortic dissection.

Given the need for additional evidence to confirm the relationship between driving pressure and postoperative hypoxemia in the patients with acute type A aortic dissection, this open-label, randomized control clinical trial aims to assess the efficacy and safety of the driving pressure-guided lung protective ventilation strategy in preventing hypoxemia and other pulmonary complications after the surgical repair for acute type A aortic dissection.

Eligibility Criteria:
Inclusion Criteria:

1. Able to sign Informed Consent and Release of Medical Information Forms;
2. Age ≥ 14 years and ≤ 70 years old;
3. Being confirmed the diagnosis by chest computed tomography angiography and receiving the surgical repair of acute type A aortic dissection.

Exclusion Criteria:

1. Age \< 14 years or \> 70 years old;
2. Sepsis before surgery;
3. Chronic pulmonary disease including lung infection or asthma requiring long-term pharmacotherapy;
4. History of lung tumor;
5. Obstructive sleep apnea hypopnea syndrome requiring long-term noninvasive mechanical ventilation support;
6. Heart failure requiring catecholamines or invasive mechanical ventilation support;
7. Body mass index \> 30 Kg·m-2;
8. Being reluctance to participate this study.