Hypoxemia, Ventilator Lung
Conditions
Keywords
Driving Pressure, Lung Protective Ventilation, Aortic Dissection, Hypoxia, Postoperative Pulmonary Complications
Brief summary
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.
Detailed description
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.
Interventions
PROCEDUREDriving pressure-guided positive end expiratory pressure
The positive end expiratory pressure setting rules are as follows: a 10-cycle experimental ventilation will be carried out at each level of positive end expiratory pressure after intubation, and the driving pressure of the last cycle will be recorded. The positive end expiratory pressure value corresponding to the lowest driving pressure is recognised as the optimal ventilation parameter. Partial pressure of carbon dioxide monitoring is employed to determine the tidal volume and respiratory rate. Inspiration/expiration pattern is adjusted based on the preoperative small airway condition. This parameter is subject to modification upon cessation of ventilation, ICU admission, and every morning throughout the ventilation period. During cardiopulmonary bypass, mechanical ventilation is maintained using the low-level parameters.
PROCEDUREOptimal oxygenation-guided positive end expiratory pressure
Positive end expiratory pressure will be maintained at the level facilitating optimal oxygenation during the off-pump period. Partial pressure of carbon dioxide monitoring is employed to determine the tidal volume and respiratory rate. Inspiration/expiration pattern is adjusted based on the preoperative small airway condition. This parameter is subject to modification upon cessation of ventilation, ICU admission, and every morning throughout the ventilation period. During cardiopulmonary bypass, mechanical ventilation is maintained using the low-level parameters.
PROCEDUREVentilation strategy
A Pressure regulated volume control mode is used in the patients before extubation. The ventilation target are: (1) a pulse oximetry ≥ 90% or a partial pressure of arterial oxygen ≥ 60mm Hg; (2) a partial pressure of arterial carbon dioxide: 35 \ 50 mm Hg and (3) a pondus hydrogenii (pH) value \> 7.20. The ventilation parameters are: (1) tidal volume: 6 \ 8 mL/Kg predictive body weight; (2) respiratory rate 10 \ 15 cycles per minute; (3) inspiratory/expiratory ratio: 1:1.5 (1:2.5 - 1:3 in the patients with chronic obstructive pulmonary disease); positive end expiratory pressure: 0 \ 8 cm centimeter water column. On-pump ventilation parameters are: (1) tidal volume: 4 mL/Kg predictive body weight; (2) respiratory rate: 4 circles per minute; (3) positive end-expiratory pressure: 4 cm centimeter water column; (4) inspiratory oxygen fraction: 21%.
PROCEDUREManagement of hypoxemia
Management of hypoxemia will be initiated immediately through the following steps: (1) carefully checking anaesthesia apparatus malfunction, airway normality, and monitoring accuracy; (2) improving cardiac function, correcting fluid overload, and alleviating systemic inflammation; (3) performing alveolar recruitment manoeuvres as described above; (4) increasing the tidal volume and positive end expiratory pressure within the upper limits; (5) increasing the respiratory rate while addressing concurrent hypercapnia; (6) titrating the fraction of inspiratory oxygen until the pulse oximetry reaches or exceeds 90%; and (7) considering the use of extracorporeal membrane oxygenation if any following situations occurred 14: (a) a partial pressure of arterial oxygen \< 50 mm Hg for more than 3 hours; (b) a partial pressure of arterial oxygen to inspiratory oxygen fraction ratio \< 80 mm Hg for more than 6 hours; or (c) a critical respiratory acidosis for more than 6 hours.
Sponsors
Yong Lin, PhD
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Intervention model description
open, randomised control trial
Eligibility
Sex/Gender
ALL
Age
14 Years to 70 Years
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The incidence of postoperative hypoxemia | Within 7 days after surgery | Postoperative hypoxemia is defined as a partial pressure of arterial oxygen to inspiratory oxygen fraction ratio less than 300 mm Hg or a pulse oximetry less than 93% at any concentration of inspiratory oxygen that occurred from admission to the operating room to 7 days post-surgery. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative pulmonary complications except hypoxemia | Within 7 days after surgery | Postoperative pulmonary complications are defined as any postoperative respiratory system complication that occurs from admission to the intensive care unit to 7 days post-surgery, encompassing (1) respiratory infection, (2) respiratory failure, (3) bronchospasm, (4) atelectasis, (5) pleural effusion, (6) pneumothorax, and (7) aspiration pneumonitis. |
| Early/late death | Within 30 days after surgery | Early death was defined as any death occurring within 72 hours of surgery, while late death was considered for deaths occurring within 30 days after the surgery was scheduled. |
| Vasoactive-inotropic score at the end of surgery | Within 7 days after surgery | The vasoactive-inotropic score is the sum of the dosages of frequently used vasoactive or inotropic agents according to the weighted values of the enrolled patients. Vasoactive-Inotropic Score = dopamine dose (μg·kg-1·min-1) + dobutamine dose (μg·kg-1·min-1) + 100 × epinephrine dose (μg·kg-1·min-1) + 10 × phosphodiesterase inhibitor (milrinone or olprinone) dose (μg·kg-1·min-1) + 100 × norepinephrine dose (μg·kg-1·min-1) +10000 × vasopressin dose (U·kg-1·min-1). |
| The trend of perioperative oxygenation function | Within 7 days after surgery | An automated blood gas analyzer will be applied for arterial blood gas analyses, with the time points: T1 (before surgery), T2 (after intubation), T3 (withdrawal from cardiopulmonary bypass), T4 (end of surgery), T5 (postoperative day 1), T6 (postoperative day 3), T7 (postoperative day 5), and T8 (postoperative day 7). |
| Length of stay in intensive care unit | Within 30 days after surgery | The duration from admission to discharge of the ICU |
| Ventilation assistance time | Depending on the time point of extubation, not exceeding 30 days | Duration from the end of the surgery to extubation. |
| Postoperative extrapulmonary complications | Within 7 days after surgery | Postoperative extrapulmonary complications include tracheotomy, rethoracotomy for exploration, wound infection, sepsis, gastrointestinal haemorrhage, and neurological complications (such as delayed recovery, delirium, cognitive dysfunction, coma, new-onset stroke, and syncope) |
| Postoperative adverse cardiovascular events | Within 7 days after surgery | The postoperative adverse cardiovascular events include new-onset lethal arrhythmias (supraventricular/ventricular tachycardia, ventricular fibrillation, or Adams-Stokes syndrome), acute myocardial infarction, cardiogenic shock, and thrombotic or embolic events. |
Countries
China
Contacts
Primary ContactYong Lin, MD
Outcome results
None listed