Potential for Inhaled Nitric Oxide and Ventilation-Perfusion Mismatch by Electrical Impedance Tomography in the ARDS Patients With Lung Recruitment

Study Overview
=================
Brief Summary
-----------------
In the recent years, the treatment of Acute Respiratory Distress Syndrome has been proved that lung recruitment re-opens the non-ventilated alveolar to improve ventilation, and inhaled Nitric Oxide dilates non-perfused pulmonary vascular to improve perfusion. Both of these could improve ventilation-perfusion mismatch to enhance oxygenation. However, Ventilation-Perfusion mismatch is devided into ventilated nonperfused lung units(dead space) or perfused nonventilated units(shunt). No published study has evaluated the availability of lung recruitment combined with inhaled Nitric oxide in patients with ARDS. The aims of our study are to measure dead space or shunt fraction before and after inhaled Nitric Oxide in moderate to severe Acute Respiratory Distress Syndrome patients indicated Nitric oxide in FEMH MICU on 2021/01-2022/12, injected a bolus of 10mL of 3% NaCl solution via the central venous catheter with two-step recruitment maneuver by Electrical Impedance Tomography, which monitors ventilation-perfusion mismatch to evaluate whether the patient has potential to improve V/Q mismatch by Nitric oxide.

Detailed Description
-----------------
Normally, pulmonary arteries in areas of alveolar hypoxia will constrict as a physiologic response to preserve ventilation/perfusion (V¬/Q¬) matching. However, in ARDS, this normal vasoconstrictive response is impaired. Because the body is unable to shunt blood away from the diseased alveoli, these nonaerated alveoli receive excessive blood flow, which contributes to severe V¬/Q¬ mismatching and an intrapulmonary right-to-left shunting of blood flow, which causes hypoxemia. In the recent years, the treatment of Acute Respiratory Distress Syndrome has been proved that lung recruitment re-opens the non-ventilated alveolar to improve ventilation, and inhaled Nitric Oxide dilates non-perfused pulmonary vascular to improve perfusion. Both of these could improve ventilation-perfusion mismatch to enhance oxygenation. However, Ventilation-Perfusion mismatch is devided into ventilated nonperfused lung units(dead space) or perfused nonventilated units(shunt). No published study has evaluated the availability of lung recruitment combined with inhaled Nitric oxide in patients with ARDS. The aims of our study are to measure dead space or shunt fraction before and after inhaled Nitric Oxide in moderate to severe Acute Respiratory Distress Syndrome patients indicated Nitric oxide in FEMH MICU on 2021/01-2022/12, injected a bolus of 10mL of 3% NaCl solution via the central venous catheter with two-step recruitment maneuver by Electrical Impedance Tomography, which monitors ventilation-perfusion mismatch to evaluate whether the patient has potential to improve V/Q mismatch by Nitric oxide.

Official Title
-----------------
Potential for Inhaled Nitric Oxide and Ventilation-Perfusion Mismatch by Electrical Impedance Tomography in the Acute Respiratory Distress Syndrome Patients With Lung Recruitment

Conditions
-----------------
Nitric Oxide, Acute Respiratory Distress Syndrome

Intervention / Treatment
-----------------
* Device: Lung recruitment combined inhaled Nitric oxide
* Device: Lung recruitment


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Moderate to severe ARDS patient on mechanical ventilation in MICU. (P/F≦ 200 with PEEP ≥ 5cmH20) (PEEP greater than or equal to 5 cm H2O and Berlin criteria for ARDS) Exclusion Criteria: Hemodynamic instability or severe COPD, pulmonary embolism Acute brain injury, seizure attack, AMI, AIDS, severe arrhythmia On pacemaker Pregnant Thoracic trauma or burn injury Pneumothorax

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 99 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Moderate to severe ARDS patient on mechanical ventilation in Far Eastern Memorial Hospital MICU
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Control group_Use Lung recruitment<br>Use the Lung recruitment, | Device: Lung recruitment<br>* Ventilator and Electrical Impedance Tomography monitor the V/Q mismatch<br>|
| Experimental: Study group_Use Lung recruitment combined inhaled Nitric oxide<br>Use the Lung recruitment combined inhaled Nitric oxide, | Device: Lung recruitment combined inhaled Nitric oxide<br>* Ventilator combined inhaled Nitric oxide and Electrical Impedance Tomography monitor the V/Q mismatch<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| V/Q mismatch | Compare the V/Q mismatch between two groups | 15 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PaO2/FiO2 ratio improvement rate | Oxygention improve rate | 15 minutes | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Electrical Impedance Tomography, Acute Respiratory Distress Syndrome, Inhaled Nitric Oxide, Ventilation-Perfusion mismatch, Lung recruitment