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

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

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

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.

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.

Electrical Impedance Tomography, Acute Respiratory Distress Syndrome, Inhaled Nitric Oxide, Ventilation-Perfusion mismatch, Lung recruitment

During this period, all patients were total sedation using continuous infusion, to prevent any spontaneous breathing .All patients were ventilated using a ventilator

Ventilator combined inhaled Nitric oxide and Electrical Impedance Tomography monitor the V/Q mismatch

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

Bluth T, Kiss T, Kircher M, Braune A, Bozsak C, Huhle R, Scharffenberg M, Herzog M, Roegner J, Herzog P, Vivona L, Millone M, Dossel O, Andreeff M, Koch T, Kotzerke J, Stender B, Gama de Abreu M. Measurement of relative lung perfusion with electrical impedance and positron emission tomography: an experimental comparative study in pigs. Br J Anaesth. 2019 Aug;123(2):246-254. doi: 10.1016/j.bja.2019.04.056. Epub 2019 May 31.

Mauri T, Spinelli E, Scotti E, Colussi G, Basile MC, Crotti S, Tubiolo D, Tagliabue P, Zanella A, Grasselli G, Pesenti A. Potential for Lung Recruitment and Ventilation-Perfusion Mismatch in Patients With the Acute Respiratory Distress Syndrome From Coronavirus Disease 2019. Crit Care Med. 2020 Aug;48(8):1129-1134. doi: 10.1097/CCM.0000000000004386.

Measurement of relative lung perfusion with electrical impedance and positron emission tomography: an experimental comparative study in pigs

Potential for Lung Recruitment and Ventilation-Perfusion Mismatch in Patients With the Acute Respiratory Distress Syndrome From Coronavirus Disease 2019