Use of Exhaled Carbon Dioxyde for Monitoring the Native Cardiac Function During Mechanical Circulatory Support With Venoarterial By-pass in Intensive Care Unit

Study Overview
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Brief Summary
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Cardiogenic shock, the most severe form of acute heart failure, is a critical situation where the body cells lack of oxygen because of cardiac dysfunction. The failure of pharmacological therapy to maintain adequate perfusion has led to attempts to improve the circulation by the use of mechanical circulatory support devices. Peripheral veno-arterial support (PVA-ECMO) is the most frequently used device. It consists of extracorporeal circulatory support. Venous blood is aspirated via the right atrium and reinjected into the descending aorta via the femoral artery. As a consequence of this by-pass, pulmonary artery flow and residual left ventricle ejection can fall drastically until zero in the most severe patients. A minimal transpulmonary blood flow is crucial to avoid left heart cavities and pulmonary artery and left heart cavities thrombosis. The gold standard technique to monitor transpulmonary blood flow is right-heart cavities catheterism (Swan-Ganz catheter) but it represents major limits: invasive technique, limited duration of utilization because of septic risk, physical limit of flow measurement (under 1 liter/minute). End-tidal pressure carbon dioxide (Pet CO2) monitoring (or capnography) is a routine and non-invasive measure in ventilated patients. Previous studies have shown that changes in PetCO2 can measure changes in cardiac output in anesthetized patients and that PetCO2 is a useful index of pulmonary artery blood flow during separation from cardiopulmonary bypass. The aim of this study is to demonstrate that PetCO2 is correlated to transpulmonary blood flow in patients under PVA-ECMO and that exhaled CO2 can provide an on-line, continuous, and noninvasive monitor of residual outflow from the heart during PVA-ECMO.

Detailed Description
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Settings This prospective study is conducted since January 2016 in our tertiary ICU and has been approved by our hospital's institutional review board. Informed consent will be obtained from all patients or their surrogates. Hemodynamic is monitored via a radial arterial catheter for continuous blood pressure monitoring, a pulmonary artery catheter (Swan-Ganz CCOmbo® CCO/SvO2, Edwards Lifesciences) inserted through the superior vena cava (jugular intern or subclavian vein) and transoesophageal echocardiography (TOE) at PVA-ECMO implantation or at operator discretion. ECMO circuit settings and patients management under ECMO PVA-ECMO consist of polyvinyl chloride tubing with a membrane oxygenator (PH.I.S.I.O and EOS; Sorin Group, Clamart, France), a centrifugal pump (Stockert; Sorin Group), and percutaneous or surgically inserted arterial and venous femoral cannulae (Fem-Flex and Fem-Track, Edwards Life- sciences, Guyancourt, France) with or without an additional 7 F cannula inserted distally into the femoral artery to prevent lower limb ischemia. An oxygen-air blender (Sechrist Industries, Anaheim, CA) ventilate the membrane oxygenator. Unfractionated heparin is administrated to maintain an activated partial thromboplastin time between 1.5 and 2 times the normal value. The lower speed flow necessary for adequate tissue perfusion is wanted. Ventilator settings, end-tidal PCO2 monitoring, blood gas analysis and transpulmonary blood flow monitoring

Official Title
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Validation of End-tidal CO2 for Transplumonary Blood Flow Monitoring During PVA-ECMO

Conditions
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Residual Cardiac Output During PVA-ECMO

Intervention / Treatment
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* Device: PetCO2 monitoring


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients under mechanical ventilation and PVA-ECMO support with low residual native cardiac output Exclusion Criteria: age less than 18 years pulmonary disorders with abnormal dead-space (obstructive pulmonary disease; acute respiratory distress syndrome) cardiac shunt (atrial or ventricular communication) significant tricuspid or pulmonary valve disease pulmonary artery catheter implantation contraindicated.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: PetCO2 monitoring|CO2 analyzer on ventilator expiratory lane. On-line, continuous, and noninvasive monitor. Routine use in anesthesia and intensive care units.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of end-tidal pressure CO2 (PetCO2) correlation with pulmonary artery flow | end-tidal pressure CO2 (PetCO2) vs pulmonary artery flow measured by pulmonary catheter or echocardiography | Up to 5 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of end-tidal pressure CO2 (PetCO2) thresholds to detect pulmonary artery flow < 1 l/min and indexed flow < 1l/min/m2 |  | Up to 5 days | 
| Assessment of Factors of end-tidal pressure CO2 (PetCO2) variation |  | Up to 5 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Intensive care, Cardiogenic shock, Peripheral veno-arterial extracorporeal membrane oxygenation, Left ventricular overload, Native cardiac output, Pulmonary artery blood flow, End-tidal carbon dioxide, Swan Ganz catheter, Blood gaz