Patient Dyspnea Under Veno-arterial Extracorporeal Circulation
Patient Dyspnea Under Veno-arterial Extracorporeal Circulation
Rationale: Patients with severe heart failure increasingly benefit from extracorporeal
 circulatory assistance (Extracorporeal Membrane Oxygenation - ECMO) that completely replaces
 the function of the heart and is in addition to mechanical ventilation (veno-arterial ECMO).
 In clinical practice, some of these patients have been found to be dyspneic, although
 circulatory assistance ensures satisfactory hematosis. Indeed, nearly half of the patients
 undergoing mechanical ventilation in intensive care have a generally intense dyspnea. In
 addition to the immediate discomfort caused by dyspnea, which can be assimilated to pain,
 this symptom is associated with a prolonged duration of mechanical ventilation and
 contributes to the genesis of neuropsychological sequelae of resuscitation such as
 post-traumatic stress syndrome.

 Objectives :

 1. To study the effectiveness and impact of an increase in ECMO sweep gas flow through the
 membrane lung or positive tele-expiratory pressure (PEP) on dyspnea in patients under
 ECMO.

 2. To understand the mechanism involved in this relief of dyspnea. Methods: in 30 patients
 of Intensive Care Unit, dyspnea will be evaluated by psychophysiological scales and
 scores as well as by neurophysiological tools (electromyography of inspiratory muscles)
 during sweep gas flow through the membrane lung incrementation and PEP increase.

 Ethical framework: Changes in ventilation parameters and ECMO will be performed in the usual
 manner, without additional or unusual diagnostic, treatment or monitoring procedures.

 Expected results and outlook: the investigators hypothesize that half of the patients on
 veno-arterial ECMO have dyspnea related to pulmonary edema. Therefore, an increase in PEP
 would alleviate this dyspnea. The investigators hypothesize that by using a relief method
 related to increased sweep gas flow through the membrane lung, the investigators can reduce
 the discomfort without inducing any associated complication.

 This study will improve the knowledge of the mechanisms determining dyspnea in patients under
 ECMO and the principle of therapeutic strategy to improve it.
Half of the patients undergoing mechanical ventilation in intensive care have moderate to
 severe dyspnea. This dyspnea has a negative impact on the prognosis and quality of life in
 the medium term.

 As ECMOs, techniques for extracorporeal assistance to supplement cardiac and pulmonary
 functions, are developing rapidly, it seems essential to study the dyspnea associated with
 the use of these techniques. In particular, understanding the main mechanisms involved in the
 genesis of dyspnea in patients under ECMO would allow the development of therapeutic
 solutions aimed at minimizing it.

 The investigators hypothesize that, in patients under veno-arterial ECMO with dyspnea, the
 dyspnea decreases in response to an increase in ECMO sweep gas flow through the membrane lung
 via modulation of central and peripheral chemoreceptors sensitive to variations in PaO2,
 PaCO2 and pH. Since dyspnea experienced by patients on veno-arterial ECMO is related to
 cardiogenic pulmonary edema, increased discharge from the left cavities by increasing
 positive expiratory pressure should also alleviate dyspnea.

 The main objective of the present study is to evaluate the impact of sweep gas flow through
 the membrane lung and PEP incrementation on dyspnea in patients with veno-arterial ECMO with
 dyspnea.

 Relief of dyspnea will be carried out by the clinician in charge of the patient. He will have
 complete control of his behaviour. He will carry out this test according to the practices in
 force in the department.

 One of the investigators will be present and will collect the data listed above. This
 investigator will not intervene in the conduct of the test.

 Each patient will participate in a dyspnea relief test according to the protocol of the
 department and according to the management of the practitioner in charge of the patient.

 Initially a recording of 5 minutes will be made in the basal state, before any therapeutic
 action.

 As soon as the D-VAS is ≤ 3 at one of these steps the data collection ends.

 If a sweep gas flow through the membrane lung increment has been decided upon to relieve
 dyspnea, a new recording will be made after each scan increment and the patient will be asked
 at each step.

 In ventilated or non-ventilated patients in whom the decision to implement non-invasive
 ventilation has been made, an increase in PEEP in 2 cmH2O steps without exceeding a plateau
 pressure of 25 cmH2O and a VT of 10ml/kg of the patient's theoretical weight will be
 achieved.
Inclusion Criteria:

 -  Circulatory support by veno-arterial ECMO for cardiogenic shock;

 -  Presence of severe respiratory distress;

 -  Presence of dyspnea ≥ 40 mm on a visual analogue scale of dyspnea (VAS-dyspnea)

 -  Decision by the clinician in charge of the patient to either modify the ECMO
 parameters or to administer non-invasive ventilation in order to decrease the
 intensity of the dyspnea;

 -  presence of an arterial catheter; :

 -  RASS score between 0 and +1 ;

 -  Absence of delirium on the CAM-ICU score;

 -  being socially insured.

 Exclusion Criteria:

 -  patient unable to express opposition;

 -  protected minor or adult patient;

 -  pregnant woman;

 -  double veno-arterial ECMO; central ECMO; left ventricular assist or long-term
 bi-ventricular assist