Hemodynamic Effects of Two Modalities of Alveolar Recruitment Maneuvers - ICU Patients

Study Overview
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Brief Summary
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The objective of this study was to investigate the hemodynamic effects of two alveolar recruitment maneuver strategies in critical care patients with acute respiratory distress syndrome.

Detailed Description
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Critical care patients are at risk of significant variations in blood volume due to long intervention times, major bleeding or serious pathological conditions, requiring invasive hemodynamic monitoring in routine practice, in order to optimize blood volume and ensure adequate perfusion of the organs, throughout their care. The installation of an arterial catheter allows continuous monitoring of blood pressure and the realization of blood tests if necessary. The installation of a central venous line allows the administration of anesthetic drugs and vasopressors as well as an accurate hemodynamic evaluation by transpulmonary thermodilution, which is the most commonly used monitoring in these situations. After hemodynamic optimization following the monitoring data, the patient will be randomized to one of the two Alveolar Recruitment Maneuver (ARM) order strategies. Mechanical ventilation will be standardized according to current international recommendations (tidal volume between 6 mL.kg-1 and 8 mL.kg-1 of theoretical ideal weight (TIP) for patients with Acute Respiratory Distress Syndrome (ARDS); PEEP equal to 6 cmH2O). Hemodynamic and ventilatory data will be collected (baseline). The successive realization of the two ARM will then be carried out with collection of the hemodynamic and ventilatory data during the last 10 seconds of each ARM. Between each ARM, conventional ventilation will be resumed for 10 minutes in order to observe a wash-out period, and to allow a return to the baseline state. Data will also be collected as before. After these measurements have been taken, all management will be left to the discretion of the practitioner caring for the patient.

Official Title
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Comparison of Hemodynamic Effects of Two Modalities of Alveolar Recruitment Maneuvers in Intensive Care Unit Patients Under Mechanical Ventilation. A Pilot Physiological Study

Conditions
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Cardiac Output, Hemodynamic Optimization, Monitoring Blood Pressure, Stroke Volume, Mechanical Ventilation, Acute Respiratory Distress Syndrome

Intervention / Treatment
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* Procedure: Alveolar Recruitment Maneuver (ARM)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient over 18 years old Patient under general anesthesia Intubated patient under controlled invasive mechanical ventilation Patient with invasive hemodynamic monitoring allowing monitoring of cardiac output and stroke volume Patient sufficiently sedated (BIS between 40 and 60) and/or curarized (TOF < 2/4 at the orbicularis) to avoid inspiratory effort Patient optimized on the hemodynamic level, in particular with regard to blood volume, following the data from hemodynamic monitoring and the recommendations of the French Society of Anesthesia and Resuscitation (RFE SFAR 2013 - Perioperative Vascular Filling Strategy) Patient covered by a Social Security plan Consent of close relatives or trusted person (if present) Patient admitted in polyvalent resuscitation within the Peri-Operative Medicine Unit of Clermont-Ferrand hospital suffering from respiratory distress syndrome for less than 24 hours Exclusion Criteria: Contraindication to the use of cardiac output measurement by transpulmonary thermodilution Cardiac arrhythmia Severe valvulopathy Contraindication to the use of the Analysis of pulmonary aeration will be performed using the non-invasive technique of electrical impedance tomography with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : technique Left ventricular ejection fraction (LVEF) < 45% and/or right ventricular failure History of pulmonary lobectomy and/or pneumectomy and/or known emphysema Patient with restrictive or obstructive lung disease Body mass index (BMI) < 16.5 or > 30 kg.m-2 Pregnancy Major under legal protection (guardianship, curators, safeguard of justice)

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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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Continuous positive airway pressure (CPAP) then extended sigh<br>Patients assigned to this group will receive a CPAP ARM (40cmH2O during 50 seconds), followed by a 10-minute pause corresponding to a period of return to basal state. Then an ARM by extended sigh (e-sigh) also 50 seconds (driving pressure at 10cmH2O and successive PEEP levels at 10, 15, 20, 25 and 30cmH2O, with respiratory frequency fixed at 30/min in controlled pressure). Hemodynamic (blood pressure, cardiac output, stroke volume) and ventilatory measurements will be performed the last 10 seconds of each recruitment maneuver. | Procedure: Alveolar Recruitment Maneuver (ARM)<br>* When patient is under general anesthesia, an arterial catheter is placed for cardiac output and stroke volume (SV) monitoring. To avoid pre-load dependency bias, the blood volume will be optimized. A 250mL fluid-challenge of a balanced crystalloid solution is administered under cover of the SV monitoring. If SV variation is greater than 10%, a new fluid-challenge is performed to obtain a reference SV, corresponding to the patient's optimal blood volume.The patient is then pre-load independent. Then, patients will be randomized into two groups: a first group will receive a CPAP ARM: 40 cmH2O for 50 seconds, followed by a 10-minute break corresponding to a period of return to basal state; then an extended sigh ARM (e-sigh) also lasting 50seconds (driving pressure: 10cmH2O and successive PEEP levels at 10,15,20,25 and 30cmH2O, a respiratory rate set at 30/min in controlled pressure - 5cycles at each PEEP level); a second group will receive the same two ARM modalities in reverse order.<br>|
| Active Comparator: extended sigh then continuous positive airway pressure (CPAP)<br>Patients assigned to this group will receive an ARM by extended sigh (e-sigh) during 50 seconds (driving pressure at 10cmH2O and successive PEEP levels at 10, 15, 20, 25 and 30cmH2O, with respiratory frequency fixed at 30/min in controlled pressure), followed by a 10-minute pause corresponding to a period of return to basal state. Then they receive a CPAP ARM (40cmH2O during 50 seconds). Hemodynamic (blood pressure, cardiac output, stroke volume) and ventilatory measurements will be performed the last 10 seconds of each recruitment maneuver. | Procedure: Alveolar Recruitment Maneuver (ARM)<br>* When patient is under general anesthesia, an arterial catheter is placed for cardiac output and stroke volume (SV) monitoring. To avoid pre-load dependency bias, the blood volume will be optimized. A 250mL fluid-challenge of a balanced crystalloid solution is administered under cover of the SV monitoring. If SV variation is greater than 10%, a new fluid-challenge is performed to obtain a reference SV, corresponding to the patient's optimal blood volume.The patient is then pre-load independent. Then, patients will be randomized into two groups: a first group will receive a CPAP ARM: 40 cmH2O for 50 seconds, followed by a 10-minute break corresponding to a period of return to basal state; then an extended sigh ARM (e-sigh) also lasting 50seconds (driving pressure: 10cmH2O and successive PEEP levels at 10,15,20,25 and 30cmH2O, a respiratory rate set at 30/min in controlled pressure - 5cycles at each PEEP level); a second group will receive the same two ARM modalities in reverse order.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The primary outcome measure is the change in cardiac output during the last 10 seconds of each ARM modality from its baseline value (determined after hemodynamic optimization and before the procedure was performed) | Cardiac output (l/min) will be measured by invasive monitoring during the last 10 seconds of each recruitment maneuver | During procedure (last 10 seconds of each ARM modality) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The secondary outcome measures are the evaluation of standard hemodynamic monitoring data | During the last 10 seconds of the recruitment maneuver, standard hemodynamic monitoring data will be recorded : blood pressure (mmHg) mean arterial pressure (mmHg) | During procedure (last 10 seconds of each ARM modality) | 
| Standard hemodynamic monitoring data | heart rate | During procedure (last 10 seconds of each ARM modality) | 
| Invasive hemodynamic monitoring data | stroke volume (ml/min) | During procedure (last 10 seconds of each ARM modality) | 
| Invasive hemodynamic monitoring data | change in stroke volume | During procedure (last 10 seconds of each ARM modality) | 
| Standard ventilatory monitoring data | tidal volume (ml) | During procedure (last 10 seconds of each ARM modality) | 
| Standard ventilatory monitoring data | positive end-expiratory pressure (PEEP), peak pressure, plateau inspiration pressure, driving pressure, | During procedure (last 10 seconds of each ARM modality) | 
| Standard ventilatory monitoring data | respiratory rate | During procedure (last 10 seconds of each ARM modality) | 
| Standard ventilatory monitoring data | inspired oxygen fraction | During procedure (last 10 seconds of each ARM modality) | 
| Standard ventilatory monitoring data | compliance of the respiratory system | During procedure (last 10 seconds of each ARM modality) | 
| Electrical impedance tomography data | Analysis of pulmonary aeration will be performed using the non-invasive technique of electrical impedance tomography with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : Tidal Impedance Variation (TIV) | During procedure (last 10 seconds of each ARM modality) | 
| Electrical impedance tomography data | Analysis of pulmonary aeration will be performed using the non-invasive technique of electrical impedance tomography with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : Center Of Ventilation (COV) and Global Inhomogeneity index (GI) | During procedure (last 10 seconds of each ARM modality) | 
| Electrical impedance tomography data | Analysis of pulmonary aeration will be performed using the non-invasive technique of electrical impedance tomography with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : Regional Ventilation Delay (RVD) | During procedure (last 10 seconds of each ARM modality) | 
| Electrical impedance tomography data | Analysis of pulmonary aeration will be performed using the non-invasive technique of electrical impedance tomography with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : End Expiratory Lung Impedance (EELI) | During procedure (last 10 seconds of each ARM modality) | 
| Electrical impedance tomography data | Analysis of pulmonary aeration will be performed using the non-invasive technique of electrical impedance tomography with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : percentages of overdistended and atelectasis areas | During procedure (last 10 seconds of each ARM modality) | 
| The secondary outcome measures are the evaluation of paraclinical data | During the last 10 seconds of the recruitment maneuver, capnography will be recorded | During procedure (last 10 seconds of each ARM modality) | 
| The secondary outcome measures are the evaluation of paraclinical data | During the last 10 seconds of the recruitment maneuver, pulse oxygen saturation (SpO2) will be recorded | During procedure (last 10 seconds of each ARM modality) |