Comparison of Hemodynamic Effects of Two Modalities of Alveolar Recruitment Maneuvers in Major Abdominal Surgery Patients

Study Overview
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Brief Summary
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The objective of this study is to investigate the hemodynamic effects of two strategies of alveolar recruitment maneuver in patients undergoing major abdominal surgery in the operating room

Detailed Description
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In practice, after induction of general anesthesia and intubation, patients will be conditioned with the recommended monitoring (arterial catheter, central venous catheter, and transpulmonary thermodilution). Once conditioning is complete, optimization of blood volume will be performed with volumetric expansions (250 mL of Ringer lactate) to achieve a change in stroke volume of less than 10%, as recommended (RFE SFAR 2013 - Perioperative Vascular Filling Strategy). The patient will then be randomized to one of the following groups: [ extended sigh then CPAP ] or [ CPAP then extended sigh ] (random order of ARMs - each patient becoming their own control). In order to homogenize the settings, the mechanical ventilation will be standardized with in particular the use of a PEEP of 6 cmH2O before inclusion and between the ARMs (for a duration of at least 10 minutes in each case). Hemodynamic values will be recorded during the last 10 seconds of each procedure. Once the two ARMs have been performed, the rest of the management will then be left to the discretion of the practitioner in charge of the patient. The included patient will be managed according to the recommendations at the time of the study.

Official Title
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Comparison of Hemodynamic Effects of Two Modalities of Alveolar Recruitment Maneuvers in Major Abdominal Surgery Patients: A Physiological Study

Conditions
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Cardiac Output, Decreased Cardiac Output, Hemodynamic Monitoring, Blood Pressure, Stroke Volume, Major Abdominal Surgery, Mechanical Ventilation, Hemodynamic Optimization

Intervention / Treatment
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* Procedure: alveolar recruitment maneuver


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patient over 18 years old patient under general anesthesia patient intubated under controlled invasive mechanical ventilation patient with invasive hemodynamic monitoring (transpulmonary thermodilution) patient sedated (BIS between 40 and 60) and/or curarized with TOF monitoring to avoid inspiratory effort patient optimized on the hemodynamic level, in particular with regard to blood volume, following the hemodynamic monitoring data 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 patient consent to participate in the study Exclusion Criteria: contraindication to the use of cardiac output measurement cardiac arrhythmia pace-maker/implantable defibrillator severe valvulopathy contraindication to the use of the tomographic electroimpedancemetry technique thoracic lesions, thoracic dressing left ventricular ejection fraction (LVEF) < 45% and/or right ventricular failure. history of pulmonary lobectomy and/or pneumonectomy and/or known emphysema patient with restrictive or obstructive lung disease body mass index (BMI) < 16.5 or > 30 kg.m-2 pregnancy intracranial hypertension or suspected intracranial hypertension patient under limitation of care patient under legal protection (guardianship, curatorship, 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: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Exploratory study testing in cross-sectional design two alveolar recruitment maneuvers referenced in practice, in patients under general anesthesia and intubated under controlled ventilation, in operating room
Masking: Single


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<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<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 MRA 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 | last 10 seconds of each ARM modality | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Standard hemodynamic monitoring data | blood pressure, mean arterial pressure, | last 10 seconds of each ARM modality | 
| Standard hemodynamic monitoring data | heart rate | last 10 seconds of each ARM modality | 
| Invasive hemodynamic monitoring data | stroke volume change in stroke volume | last 10 seconds of each ARM modality | 
| Invasive hemodynamic monitoring data | change in stroke volume | last 10 seconds of each ARM modality | 
| Evaluation of standard ventilatory monitoring data | tidal volume (ml) | last 10 seconds of each ARM modality | 
| Evaluation of standard ventilatory monitoring data | positive end-expiratory pressure (PEEP), peak pressure, plateau inspiration pressure, driving pressure | last 10 seconds of each ARM modality | 
| Evaluation of standard ventilatory monitoring data | respiratory rate, | last 10 seconds of each ARM modality | 
| Evaluation of standard ventilatory monitoring data | inspired oxygen fraction, | last 10 seconds of each ARM modality | 
| Evaluation of standard ventilatory monitoring data | compliance of the respiratory system | last 10 seconds of each ARM modality | 
| Electro-impedancemetry data | Analysis of pulmonary aeration will be performed using the non-invasive technique of tomographic electroimpedancemetry with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : COV : Center Of Ventilation and GI : Global Inhomogeneity index | last 10 seconds of each ARM modality | 
| Electro-impedancemetry data | Analysis of pulmonary aeration will be performed using the non-invasive technique of tomographic electroimpedancemetry with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : TIV : Tidal Impedance Variation | last 10 seconds of each ARM modality | 
| Electro-impedancemetry data | Analysis of pulmonary aeration will be performed using the non-invasive technique of tomographic electroimpedancemetry with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : RVD : Regional Ventilation Delay | last 10 seconds of each ARM modality | 
| Electro-impedancemetry data | Analysis of pulmonary aeration will be performed using the non-invasive technique of tomographic electroimpedancemetry with the placement of an electrode belt on the patient's chest. Values will be recorded with this belt : EELI : End Expiratory Lung Impedance | last 10 seconds of each ARM modality | 
| Electro-impedancemetry data | Analysis of pulmonary aeration will be performed using the non-invasive technique of tomographic electroimpedancemetry 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 | last 10 seconds of each ARM modality | 
| Paraclinics data | During the last 10 seconds of the recruitment maneuver, capnography will be recorded | last 10 seconds of each ARM modality | 
| Paraclinics data | During the last 10 seconds of the recruitment maneuver, SpO2 will be recorded | last 10 seconds of each ARM modality | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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mechanical ventilation,, hemodynamics,, ARM,, CPAP,, extended sigh,, cardiac output