Ventilator Hyperinflation and Hemodynamics

Study Overview
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Brief Summary
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Ventilator hyperinflation (VHI) has been shown to be effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated patients; however, the literature is scarce concerning its safety and adverse effects. Thus, the aim of this study is to compare the hemodynamic repercussions of VHI in volume-controlled mode. In a randomized, controlled and crossover design, 24 mechanically ventilated patients will undergo 2 modes of ventilator hyperinflation (with and without an inspiratory pause) and a control intervention. Cardiac output, cardiac index, mean arterial pressure, pulmonary vascular resistance, systolic volume and other hemodynamic variables will be recorded during the interventions.

Detailed Description
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Background: ventilator hyperinflation (VHI) has been shown to be effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated patients; however, the literature is scarce concerning its safety and adverse effects. Thus, the aim of this study is to compare the hemodynamic repercussions of VHI in volume-controlled mode. Methods: in a randomized, controlled and crossover design, 24 mechanically ventilated patients will undergo 2 modes of ventilator hyperinflation (with and without an inspiratory pause of 2 seconds) and a control intervention. For the VHI interventions, the inspiratory flow will be set at 20 Lpm, and tidal volume will be increased until a peak pressure of 40cmH2O is achieved. During the control intervention, the patients will remain in volume-control ventilation with an inspiratory flow = 60Lpm and tidal volume = 6mL/IBW. The interval between interventions (washout) will be of 10 minutes or more, according to the time needed to recover the cardiac index to baseline values (maximum difference of 10%). Cardiac output, cardiac index, mean arterial pressure, pulmonary vascular resistance, systolic volume and other hemodynamic variables will be recorded during the interventions by using impedance cardiography.

Official Title
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Hemodynamic Repercussions of Ventilator Hyperinflation Using Volume-controlled Ventilation: a Randomized Controlled Trial

Conditions
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Respiratory Failure, Respiratory Disorders

Intervention / Treatment
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* Device: Baseline Mechanical Ventilation
* Device: VHI With Inspiratory Pause
* Device: VHI Without Inspiratory Pause


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients under mechanical ventilation for more than 48h Exclusion Criteria: mucus hypersecretion (defined as the need for suctioning < 2-h intervals), absence of respiratory drive, atelectasis, severe bronchospasm, positive end expiratory pressure > 10cmH2O, PaO2-FiO2 relationship < 150, mean arterial pressure < 60mmHg, inotrope requirement equivalent to >15 ml/h total of adrenaline and noradrenalin, intracranial pressure > 20mmHg

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Baseline Mechanical Ventilation<br>The subjects will be kept in Volume Control Continuous Mandatory Ventilation (VC-CMV) with an inspiratory flow = 60Lpm and tidal volume = 6mL/IBW. Positive end-expiratory pressure and the inspired oxygen fraction will not be modified. | Device: Baseline Mechanical Ventilation<br>* The subjects will be kept in Volume Control Continuous Mandatory Ventilation (VC-CMV).<br>|
| Experimental: VHI With Inspiratory Pause<br>Application of a ventilator hyperinflation intervention with Volume Control Continuous Mandatory Ventilation (VC-CMV). The inspiratory flow will be set at 20Lpm, the tidal volume will be increased in steps of 200mL until the peak airway pressure of 40cmH2O is achieved, and an inspiratory pause will be applied at the end of inspiration. After achieving the target pressure, this ventilatory regimen will last 15 minutes. Positive end-expiratory pressure and the inspired oxygen fraction will not be modified. | Device: VHI With Inspiratory Pause<br>* Application of a ventilator hyperinflation intervention with Volume Control Continuous Mandatory Ventilation (VC-CMV) with an inspiratory pause.<br>|
| Experimental: VHI Without Inspiratory Pause<br>Application of a ventilator hyperinflation intervention with Volume Control Continuous Mandatory Ventilation (VC-CMV). The inspiratory flow will be set at 20Lpm and the tidal volume will be increased in steps of 200mL until the peak airway pressure of 40cmH2O is achieved. After achieving the target pressure, this ventilatory regimen will last 15 minutes. Positive end-expiratory pressure and the inspired oxygen fraction will not be modified. | Device: VHI Without Inspiratory Pause<br>* Application of a ventilator hyperinflation intervention with Volume Control Continuous Mandatory Ventilation (VC-CMV) without an inspiratory pause.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Cardiac Output | Estimation of cardiac output variation using thoracic bioimpedance | Baseline (before) and 10 minutes after the onset of VHI modesBasel | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Cardiac Index | Estimation of cardiac index variation using thoracic bioimpedance | Baseline (before) and 10 minutes after the onset of VHI modes | 
| Change in Vascular pulmonary resistance | Estimation of vascular pulmonary resistance variation using thoracic bioimpedance | Baseline (before) and 10 minutes after the onset of VHI modes | 
| Change in Systolic Volume | Estimation of systolic volume variation using thoracic bioimpedance | Baseline (before) and 10 minutes after the onset of VHI modes | 
| Change in Mean Arterial Pressure | Recording of mean arterial pressure variation using an automatic noninvasive device | Baseline (before) and 10 minutes after the onset of VHI modes | 
| Change in Cardiac Output II | Estimation of cardiac output variation using thoracic bioimpedance | Baseline (before) and 5 minutes after the end of VHI modes | 
| Change in Cardiac Index II | Estimation of cardiac index variation using thoracic bioimpedance | Baseline (before) and 5 minutes after the end of VHI modes | 
| Change in Vascular pulmonary resistance II | Estimation of vascular pulmonary resistance variation using thoracic bioimpedance | Baseline (before) and 5 minutes after the end of VHI modes | 
| Change in Systolic Volume II | Estimation of systolic volume variation using thoracic bioimpedance | Baseline (before) and 5 minutes after the end of VHI modes | 
| Change in Mean Arterial Pressure II | Recording of mean arterial pressure variation using an automatic noninvasive device | Baseline (before) and 5 minutes after the end of VHI modes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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mechanical ventilation, physiotherapy, ventilator hyperinflation, airway clearance technique