Effect of Variable PSV in Acute Lung Injury: Part I and Part II

Study Overview
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Brief Summary
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Noisy Pressure Support Ventilation (noisy-PSV) would lead to improved lung function, while preserving respiratory muscle unloading. Basically, noisy PSV differs from other assisted mechanical ventilation modes that may also increase the variability of the respiratory pattern (e.g. proportional assist ventilation) by the fact that the variability does not depend on changes in the patient's inspiratory efforts. The aim of this study is to evaluate the optimal variability for noisy PSV in patients with ALI based on its effects on respiratory mechanics, breathing comfort, gas exchange, and hemodynamics. The investigators hypothesize that noise in pressure support leads to variations in VT that are able to improve lung function and that physiologic variables respond differently to the degree of variability in pressure support

Official Title
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Physiological Research on Variable Pressure Support Ventilation in Patients With Acute Acute Lung Injury: Part I and Part II

Conditions
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Acute Lung Injury (ALI), Acute Distress Respiratory Syndrome (ARDS)

Intervention / Treatment
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* Other: Noisy-PSV 1
* Other: Noisy-PSV 2


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years Intubated/tracheostomized patients in assisted mechanical ventilation PaO2/FiO2 100-300, with PEEP ≥ than 5 cmH2O. Exclusion Criteria: Pregnancy History of chronic lung disease (COPD) Presence of thoracic drainage

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Noisy-PSV 1<br>different levels of variable pressure support | Other: Noisy-PSV 1<br>* Noisy-PSV 1: different levels of variable pressure support (PS) will be randomized: a) PS variability equal to 0%, b) PS variability equal to 45%, c) PS variability equal to 90%.<br>|
| Other: Noisy-PSV 2<br>different levels of variable pressure support | Other: Noisy-PSV 2<br>* Noisy-PSV 2 : different levels of variable Pressure Support (PS) will be randomized: a) PS equal to Baseline and variability 0%; b) PS equal to Baseline and variability set in order achieve an increase or decrease of pressure of 5 cmH2O; c) PS equal to Baseline - 5 cmH2O and variability 0%; d) PS equal to Baseline - 5 cmH2O and set in order achieve an increase or decrease of pressure of 5 cmH2O.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect on arterial oxygenation in each setting of variability | The investigators perform an arterial blood gas and oxygenation is evaluated with PaO2/FiO2 ratio | after 45 minutes of mechanical ventilation with each level of variable pressure support | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| work of breathing | work of breathing will be recorded as pressure-time product (PTP) measured on the esophageal pressure curve. | every 9 minutes, up to 45 minutes, of mechanical ventilation in each level of variable pressure support | 
| effects on hemodynamic | the investigator will record blood pressure and cardiac output | after 45 minutes of mechanical ventilation with each level of variable pressure support | 
| effect on arterial carbon dioxide | The investigators perform an arterial blood gas and arterial carbon dioxide is evaluated with PaCO2. | after 45 minutes of mechanical ventilation with each level of variable pressure support | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ALI, ARDS, Noisy pressure support ventilation