Proportional Assist Ventilation (PAV) in Early Stage of Critically Ill Patients

Study Overview
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Brief Summary
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To evaluate the effectiveness of high assistance proportional assist ventilation (PAV+) (objective 80% gain) as main ventilatory support in early stage of critically ill patients in comparison with standard volume-assist control ventilation (ACV).

Detailed Description
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The goal of this proposal is to apply PAV+ as routine ventilatory mode in the early stage of critically ill patients, taking advantages of spontaneous breathing and better patient-ventilator interaction. The standard treatment in patients with acute respiratory failure is mechanical ventilation in control-mode for the first days of acute illness. This procedure is usually associated with patient-ventilator dyssynchrony, higher needs of sedation and/or relaxation, muscle atrophy, etc. PAV + is a new ventilatory mode that applies pressure in proportion to spontaneous patient inspiratory effort allowing better adaptation to changes in internal homeostasis. Up to now, several reports compare PAV with assisted modes as a feasible alternative only in the weaning phase. However, PAV is able to unload patient effort in different levels, suggesting that high-assistance PAV (about 80%) could be comparable with assist-control modes in terms of respiratory muscles unload. Whether PAV is as effective as traditional ACV in terms of ventilation muscle unload in the acute phase of illness has not been established and we aim to address this question. We plan to prospectively enroll patients on mechanical ventilation early at ICU admission, and to ventilate them randomly under ACV (volume-assist control ventilation) or PAV+ (beginning with 80% if possible). We will evaluate length of mechanical ventilation, sedation requirements and respiratory-hemodynamic variables from the very beginning and until attending clinicians decide that patients are ready to be weaned.

Official Title
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High-assistance Proportional Assist Ventilation (PAV) vs. Assist-Control Ventilation (ACV) in Early Stage of Critically Ill Patients

Conditions
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Respiratory Failure, Mechanical Ventilation

Intervention / Treatment
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* Other: Mechanical ventilation mode (PAV+ vs. ACV)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients 18 years of age or older Anticipated MV > 24 hours Availability of informed consent from patient or next of kin Ventilation parameters measured under PAV+ 80% gain: PaO2/FiO2 >100 RPAV <10 cm H2O/l/s CPAV > 30 ml/cm H2O WOBTOT <1.5 J/l VE <18 l/min Exclusion Criteria: Patients on moribund state or with life-sustaining therapy withholding decision. Patients with unstable respiratory/hemodynamic state, PaO2/FiO2 <100, Dopamine >15 microg/Kg/min or epinephrine >0.1 microg/kg/min. Pregnancy. Air leak. Patients needing deep sedation or muscle paralysis Patients needing hyperventilation (brain trauma). Patients with severe muscle weakness. Recruitment maneuvers or prone position.

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: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High assistance PAV+<br>Ventilatory support performed by PAV at 80% assistance (PB 840-plus) FiO2 and PEEP according to routine practice | Other: Mechanical ventilation mode (PAV+ vs. ACV)<br>* Compare two ventilatory modes in the acute phase of illness<br>* Other names: Mechanical ventilation;|
| Active Comparator: Assist-control ventilation<br>Tidal volume, FiO2 and PEEP set according to routine practice | Other: Mechanical ventilation mode (PAV+ vs. ACV)<br>* Compare two ventilatory modes in the acute phase of illness<br>* Other names: Mechanical ventilation;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Length of mechanical ventilation | Reduction of mechanical ventilation days when ventilated with high assistance PAV+ compared with ACV. | 28 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Non-inferiority of PAV+ compared to ACV in terms of gas exchange | Non-inferiority of high assistance PAV+ compared to ACV in terms of gas exchange | 28 days | 
| Noninferiority of PAV in short term complications | Similar incidence in the complications composite outcome (barotrauma, ARDS, atelectasis and pneumonia) | 28 days | 
| Noninferiority of PAV in weaning success | Similar rate of weaning success defined as the composite end-point: time to resume spontaneous ventilation, rate of extubation success, need for non invasive ventilation (NIV) as rescue therapy, and reintubation rate. | 28 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Proportional Assist Ventilation plus, Acute respiratory failure, Mechanical ventilation