Conventional vs Neurally Adjusted Ventilatory Assist in Difficult Weaning From Mechanical Ventilation

Study Overview
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Brief Summary
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The NAVA, by its more physiological aspect and a better adaptation of the patient to the ventilator with a decrease of asynchronies patients-ventilators, could decrease the duration of weaning and so decrease the duration of invasive mechanical ventilation and the morbi-mortality. The objective of this study is to compare the neurally adjusted ventilatory assist versus the usual management of weaning from mechanical ventilation, in term of duration of weaning, at the patients in period of difficult weaning from the invasive mechanical ventilation.

Detailed Description
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- Background: The NAVA is a new mode of ventilation which works from the continuous recording of the electromyogram of the diaphragm. In theory, the NAVA delivred a proportional and synchronous assistance, to respiratory efforts allowing a more adequate ventilatory support. However, no study estimates the NAVA in the weaning from mechanical ventilation. - Purpose: The NAVA, by its more physiological aspect and a better adaptation of the patient to the ventilator with a decrease of asynchronies patients-ventilators, could decrease the duration of weaning and so decrease the duration of invasive mechanical ventilation and the morbi-mortality. The objective of this study is to compare the neurally adjusted ventilatory assist versus the usual management of weaning from mechanical ventilation, in term of duration of weaning, at the patients in period of difficult weaning from the invasive mechanical ventilation. - Detailed description: Approximately 20 to 25 % of the patients under mechanical ventilation who have the general criteria of weaning will not pass a first SBT (Spontaneous Breathing Trial). At this moment, the management of the weaning ventilatoire are made with PSV. The NAVA is proportional assistance and depends on the intensity of the electric diaphragmatic signal (Edi). The respiratory effort of the patient is directly detected from the Edi signal. In theory, the NAVA is a proportional and synchronous respiratory. After a first failure of a SBT, patients respecting the inclusion criteria and exlusion criteria described above are then included in the study and randomized in two groups (control group or NAVA group). In the control group, the PSV is decreased of 2cmH2O daily or several times a day to obtain a good clinical and biologic tolerance, with a respiratory frequency between 15 and 30/min and a tidal volume at 6ml/kg. In the NAVA group, the level of NAVA is daily adjusted to obtain Eadimax corresponding to 60 % of Eadimax of the patient during the SBT to obtain a good clinical and biologic tolerance, with a respiratory frequency between 15 and 30/min and a tidal volume at 6ml/kg. Twice a day, the criteria of SBT are looked for. When they are present, a SBT is realized. If it is a success, the patient will be extube. If it is a failure, the patient will be reventilated in PSV or NAVA according to their group. A non-invasive ventilation preventive or of rescue can be administered post-extubation according to criteria. The reintubated criteria are also defined.

Official Title
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A Prospective, Randomized and Controlled Study Estimating the Neurally Adjusted Ventilatory Assist (NAVA) Versus the Pressure Support Ventilatory (PSV) in Difficult Weaning From Mechanical Ventilation

Conditions
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Respiratory Failure

Intervention / Treatment
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* Device: Neurally adjusted ventilatory assist
* Device: Noninvasive pressure support ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age >18 years Under mechanical ventilation > 48 hours A first failure of a SBT Plateau pressure 30cmH2O with tidal volume 8ml / kg SpO2 ≥ in 90 % with a FiO2 ≥ 50 %, or PaO2 / FiO2 > 150mmHg Positive expiratory pressure 8cmH2O No more of one mg/hour of noradrenaline or adrenalin Temperature >36 and <39°C. Stable neurological state (Glasgow scale > 4) without sedation (or very low sedation). Consent, dated and signed by the patient or his representative. Exclusion Criteria: Contraindications to the NAVA (recent high digestive suture or oesophageal varices bleeding < 4 days). Pregnant woman. Age <18 years. Tracheotomy. Cardiac arrest with a reserved neurological prognostic. Therapeutic limitation.

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: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: NAVA group<br>Management of the difficult weaning from mechanical ventilation by the NAVA. | Device: Neurally adjusted ventilatory assist<br>* In the NAVA group, the level of NAVA is daily adjusted to obtain Eadimax corresponding to 60 % of Eadimax of the patient during the SBT to obtain a good clinical and biologic tolerance, with a respiratory frequency between 15 and 30/min and a tidal volume at 6ml/kg.<br>|
| Active Comparator: Control group<br>Conventional management of the difficult weaning from mechanical ventilation, with the pressure ventilation. | Device: Noninvasive pressure support ventilation<br>* In the control group, the PSV is decreased of 2cmH2O daily or several times a day to obtain a good clinical and biologic tolerance, with a respiratory frequency between 15 and 30/min and a tidal volume at 6ml/kg.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration of weaning from the mechanical invasive ventilation. | This duration is defined by the period between the first failure of the spontaneous breathing trial (SBT) and 48 hours after the extubation. | 48 hours after the extubation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration between the inclusion and the success of the SBT |  | 28th day | 
| Duration of invasive mechanical ventilation |  | 28th day | 
| Rate of failure of SBT |  | 28th day | 
| Rate of success of SBT |  | 28th day | 
| Rate of ventilator-associated pneumonia |  | 28th day | 
| Length of intensive care unit stay |  | 28th day | 
| Duration of hospitalization |  | 28th day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Neurally adjusted ventilatory assist, Weaning, Mechanical ventilation, Extubation