Electrical Impedance Tomography in Evaluating the Effects of Noninvasive Ventilation in Post-Operative Cardiac Surgery

Study Overview
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Brief Summary
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NTRODUCTION: cardiac surgery can lead to pulmonary complications such as hypoxemia and atelectasis. Noninvasive ventilation has been used to prevent and treat such complications. Electrical impedance tomography has been a useful tool in bedside evaluation of ventilation and pulmonary ventilation. OBJECTIVE: To compare the effects of non-invasive ventilation with oxygen therapy in cardiac post-operative patients. MATERIALS AND METHODS: It will be a randomized controlled clinical trial where patients will be divided into two groups: a group that will perform NIV for 1 hour and the group that will only use oxygen therapy. They will be evaluated through Electrical Impedance Tomography and arterial gasometry analysis just before extubation, soon after extubation, during the intervention and after the intervention for a period of 2 hours after extubation. EXPECTED RESULTS: It is expected that the NIV group will present higher pulmonary ventilation and aeration and better gas exchange than the oxygen therapy group, and that the time of therapeutic effect will be higher in the NIV group.

Detailed Description
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The proposal basically consists of Validation of the hypothesis: The use of Non-invasive Ventilation in patients in the postoperative cardiac surgery results in greater ventilation, greater aeration, and improved gas exchange when compared to the oxygen therapy group. The use of noninvasive ventilation in the postoperative cardiac surgery has been widely used in clinical practice, but the evidence of the benefits of this technique in this population in relation to some criteria have not yet been elucidated in the scientific literature, such as the effect of NIV in ventilation and pulmonary ventilation, and how long does this effect last.

Official Title
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Use of Electrical Impedance Tomography in Evaluating the Effects of Noninvasive Ventilation in the Post-Operative Cardiac Surgery: Controlled and Randomized Clinical Trial

Conditions
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Thoracic Surgery

Intervention / Treatment
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* Device: Non invasive ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Immediate postoperative period of cardiac surgery age between 18 and 65 years BMI between 18.5 and 30 kg / m2 Patients still intubated when admitted to the ICU without previous history of severe pulmonary diseases such as chronic obstructive pulmonary disease, pulmonary fibrosis, or chronic renal failure, or associated neuromuscular diseases Exclusion Criteria: Patients considered to be at risk for extubation failure (hypercapnia, more than failure in the autonomic test, AVM time greater than 72 hours, ineffective cough) Cardiopulmonary bypass time more than 150 minutes Hemodynamic instability (arrhythmias, cardiogenic shock, severe hypotension with SBP <90mmHg) Episodes of abdominal distension, nausea and vomiting Hypoxemia (PO2 <50mmHg with FiO2 50%) or hypercapnia (PaCO2> 55mmHg with pH <7.30) Patients who are at high surgical risk according to Euroscore II

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

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
Interventional Model Description: A parallel group study is a simple and commonly used clinical design which compares two treatments. Usually a test therapy is compared with a standard therapy. The allocation of subjects to groups is usually achieved by randomisation. The groups are typically named the treatment group and the control group. Parallel group designs do not require the same number of subjects in each group, although often similar numbers are observed. The design is commonly used in randomised controlled trials. Statistical analysis often boils down to a simple t-test of the between group difference in the outcome, which is usually a mean or a proportion.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group VNI 1h<br>Intervention: Non invasive ventilation, applied for 1 hour | Device: Non invasive ventilation<br>* Non invasive ventilation is a mode of mechanical ventilation that does not require the use of artificial airway.<br>|
| No Intervention: Group O2<br>Oxygen therapy | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in electrical impedance measures | impedance variation data recorded by impedance electrical tomography | data recorded 5 minutes before extubation, 5 minutes after extubation, at the first 5 minutes of therapy, 25 to 30 minutes after beginning of therapy, 55 to 60 minutes after beginning of therapy, and 1,5 hour and 2 hours after beginning of therapy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in Blood gases analysis - PaO2 (mmHg), PaCO2 (mmHg), PaO2/FiO2 | Collected by a Laboratory professional | recorded 5 minutes before extubation and 1 hour after extubation |