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

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

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.

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.

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