Thoracic Surgery
Conditions
Brief summary
This study evaluates the effects of VCV, PCV and PSV ventilatory modes during the immediate postoperative period on the variables resulting from regional and global pulmonary electrical impedance and diaphragmatic mobility, as well as perform ventilator synchrony analysis in PSV mode by mechanical ventilator. Half of the participants will receive VCV followed by PSV for weaning, while the other half will receive PCV followed by PSV for weaning.
Detailed description
In the immediate postoperative period of cardiac surgery, patients are found under mechanical ventilatory support. Commonly, they are ventilated in controlled and assisted-controlled volume (VCV) or pressure (PCV) modes, with weaning at pressure support (PSV). Systematic reviews indicate that there is no difference between the VCV and PCV ventilatory modes for some clinical outcomes or that the existing evidence is insufficient. The distribution of regional ventilation and diaphragmatic mobility can be measured from the use of electrical impedance tomography (EIT) and diaphragmatic ultrasonography (US) to clarify the physiological changes and / or mechanisms of adaptation of the organism submitted to controlled modes cycled at volume or at pressure and spontaneously flow cycled mode. Besides EIT and US measures, gasometric, hemodynamic and respiratory data will also be recorded. The statistical analysis will be considered α≤0.05 for a statistically significant difference.
Interventions
DEVICEVCV+PSV
invasive mechanical mechanical modes by volume cycling and by pressure support which the patients will be submitted to before weaning. Post-operative mechanical ventilation average time: 6 hours after ICU admission.
DEVICEPCV+PSV
invasive mechanical mechanical modes by pressure cycling and by pressure support which the patients will be submitted to before weaning. Post-operative mechanical ventilation average time: 6 hours after ICU admission.
Sponsors
Real Hospital Português de Beneficência em Pernambuco
Universidade Federal de Pernambuco
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
DIAGNOSTIC
Masking
DOUBLE (Subject, Outcomes Assessor)
Intervention 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.
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* IMC 18.5-29.9 kg/m² * Two thoracic tubes (one mediastinal and one left-sided pleural) * under mechanical ventilation after surgery * submitted to intraoperative extracorporeal circulation
Exclusion criteria
* Over 2h of cardiopulmonary bypass * Over 12h of post-operative mechanical ventilation * Post-operative bleeding above 500 ml in the first hour or above 300 ml in the first two hours * History of special conditions (neuromuscular and chronic pulmonary disease, thoracic deformity, abdominal distension).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| electrical impedance measures | 5 minutes of recording at each step of mechanical ventilation progression before extubation. | impedance variation data recorded by a tomograph. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| arterial gas blood analysis data | up to 12h, following routine care while patients are mechanically ventilated | measures of pH, PaCO2 (mmHg), PaO2 (mmHg), PaO2/FiO2 |
| patient-ventilator synchrony | 5 minutes of recording at each step of mechanical ventilation progression before extubation | events of discomfort between patient and ventilator: ineffective efforts and auto-triggering. Expressed in present or ausent. |
Countries
Brazil
Outcome results
None listed