Non-invasive Mechanical Ventilation After Cardiac Surgery
Non-invasive mechanical ventilation (NIV) has been used in hypoxic post-operative cardiac patients but more studies are necessary to clarify its respiratory and hemodynamic effects. Therefore, the investigators objective was to study its effects in the oxygenation index (PaO2/FiO2) and in hemodynamic variables in this group of patients.
|Study Design:||Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
|Official Title:||Effects of Non-invasive Mechanical Ventilation on Hemodynamics and Gas Exchanges Parameters After Cardiac Surgery in Patients With Relative Hypoxemia|
- Oxygenation index (PaO2/FiO2) [ Time Frame: 5 hours ] [ Designated as safety issue: Yes ]
- Heart rate (HR) [ Time Frame: 5 hours ] [ Designated as safety issue: Yes ]
- Mean arterial pressure (MAP) [ Time Frame: 5 hours ] [ Designated as safety issue: Yes ]
- Pulmonary capillary wedge pressure (PCWP) [ Time Frame: 5 hours ] [ Designated as safety issue: Yes ]
- Cardiac output (CO) [ Time Frame: 5 hours ] [ Designated as safety issue: Yes ]
|Study Start Date:||April 2008|
|Study Completion Date:||May 2009|
|Primary Completion Date:||May 2009 (Final data collection date for primary outcome measure)|
Experimental: VPAP II®
VPAP II® Group
Device: VPAP II®
VPAP group:inspiratory pressure to generate 6ml/kg of weight and expiratory pressure of 7cmH2O plus oxygen therapy (FIO2=40%) during three hours.
Other Name: VPAP II -STA (Resmed®)
- Postoperative cardiac surgery patients having a Swan-Ganz catheter and showing a PaO2/FiO2 between 150 and 300 (with FIO2 0.31), one hour after extubation, were included.
- Then, the patients were randomized into two groups: control and intervention group. Intervention group used NIV with a bi-level positive airway pressure (an inspiratory pressure to generate a tidal volume of 6ml/kg and an expiratory pressure of 7cmH2O) with a FIO2 0.4. Control group used oxygen by Venturi mask(FIO2 0.4) in order to keep a good oxygenation.
- In both groups measurements were done in basal situation, one and three hours after beginning the treatment and one hour after stop the treatment (FiO2 0.31).
- Variables studied included: PaO2/FiO2, PaO2, PaCO2, heart rate (HR), mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP) and cardiac output (CO).
|Santa Casa de Misericórdia de Porto Alegre|
|Porto Alegre, Rio Grande do Sul, Brazil, 90020-090|
|Principal Investigator:||Alessandra P Werlang, MsC||Federal University of Rio Grande do Sul|