Avaliação ecodopplercardiográfica das repercussões hemodinâmicas à aplicação de dois níveis pressóricos em vias aéreas

Abstract

Purpose: Application of noninvasive positive airway pressure triggers significant cardiopulmonary interactions. This study aimed to identify the hemodynamic effects arising from the application of bilevel pressure to the airways evaluated by echocardiography. Methods: Randomized, double-blind, controlled study was conducted with 19 healthy participants. Random sequence of three expiratory positive airway pressures (EPAPs) was applied for 5 minutes each. The inspiratory pressure remained constant at 5 cmH2O above the established EPAP. Hemodynamic variables, determined using Doppler echocardiography, a non-invasive ventilator, and a heart monitor were recorded. Results: Comparing baseline data with that collected under various EPAPs of 5, 10, and 15 cmH2O showed reduced aortic velocity time integral (p < 0.001), pulmonary velocity time integral (p = 0.003), mean systolic velocity (p = 0.01), atrial filling (p < 0.001), left atrial volume (p = 0.008), heart rate (p < 0.001), stroke volume (SV - p = 0.006), cardiac output (p < 0.001), and distensibility vena cava (p = 0.01). In addition, increased peripheral oxygen saturation (p =<0.001), tidal volume (p = 0.002), and minute ventilation (p < 0.001) were found. There were important and significant correlations between VS and VTIm (r = 0.76; p < 0.001) and VTIa (r = 0.64; p < 0.001) as well as VTIm and CO (r = 0 61; p < 0.001). Conclusion: The cardiopulmonary and interventricular repercussions by echocardiography, were expressed by reducing the left ventricular preload and increasing the biventricular preload, stroke volume, and cardiac output, ensuring increased tidal volume and blood oxygenation.