Abstract
The patient in the postoperative period of Coronary Artery Bypass Grafting(CABG)has impaired cardiac autonomic function. This study to evaluate the autonomic behavior and correlate it with the hemodynamic changes with two models of mechanical ventilators in patients after CABG. Methods: Quantitative, prospective, randomized and crossover study. Patients on the first day postoperative CABG to perform the procedure NIV with two different ventilators: conventional and the specific and use NIV for 30 minutes each. The block randomization was used to determine the technique which started to approach then, by crossover perform sequential technique. The PEEP was set at 8 cmH2O, the FiO2 to maintain SpO2 above 90%, the support pressure or inspiratory pressure adjusted to a tidal volume(VT) of 8mL/kg of the ideal body weight. The heart rate variability (HRV), hemodinamics and respiratory parameters were evaluated before, during NIV and after the procedure. For statistic analysis was used the Shapiro-Wilk, Wilcoxon test and correlation by Spearman's Postos (p <0.05). Result:NIV with specific ventilator there was significant increase in the HF index (p = 0.0469), systolic blood pressure (p = 0.0003) and diastolic blood pressure (p = 0.0108). However, during the application of NIV with conventional ventilator there was an increase in HR (p = 0.0228). There was no difference between the HRV before and after the procedure. There was also no significant correlation between hemodynamic variables and HRV. Conclusion: NIV changed the cardiac autonomic nervous control, increasing vagal activation with specific ventilator. There were no hemodynamic changes associated with autonomous behavior on both machines.
- Copyright ©ERS 2015