Comparison of respiratory mechanics measurements in the volume cycled ventilation (VCV) and pressure controlled ventilation (PCV)

Abstract

Introduction: Monitoring respiratory mechanics may provide important information for the intensivist, assisting in the early detection of pulmonary function changes of patients hospitalized in ICU. Objective: To compare measurements of respiratory mechanics in VCV and PCV modes, and correlate them with age and oxygenation index. Materials and methods: Cross-sectional study conducted in the adult ICU of the Hospital Nossa Senhora da Conceição, in Tubarão - SC. A hundred and twenty individuals were selected between March and August 2013. The respiratory mechanics measurements were evaluated using compliance and resistance static measures of the respiratory system in PCV and VCV modes between the 1st and 5th day of hospitalization. Simultaneously, the oxygenation index PaO2/FiO2 was collected. Results: The obtained results were: compliance (VCV) = 40.9 ± 12.8 mL/cmH2O, compliance (PCV) = 35.0 ± 10.0 mL/cmH2O, resistance (VCV) = 13.2 ± 4.9 cmH2O/L/s, resistance (PCV) = 27.3 ± 16.2 cmH2O/L/s and PaO2/FiO2 = 236.0 ± 97.6 mmHg. There was statistical difference (p < 0.001) between the compliance and resistance measures in VCV and PCV modes. The correlations between the oxygenation index and compliance in VCV and PCV modes and resistance in VCV and PCV modes were, respectively, r = 0.381 (p < 0.001), r = 0.398 (p < 0.001), r = -0.188 (p = 0.040), r = -0.343 (p < 0.001). Conclusion: Despite the differences between the respiratory mechanics measurements the monitoring using VCV and PCV modes seems to show complementary aspects.