During cardiac surgery, extracorporeal circulation (ECC) causes lung injury. In these inhomogenously affected lungs, the pressure control ventilation (PCV) cannot adequately ventilate differently damaged lung compartments. We invented and used original multilevel lung ventilation method named 3-LV based on alternating 3 or more pressure levels, ventilation frequencies and delivered tidal volumes. The goal of this article is to compare lung mechanics in cardiac surgery patient after ECC using standard PCV when compared to 3LV ventilation.
This study was performed on 88 cardiac surgery patients after disconnection from ECC; the patients were randomly (allocation by weekdays) divided into two groups and ventilated by PCV and 3LV. Group 1 (n = 44) started with 1 hour PCV followed by a second hour with the 3-LV mode. Group 2 (n = 44) was ventilated in the reverse order. Measured parameters were statistically evaluated by the Student's paired t-test.
The static compliance (Cst) and PaO2/FiO2 ratio in 3-LV ventilation mode improved by 25-32% (p < 0.01) and 31% (p < 0.01), in group actually ventilated by 3LV ventilation. The respiratory rate after weaning in Group 1 significantly decreased compared with that in Group 2 (p < 0.05). An improved CO2 washout was observed in each group after switching to 3LV.
3-LV showed a better lung recruitment ability compared with PCV in patients after cardiac surgery, without using high PEEP level.