Abstract
BackgroundIn pressure-controlled (PC) ventilation, tidal volume (VT) and transpulmonary pressure (PL) result from the addition of ventilator pressure and the patient’s inspiratory effort. PC modes can be classified into fully, partially, and non-synchronized modes, and the degree of synchronization may result in different VT and PL despite identical ventilator settings. This study assessed the effects of three PC modes on VT, PL, inspiratory effort (esophageal pressure–time product, PTPes), and airway occlusion pressure, P0.1. We also assessed whether P0.1 can be used for evaluating patient effort.MethodsProspective, randomized, crossover physiologic study performed in 14 spontaneously breathing mechanically ventilated patients recovering from acute respiratory failure (1 subsequently withdrew). PC modes were fully (PC-CMV), partially (PC-SIMV), and non-synchronized (PC-IMV using airway pressure release ventilation) and were applied randomly; driving pressure, inspiratory time, and set respiratory rate being similar for all modes. Airway, esophageal pressure, P0.1, airflow, gas exchange, and hemodynamics were recorded.ResultsVT was significantly lower during PC-IMV as compared with PC-SIMV and PC-CMV (387 ± 105 vs 458 ± 134 vs 482 ± 108 mL, respectively; p < 0.05). Maximal PL was also significantly lower (13.3 ± 4.9 vs 15.3 ± 5.7 vs 15.5 ± 5.2 cmH2O, respectively; p < 0.05), but PTPes was significantly higher in PC-IMV (215.6 ± 154.3 vs 150.0 ± 102.4 vs 130.9 ± 101.8 cmH2O × s × min−1, respectively; p < 0.05), with no differences in gas exchange and hemodynamic variables. PTPes increased by more than 15% in 10 patients and by more than 50% in 5 patients. An increased P0.1 could identify high levels of PTPes.ConclusionsNon-synchronized PC mode lowers VT and PL in comparison with more synchronized modes in spontaneously breathing patients but can increase patient effort and may need specific adjustments.Clinical Trial Registration Clinicaltrial.gov # NCT02071277
Highlights
In pressure-controlled (PC) ventilation, tidal volume (VT) and transpulmonary pressure (PL) result from the addition of ventilator pressure and the patient’s inspiratory effort
The primary objective of this study was to assess whether non-synchronized modes of ventilation result in more protective ventilation strategy over the two other PC modes as evaluated by VT and PL; secondary objectives included the effect of different degree of inspiratory synchronization on inspiratory effort determined by esophageal pressure–time product (PTPes) and by P0.1
We found that average VT and VT per predicted body weight were significantly lower during PCIMV in comparison with the two other modes (PC-IMV vs PC continuous mandatory ventilation (PC-CMV), p < 0.001; PC intermittent mandatory ventilation (PC-IMV) vs PC-SIMV, p = 0.049)
Summary
In pressure-controlled (PC) ventilation, tidal volume (VT) and transpulmonary pressure (PL) result from the addition of ventilator pressure and the patient’s inspiratory effort. This study assessed the effects of three PC modes on VT, PL, inspiratory effort (esophageal pressure– time product, PTPes), and airway occlusion pressure, P0.1. Under passive conditions in PC mode, the ventilator is the only respiratory pump and VT depends entirely on the set pressure, inspiratory time, and the respiratory system mechanics [2]. Rittayamai et al Ann. Intensive Care (2017) 7:100 make spontaneous breathing efforts, the total driving pressure will be the sum of the pressure generated by the ventilator (Paw) and the patient’s respiratory muscles. Transpulmonary pressure (PL) and VT are more difficult to control and may exceed safe limits in patients who require lung-protective ventilation, such as acute respiratory distress syndrome (ARDS)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
