Assessing Respiratory Mechanics in Ventilated Patients

Our lab is interested in developing clinically feasible and personalized strategies to assess respiratory mechanics in mechanically-ventilated patients. Recently, we have utilized variable ventilation (VV), which delivers a unique tidal volume and frequency per every breath for the patient, to achieve this goal. The natural variation in VV occurs at physiological breathing rates and tidal volumes and allows assessing continuously without any additional equipment respiratory impedance (Z) from which Resistance and Elastance are calculated as functions of breathing rate. The technique, termed ZVV (Z+VV), was applied to 5 human patients with mild acute respiratory distress syndrome (ARDS), in controlled experiments on 5 initially healthy mice followed by inducing lung injury (lung lavage) to model ARDS, and verified for accuracy and robustness using a computational study. Splitting the analyzed data into two time segments (P1 and P2 in figure) revealed decrease in Resistance and Elastance with time providing preliminary support that VV can serve both as a diagnostic and therapeutic ventilation strategy.