As you know, patients with severe asthma and status asthmaticus develop dynamic hyperinflation syndrome and autoPEEP meaning that the inhaled air does not get exhaled completely and the pressure is built up inside the alveoli. This is caused by not enough expiratory time due to the high time constant of the airways. My question, what will happen next if the process continues?
How does dynamic hyperinflation progress if no change in the expiratory time made on the ventilator?
0%Continues to build till the lung ruptures
0%Stops on its own due to increased driving pressure
0%I do not know!
You may want to see this video to help you understand the concept.
It should stop when the higher elastic recoil caused by the hyperinflation permits the expiration to be be faster enough to be completed (provided this equilibrium takes Place within the limits of lung parenchima integrity otherwise barotrauma May result). Time constant (compliance x resistance) Is the core variabile.Shall we Say that the equilibrium Is found without barotrauma when the decrease in compliance can compensate for the increased resistance?and on the other end that we may have a PNX when the residence Is so High that the compliance required to balance It must be so low that in would require the lung to be that overstached that It goes beyond its limits?