A biomechanical model of pendelluft induced lung injury

Independent Lung Ventilation-Experimental Studies on a 3D Printed Respiratory Tract Model

“…In all cases presented in Figure 7 , incomplete Q–V loops (marked with red circles) indicate that the gas volume did not completely return to the baseline at the end of expiration phase, signifying the possibility of trapped gas. This can be clearly seen also in volume–time variation graphs V(t/T)—all the lines do not reach the volume value equal zero (marked with red circles), as should occur in normal conditions with balanced compliances [ 25 ]. The residual gas volume could be attributed to the interregional gas exchange (pendelluft flow) during the cycle.…”

“…The increased turbulence and recirculation zone were found to strongly influence the flow distribution in the same way as it was detected during experimental tests—more air is distributed to the lower lobe (outlet) than to the upper one. Noteworthily, the occurrence of high wall shear stress at the impingement sites is considered to be a risk to the wall epithelium layer as it may result in damage and inflammation that leads to ventilator-induced lung injury [ 25 ].…”

“…The effect of two opposite flow-time dependences in the inspiration phase ( Figure 5 and Figure 6 ), directly proportional for the lower outlet (higher compliance) and inversely proportional for upper outlet (lower compliance) can be explained in the following way—the branch with higher compliance had higher time constant (τ = Resistance × Compliance) than branch with lower compliance [ 26 ]. As a consequence, at the end inspiration phase, branch UO started expiring (in-phase) while branch LO was still inspiring (out-of-phase), a situation which caused the expired air from branch UO to fill in branch LO, simulating the pendelluft effect [ 25 ]. Higher system compliance enhanced the observed for normal compliance effect of gas transport between adjacent respiratory units with different compliances.…”

A 59-Year-Old Man With ARDS Receiving “Protective” Ventilation

“…4,5 Added to the tidal volume, even at protective levels, pendelluft results in an overdistension of these gravity-dependent and injured regions. [4][5][6] This case shows that besides being a good tool to monitor lung aeration over time and response to therapies offered, 2 the ultrasonography has the potential to demonstrate the adequacy and the consequences of the ventilatory support in real time and responses of different lung regions to the same ventilatory support. Specifically, in this patient, the ultrasound shows that despite ventilatory parameters that work as protectors, the fact that the patient triggers the respiratory cycles makes it a possible harmful management.…”

Consequences to the Lungs When Gas Swings Between Lung Units During Patient Triggered Mechanical Ventilation

“…Pendelluft can occur during patient triggered mechanical ventilation or spontaneous breathing, but typically does not occur during controlled ventilation, except in patients with chronic lung disease. [3][4][5] Pendelluft is also considered one of the mechanisms that explain gas transport during highfrequency jet ventilation or high-frequency oscillation. 6 Pendeluft may be marked when mechanical ventilation is used in a patient with heterogeneous impedances.…”