Optimal Expiratory Volume Profile in Tidal Liquid Ventilation under Steady State Conditions, Based on a Symmetrical Lung

Liquid-assisted ventilation (LAV) using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation. During tidal liquid ventilation (TLV) the residual capacity of the lungs is filled with PFC and a liquid ventilator is necessary to inhale and exhale the tidal volume of PFC. However, during the expiration phase, a flow limitation (choked flow) can be observed, which compromises minute ventilation and consequently the gas exchange. The hypothesis of the pre-sented works is that the choked flow can be avoided by profiling the expiratory volume. To validate this concept, an elastic symmetrical lung numerical model, used to character-ize forced expiration in gas ventilation, was transposed to TLV. The parameters of the developed numerical model were fitted from experimental data obtained on a newborn lamb. The results obtained demonstrate that general observation