Recent advances in TLV techniques have shown clinical feasibility and its use will depend, in part, on the safe and effective transition to partial liquid ventilation PLV and then SB. We hypothesized that newborn lambs can be safely returned to SB after TLV. To test this hypothesis 12 lambs were initially gas ventilated (GV:B1; baseline) followed by TLV, PLV & SB. Selected lambs were time killed after TLV, PLV,& SB for histology: GV:B1(n=12: 1hr); TLV(n=12: 4hrs); PLV (n=5; 4hrs); & SB (n=3; 16hrs). At GV:B1 and at 24 hrs, animals were intubated, arterial and venous catheters inserted, followed by a period of GV (FiO2= 1.0, IMV = 30 br/min, PIP/PIP =19/4 cm H2O). For TLV a functional residual capacity was established using a perfluorochemical (PFC) (30 ml/kg; LiquiVent® and TLV commenced (frequency 3 br/min, tidal volume = 26 ml/kg, I:E ratio=1:3, FiO2=0.5-1.0). Throughout the study arterial blood gases (ABG mmHg), and mean arterial blood pressure(MAP mmHg) were measured and chest x-rays (CXR) were obtained. Oxygen index(OI) and lung compliance (CDyn ml/cmH2O/kg) were calculated, and all data are expressed as means±SEM; p<0.05. Endpoint data PLV and SB were compared to GV:B1. For TLV, there were no differences as a function of time for pH (7.30±0.01), pCO2 (49±0.7), pO2 (329±9), CDyn(1.8±0.11), MAP (83±1). There were no differences between GV:B1 vs. PLV and GV:B1 vs. SB in pH, pCO2, OI, CDyn and MAP. CXR appearance at GV:B1 = normal lung; PLV = partial clearing of PFC, and SB = small residual of PFC. Lung histology is ongoing. These data demonstrate safe and effective gas exchange, compliance, and cardiovascular stability during TLV and the transition from TLV to SB. Table

Table 1 No caption available.
Full size table