Small dose of exogenous surfactant combined with partial liquid ventilation in experimental acute lung injury: effects on gas exchange, haemodynamics, lung mechanics, and lung pathology

A combination of exogenous surfactant and partial liquid ventilation (PLV) with perfluorocarbons should enhance gas exchange, improve respiratory mech anics and reduce tissue damage of the lung in acute lung injury (ALI). We u sed a small dose of exogenous. surfactant with and without PLV in an experi mental model of ALI and studied the effects on gas exchange, haemodynamics, lung mechanics, and lung pathology. ALI was induced by repeated lavages (P a-O2/Fl(O2) less than 13 kPa) in 24 anaesthesized, tracheotomized and mecha nically ventilated (Fl(O2) 1.0) juvenile pigs. They were treated randomly w ith either a single intratracheal dose of surfactant (50 mg kg(-1), Curosur f (R), Serono AG, Munchen, Germany) (SURF-group, n=8), a single intratrache al dose of surfactant (50 mg kg(-1), Curosurf (R)) followed by PLV with 30 ml kg(-1) of perfluorocarbon (PF 5080, 3M, Germany) (SURF-PLV-group, n=8) o r no further intervention (controls, n=8). Pulmonary gas exchange, respirat ory mechanics, and haemodynamics were measured hourly for a 6 h period. In the SURF-group, the intrapulmonary right-to-left shunt (QS/QT) decreased si gnificantly from mean 51 (SEM 5)% after lavage to 12 (2)%, and Pa-O2 increa sed significantly from 8.1 (0.7) to 61.2 (4.7) kPa compared with controls a nd compared with the SURF-PLV-group (P <0.05). In the SURF-PLV-group, QS/QT decreased significantly from 54 (3)% after induction of ALI to 26 (3)% and Pa-O2 increased significantly from 7.2 (0.5) to 30.8 (5.0) kPa. compared w ith controls (P <0.05). Static compliance of the respiratory system (C-RS), Significantly improved in the SURF-PLV-group compared with controls (P <0. 05). Upon histological examination, the SURF-group revealed the lowest tota l injury score compared with controls and the SURF-PLV-group (P <0.05). We conclude that in this experimental model of ALI, treatment with a small dos e of exogenous surfactant improves pulmonary gas exchange and reduces the l ung injury more effectively than the combined treatment of a small dose of exogenous surfactant and PLV.