TOTAL LIQUID VENTILATION WITH PERFLUOROCARBONS INCREASES PULMONARY END-EXPIRATORY VOLUME AND COMPLIANCE IN THE SETTING OF LUNG ATELECTASIS

Objective: To compare compliance and end-expiratory lung volume during reexpansion of normal and surfactant-deficient ex vivo atelectatic lu ngs with either gas or total liquid ventilation. Design: Controlled, a nimal study using an ex vivo lung preparation. Setting: A research lab oratory at a university medical center. Subjects: Thirty-six adult cat s, weighing 2.5 to 4.0 kg. Interventions: Heparin(300 U/kg) was admini stered, cats were killed, and lungs were excised en bloc. Normal lungs and saline-lavaged, surfactant-deficient lungs were allowed to passiv ely collapse and remain atelectatic for 1 hr. Lungs then were placed i n a plethysmogragh and ventilated for 2 hrs with standardized volumes of either room air or perfluorocarbon. Static pulmonary compliance and end expiratory lung volume were measured every 30 mins. Measurements and Main Results: Reexpansion of normal atelectatic lungs with total l iquid ventilation was associated with an 11 fold increase in end-expir atory lung volume when compared with the increase in end-expiratory lu ng volume observed with gas ventilation (total liquid ventilation 50 /- 14 mL, gas ventilation 4 +/- 9 mL, p < .0001). The difference was e ven more pronounced in the surfactant-deficient lungs with an similar to 19-fold increase in end-expiratory lung volume observed in the tota l liquid ventilated group, compared with the gas ventilated group (tot al liquid ventilation 44 +/- 17 mL, gas ventilation 2 +/- 8 mL, p = .0 001). Total liquid ventilation was associated with an increase in pulm onary compliance when compared with gas ventilation in both normal and surfactant-deficient lungs (normal: gas ventilation 6 +/- 1 mL/cm H2O , total liquid ventilation 14 +/- 4 mL/cm H2O, p < .0001; surfactant-d eficient: gas ventilation 4 +/- 1 mL/cm H2O, total liquid ventilation 9 +/- 3 mL/cm H2O, p < .01). Conclusions: End-expiratory lung volume a nd static compliance are increased significantly following attempted r eexpansion with total liquid ventilation when compared with gas ventil ation in normal and surfactant-deficient, atelectatic lungs. The abili ty of total liquid ventilation to enhance recruitment of atelectatic l ung regions may be an important means by which gas exchange is improve d during total liquid ventilation when compared with gas ventilation i n the setting of respiratory failure.