Alveolar Recruitment During and After Tracheal Instillation of LiquiVent® in Infants on Partial Liquid Ventilation (PLV). ♦ 1501

PLV with perfluorochemical liquids in animal models and humans with respiratory distress has been associated with an improvement in gas exchange, dynamic lung compliance (CI/kg), tidal volume (TV) and ventilator requirements. We hypothesized that alveolar recruitment with PLV would be dependent on patient age and severity of lung disease. To test this hypothesis we evaluated indices of alveolar recruitment in 18 critically ill neonates during PLV: (Gr I) preterm infants, wt=1.26 kg., n=7 and (Gr II) term infants on ECMO, wt=3.4 kg., n=11. Clinical responses and pulmonary function were evaluated during instillation of PFC fluid(LiquiVent®) and serially over 4 days. In all patients, targeted PFC filling (initial dose, 10-15 ml/kg) was completed in less than 2 hrs. Mean± SE baseline CI/kg (ml/cm H₂O/kg) and TV (ml/kg) was 0.16± 0.017 SE and 4.2 ± 0.22 SE for Gr I; 0.09 ± 0.023 SE and 1.6 ± 0.3 SE ml/kg for Gr II, respectively. After the initial fill, Cl/kg and TV significantly increased 50% (p < 0.05) and 24% (p < 0.05) for Gr I, and 18% (NS) and 50% (NS) for Gr II, respectively. Across both groups, it was found that partial filling (50-80% of the initial target dose) resulted in a 59% increase in Cl/kg. Serial Cl/kg data increased over 4 days in both groups: at 24 hrs, Cl/kg increased 160% and 64% in Gr I and Gr II, respectively; at 96 hrs, Cl/kg increased 194% and increased 260% in Gr I and Gr II, respectively. For Gr I, the changes in Cl/kg and TV paralleled FiO2 and ventilator pressure requirements. Baseline FiO₂=0.96 and PIP=34 cmH₂O; at 24 hrs, FiO₂=0.50 and PIP=22 cmH₂O; and at 96 hrs, FiO₂=0.38 and PIP=23 cmH₂O. These findings show that alveolar recruitment as measured by Cl/kg and clinical responses differed between patient populations. In patients with primary surfactant deficiency (Gr I), as compared to ARDS and CDH patients (Gr II), alveolar recruitment with PFC instillation was more immediate and required less ventilator support. By 24 and 96 hours, alveolar recruitment indices for both groups were comparable. These findings suggest that PFC filling and subsequent ventilator management as most critical during and after the initial fill, particularly in the preterm RDS infants.(LiquiVent® supplied by Alliance Pharmaceutical, Hoechst-Marion Roussel).

Supported in part by NIH RR00240