Nebulisation of surfactants in an animal model of neonatal respiratory distress

Aims-To evaluate pulmonary deposition and gas exchange following nebulisation of two surfactants by either a jet or an ultrasonic nebuliser. Method-After bronchoalveolar lavage (BAL), 19 rabbits were ventilated in four groups. Group A1 (n=5) and A2 (n=6) received Technetium-99m labelled Exosurf, and groups B1 (n=4) and B2 (n=4) received radiolabelled Survanta. Groups A1 and B1 received jet nebuliser therapy, whereas groups A2 and B2 received ultrasonic nebuliser. Pulmonary deposition, distribution, and blood gases were determined. Results-Pulmonary deposition as per cent of initial dose and mg lipid) was 0.28(0.10)% or 0.59(0.21) mg in group A1, 1.05(0.23)% or 2.21(0.48) mg in group A2, 0.08(0.02)% or 0.30(0.08) mg in group B1, and 0.09(0.02)% or 0.34(0.08) mg in group B2. Deposition in group A2 was greater than in other groups (p=0.001). Group A2 showed a small improvement in blood gases. Conclusions-Even the highest deposition-ultrasonic nebuliser with Exosurf-achieved limited clinical effect. The aerosol route is currently not effective for surfactant treatment.