Surfactant Nebulisation Versus Instillation in Lung Lavaged Rabbits 68

Aim Evaluate the influence of surfactant nebulisation on lung function, haemodynamic side effects and surfactant distribution over the lungs.

Subjects Lung lavaged rabbits with severe respiratory failure.

Intervention ^99mTc labelled Alvofact was instilled or nebulised. Assessed were PaO₂, dynamic compliance, cerebral bloodflow and after sacrifice static lung compliance and surfactant distribution.

Results PaO₂ rose after instillation in 15 min from 8.7± 1.3kPa (mean±sem) to 24.9 ± 6.4 (p<0.05), during nebulisation in 120 min from 8.0 ± 0.5 to 24.5 ± 4.6(p<0.05). Dynamic complicances were 0.40 ± 0.04 ml/cmH₂O/kg before and 0.42 ± 0.04 (ns) 120 min after instillation versus 0.43± 0.03 before and 0.33 ± 0.04 (ns) after nebulisation. Quasi static compliance were 0.92 ± 0.08 ml/cmH₂O/kg and 0.65 ± 0.09 (p<0.05) for instillation and nebulisation resp. Surfactant distribution was more uniform after nebulisation than after instillation. Cerebral bloodflow fell quickly in 8 min 64 ± 11% after instillation, during nebulisation it gradually decreased over 90 min 30 ± 15%(p<0.05).

Conclusions Surfactant nebulisation improves lung function in lung lavaged rabbits, although less than instillation. Nebulised surfactant is distributed more uniformly over the lungs and has less haemodynamic side effects than instillation.