SURFACTANT NEBULIZATION PREVENTS THE ADVERSE-EFFECTS OF SURFACTANT THERAPY ON BLOOD-PRESSURE AND CEREBRAL BLOOD-FLOW IN RABBITS WITH SEVERERESPIRATORY-FAILURE

Objective: Surfactant replacement therapy for the neonatal respiratory distress syndrome has shown beneficial effects on lung function and s urvival. Recently, rapid fluctuations of haemodynamics and cerebral pe rfusion following surfactant instillation have beer, described and an association with the development of intraventricular haemorrhage has b een proposed. Therefore, alternative methods of surfactant therapy tha t reduce the effects on cerebral perfusion have to be explored. Does i nstillation of surfactant influence blood pressure and cerebral blood flow in rabbits with severe respiratory failure? Can nebulisation of s urfactant prevent these adverse effects on blood pressure and cerebral blood flow? Interventions: Surfactant (Alveofact, 100 mg/kg body weig ht) was nebulised using the MiniNEB nebuliser, or instilled, in 12 rab bits with severe respiratory failure induced by lung lavage. Assessed were blood gasses, mean arterial blood pressure (MABP) and cerebral bl ood flow over the left carotid artery, using ultrasonic transit-time f low probes. Results: Partial pressure of oxygen in arterial blood incr eased quickly after instillation, from 8.7 +/- 1.3 to 24.9 +/- 6.4 kPa after 15 min, and increased gradually during nebulisation from 8.0 +/ - 0.5 to 24.5 +/- 4.6 after 120 min. After instillation, MABP decrease d 22 +/- 5 % (in 8 min) and cerebral blood flow dropped even more: 64 +/- 9 % within 8 min. During nebulisation, MABP did not change signifi cantly and cerebral blood flow decreased gradually, 31 +/- 14 % over 9 0 min. Conclusions: Surfactant instillation was followed by a rapid de crease in MABP and an even more pronounced drop in cerebral blood flow , while during nebulisation MABP did not change and cerebral blood flo w decreased less and more gradually.