Chapter 12 - Newer Strategies for Surfactant Delivery

Abstract

The evolution to less invasive forms of respiratory support for the preterm infant with respiratory distress syndrome (RDS) has brought with it a dilemma regarding exogenous surfactant therapy. Given that an endotracheal tube is no longer placed routinely, the usual conduit for surfactant delivery is lacking. Beyond a period of brief intubation solely for surfactant administration, other techniques for delivering surfactant to a nonintubated, spontaneously breathing subject have been explored and are beginning to become part of standard care. By virtue of their individual limitations, aerosolization, pharyngeal instillation, and delivery via laryngeal mask are methods of surfactant delivery that have not yet been adopted to any degree in clinical practice, but each is being actively pursued in research. Methods of surfactant administration via brief tracheal catheterization, on the other hand, have become widely known and are being tested in many neonatal intensive care units for infants with RDS who are being managed with noninvasive modes of respiratory support. Several forms of thin catheters have been used for this purpose and are passed into the trachea under direct laryngoscopic vision, both with and without mechanical aids to guide the catheter tip through the vocal cords. Published experience of surfactant delivery by a thin catheter in observational studies and clinical trials now amounts to several thousand infants, who in most instances are treated without sedating premedication. The effect on oxygenation is rapid and sustained, suggesting effective surfactant delivery to, and distribution within, the lung. In five randomized controlled trials comparing surfactant delivery via a thin catheter (aided by spontaneous breathing) with surfactant administration via an endotracheal tube (aided by positive pressure), the former approach appeared to be more effective, with shorter durations of mechanical ventilation and oxygen therapy in some studies, and in pooled data an improvement in survival without chronic lung disease. Use of a thin catheter for surfactant delivery appears to be safe, with brief periods of bradycardia and hypoxia occurring relatively frequently, but advanced resuscitation or immediate intubation rarely required. Further studies and trials of this mode of surfactant administration are needed, but in the interim, some recommendations regarding the clinical conditions under which it could be considered are provided.