Issues in Neonatal Ventilation and Surfactant Therapy

Natural surfactant extract versus synthetic surfactant for neonatal respiratory distress syndrome
Surfactant preparations are now widely used and have been credited with recent improvements in overall infant mortality (Horbar 1993b, Schwartz 1994). A wide variety of surfactant preparations have been developed and tested. These include synthetic surfactants and surfactants derived from animal sources. Although clinical trials have demonstrated that both synthetic surfactants and natural surfactant preparations are effective, comparison in animal models has suggested that there may be greater efficacy of natural surfactant products, perhaps due to the protein content of natural surfactant (Tooley 1987).

Objectives: To compare the effect of synthetic surfactant to natural surfactant in premature infants at risk for or having respiratory distress syndrome.

Reviewers’ conclusions: Both natural surfactant extracts and synthetic surfactant extracts are effective in the treatment and prevention of respiratory distress syndrome. Comparative trials demonstrate greater early improvement in the requirement for ventilator support, fewer pneumothoraces, and fewer deaths associated with natural surfactant extract treatment. Natural surfactant may be associated with an increase in intraventricular hemorrhage, though the more serious hemorrhages (Grade 3 and 4) are not increased. Despite these concerns, natural surfactant extracts would seem to be the more desirable choice when compared to currently available synthetic surfactants.

Early versus delayed selective surfactant treatment for neonatal respiratory distress syndrome

Objectives: To compare the effects of early vs. delayed selective surfactant therapy for newborns intubated for respiratory distress within the first two hours of life. Planned subgroup analyses include separate comparisons for studies utilizing natural surfactant extract and synthetic surfactant.

Reviewers’ conclusions: Early selective surfactant administration given to infants with RDS requiring assisted ventilation leads to a decreased risk of acute pulmonary injury (decreased risk of pneumothorax and pulmonary interstitial emphysema) and a decreased risk of neonatal mortality and chronic lung disease compared to delaying treatment of such infants until they develop established RDS.

Multiple versus single dose natural surfactant extract for severe neonatal respiratory distress syndrome

Objectives: To compare the effect of multiple doses of natural surfactant extract to single doses of natural surfactant extract in premature infants with established respiratory distress syndrome.
Reviewers’ conclusions: In infants with established respiratory distress, a policy of multiple doses of natural surfactant extract results in greater improvements regarding oxygenation and ventilatory requirements, a decreased risk of pneumothorax and a trend toward improved survival. The ability to give multiple doses of surfactant to infants with ongoing respiratory insufficiency leads to improved clinical outcome and appears to be the most effective treatment policy.
Nasal intermittent positive pressure ventilation (NIPPV) versus nasal continuous positive airway pressure (NCPAP) for preterm neonates after extubation

Background: Previous randomised trials and meta-analyses have shown nasal continuous positive airway pressure (NCPAP) to be a useful method of respiratory support after extubation. However, infants managed in this way sometimes “fail” and require endotracheal reintubation with its attendant risks and expense. Nasal intermittent positive pressure ventilation (NIPPV) is a method of augmenting NCPAP by delivering ventilator breaths via the nasal prongs. Older children and adults with chronic respiratory failure have been shown to benefit from NIPPV and the technique has been applied to neonates. However severe side effects including gastric perforation have been reported and clinicians remain uncertain about the role of NIPPV in neonatology. It has recently become possible to synchronise delivery of NIPPV with the infant’s own breathing efforts which may make the modality more useful in this patient group.

Objectives: To determine whether the use of NIPPV as compared to NCPAP, in the preterm infant extubated following a period of intermittent positive pressure ventilation, decreases the rate of extubation failure without adverse effects.

Reviewers’ conclusions: Implications for practice: NIPPV is a useful method of augmenting the beneficial effects of NCPAP in preterm infants. Its use reduces the incidence of symptoms of extubation failure more effectively than NCPAP. Within the limits of the small numbers of infants randomised to NIPPV there is a reassuring absence of the gastrointestinal side effects that were reported in previous case series.

Implications for research: Future trials should enrol sufficient infants to detect differences in important outcomes such as chronic lung disease and gastrointestinal perforation. The impact of synchronisation of NIPPV on the technique’s safety and efficacy should be established in future trials.

(All citations from The Cochrane Library, Issue 2, 2004)