CONTROVERSIES - SYNTHETIC OR NATURAL SURFACTANT TREATMENT FOR RESPIRATORY-DISTRESS SYNDROME - THE CASE FOR SYNTHETIC SURFACTANT

The choice of surfactant for prophylactic or ''rescue'' treatment of R DS is dependent on a number of different considerations: a) Randomised controlled trials have shown that natural and synthetic surfactants i ncrease survival whether used prophylactically or as rescue. No statis tically significant difference in mortality has been shown when the tw o types of surfactant have been compared in randomised trials. b) Poss ible adverse effects of surfactant treatment include: (i) Intraventric ular haemorrhage (IVH). Two randomised trials of natural surfactant ha ve shown a significant increase in IVH with natural surfactant treatme nt. In meta-analyses, IVH has not been significantly reduced despite d ecreased mortality. Acute changes in cerebral haemodynamics and EEG ha ve been demonstrated following natural surfactant administration. Thes e changes are less marked or absent with synthetic surfactant. (ii) Th e antigenicity of animal surfactant has not been shown to have clinica l consequences. (iii) Prions are infectious particle (resistant to som e sterilising techniques) which are responsible for slow encephalopath ies, some of which have crossed species barriers. Contamination of bov ine surfactant with prion particles from nervous tissue has been a the oretical concern. Synthetic surfactant has no risk of prion contaminat ion. (iv) One natural surfactant has been shown to contain platelet ac tivating factor (PAF). Synthetic surfactants can be made with greater chemical purity. c) Natural surfactants improve oxygenation faster tha n do synthetic surfactants. A rapid effect is not necessarily better w ith respect to later outcomes. d) Synthetic surfactant preparations ar e generally cheaper per dose than natural surfactant preparations. Syn thetic surfactant treatment increases survival with less concern about adverse effects and generally lower cost per dose than natural surfac tant.