The foundations of surfactant therapy have been under study for almost one hundred years. Dating back to 1929, Kurt von Neergaard created experiments suggesting a correlation between pulmonary surfactant and a newborn’s first breath (Halliday, 2008). Thirty years later, Avery and Mead reported on the deficiency of this surface-active material in the lungs of preterm babies with respiratory distress syndrome (RDS) (Halliday, 2008). These findings along with subsequent research have supported the fact that surfactant replacement therapy is now a standard and widely used therapy for the treatment of RDS (Mirhadi, Keyvan & Khairollah, 2016).
Surfactant is a complex mixture of lipids and proteins that reduces surface tension (Niemarkt, Hutten & Kramer, 2017). Surfactant replacement therapy is most commonly administered to the neonatal population. This is due to the fact that preterm neonates produce insufficient amounts of surfactants, leading to decreased lung compliance and increased alveolar surface tension (Mirhadi et al., 2016). Method of therapy administration, as well as type of surfactant used, may differ. There are two main types of surfactant: natural and synthetic (Mirhadi et al., 2016). Natural surfactants have exhibited a superior prognosis when compared to synthetic surfactants (Mirhadi et al., 2016). The natural proteins improve surfactant activity, furthermore stabilizing the film/liquid interface (Tridente, Martino & De Luca, 2019). Natural surfactants include bovine (calf) and porcine (pig) derived versions. Although the effectiveness of natural surfactant has been established in the RDS population, it is unclear as to which natural surfactant is preferable (Mirhadi et al., 2016).
Tridente and colleagues (Tridente et al., 2019) underwent an exhaustive review of published data to determine whether porcine or bovine surfactants should be preferred to treat RDS in preterm neonates. This meta-analysis compared poractant-a (internationally marketed porcine surfactant) with all bovine surfactants (Tridente et al., 2019). Outcomes across fourteen articles showed that neonates treated with poractant-a (at 200mg/kg) expressed respiratory outcomes such as a lower incidence of air leaks and less need for retreatment (Tridente et al., 2019). The meta-analysis concluded that porcine derived natural surfactant yielded respiratory measures exceeding that of all bovine derivatives (Tridente et al., 2019). A Cochrane meta-analysis published in 2015 also supports these results, stating “neonates treated with porcine minced surfactant had more favorable outcomes than those treated with bovine minced lung surfactant.” (Singh, Halliday, Sevens, Suresh, Soll & Rojas-Reyes, 2015, p. ). Ramanathan and colleagues (Ramanathan, Rasmussen, Gerstmann, Finer & Sakar, 2004) established that treatment with poractant-a in preterm neonates less than 35 weeks gestation resulted in a rapid reduction in supplemental oxygen administration compared to bovine therapy patients. Additional measures such as days spent on ventilator and time spent admitted to hospital also favour the poractant-a surfactant therapy (Baroutis, 2004). Poractant-a use also demonstrated a reduced rate of mortality in comparison to neonates treated with bovine surfactant (Cheng-Hwa Ma & Sze, 2012). Additionally, neonates treated with poractant-a are more likely to only need one dose of surfactant, providing economic advantages as well (Halliday, 2008).
Arguably one of the biggest advances in respiratory care was the introduction of surfactant therapy, as it was associated with an overall reduction of 6% in infant mortality in the United States alone (Halliday, 2008). This statistic along with the latter paragraph express the importance and value surfactant therapy holds in saving lives within the neonatal population.
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