Impact of the Introduction of Minimally Invasive Surfactant Therapy in Preterm Infants at 25 to 28 Weeks’ Gestation

Introduction: There is an increasing use of nasal continuous positive airway pressure (CPAP) as the primary mode of respiratory support in extremely preterm infants to avoid the adverse effects of mechanical ventilation. However, these infants are at risk of CPAP failure requiring intubation and surfactant treatment for respiratory distress syndrome (RDS). A technique of providing surfactant without endotracheal intubation via a thin catheter has been described. This provides minimally invasive surfactant therapy (MIST) in preterm infants with RDS, thus avoiding intubation and ventilation. The aim of this study was to investigate the impact of the introduction of MIST in preterm infants at 25 to 28 weeks’ gestation in the tertiary neonatal intensive care unit at the Middlemore Hospital in Auckland, New Zealand.

Materials and Methods: Preterm infants born between 25⁺⁰ and 28⁺⁶ days of gestation admitted to the neonatal unit in Middlemore Hospital who were stabilized on CPAP from birth were included. Those intubated and ventilated within 1 hour after birth were excluded. Epoch 1 consisted of infants born from January 2010 to December 2013; this was the period before introduction of MIST. Infants would be intubated if FiO₂ exceeded 0.40 or if there was persistent respiratory acidosis, and surfactant would be given via endotracheal tube and mechanical ventilation was continued. Epoch 2 was from January 2014 to June 2017 where infants with RDS could be given surfactant via MIST if FiO₂ exceeded 0.30, and infants would be intubated if FiO₂ continued to escalate or if there was persistent respiratory acidosis following MIST.

Results: There were 90 infants in Epoch 1 and 84 infants in Epoch 2. Median birth weight was 1,017 versus 1,122 g (p = 0.12). Median gestational age was 27 versus 28 weeks (p = 0.032). All comparisons were adjusted for birth weight, gestation, gender, and antenatal steroid use. There was a significant reduction in number of infants requiring ventilation by age 72 hours, 21.1 versus 7.1% (p = 0.017). There was a significant increase in number of infants treated with surfactant 20 versus 34.5% (p = 0.014). The median age of first surfactant therapy reduced from median of 12 to 3 hours (p = 0.008). There was a trend to reduction in mortality, but this was not significant, 10 versus 2.4% (p = 0.23). There was a nonsignificant reduction in chronic lung disease (CLD) 34.4 versus 26.2% (p = 0.3) and CLD/death 42.2 to 28.6% (p = 0.23). Frequency of other morbidities remained unchanged.

Conclusion: The introduction of MIST in preterm infants at 25 to 28 weeks’ gestation has resulted in lower incidence of CPAP failure and earlier age of treatment with surfactant.

Keywords: preterm, respiratory distress syndrome, CPAP surfactant

Table 1 Impact of the introduction of MIST in preterm infants at 25 to 28 weeks’ gestation

	Epoch 1 2010 to 2013 (n = 90)	Epoch 2 2014 to Jun 2017 (n = 84)	p-Value
Birthweight (gms) median (IQR)	1017 (882–1226)	1122 (925–1275)	0.12
Gestational age (wks) median (IQR)	27 (26–28)	28 (27–28)	0.032
Gender (M:F)	44:46	46:38	0.45
Antenatal steroids (none/<24h/complete)	10/20/60	5/14/65	0.27
Ventilation by age 72 hrs n (%)	19 (21.1)	6 (7.1)	0.017
Any ventilation n (%)	34 (37.8)	14 (16.7)	0.012
Surfactant n (%)	18 (20)	29 (34.5)	0.014
Age of first surfactant (hrs) median (IQR)	12 (4.7–20)	3 (1.9–4.8)	0.008