Less invasive surfactant administration versus endotracheal surfactant instillation followed by limited peak pressure ventilation in preterm infants with respiratory distress syndrome in China: study protocol for a randomized controlled trial
Authors: Zhu Jiajun , Bao Yingying , Du Lizhong , Huang Huafei , lv Qin , Jiang Yejun , Dai Yuxuan , Chen Zhijun , Shi Jingyun , Shi Yongyan , Yang Chuangzhong , Mei Hua , Jiang Hong , Sun Yanhui , Sun Xuemei 
Published: June 2020

Abstract
Background
Less invasive surfactant administration (LISA) is a way of giving surfactant without endotracheal intubation and has shown to be promising in reducing the incidence of bronchopulmonary dysplasia (BPD) in preterm infants. However, the mechanism underlying its beneficial effect and variations in the technique of administration may prevent its widespread use. This trial aims to evaluate the effects of two methods of surfactant administration, LISA or endotracheal surfactant administration followed by low peak pressure (LPPSA) ventilation, in preterm infants with respiratory distress syndrome (RDS).

Methods
The LISA Or Low Peak Pressure trial is to be conducted in 14 tertiary neonatal intensive care units in China. A total of 600 preterm infants born with gestational age between 250/7 and 316/7 weeks and with a primary diagnosis of RDS will be involved in the study. Infants will be randomized to the LISA or LPPSA group when surfactant therapy is indicated. Primary outcomes include mortality, severity of bronchopulmonary dysplasia at 36 weeks of postmenstrual age (PMA), and mechanical ventilation (MV) in the first 72 h of life. Secondary outcomes include the days of MV, duration of all sorts of non-invasive respiratory support, fraction of inspired oxygen, oxygen saturation before and after surfactant administration, and time required to perform the procedure for surfactant administration. The incidence of comorbidities, including retinopathy of prematurity (ROP), necrotizing enterocolitis (NEC), intraventricular hemorrhage (IVH), hemodynamically significant patent ductus arteriosus (hsPDA), pneumothorax, and massive pulmonary hemorrhage within 48 h of surfactant administration, and the failure rates of each technique will be determined.

Discussion
Data from recent systematic review and meta-analysis have suggested a possible improvement in outcomes of preterm infants with RDS by the LISA technique. However, robust evidence is lacking. Why LISA plays a potential role in reducing respiratory morbidity, mainly BPD in preterm infants, remains unclear. The possible explanations are the active and uninterrupted delivery of continuous positive airway pressure during the LISA procedure and the avoidance of complications caused by intubation and relatively high pressure/volume ventilation following surfactant administration. We hypothesized that LISA’s effectiveness lies mainly in avoiding relatively high-pressure positive ventilation immediately following surfactant administration. Thus, this multicenter randomized controlled trial will focus on issues of endotracheal intubation and the pressure/volume used during conventional surfactant administration. The effectiveness, safety and comorbidities of preterm infants following LISA or LPPSA will be evaluated.

Trial registration
Chinese Clinical Trial Registry: ChiCTR1900020970. Registered on 23 January 2019.