Objective: Non-invasive positive pressure ventilation has increasingly been chosen as the primary ventilation mode in respiratory distress syndrome (RDS) in preterm infants. In order to further understand the application of various non-invasive positive pressure ventilation modes, we compared the advantages and disadvantages of three modes as a primary mode of ventilation in premature infants with RDS.
Method: From December 2011 to March 2013, 107 preterm infants with RDS who received intubation-pulmonary surfactant (PS) -extubation in our NICU were randomly divided (by means of random number table) into three groups based on the primary mode of ventilation: nasal continuous positive airway pressure [NCPAP, n = 39, male/female ratio was 27/12, mean gestational age (GA) was (32.0 ± 2.1)weeks, mean birth weight (BW) was (1752 ± 457)g], bi-level positive airway pressure [BiPAP, n = 35, male/female ratio was 25/10, GA was (31.4 ± 2.0) weeks, BW was (1530 ± 318) g], and synchronized bi-level positive airway pressure [SBiPAP, n = 33, male/female rate was 25/8, GA was (31.5 ± 2.2) weeks, BW was (1622 ± 447) g]. Ventilation settings including FiO(2) were adjusted according to transcutaneous SPO(2) monitoring or blood gas analysis. Various settings and adverse events were recorded as well. The main parameter was the FiO(2) at 24 h post-positive-pressure ventilation. Statistical analyses were performed using χ(2) test, rank sum test, one-way analysis of variance for least-significant difference value, paired-sample t-test, two related sample Wilcoxon signed rank sum test and Logistic regression.
Result: The PaCO(2) (mmHg, 1 mmHg = 0.133 kPa), oxygen index (OI) at 12-24 h, and FiO(2) at 24 h post-ventilation in BiPAP and SBiPAP groups were lower than that in NCPAP groups with significant difference (44 ± 9 and 45 ± 9 vs. 50 ± 9, 2.76 ± 0.96 and 2.79 ± 0.60 vs. 3.24 ± 0.72, 0.34 ± 0.10 and 0.35 ± 0.07 vs. 0.39 ± 0.07; F = 4.456, 5.146 and 4.123; P = 0.014, 0.007 and 0.019, respectively). There was no significant difference between BiPAP and SBiPAP groups. There was no significant difference among three groups (all P > 0.05) in the following events: respiratory index (RI) at 12-24 h post-ventilation, abdominal distension, period of non-invasive ventilation, ratio of intubation for invasive ventilation if failed noninvasive ventilation, air-leak syndrome, neonatal necrotizing enterocolitis, periventricular-intraventricular haemorrhage, bronchopulmonary dysplasia, retinopathy of prematurity, mortality rate after 36 h of age or rate of abandon for discharge. The independent risk factors for failure of non-invasive positive pressure ventilation were gender, gestational age, antepartum steroid at 24 h before birth to 7 d, and birth weight, with the OR (95% confidence interval) being 14.120 (1.135, 175.662), 2.862 (1.479, 5.535), 61.084 (3.115, 1 198.031), and 8.306 (1.488, 46.383), respectively.
Conclusion: As the primary mode of ventilation in premature infants with RDS, both BiPAP and SBiPAP are more beneficial than NCPAP in improving oxygenation and reducing CO(2) retention without increasing the incidence of adverse events.