Effects of mechanical ventilation in treatment of respiratory distress syndrome in premature infants

Abstract

Objective To investigate the treatment outcomes of pressure support ventilation (PSV) combined with volume guarantee ventilation (VGV) mode and synchronized intermittent mandatory ventilation (SIMV) combined with VGV mode on respiratory distress syndrome (RDS) in premature infants, and explore predictive value of interleukin (IL)-17 in predicting prognosis of premature infants with RDS. Methods A total of 68 premature infants with RDS and gestational ages at birth <37 weeks in neonatal intensive care unit (NICU) of Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region from January 1, 2013 to June 30, 2017 were enrolled as research subjects. The subjects were randomly assigned into SIMV+ VGV group (n=34, received SIMV combined with VGV treatment) and PSV+ VGV group (n=34, received PSV combined with VGV treatment) by online random assignment. All premature infants were treated with pulmonary surfactant within 2 to 12 hours after birth. Serum IL-17 levels of all preterm infants were measured by enzyme-linked immunosorbent assay (ELISA) before and after mechanical ventilation (28 days after birth). Statistical analysis was performed on the gestational age at birth, birth weight, and serum IL-17 levels before and after treatment by independent-samples t test between two groups. Chi-square test or continuous correction chi-square test was performed to compare the constituent ratios of gender and delivery mode, incidences of intraventricular hemorrhage, retinopathy of prematurity and atelectasis after tracheal intubation, and rates of oxygen dependence and tracheal reintubation, and mortality of premature infants, and maternal prenatal hormone use rate, etc. between two groups. To predict prognosis (death or survival) of preterm infants with RDS, receiver operating characteristic (ROC) curve of serum IL-17 level before mechanical ventilation treatment in predicting prognosis (death or survival) of premature infants with RDS was plotted. And the area under ROC curve (ROC-AUC) was calculated. The optimal cut-off point of serum IL-17 level before mechanical ventilation treatment was obtained when Youden index reached the maximum value. And predictive parameters such as sensitivity and specificity were also calculated. The procedures followed in this study was in line with the World Medical Association Declaration of Helsinki revised in 2013. Results ①There were no significant differences in gestational age at birth, birth weight, gender ratio, constituent ratio of delivery mode, maternal antenatal hormone use rate, serum IL-17 level before mechanical ventilation treatment between two groups (P>0.05). ②In PSV+ VGV group, the oxygen dependence rate at 28-day after birth, incidence of atelectasis after tracheal intubation, and tracheal intubation rate were 5.9% (2/34), 8.8% (3/34), and 2.9% (1/34), respectively, which all were significantly lower than those in SIMV+ VGV group 23.5% (8/34), 35.3% (12/34), and 67.6% (23/34), and all the differences were statistically significant (χ2=4.221, 6.928, 31.167; P=0.040, 0.008, <0.001). ③In SIMV+ VGV group and PSV+ VGV group, the serum IL-17 levels after mechanical ventilation treatment were (1 740.8±522.6) pg/mL and (519.3±187.4) pg/mL, respectively, which were significantly lower than those before treatment (2 227.3±882.9) pg/mL and (2 397.1±795.9) pg/mL, respectively, and both the differences were statistically significant (t=11.035, 2.578; P<0.001, =0.016), and serum IL-17 level after treatment in SIMV+ VGV group was significantly higher than that in PSV+ VGV group, and the difference also was statistically significant (t=-12.83, P<0.001). ④Before mechanical ventilation treatment, the average serum IL-17 level of dead premature infants was significantly higher than that of survival ones, and the difference was statistically significant (t=3.146, P=0.009). After treatment, the average serum IL-17 level of all premature infants decreased significantly, however, the average serum IL-17 level of dead premature infants was still significantly higher than that of survival premature infants, and the difference was statistically significant (t=4.000, P=0.002). ⑤The ROC-AUC of serum IL-17 level before mechanical ventilation treatment in predicting prognosis of premature infants with RDS was 0.810 (95%CI: 0.627-0.993, P=0.001). According to the maximum principle of Youden index, the optimal cut-off value of serum IL-17 level before mechanical ventilation treatment in predicting prognosis of premature infants with RDS was 2 759.1 pg/mL, and sensitivity was 81.8%, and specificity was 91.2%. Conclusions PSV combined with VGV mode can significantly reduce the oxygen dependence rate at 28-day after birth, the incidence of atelectasis after tracheal intubation and reintubation rate, and also reduce the serum IL-17 level in premature infants with RDS. The serum IL-17 level before mechanical ventilation treatment has predictive value for the prognosis of premature infants with RDS. Key words: Respiratory distress syndrome, newborn; Respiration, artificial; Volume guarantee ventilation; Pressure support ventilation; Interleukins; Prognosis; Infant, premature