探讨压力支持通气(PSV)联合容量保证通气(VGV)模式与同步间歇指令通气(SIMV)联合VGV模式，对早产儿呼吸窘迫综合征(RDS)的疗效，以及白细胞介素(IL)-17对RDS早产儿预后判断价值。

选择2013年1月1日至2017年6月30日，广西壮族自治区妇幼保健院新生儿重症监护病房(NICU)收治的68例出生时胎龄<37周的RDS早产儿为研究对象。通过在线随机分配网站，将68例早产儿随机分为SIMV＋VGV组(n＝34，接受SIMV＋VGV模式治疗)与PSV＋VGV组(n＝34，接受PSV＋VGV模式治疗)。对所有早产儿均于出生后2～12 h内，采用肺表面活性物质治疗。采用酶联免疫吸附测定(ELISA)法，检测所有早产儿机械通气治疗前及治疗后(出生28 d后)血清IL-17水平。采用成组t检验，对2组早产儿出生胎龄、出生体重及机械通气治疗前、后血清IL-17水平等进行统计学比较。采用χ²检验或连续性校正χ²检验，对2组早产儿性别、娩出方式构成比，早产儿脑室出血、早产儿视网膜病、气管拔管后肺不张发生率，氧依赖率、再插管率、死亡率及母亲产前激素使用率等进行比较。绘制机械通气治疗前血清IL-17水平预测RDS早产儿预后(死亡、存活)的受试者工作特征(ROC)曲线，计算ROC曲线下面积(ROC-AUC)，根据约登指数最大原则，确定机械通气治疗前血清IL-17水平预测RDS早产儿预后的最佳临界值，并计算其敏感度和特异度。本研究遵循的程序符合2013年修订的《世界医学协会赫尔辛基宣言》要求。

①2组早产儿出生胎龄、出生体重，性别、娩出方式构成比，早产儿机械通气治疗前血清IL-17水平及母亲产前激素使用率等一般临床资料比较，差异均无统计学意义(P>0.05)。②PSV＋VGV组RDS早产儿出生28 d后的氧依赖率、气管拔管后肺不张发生率、再插管率分别为5.9%(2/34)、8.8%(3/34)、2.9%(1/34)，均显著低于SIMV＋VGV组的23.5%(8/34)、35.3%(12/34)、67.6%(23/34)，2组比较，差异均有统计学意义(χ²＝4.221、6.928、31.167，P＝0.040、0.008、<0.001)。③SIMV＋VGV组、PSV＋VGV组早产儿治疗后血清IL-17水平分别为(1 740.8±522.6)pg/mL与(519.3±187.4)pg/mL，均显著低于治疗前的(2 227.3±882.9)pg/mL与(2 397.1±795.9)pg/mL，差异均有统计学意义(t＝11.035、2.578，P<0.001、＝0.016)；并且SIMV＋VGV组早产儿治疗后血清IL-17水平显著高于PSV＋VGV组，2组比较，差异有统计学意义(t＝－12.83，P<0.001)。④机械通气治疗前，死亡早产儿血清IL-17水平显著高于存活早产儿，并且差异有统计学意义(t＝3.146，P＝0.009)。机械通气治疗后，死亡与存活早产儿血清IL-17水平均显著下降，但是死亡早产儿血清IL-17水平仍然显著高于存活早产儿，差异亦有统计学意义(t＝4.000，P＝0.002)。⑤机械通气治疗前血清IL-17水平预测RDS早产儿预后的ROC-AUC为0.810(95%CI：0.627～0.993，P＝0.001)。根据约登指数最大原则，机械通气治疗前血清IL-17水平预测RDS早产儿预后的最佳临界值为2 759.1 pg/mL，而且预测RDS早产儿预后的敏感度为81.8%，特异度为91.2%。

PSV联合VGV模式治疗RDS早产儿，可显著降低其出生28 d后氧依赖率、气管拔管后肺不张发生率、再插管率，降低RDS早产儿血清IL-17水平。RDS早产儿机械通气治疗前血清IL-17水平对其预后具有预测价值。

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.

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.

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%.

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.