Endothelin in Preterm Neonates with Respiratory Distress syndrome

Abstract

Bronchopulmonary dysplasia is usually defined as a need for supplemental oxygen at 36 wks after conception (Stoll et al., 2004). Functional data on endothelin-1 action suggests that Endothelin-1 is not only a marker but also a mediator of respiratory disease in newborn infants including BPD (Kambas et al., 2011). The presumptive relation between ET-1 and respiratory distress syndrome was the stimulus for this study to characterize the relationship between serum ET-1 levels on day 3 of life and the outcome of respiratory distress in neonates. This study also aimed at determination whether levels of ET-1 can be used in prediction of development of BPD. The neonates included in the present study were all premature infants with respiratory distress syndrome, divided into 2 groups: 1. The study group: included 17 preterm neonates developed BPD with mean gestational age 30.5+1.81 weeks and mean birth weight 1.27+0.29 Kg. 2. The control group: included 22randomly selected from the group of RDS patients who were not complicated with BPD with mean gestational age 32.4+2.09 weeks and mean birth weight 1.58+0.29 Kg. Both groups were subjected to complete history taking laying stress on PROM>18 hours & mode of delivery & Apgar score , thorough clinical examination, gestational age assessment, birth weight measurement, Days of NICU stay, days on each type of oxygenation support & development of BPD. CBC with differential count, CRP were done on 1st and 3rd day of postnatal life, blood culture was done on 1st day of postnatal life. Serum Endothelin-1 level was measured by ELISA technique on day 3 of postnatal life. In our study, the frequency of BPD among the studied patients was 7.2% of total preterm neonates (233) with RDS. In the present study, cases group had significant lower gestational age 30.5+1.81weeks & birth weight 1.27+0.29 Kgcompared to the control group 32.4+2.09 weeks & 1.58+0.29 Kg respectively. In the present study, there was no significant difference between study and control groups as regards Apgar score at 1 & 5 minutes.

Also, we didn’t find significant difference between cases and control as regards gender or mode of delivery. In the present study, serum Endothelin-1 level done at day 3 of postnatal life was significantly higher in neonates who developed BPD later in life 435.29+172.83 ng/lcompared to the control group with no BPD 304.32+54.46 ng/l. In our study, there was no significant difference between cases and control groups regarding CBC & CRP done on day 1 and day 3 of life. Also, there was no significant difference between both groups regarding blood culture result, or type of organisms. In the present study, the neonates who developed BPD spent significant more days on SIMV 28.88±10.03 vs. 3.09±5.11, CPAP 19.88±8.26 vs. 5.77±2.99, other O2 therapy 5.71±5.80 vs. 2.55±1.95 and overall longer days of hospital stay 57±13.67 vs. 20.55±7.40 in comparison with neonates with non BPD. No significant difference was found between both groups as regards mortality. Neutrophil count on day 3 of life was positively correlated with level of Endothelin-1. Otherwise, there was no significant correlation between level of Endothelin-1 and other laboratory parameters. There was no significant correlation between level of Endothelin-1 and gestational age or birth weight. In our study, risk factors of BPD are lower birth weight, lower gestational age and higher serum Endothelin-1 on day 3 of life. While, PROM>18 hours and using of surfactant were not significant risk factors for BPD. We demonstrated that Endothelin-1 level at a cutoff point of 295.5 can predict BPD with sensitivity of 94% and specificity of 59%.