Diagnostic value of endothelin - 1 [ET - 1] in perinatal asphyxia

ABSTRACT

Asphyxia denotes progressive hypoxia, accumulation of carbon dioxide, and acidosis. It may result in permanent brain injury or death. Perinatal asphyxia is one of the leading causes of perinatal morbidity and mortality. Hypoxic ischaemic encephalopathy [HIE] is the effect of perinatal asphyxia on the brain. Research works are in a continuous challenge for construction of new methods whether radiological or laboratory for diagnosis and assessment of perinatal asphyxia. It is the leading cause of perinatal morbidity and mortality and disability later on among survivors. Endothelin-1 [ET-1] is a novel potent vasoconstrictor endothelium derived peptide. It is formed of 21 aminoacids. It is encoded by a single gene localized on chromosome[6]. ET-1 immunoreactivity has been detected in the kidney, spleen, skeletal muscle, lung as well as in plasma. Recent clinical observations have been shown that circulating [ET-1] is increased in certain diseases such as acute renal failure, surgical stress, acute myocardial infarction and intracranial hemorrhage. The present study was intended to assess plasma [ET-1] level in newborns with HIE in the first day of life to uncover the role of [ET-1] during perinatal asphyxia. This study was performed on 70 newborns [50 cases with perinatal asphyxia and 20 healthy control newborns. The 50 cases were 27 males and 23 females with gestational age between [32 to 40] wks. They were grouped into stage 1 [n=15], stage II [n=22] and stage III [n=13] according to Sarnat and Sarnat classification. Inclusion criteria included. Low Apgar scores at 1st and 5th min and needed active resuscitation. Low pH [<7.2] of cord blood and presence of neurological manifestation infants were excluded if they had early neonatal sepsis. All newborns [cases and controls] were subjected to thorough maternal and neonatal history taking and meticulous clinical examination of the newborn. The results revealed that, most asphyxiated cases were complicated by respiratory distress, maternal hypertension, advanced maternal age and difficult labor, C.S and ventouse delivery. There was marked decrease in Apgar score in 1, 5, 10 and 20 min. There were hyponatraemia, hyperkalaemia, and hypocalcemia. These electrolyte changes were also more evident in stage [III-HIE]. Hypoxia, hypcrcarpia and acidosis were more evident in stage III. Plasma ET-1 was significantly increased in asphyxiated infants. It was negatively correlated with PaO2, HCO3 and Apgar score which reveal the strong relation between plasma ET-1 level and degree of asphyxia. Elevated plasma ET-1 was more evident in stage III asphyxia and patients with ventilatory support. Conclusion, ET-1 can be considered as a marker for HIE diagnosis. It can be considered also an indicator for degree of HIE. So, it has a diagnostic and prognostic value for evaluation of perinatal asphyxia. However, we recommend further studies to emphasize these results: