The effect of blood gas and Apgar score on cord blood cardiac troponin I.
OBJECTIVE
The aims of this study were to (a) establish a reference range for cardiac troponin I (cTnI) in the cord blood of healthy infants, and (b) investigate the effect of Apgar score, cord blood gas, gestational age, and creatine kinase (CK) and creatine kinase MB (CK-MB) fraction levels on cord blood cTnI levels.


METHODS
112 perinatal hypoxic and 84 control newborns without perinatal hypoxia were enrolled in this study. Cord blood samples were collected from the babies for arterial blood gas analysis, cTnI, CK and CK-MB measurements. Gestational age, birth weight, sex, Apgar score and history of fetal distress were recorded. Hypoxic ischemic encephalopathy (HIE) group, hypoxic but without HIE group and control groups were identified according to clinical observations during the first 72 h in the newborn unit.


RESULTS
HIE and perinatal hypoxic without HIE groups had a significantly higher cord blood cTnI level according to the control group (1.8 ng/mL (0-13), 0 ng/ml (0-1.1) and 0 ng/ml (0-0.3) respectively). Cord blood cTnI level did not have a correlation with birth weight and gestational age (r = -0.02, p > 0.05 and r = 0.08, p > 0.05 respectively). Cord blood cTnI level also had a negative correlation with pH, bicarbonate, base deficit, and Apgar score (r = -0.40, p < 0.001; r = -0.39 p < 0.001; r = -0.45 p < 0.001; r = -0.41, p < 0.001) respectively). Cord blood cTnI level showed a positive correlation with CK and CK-MB levels (r = 0.45, p < 0.001 and r = 0.37, p < 0.001 respectively). Receiver operator curve analysis revealed that the most sensitive factor for prediction of perinatal hypoxia is cord cTnI value [area under curve = 0.929]. The optimal cut-off value of cord cTnI was 0.35 ng/ml for hypoxia.


CONCLUSIONS
cTnI levels in the cord blood are not affected by gestational age and birth weight. cTnI together with CK and CK-MB has been found to be elevated in hypoxic infants compared to normal infants. Therefore cTnI may be an indicator for perinatal hypoxia in neonates.
Türker
Gülcan
G
Department of Pediatrics and Biochemistry, Faculty of Medicine Kocali University, 41900 Kocali, Turkey.
Babaoğlu
Kadir
K
Duman
Can
C
Gökalp
Ayşe
A
Zengin
Emine
E
Arisoy
Ayşe Engin
AE
D000465:Algorithms; D001034:Apgar Score; D001784:Blood Gas Analysis; D016022:Case-Control Studies; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form; D005312:Fetal Blood / Q000737:chemistry*; D005865:Gestational Age; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000097:blood*; D007231:Infant, Newborn; D007527:Isoenzymes / Q000097:blood; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D019210:Troponin I / Q000097:blood*; D014421:Turkey
D007527:Isoenzymes; D019210:Troponin I; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form