BACKGROUND: Perinatal asphyxia is associated with cardiac dysfunction secondary to myocardial ischaemia. Cardiac troponin I (cTnI) is a marker of myocardial necrosis. Raised concentrations in the blood are related to perinatal asphyxia and increased morbidity. OBJECTIVE: To assess porcine myocardial damage from enzyme release during hypoxaemia induced global ischaemia, and subsequent resuscitation with ambient air or 100% O(2). To investigate whether CO(2) level during resuscitation influences myocardial damage. DESIGN: Newborn piglets (12-36 hours) were exposed to hypoxaemia by ventilation with 8% O(2) in nitrogen. When mean arterial blood pressure had fallen to 15 mm Hg, or base excess to < -20 mmol/l, the animals were randomly resuscitated by ventilation with either 21% O(2) (group A, n = 29) or 100% O(2) (group B, n = 29) for 30 minutes. Afterwards they were observed in ambient air for another 150 minutes. During resuscitation, the two groups were further divided into three subgroups with different CO(2) levels. ANALYSIS: Blood samples were analysed for cTnI, myoglobin, and creatine kinase-myocardial band (CK-MB) at baseline and at the end of the study. RESULTS: cTnI increased more than 10-fold (p < 0.001) in all the groups. Myoglobin and CK-MB doubled in concentration. CONCLUSION: The considerable increase in cTnI indicates seriously affected myocardium. Reoxygenation with 100% oxygen offered no biochemical benefit over ambient air. CK-MB and myoglobin were not reliable markers of myocardial damage. Normoventilation tended to produce better myocardial outcome than hyperventilation or hypoventilation.
BACKGROUND:Perinatal asphyxia is associated with cardiac dysfunction secondary to myocardial ischaemia. Cardiac troponin I (cTnI) is a marker of myocardial necrosis. Raised concentrations in the blood are related to perinatal asphyxia and increased morbidity. OBJECTIVE: To assess porcine myocardial damage from enzyme release during hypoxaemia induced global ischaemia, and subsequent resuscitation with ambient air or 100% O(2). To investigate whether CO(2) level during resuscitation influences myocardial damage. DESIGN: Newborn piglets (12-36 hours) were exposed to hypoxaemia by ventilation with 8% O(2) in nitrogen. When mean arterial blood pressure had fallen to 15 mm Hg, or base excess to < -20 mmol/l, the animals were randomly resuscitated by ventilation with either 21% O(2) (group A, n = 29) or 100% O(2) (group B, n = 29) for 30 minutes. Afterwards they were observed in ambient air for another 150 minutes. During resuscitation, the two groups were further divided into three subgroups with different CO(2) levels. ANALYSIS: Blood samples were analysed for cTnI, myoglobin, and creatine kinase-myocardial band (CK-MB) at baseline and at the end of the study. RESULTS:cTnI increased more than 10-fold (p < 0.001) in all the groups. Myoglobin and CK-MB doubled in concentration. CONCLUSION: The considerable increase in cTnI indicates seriously affected myocardium. Reoxygenation with 100% oxygen offered no biochemical benefit over ambient air. CK-MB and myoglobin were not reliable markers of myocardial damage. Normoventilation tended to produce better myocardial outcome than hyperventilation or hypoventilation.
Authors: S E Lipshultz; N Rifai; S E Sallan; S R Lipsitz; V Dalton; D B Sacks; M E Ottlinger Journal: Circulation Date: 1997-10-21 Impact factor: 29.690
Authors: D Fugelseth; W B Børke; K Lenes; I Matthews; O D Saugstad; E Thaulow Journal: Arch Dis Child Fetal Neonatal Ed Date: 2005-05 Impact factor: 5.747