Blunted sympathoadrenal activation accompanies hemodynamic stability after early ventilation and delayed cord clamping at birth in preterm lambs.
Pediatr Res
; 86(4): 478-484, 2019 10.
Article
em En
| MEDLINE
| ID: mdl-31181565
ABSTRACT
BACKGROUND:
As surges in circulating norepinephrine and epinephrine have chronotropic, pressor, and inotropic effects, we tested the hypothesis that blunted rises in these catecholamines during preterm birth accompanied hemodynamic stability observed after early ventilation and delayed cord clamping (DCC), with findings compared to immediate cord clamping (ICC) and a non-asphyxial cord clamp-to-ventilation interval.METHODS:
Anesthetized preterm fetal lambs were instrumented with arterial micromanometers to obtain pressure and the maximal rate of pressure rise (dP/dtmax) as a surrogate of ventricular contractility and an aortic catheter to obtain blood samples for catecholamine assay. Fetuses were delivered and mechanically ventilated before cord clamping â¼1.5 min later (DCC, n = 9) or subjected to ICC with ventilation started â¼40 s later (n = 8).RESULTS:
Perinatal hemodynamics were stable after DCC, with greater fluctuations evident following birth after ICC (P ≤ 0.05). With DCC, circulating norepinephrine and epinephrine were unchanged after early ventilation but rose following cord clamping (P ≤ 0.01), with concentrations below the threshold for hemodynamic effects. Norepinephrine was higher in the ICC group after cord clamping and immediately after ventilation (P < 0.025), but catecholamine levels were otherwise similar between groups.CONCLUSION:
Hemodynamic stability at birth after DCC is accompanied by sub-threshold rises in circulating norepinephrine and epinephrine and thus blunted sympathoadrenal activation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Cordão Umbilical
/
Epinefrina
/
Norepinefrina
Limite:
Animals
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article