Abstract
OBJECTIVE
To investigate postnatal changes in the direction of blood flow through the ductus arteriosus in neonates with meconium-stained amniotic fluid, we measured preductal and postductal oxygen saturation in normal neonates, neonates with meconium-stained amniotic fluid, and a neonate with persistent pulmonary hypertension of the newborn.
DESIGN
Prospective, observational case series report.
SETTING
A single, tertiary neonatal intensive care unit.
PATIENTS
Twelve normal neonates, seven neonates with meconium-stained amniotic fluid, and a neonate with persistent pulmonary hypertension of the newborn.
INTERVENTIONS
SpO2 is simultaneously monitored in the right upper and lower limbs after birth.
MEASUREMENTS AND MAIN RESULTS
Compared with normal neonates, three neonates with meconium-stained amniotic fluid required longer than +2 SD of the mean time for the postductal SpO2 to reach 90% and/or 95%. In a neonate with meconium-stained amniotic fluid, intense crying triggered frequent decreases to <70% in the postductal SpO2 from 25 mins after birth, while the preductal SpO2 remained at 95% or above. When the other newborn with meconium-stained amniotic fluid was held in the father's arms after 98 mins, the postductal SpO2 decreased rapidly to <80%, while the preductal SpO2 remained at 95%. Thus, 5% or greater difference between the preductal and postductal SpO2 was observed from 25 mins after birth until 120 mins in all neonates with meconium-stained amniotic fluid, whereas the difference disappeared after 25 mins in 12 normal neonates. In a neonate with persistent pulmonary hypertension of the newborn who required vigorous resuscitation, 5% or greater difference between the preductal and postductal SpO2 levels was observed until 6 hrs after birth.
CONCLUSIONS
Right-to-left shunting in the ductus arteriosus may be induced readily by intense crying and rapid postural change in infants with meconium-stained amniotic fluid. It is important to monitor SpO2 at both pre- and postductal regions until 120 mins after birth in neonates with meconium-stained amniotic fluid and to subject these infants to minimal manipulations.
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