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Non-invasive measurements of ductus arteriosus flow directly after birth
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  • Published on:
    Answer to: "Physiolgical transition ?"
    • Jeroen J van Vonderen, PhD-student
    • Other Contributors:
      • Arjan B. te Pas, Stuart B. Hooper and Arno A.W. Roest

    Response to "Physiological transition ?"

    Thank you for your response to our research "Non-invasive measurements of ductus arteriosus flow directly after birth".

    We agree with Dr. Hutchon that a caesarian section can influence the respiratory transition of a newborn infant. As such, our results reflect the transition after elective caesarian section with cord clamping within 1 minute after birth, which...

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    Conflict of Interest:
    None declared.
  • Published on:
    Physiolgical transition ?
    • David J Hutchon, Emeritus Consultant Obstetrician Darlington Memorial Hospital

    Dear Sir,

    We congratulate the authors on this study of neonatal transitional circulation performed so quickly after birth. The authors state that the ductal flow ratio reported in their study reflects pulmonary and haemodynamic transition and can be used to monitor neonatal transition in healthy infants. The implication is that their study describes a physiological transition in healthy term infants, but we question that this is the case.

    Delivery by elective caesarean section is not a physiological birth but it does permit the neonate an atraumatic birth. We are particularly concerned that the transition may have been disrupted by the timing of cord clamping which was between 30 and 60 seconds. While this is considered delayed cord clamping by some, most guidelines recommend a minimum of 60 seconds have elapsed before the circulation is interrupted by cord clamping. The WHO advises 3 minutes.(1) Not all of the babies in the series had established respiration before clamping and cord clamping before the onset of respiration has a marked effect on cardiac output.(2) It is therefore questionable that the mean and range of results published represents a normal transition in healthy infants.

    The normal fetal circulation is well described with the two ventricles pumping in parallel, the right ventricular output being significantly more than the left and the flow across two shunts, right to left in the ductus arteriousus and right to left across the foram...

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    Conflict of Interest:
    I am a co-inventer of the LifeStart trolley