Brief asphyxial state following immediate cord clamping accelerates onset of left-to-right shunting across the ductus arteriosus after birth in preterm lambs
Autor: | Michael Cheung, Joseph J. Smolich, Jonathan P. Mynard, Kelly R. Kenna |
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Rok vydání: | 2020 |
Předmět: |
Systole
Physiology Hemodynamics 030204 cardiovascular system & hematology Ventricular Function Left Constriction Asphyxia 03 medical and health sciences 0302 clinical medicine Diastole Pregnancy 030225 pediatrics Physiology (medical) Ductus arteriosus medicine Animals Fetus Sheep business.industry Parturition Ductus Arteriosus Fetal Blood medicine.disease Shunting medicine.anatomical_structure Anesthesia Breathing Female medicine.symptom business |
Zdroj: | Journal of Applied Physiology. 128:429-439 |
ISSN: | 1522-1601 8750-7587 |
DOI: | 10.1152/japplphysiol.00559.2019 |
Popis: | Reversal of shunting across the ductus arteriosus from right-to-left to left-to-right is a characteristic feature of the birth transition. Given that immediate cord clamping (ICC) followed by an asphyxial cord clamp-to-ventilation (CC-V) interval may augment left ventricular (LV) output and central blood flows after birth, we tested the hypothesis that an asphyxial CC-V interval accelerates the onset of postnatal left-to-right ductal shunting. High-fidelity central blood flow signals were obtained in anesthetized preterm lambs (gestation 128 ± 2 days) after ICC followed by a nonasphyxial (∼40 s, n = 9) or asphyxial (∼90 s, n = 9) CC-V interval before mechanical ventilation for 30 min after birth. Left-to-right ductal flow segments were related to aortic isthmus and descending aortic flow profiles to quantify sources of ductal shunting. In the nonasphyxial group, phasic left-to-right ductal shunting was initially minor after birth, but then rose progressively to 437 ± 164 ml/min by 15 min ( P < 0.001). However, in the asphyxial group, this shunting increased from 24 ± 21 to 199 ± 93 ml/min by 15 s after birth ( P < 0.001) and rose further to 471 ± 190 ml/min by 2 min ( P < 0.001). This earlier onset of left-to-right ductal shunting was supported by larger contributions ( P < 0.001) from direct systolic LV flow and retrograde diastolic discharge from an arterial reservoir/windkessel located in the descending aorta and its major branches, and associated with increased pulmonary arterial blood flow having a larger ductal component. These findings suggest that the duration of the CC-V interval after ICC is an important modulator of left-to-right ductal shunting, LV output and pulmonary perfusion at birth.NEW & NOTEWORTHY This birth transition study in preterm lambs demonstrated that a brief (∼90 s) asphyxial interval between umbilical cord clamping and ventilation onset resulted in earlier and greater left-to-right shunting across the ductus arteriosus after birth. This greater shunting 1) resulted from an increased left ventricular output associated with a higher systolic left-to-right ductal flow and increased retrograde diastolic discharge from a lower body arterial reservoir/windkessel, and 2) was accompanied by greater lung perfusion after birth. |
Databáze: | OpenAIRE |
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