Retrograde lower body arterial reservoir discharge underlies rapid reversal of ductus arteriosus shunting after early cord clamping at birth in preterm lambs.
Retrograde lower body arterial reservoir discharge underlies rapid reversal of ductus arteriosus shunting after early cord clamping at birth in preterm lambs.
复制标题
早产羔羊出生时早期脐带夹紧后，下体动脉库逆行放电是动脉导管分流快速逆转的基础。
DOI：
10.1152/japplphysiol.00794.2015
复制
发表时间：
2016
影响因子：
3.3
通讯作者：
J. Mynard
中科院分区：
文献类型：
--
作者：
J. Smolich;Kelly R. Kenna;J. Mynard
动脉储库（“windkessel”）功能是一种公认的生理现象，即在收缩期将部分左心室（LV）输出储存在弹性动脉中并在舒张期排出。然而，其在出生后动脉导管分流的快速逆转（从左到右）和收缩期至舒张期转变中的作用尚不清楚。为了解决这个问题，在脐带夹紧之前和之后以及随后的早期机械通气和出生后 30 分钟内，使用高保真渡越时间探针测量了 6 只麻醉的早产羔羊的导管和主动脉峡部流量。降主动脉流量计算为峡部流量和导管流量之和。从左到右的导管血流剖面与峡部和降主动脉的血流剖面相关，上半身动脉血库放电由正向舒张期峡部血流指示，逆行下半身动脉血库放电由负舒张期降主动脉血流指示。脐带夹紧后立即出现从左到右的导管分流（P < 0.001），这完全是由于新出现的逆行下半身储库放电所致，并且随着下半身储库放电增加而通气而上升（P < 0.005），辅以45秒后上身储库放电（P < 0.025）和3分钟后左心室收缩流量（P = 0.025）。 ≥15 分钟时，下半身水库流量对左向右导管分流的贡献降至 55 ± 8% (P < 0.001)，但仍高于 (P < 0.002) 左心室收缩流量 (33 ± 8%) 或上身水库流量 (12 ± 5%)。这些结果表明，下半身动脉储库逆行放电在脐带夹紧和出生时早期通气后导管分流的快速逆转和收缩期至舒张期转变中起着关键作用。
Arterial reservoir ("windkessel") function, whereby a part of left ventricular (LV) output is stored in elastic arteries during systole and discharged in diastole, is a well-established physiological phenomenon. However, its role in rapid reversal (to left-to-right) and a systolic-to-diastolic shift of shunting across the ductus arteriosus after birth is unknown. To address this question, ductal and aortic isthmus flows were measured with high-fidelity transit-time probes in six anesthetized preterm fetal lambs before and after cord clamping and subsequent early mechanical ventilation and for 30 min postbirth. Descending aortic flow was calculated as the sum of isthmus and ductal flows. Left-to-right ductal flow profiles were related to those of the isthmus and descending aorta, with upper body arterial reservoir discharge indicated by forward diastolic isthmus flow, and retrograde lower body arterial reservoir discharge by negative diastolic descending aortic flow. Left-to-right ductal shunting appeared immediately after cord clamping (P < 0.001), due entirely to newly emergent retrograde lower body reservoir discharge, and rose with ventilation via increased lower body reservoir discharge (P < 0.005), supplemented by upper body reservoir discharge after 45 s (P < 0.025) and LV systolic flow after 3 min (P = 0.025). The contribution of lower body reservoir discharge to left-to-right ductal shunting fell to 55 ± 8% at ≥15 min (P < 0.001) but remained higher (P < 0.002) than LV systolic flow (33 ± 8%) or upper body reservoir discharge (12 ± 5%). These results suggest that retrograde lower body arterial reservoir discharge plays a key role in rapid reversal and a systolic-to-diastolic shift of ductal shunting after cord clamping and early ventilation at birth.