Noninvasive continuous monitoring of the effects of head position on brain hemodynamics in ventilated infants
Noninvasive continuous monitoring of the effects of head position on brain hemodynamics in ventilated infants
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DOI：
10.1542/peds.109.3.434
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发表时间：
2002-03-01
期刊：
影响因子：
8
通讯作者：
Cabañas, F
中科院分区：
文献类型：
--
作者：
Pellicer, A;Gayá, F;Cabañas, F
假说.仰卧位，头部处于中线位，通过防止颈部血管功能性闭塞，改善脑静脉回流。采用非侵入性方法评估通气患者的脑血容量（DeltaCBV）和脑血流量（CBF）随头部位置的变化。评估通气方式和出生体重的影响。13名常规通气和8名高频振荡通气婴儿，平均胎龄和出生体重分别为31 ± 5周（24-38）和1575 ± 803 g（560-3000），在出生后5.8 ± 7.8天（1-33）进行研究。采用近红外光谱法测量头仰卧中线位（DeltaCBVs，CBFs）和头旋转90 °（DeltaCBVlat，CBFlat）时的DeltaCBV（mL/100 g）和CBF（mL/100 g/min）。连续监测心率、外周血氧饱和度、经皮PCO 2和血压。通气设置在整个研究期间保持不变。平均DeltaCBV低于平均DeltaCBVlat，但血压、经皮PCO 2、氧合或心率未发生变化。DeltaCBV的这种变化与通气类型或出生体重无关，但在最小的婴儿（< 1200 g）中，差异往往更大（dDeltaCBV = DeltaCBVlat-DeltaCBVs）。相反，CBF没有变化。仰卧位有利于脑静脉回流，有助于防止CBV升高。这一发现在生命的最初几天可能是重要的，特别是在肺部疾病恢复的微小早产儿中，肺部顺应性改善，应避免脑静脉引流功能性阻塞。
Hypothesis. Laying supine with the head in midline position improves cerebral venous return by preventing functional occlusion of the vessels of the neck.Objectives. To assess changes in cerebral blood volume (DeltaCBV) and cerebral blood flow (CBF) with the position of the head in ventilated patients using a non-invasive method. The influence of the type of ventilation and birth weight was evaluated.Methods. Thirteen conventionally ventilated and 8 high-frequency oscillatory ventilated infants, with mean gestational ages and birth weights of 31 +/- 5 weeks (24-38) and 1575 +/- 803 g (560-3000), respectively, were studied 5.8 +/- 7.8 days (1-33) after birth. DeltaCBV (mL/100 g) and CBF (mL/100 g/min) were measured by near-infrared spectroscopy with the head in supine midline position (DeltaCBVs, CBFs) and rotated 90degrees to one side (DeltaCBVlat, CBFlat). Heart rate, peripheral saturation, transcutaneous PCO2, and blood pressure were monitored continuously. Ventilatory settings remained constant throughout the study period.Results. Mean DeltaCBVs was lower than mean DeltaCBVlat, although no changes in blood pressure, transcutaneous PCO2, oxygenation, or heart rate occurred. This change in DeltaCBV was not associated with the type of ventilation or birth weight, but the differences tended to be greater (dDeltaCBV = DeltaCBVlat-DeltaCBVs) in the smallest infants (< 1200 g). In contrast, CBF did not vary.Conclusion. The supine midline position of the head favors cerebral venous drainage and helps to prevent elevation of CBV.Speculation. This finding may be important in the first days of life, particularly in tiny preterm infants recovering from lung disease with improving lung compliance, in which functional obstruction of cerebral venous drainage should be avoided.