Neonatal Intensive Care Unit, Rambam Medical Center, Haifa, Israel.
Division of Neonatology, Department of Pediatrics, University of British Columbia, Vancouver, Canada.
J Pediatr. 2014 May;164(5):999-1004.e1. doi: 10.1016/j.jpeds.2014.01.028. Epub 2014 Feb 25.
To determine the relationship between left ventricular cardiac output (LVCO), superior vena cava (SVC) flow, and brain injury during whole-body therapeutic hypothermia.
Sixteen newborns with moderate or severe hypoxic-ischemic encephalopathy were studied using echocardiography during and immediately after therapeutic hypothermia. Measures were also compared with 12 healthy newborns of similar postnatal age. Newborns undergoing therapeutic hypothermia also had cerebral magnetic resonance imaging as part of routine clinical care on postnatal day 3-4.
LVCO was markedly reduced (mean ± SD 126 ± 38 mL/kg/min) during therapeutic hypothermia, whereas SVC flow was maintained within expected normal values (88 ± 27 mL/kg/min) such that SVC flow represented 70% of the LVCO. The reduction in LVCO during therapeutic hypothermia was mainly accounted by a reduction in heart rate (99 ± 13 vs 123 ± 17 beats/min; P < .001) compared with immediately postwarming in the context of myocardial dysfunction. Neonates with brain injury on magnetic resonance imaging had higher SVC flow prerewarming, compared with newborns without brain injury (P = .013).
Newborns with perinatal hypoxic-ischemic encephalopathy showed a preferential systemic-to-cerebral redistribution of cardiac blood flow during whole-body therapeutic hypothermia, which may reflect a lack of cerebral vascular adaptation in newborns with more severe brain injury.
确定全身治疗性低温期间左心室心输出量（LVCO）、上腔静脉（SVC）血流量与脑损伤之间的关系。
本研究使用超声心动图对 16 例中重度缺氧缺血性脑病新生儿在治疗性低温期间和治疗性低温后即刻进行研究。还将测量值与 12 例相似出生后年龄的健康新生儿进行比较。行治疗性低温的新生儿也在出生后第 3-4 天进行常规临床脑部磁共振成像检查。
治疗性低温期间 LVCO 明显降低（平均 ± 标准差 126 ± 38 mL/kg/min），而 SVC 血流量保持在预期正常范围内（88 ± 27 mL/kg/min），使得 SVC 血流量占 LVCO 的 70%。与复温后即刻相比，LVCO 在治疗性低温期间的降低主要归因于心率降低（99 ± 13 次/min 比 123 ± 17 次/min；P <.001），而此时存在心肌功能障碍。磁共振成像显示有脑损伤的新生儿在预升温时的 SVC 流量更高，与无脑损伤的新生儿相比（P =.013）。
围产期缺氧缺血性脑病新生儿在全身治疗性低温期间表现出心脏血流向全身到脑部的优先再分布，这可能反映了更严重脑损伤的新生儿中缺乏脑血管适应性。
