新生儿寒冷损伤综合征心输出量与脑肾动脉血流速度动态研究

EFFECTS OF COLD INJURY ON CARDIACOUTPUT,CEREBRAL AND RENAL ARTE-RIAL BLOOD FLOW VELOCITIS IN NEONATES

采用多普勒方法，对１６例新生儿寒冷损伤综合征患儿的心输出量、颈内动脉及两侧肾动脉血流速度进行了动态研究。结果表明，低温（≤３２℃）时心输出量降低伴有脑、肾动脉血流速度显著降低。颈内动脉平均流速为正常的５０％～６０％；肾动脉平均流速为正常的６０％。复温至３５℃时，心输出量已恢复至接近正常，颈内动脉血流速度达到正常值的７０％，而肾动脉血流速度无明显增加，需复温至３７℃才能达正常水平。脑、肾动脉血流在低温及复温过程中变化的不一致，提示寒冷损伤时新生儿有类似“潜水反射”机制参与，内脏相对缺血。

ffects of cold injury on cardiac output,internalcarotid arterial blood flow velocities (CBFV)and renalblood flow velocities(RBFV)were examined in 16neonates by pulsed Doppler technique. Hypothermia(core body temperature≤32℃)significantly decreasedcardiac output,CBFV and RBFV,Mean CBFV andRBFV in hypothermic neonates were only 50%～60%and 60%of control values, respectively. Rewarmingof the body to 35℃significantly increased CBFV com-pared with hypothermic state,but RBFV was not re-covered until a normal body temperature (37℃) wasreached. The discrepancy in changes between CBFVand RBFV during rewarming indicates that dive reflexlike mechanism is probably involved in the pathophysi-ology of neonatal cold injury,The results suggest thata specific reduction in visceral perfusion is present inneonatal hypothermia,and an enteric feeding shouldbe withheld before the restoration of normal body tem-perature.