正常新生儿娩出后立即建立肺呼吸,从胎儿循环转变到新生儿循环,经历了从解剖结构到生理功能多种变化,这些变化必然反映在心脏作功及收缩时间间期上(ventricular systolic time internal简称STI)。70年代以来广泛应用多种非侵入性检查如心机械图、血流阻抗图及M型超声心动图等,后者迅速准确地测定左右心室收缩时间间期及 Normal neonatal lung ventilation immediately after delivery, from the fetal cycle to the neonatal cycle, has undergone many changes from anatomical to physiological functions, and these changes are necessarily reflected in the cardiac work and the systolic time (ventricular systolic time internal Referred to as STI). Since the 1970s, a variety of noninvasive tests such as cardiograph, flow impedance map and M-mode echocardiography have been widely used. The latter is rapid and accurate to determine the time interval between left and right ventricular contraction and