Myhrman P, Granerus G, Karlsson K, Lundgren Y
Scand J Clin Lab Invest. 1982 Oct;42(6):513-20.
Impedance cardiography was used to study cardiodynamic changes throughout normal pregnancy. Stroke volume, heart rate and cardiac output were determined in fourteen normal primigravidae from early pregnancy until 6-25 weeks after delivery. To elucidate the influence of the patient's position on cardiac output, measurements were made in the supine as well as in the left and right lateral positions. Stroke volume and cardiac output increased up to the 28th week of pregnancy and then decreased during late pregnancy. These changes seemed to be independent of the patient's position. After delivery a further reduction in cardiac output due to a significant decrease in heart rate was found. No significant differences in cardiac output were found between right and left lateral position. However, during pregnancy as well as after delivery, cardiac output measured by impedance cardiography was significantly higher in the supine position than in the lateral positions. Thus, the impedance method does not seem to be reliable in measuring absolute values of stroke volume and cardiac output but may be used for relative measurements during pregnancy.
采用阻抗心动图研究正常妊娠全过程的心脏动力学变化。测定了14例正常初孕妇从妊娠早期直至产后6 - 25周的每搏输出量、心率和心输出量。为阐明患者体位对心输出量的影响，分别在仰卧位以及左侧卧位和右侧卧位进行了测量。每搏输出量和心输出量在妊娠第28周前增加，随后在妊娠晚期下降。这些变化似乎与患者体位无关。产后发现由于心率显著下降，心输出量进一步降低。右侧卧位和左侧卧位的心输出量未发现显著差异。然而，在妊娠期间以及产后，通过阻抗心动图测量的心输出量在仰卧位显著高于侧卧位。因此，阻抗法在测量每搏输出量和心输出量的绝对值时似乎不可靠，但可用于妊娠期间的相对测量。
