森 晃¹, 和泉 俊一郎¹, 佐分 義之¹, 鈴木 昇²

Akira MORI¹, Syunichiro IZUMI¹, Yoshiyuki SABURI¹, Noboru SUZUKI²

¹東海大学産婦人科, ²鈴木医院

¹Tokai Univessity, School of Medicine, ²Suzuki Clinic

キーワード : diameter pulse waveform, fetal circulation, ultrasonic echo tracking method

複雑な胎児循環を評価するためには, 心拍数, 末梢循環抵抗, 血圧, 心収縮能などの情報を必要とする. 超音波ドプラや胎児心拍数変動がこれまでその評価に使用されてきた. 超音波エコートラッキング法による血管壁の動き(血管径拍動波形)を計測する方法が胎児循環(胎児血圧)評価に新しい可能性を開いてきている. 直接内圧波形と血管径拍動波形は, 相似形を示す. 胎児下行大動脈, 下大静脈の血管径拍動波形の記録が可能であり, 胎児発育過程における血圧変動を計測することが可能である.

Evaluation of complex cardiovascular hemodynamics requires information concerning heart rate, peripheral resistance, blood pressure, and cardiac contractility. Cardiovascular assessment is usually based on Doppler ultrasonographic and cardiotocographic evidence. Fetal circulation must be studied noninvasively. Noninvasive measurement of pulsatile diameter changes (pulse waveform) in the fetal descending aorta (DA) and inferior vena cava (IVC) during fetal development using an ultrasonic phase-locked echo tracking system at a sampling frequency of 5000 Hz provides important physiologic information. Simultaneous recording of pressure and diameter pulse waveforms in humans has shown their concordance. These waveforms may be used to represent the direction and relative magnitude of changes in arterial and venous pressure, and thus make it possible to monitor variation in blood pressure in cardiac afterload occurring through fetal development.