低酸素状態におけるFHR variabilityの動態に関する研究 : 日本シバヤギ胎仔chronic preparation法を用いて The FHR Variability of "Shiba Goats" in Acute Hypoxic State

この論文をさがす

著者

    • 岡井 崇 OKAI Takashi
    • 東京大学医学部産科婦人科学教室 Department of Obstetrics and Gynecology, Faculty of Medicine, University

抄録

日本シバヤギ胎仔を用いたchronicpreparation法によって,低酸素状態に於けるfetal heartrate variabilltyの経時的な変化を検討した.variabilityは0.1msec精度のpeakdetectorを使用し,chronicallyに胎仔に装着された心電電極よりの直接誘導心電信号のR-R intewalを検出し,STV=1/(256)Σ^^256__i=1|T_<i+1>-T_i|, LTV=√<1/(256)Σ^^256__i=1(T_i-T)^2>(Ti=R-Rinterval)と定義して,マイクロコンピュータを用いて算出した.胎仔低酸素状態は,母体に一定酸素濃度ガスを吸入させることにより作製し,胎仔状況は胎仔頸動脈血ガス分析値により評価した.母体に8~10%の低酸素ガスを吸入させた軽度の低酸素状態では,STV及びLTVは共に低酸素負荷開始後10~20分で増加し,30~40分で減少したが,対照よりは高値に止まった.一方母体に4~6%の低酸素ガスを吸入させた高度の低酸素状況では,STV及びLTVは共に10~20分で増加し,30~40分では対照より低値まで減少した.STV及びLTVが対照より低値となった高度低酸素状態30~40分では,胎仔頸動脈血PO。は10~20分と差はなかったが,pHとBEは有意な低下を示した.胎仔頸動脈逝PO_2とSTV,LTVの間には,pH及びBEが低値を示す高度の低酸素状態30~40分を除くと,有意な負の相関があり,PO_2が低い程STV,LTVは増加する傾向が認められた.以上のことから,variabilityはSTV,LTV共,急性の低酸素状態では増加し,低酸素状態の持続によって代謝性アシドーシスが進行して初めて減少してくることが示唆された.

Fetal heart rate variability in an experimentally induced acute hypoxic state was investigated using chronically prepared fetal goats. FHR variability was calculated using a microcomputer with the R-R intervals of the direct fetal ECG signal measured with a peak detector. The accuracy of the peak detector was 0.1 msec. The formula for FHR variability was as follows :STV=1/(256)Σ^^256__i=1|T_<i+1>-T_i|, LTV=√<1/(256)Σ^^256__i=1(T_i-T)^2 A fetal acute hypoxic state was induced by maternal inhalation of a gas mixture low in O_2 concentration. The fetal condition was evaluated by blood gas analysis of the fetal carotid artery. In mild fetal hypoxemia due to the maternal inhalation of a gas mixture including 8-10% of O_2, both STV and LTV were increased at 10-20 minutes after the beginning of the experiment. Subsequently, both were decreased at 30-40 minutes, but maintained a level higher than that of the control. When severe fetal hypoxemia was induced by the maternal inhalation of the gas mixture containing 4-6% of 0_2, both STV and LTV increased at l0-20 minutes after induction, then decreased to a level lower than that of the control at 30-40 minutes. No significant difference in fetal PO_2 was observed between the 10-20 min. period and the 30-40 min. period of the severe hypoxemic state. But significant differences in pH and BE values were found when the 10-20 min. period and the 30-40 min. period were compared. When data showing the fetal arterial pH and BE to be significantly lower than those of the control at 30-40 min. of the severe hypoxemic state were excluded, significant negative correlations were found between PO_2 and STV and between P0_2 and LTV. It appeared that FHR variability, both STV and LTV, would increase during the acute hypoxemic state and that they would decrease to a level lower than that of the control after metabolic acidosis occurred due to continuing hypoxemia.

収録刊行物

  • 日本産科婦人科學會雜誌

    日本産科婦人科學會雜誌 36(4), 539-548, 1984

    日本産科婦人科学会

被引用文献:  2件中 1-2件 を表示

各種コード

  • NII論文ID(NAID)
    110002112271
  • NII書誌ID(NCID)
    AN00190060
  • 本文言語コード
    JPN
  • 資料種別
    雑誌論文
  • データ提供元
    CJP引用  NII-ELS  NDL-Digital 
ページトップへ