排尿モデルによる尿流曲線の近似

Abstract

尿道の慣性抵抗, 摩擦抵抗と弾性抵抗を考慮にいれた排尿モデルを, 実際に測定した尿流曲線に適用して尿流曲線の近似式をえた。それにより尿道および計算上の膀胱内圧の特性を示す係数を求めることができた。また, 尿流曲線に対応する計算上の膀胱内圧曲線も結果的に描くことができた。尿流曲線と膀胱内圧線のピークはずれており, 位相差を示した。正常例では排尿中の膀胱内圧の変化量は異常例よりも大きかった。排尿モデルとして膀胱内圧を駆動力とし, 慣性抵抗, 摩擦抵抗と弾性抵抗の3つの抵抗を全抵抗とする系を考えると, 尿流曲線をかなり精密に近似できることがわかった

One hundred and two uroflowmetric curves obtained from adult men were approximated to investigate the individual micturition quantitatively. We obtained a differential equation under the hypothesis that the factors concerned with micturition are the vesical pressure as the driving force and inertia of urine, friction resistance and elasticity of urethra as resistance. Using one of the solutions of this differential equation, we could approximate the uroflowmetric curves for normal and abnormal micturition. Furthermore, we could describe the calculated vesical pressure curve from the differential equation. There was a lag in the phase of the calculated vesical pressure curve against the uroflowmetric curve, which was considered to appear according to the resistance due to both inertia of urine and elasticity of urethra. The mean value of the difference of the calculated vesical pressure during micturition in normal cases was larger than that in abnormal cases. This suggests that it is necessary to maintain a high vesical pressure during micturition in abnormal cases, to maintain a small difference of the vesical pressure. In conclusion, we approximated the uroflowmetric curves, described the calculated vesical pressure curves and estimated them quantitatively.