[The cardiotocographic score of Hammacher in computer analysis]

After the quantitative, fully computerized evaluation of cardiotocography (CTG) after G.S. Dawes had yielded reliable results, an investigation was to be carried out to see whether a semiquantitative CTG analysis together with a CTG score (K. Hammacher) produced similarly useful results, too.

The last 120 directly recorded intrapartum CTG minutes (HP 8040A, 80300A) of 393 vaginally delivered fetuses were evaluated by simple means (magnifying glass, dividers, Plexiglas sliding caliper). The number of turning points, the bandwidth and the mean frequency level were determined for each individual CTG minute. Further, all decelerations were registered numerically (start, end and depth of decelerations), both qualitatively (28 key positions) and quantitatively. The CTG score of Hammacher was programmed in Fortran IV and integrated as a subroutine into a larger software system.

Score 4 was noted most frequently (35.4%) during the last 30 min ante partum. The score values 10, 11, 12, 14, 15, 16, 17 and 18 were not seen at all. On the basis of the 'percent distribution of points' of the three score components, it could be shown that the decelerations were numerically overrepresented in comparison with the two other factors. The rank correlation between the score value and the relevant blood pH of the umbilical artery was highly significant (p << 0.001). The scoring of the CTG rises perceptibly only above pH 7.15. The sensitivity of score < or =4 is 87.2% for pH 7. 10 and 100% for pH 7.00.

The interpretation of the cardiotocogram by means of the Hammacher score, which is based on a semiquantitative evaluation, yields clinically useful results. These may further be improved by changing the score structure. Beside the fully computerized analysis, the semiquantitative CTG analysis is able to finally determine the reliability of this monitoring method.