DIAGNOSIS OF UMBILICAL-CORD COMPRESSION BY DOPPLER VELOCIMETRY

Objective: Different degrees of umbilical cord compression during labo r can be recognized by Doppler velocimetry. The purpose of this resear ch is to describe these velocimetry variations and to diagnose patholo gical cord compression by this method. Methods: When the umbilical cor d of the fetal sheep is experimentally compressed, characteristic vari ations in Doppler velocimetry waveforms occur, as previously reported. In the present study a flat Doppler transducer was used to effectivel y recognize cord compression in laboring humans. Results: The variatio ns essentially consisted of a decrease of the diastolic waveform propo rtional to the degree of compression. With severe compression, the dia stolic component is frequently absent for a large segment of the wavef orm. Characteristically, the diastolic decrease was observed only duri ng uterine contractions and was not associated with noticeable variati ons in the systolic waveform. Umbilical vein waveform also decreased. Conclusion: The clinical diagnosis of pathological cord compression ca n sometimes be difficult. Velocimetry can be an important adjuvant tec hnique in making this diagnosis.