Describe Fetal Heart Rate Monitorin

EFM may be external, internal or a combination In the US, the majority of women have EFM during some or all of their labors Each modality has both pros and cons Describe Doppler Ultrasound The doppler US transducer is used to assess FHR characteristics and patterns. The transducer translates sound wave reflections into waveforms which are interpreted by a computer and then exported as an audible sound and a waveform pattern. Problems: FHR artifact, doubling, halving, and detection of maternal heart rate Current ultrasound FHR signal processing uses autocorrelation techniques and interpretation of EFM data is based on this assumption Describe internal fetal electrode The FSE directly measures the FHR by measuring R to R waves in successive QRS complexes. To place an FSE, adequate cervical dilation (usually at least 2 cm) and ROM are needed. Contraindications: placenta previa, hemophilia, maternal HIV, herpes infections, or when presenting part is not identifiable Problems: artifact, slight risk of fetal infection/injury, doubling or halving of the FHR, and pick up of the MHR with fetal demise Other relative contraindications: syphilis, gonorrhea (not recommended but may be placed if a clear benefit to a mother and fetus can be demonstrated by its use) Describe external uterine monitoring The tocotransducer (TOCO) is a pressure sensitive button-like device that detects changes in the abdominal contour when there is a uterine contraction. The specific location is determined by abdominal palpation and is ideally a smooth part of the uterus where no fetal small parts are felt. Usually this is the fundus or whatever uterine contractions are most easily palpated The TOCO can best provide: relative strength, approximate duration, and approximate frequency of contractions but cannot determine actual intensity. PALPATION IS ESSENTIAL Problems: include its inherent limitations, possibility of inverted contractions and issues with obesity Describe internal uterine monitoring IUPC allows for greater quantitative measurement of uterine contraction frequency, duration, and intensity or peak intrauterine pressure and resting tone Three types: fluid-filled (other countries), transducer-tipped, and air-coupled or sensortipped (what we used)