Ob1 Lec - Intrapart Asses

OBSTETRICS I – Intrapartum Assessment (Lecture by Dra Coloma) USTMED ’07 Sec C - AsM CONDUCT OF LABOR AND DELIVERY Monitoring • Maternal o Vital signs, uterine contractions, general condition • Fetal o FHR • Progress of labor o dilatation and descent Monitoring the fetus • Clinical o Auscultation of fetal heart tones o Character of the amniotic fluid • Electronic FHR monitoring = cardiotocograph ( CTG)

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o Parasympathetic Chemo- and baro-receptors

ADVANCING GESTATION, • Parasympathetic dominance (vagus nerve) • Decreasing rate • Increasing variability BASELINE RATE • Approximate mean rate rounded to increments of 5 bpm during a 10-minute segment, minimum interpretable duration of 2 min • Normal: 110-150 bpm

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Bradycardia : < 110 bpm, for at least 3 min. o moderate 80-100 o severe less than 80 Tachycardia: > 160 bpm o mild 161-180 bpm o severe > 180 bpm

!!!LOOK OUT FOR FETAL DISTRESS!!! AMNIOTIC FLUID Fetal hypoxia

Pituitary release of arginine vasopressin Increased intestinal peristalsis Passage of meconium

Auscultation • Stethoscope or Doppler devices • The maternal pulse must be counted as the FHR is counted.

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The fetal heart must be auscultated IMMEDIATELY AFTER A CONTRACTION.

** Changes in the fetal heart rate that are most likely to be ominous almost always are detectable immediately after a uterine contraction. Suspect compromise if: • FHT repeatedly below 110 bpm, even though there is recovery to 110-160 bpm • Further labor if allowed should be should be monitored electronically Recommendations In the absence of any abnormalities • First stage – every 30 min • Second stage – every 15 minutes High-risk pregnancies • First stage – every 15 minutes • Second stage – every 5 minutes Electronic FHR monitoring ADMISSION TEST (baseline trace) • Normal: o intermittent auscultation, o trace every 2 hrs • Abnormal trace or high-risk case: o continuous trace Reading EFM trace • Baseline heart rate • Baseline variability • Accelerations • Decelerations FHR regulation • Central nervous system • Autonomic nervous system o Sympathetic

BASELINE VARIABILITY • Oscillations at the baseline (jiggliness) • Figure 14-10. Edwards text Grades of baseline variability • Absent variability • Minimal (poor) +/< 5 bpm • Moderate = NORMAL 6-25 bpm • Marked > 25 bpm Periodic patterns • ACCELERATION o Visually abrupt increase above baseline o Intact neurohormonal cardiovascular control mechanisms o Favorable sign of fetal well-being •

DECELERATION

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Early – head compression Late – placental insufficiency Variable – cord compression

INTERPRETATION FIGO classification • Normal • Suspicious • Abnormal NICHD • Reassuring = FIGO normal • Non-reassuring = FIGO suspicious • Ominous = FIGO abnormal NORMAL TRACE or REASSURING PATTERN • Baseline rate 110-160 bpm • Baseline variability 6-25 bpm • Accelerations present • Decelerations absent SUSPICIOUS • Absence of accelerations and any one of the following: 1. abnormal baseline rate < 110bpm or > 150 bpm 2. reduced baseline variability < 10bpm for >40mins 3. variable decelerations without ominous features Abnormal

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Baseline < 100bpm or >170bpm Baseline variability <5 bpm for >40 mins Severe variable decelerations Severe repetitive early decelerations Prolonged decelerations Late decelerations

• Sinusoid pattern SEVERELY ABNORMAL CTG PATTERNS • Poor to absent variability • Persistent late or variable decelerations • Prolonged bradycardia

Management approach to non-reassuring FHR pattern Intrauterine Resuscitation • Administer oxygen to mother • Reposition patient • Discontinue uterine stimulamnts • Hydrate patient • Vaginal examination • Alert anesthesia, nursing and neonatal care staff • Possible abdominal delivery Intrapartum Assessment • Electronic monitor trace • Clinical context [email protected]