5.2b Monitoring Techniques

Question 1

Intermittent Auscultation

Answer 1

• Listening to FHR at periodic intervals

Done with

• Doppler Ultrasound
• Ultrasound Stethoscope
• DeLee-Hillis Fetoscope

Benefits
- Easy to use, inexpensive, less invasive than EFM, more comfortable, permits freedom of movement

Question 2

Procedure for Intermittent Auscultation

Answer 2

• Leopold maneuver to identify fetal position/presentation
• Apply ultrasonic gel if using doppler
• Place device over maximal intensity/clarity of FHR (usually over fetal back)
• Count maternal pulse while listening to FHR to differentiate the two
• Count FHR for 30-60 seconds after uterine contraction to identify baseline
• Auscultate FHR before, during and after contraction to identify increase/decrease in FHR

Question 3

Frequency for Low Risk Women Not Receiving Oxytocin

Answer 3

Latent (<4cm) - Hourly
Latent (4-5cm) - 15-30 min
Active (>6cm) - 15-30 min
Second Stage Passive - 15 min
Second Stage Active - Every 5-15 min

Question 4

IA Uterine Activity

Answer 4

• Done through palpation
  Intensity
• Mild, Moderate, Strong
  Duration
• Measured in seconds from beginning to end
  Frequency
• Measured in minutes from beginning of 1 contraction to the beginning of the next.
• Hand over fundus after contraction to evaluate uterine resting tone and relaxation between contractions (Soft/Hard)

Question 5

Electronic Fetal Monitoring

Answer 5

• Assesses adequacy of fetal oxygenation

External - Assesses FHR and UA (Uterine Activity)
Internal - Spinal electrodes to assess FHR and Intrauterine Pressure Catheter (IUPC) to assess UA

Question 6

Ultrasound Transducer (FHR)

Answer 6

Uses high frequency sound waves

Weak Signals caused by

• Obesity
• Occiput posterior position of fetus
• Anterior attachment of placenta

Question 7

Toco Transducer

Answer 7

• Measures UA
• Placed over fundus
• Measures Frequency and Duration but not Intensity
• Obesity can skew results
• May not work properly for pre-term

Question 8

Internal Monitoring

Answer 8

• More accurate and not affected by maternal size or fetal movement
• Membranes must be ruptured
• Cervix must be dilated at least 2-3 cm
• Presenting part of fetus must be low enough to attach spiral electrodes and IUPC
• Measures Frequency, Duration, and Intensity

Question 9

Montevideo Units (MVU)

Answer 9

• Subtract baseline uterine pressure from peak contraction pressure for each contraction in 10 minute window.
• Add each pressure together of each contraction within the 10 minutes
• MVU between 80-120 is spontaneous labor

Question 10

Interpretation of Monitor

Answer 10

• FHR displayed on top
• UA displayed on bottom

Each small square is 10 seconds
Each larger box is a minute