Basic Fetal Monitoring

Basic Fetal Monitoring

Southwest Washington Perinatal Education Consortium

Kathleen Murray, CNM, MN, RN

Objectives

• Identify the components of a fetal heart rate pattern: baseline, variability, accelerations, decelerations, periodic, and non-periodic changes

• Discuss maternal and fetal physiology and how it influences fetal heart rate patterns

• Differentiate criteria for reassuring and non-reassuring fetal heart rate patterns

Fetal Heart Rate Monitoring Techniques

• Auscultation

• Fetoscope

Auscultation

• Fetoscope Low tech Need quiet room

Auscultation

• Doppler

Motion detector Portable Some models are

made for underwater use (in tub)

Doppler

Doppler used throughout pregnancy and labor

Auscultation Benefits

• Detects baseline• FHR rhythm and dysrhythmias• Hear changes in fetal heart rate• Differentiates maternal from fetal heart rate

Auscultation Limitations

• Not continuous• No printout or computer record• Can’t demonstrate variability• Requires some 1:1 nurse-time• May be limited by position of mother

Fetal Heart Rate Monitoring Techniques

• Electronic Fetal Monitoring

External Internal

Fetal Monitoring Strip

What’s the Purpose

of Fetal Monitoring???

Purpose of Electronic Fetal Monitoring

• Identify reassuring signs of fetal well-being• Screen for non-reassuring signs of a fetus

who is at risk

Benefits of External Fetal Monitoring (EFM)

• Noninvasive• Paper document• Demonstrates variability• Less labor intensive

Limitations of EFM

• Restricts patient movement• Measures cardiac motion, is not ECG• Doubling or half-count of FHR possible• Might pick up maternal HR instead

Internal Fetal Monitoring

• Spiral electrode (FSE) provides direct ECG• Measures interval between R waves • Produces very accurate picture of FHR

Benefits of Internal Monitoring (Using FSE)

• Accurate measure of FHR and variability• May detect dysrhythmias• Can allow for more patient movement

Limitations of FSE

• Membranes must be ruptured to use• Risk of infection• If fetus has died, may pick up maternal

heart rate accidentally

Uterine Activity Monitoring

• External: tocotransducer• Detects frequency and length, not strength• Requires palpation to assess strength of

contractions

Uterine Monitoring

• Note the normal-looking UC first

• Then baseline rises and next few UC’s seem high (false)

• External UC monitor does not accurately show strength

External Uterine Monitoring

• BENEFITS• Noninvasive• Provides

documentation of UC frequency and duration

• LIMITATIONS• Does not measure

strength of contraction, nor resting tone of uterus

• Difficult to use in maternal obesity, in some positions

Monitoring With Internal Uterine Pressure Catheter (IUPC)

• Accurate measure of uterine pressure• Contraction strength, and resting tone• Measured in mmHg• Accurate timing of FHR changes in relation

to UC’s

IUPC

• INDICATIONS• External reading not

adequate• Labor dystocia• Fetal distress• Amnioinfusion for

cord compression

• RISKS• Infection• Uterine perforation• Placental injury• Extraovular placement

IUPC placement

Are You Worried?

Fetal Heart Rate Monitoring• Baseline, rounded up to nearest 5 bpm• Variability• Accels and Decels• Periodic changes (with UC’s)• Non-periodic changes (spontaneous)

Fetal Heart Rate Monitoring

• Baseline• Normal: 110-160 bpm• Tachycardia : >160 bpm for >10 minutes• Bradycardia: <110 bpm for >10 minutes

Variability

• Characteristic of FHR baseline• Smoothness, or roughness of the line• Very important characteristic of FHR, must

be present for reassuring strip

Variability

• Assessed in between UC’s and periodic changes

• Absent: undetectable• Minimal: 1-5 bpm amplitude• Moderate: 6-25 bpm (normal) • Marked: >25 bpm (also called saltatory)

Causes of Decreased Variability

• Non hypoxic causes• Fetal sleep (20 min)• Medications• Tachycardia (such as

from maternal fever)• Fetal anomaly• dysrhythmia

• Hypoxic causes• Uteroplacental

insufficiency• Cord compression• Mat. Hypotension• Tachysystole• Abruption• Tachycardia

Interventions

• Determine cause• Position change• IV fluids• Oxygen 10 liters snug face mask• Stop or turn down pitocin• Place internal FSE• Notify MD/CNM without delay

Sinusoidal Pattern

• Not to be confused with variability!!• Regular, sine-like wave pattern with amplitude of

5-15 bpm above and below baseline• Ominous in most cases, requires prompt

intervention, usually immediate C-section• Usually caused by severe fetal anemia, can be

from hypoxia, or briefly from narcotic dose

Causes of Increased Variability

• Uteroplacental insufficiency or• Cord Compression or• Fetal Activity and• A compensatory response to a mild hypoxic

event

Interventions

• Determine cause• Position change• Assess fetal response

Accelerations

• Caused by sympathetic nervous system response to fetal movement or stimuli, normal and reassuring, rules out acidosis

• But, periodic accels, with UC’s are mild cord compression

Criteria for Accelerations

• <32 weeks gestation, stays 10 beats above baseline for at least 10 seconds

• For > 32 weeks, acceleration stays 15 beats above baseline for at least 15 seconds

Early Decelerations

• Caused by pressure on fetal head, vagal response

• Uniform, mirrors contraction• Gradual onset, reaches nadir >30 sec.• Reaches nadir at peak of UC, returns to

baseline by the end of UC• Benign

Variable Decelerations

• Caused by cord compression, baroceptor response quickly slows FHR to compensate

• Abrupt onset, reaches nadir < 30 sec.• Decel. Of >15 bpm lasting > 15 sec., and

return to baseline < 2 minutes

Causes of Variable Decelerations

• Intrauterine• Nuchal cord, or body

entanglement• Oligohydramnios• Rupture of membranes• Short cord or true knot• Occult prolapse of

cord

• Maternal conditions• Positioning• Second stage labor

with descent• Monoamniotic

multiple gestation

Variable Decel. Characteristics

• Shape, depth, and duration vary (not uniform), can be V, W, U shaped

• Timing may vary• Watch for fetal compromise• increasing baseline• loss of variability• slow return to baseline

Interventions

• Vag. Exam rule out prolapse

• Position change• IV fluids• Oxygen 10 l/mask• Turn pit off or down• Assess fetal response• Call MD/CNM

• Same list as with late decels, except added vag exam, and

• If ordered, start amnioinfusion

Late Decelerations

• Caused by uteroplacental insufficiency• Fetus runs low on oxygen during a UC• Maternal, placental, or fetal cause of

inadequate oxygen to fetal heart• Often indicates metabolic acidosis• Needs urgent response

Late Decel. Characteristics

• Always associated with a UC, with delay in timing

• Gradual decrease from baseline to nadir >30 seconds

• Nadir occurs after peak of UC• Depth of decel usually only 5-30 bpm

Interventions

• Lateral position, (usually left works best)

• Increase IV fluids• Oxygen 10 l/mask• Stop pitocin• Call MD/CNM

• Determine cause, and correct if possible

• Assess fetal response• Prepare for possible

delivery

Prolonged deceleration

• Deceleration of >15bpm, lasting more than 2 minutes, less than 10 minutes

• Measured from onset until return to baseline• Often is long, exaggerated variable• Cause often: cord compression, or tachysystole, or maternal hypotension

Interventions

Without Looking at Your Notes, Tell Me What You’d Do for a Prolonged

Decel?Hint: Same List As for lates

Interventions

• Lateral position• Increase IV fluids• Oxygen 10 l/mask• Stop pitocin• Call MD/CNM

• Determine cause, and correct

• Assess fetal response• Prepare for possible

delivery, moving into O.R. by 3rd minute if not resolving

Uterine Contractions

Contraction Monitoring

• Interval “how far apart are they?”• Duration “how long do they last?”• Resting tone: how does the uterus feel between

contractions• Intensity “how hard are they?” mild moderate strong

Electronic Fetal Monitoring

Strip Interpretation

Systematic Review of strip

• Baseline Normal is ___________• Variability Expressed as _________• AccelerationsPresent, or absent

• DecelerationsPresent, or absent3 major types:________________________________________________• Contraction pattern

Begin….

• By looking at what is reassuring on the strip

• Then, note any concerning features

Documentation

• Critical job for you, your hospital, the patient

• Chart as if the hard copy of your strip will get lost later…10% or more of all strips do

• Clear, concise language• Institution-specific• Standards of care

Documentation on the strip

• Label/write patient name, date etc.• Events, actions, nursing interventions• Calls to MD, CNM, nursery, etc.• What not to write on strip

Auscultation documentation

• Rate• Rhythm (regular, irregular)• Increases in rate (audible accels)• Decreases (audible decels, and the timing)

FHR Documentation Intervals

Auscultation or EFM• Low risk patient: Active labor every 30 minutes 2nd stage every 15 minutes• High risk patient Active labor every 15 minutes 2nd stage every 5 minutes

If Confusing Pattern

• Complex patterns, combination of 2 types of decelerations sometimes exist

• Focus on: baseline stable or not, variability and accels, whether decels are periodic or not, timing related to UC’s, abruptness of change from baseline

• Sometimes helps to draw decel in your chart notes

Documenting Uterine Activity

• What four characteristics do you note?• ____________________• ____________________• ____________________• ____________________

Example of Charting

2100-FHR baseline 130, accels to 160 present, no decels. UC’s q 2.5 minutes x 60-80 seconds, palpate moderate, resting tone soft. K Jones, RN

Non-reassuring FHR Patterns

• Document the following: Pattern Nursing intervention Evaluation of response Notification of MD or CNM

Example of Charting

• 2120- FHR 170, minimal variability, no accels, no decels. UC’s q 2.5-3 minutes x 80-130 seconds, peaks 40-50mmHg, resting tone 25.

• Positioned Left-lateral, O2 on 10 l per tight mask, pitocin turned off, IV rate increased. No change in FHR pattern. Phoned Dr James with report of non-reassuring strip and asked him to come now to evaluate. He stated he is on his way. Explained to patient and husband. K Jones, RN

Conclusion

• Methods of fetal monitoring• Components of FHR, and uterine activity• Causes of various changes• Nursing interventions• Systematic review of strip• Documentation

References

Abcdefm:electronic fetal monitoring , Curran, Carol, and Torgersen, Keiko, Colley Avenue Copies & Graphics, Virginia Beach, VA, 2006, pp.31,158-9, 167,169,170,178-9.

Fetal Heart Monitoring Principles & Practices 4th ed., Lyndon, Audrey et al editors, AWHONN, Kendall/Hunt, Dubuque, Iowa, 2003.

NCC Monograph, Vol 2, No. 1, 2006, National Certification Corporation, pages 6-11.