Ch. 14.
This presentation is the property of its rightful owner.
Sponsored Links
1 / 25

Ch. 14. INTRAPARTUM ASSESSMENT PowerPoint PPT Presentation


  • 156 Views
  • Uploaded on
  • Presentation posted in: General

Ch. 14. INTRAPARTUM ASSESSMENT. 부산백병원 산부인과 R1 손영실. # Intrapartum Fetal Assessment. INDEX. 1. Internal Electronic Fetal Hearth Rate Monitoring 2. External (Indirect) Electronic Fetal Heart Rate Monitoring 3. Fetal Heart Rate Pattern - Baseline Fetal Heart Activity.

Download Presentation

Ch. 14. INTRAPARTUM ASSESSMENT

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Ch 14 intrapartum assessment

Ch. 14.

INTRAPARTUM ASSESSMENT

부산백병원 산부인과

R1 손영실


Ch 14 intrapartum assessment

# Intrapartum Fetal Assessment


Ch 14 intrapartum assessment

INDEX

1. Internal Electronic Fetal Hearth Rate

Monitoring

2. External (Indirect) Electronic Fetal Heart Rate

Monitoring

3. Fetal Heart Rate Pattern

- Baseline Fetal Heart Activity


Ch 14 intrapartum assessment

◎ Continuous graph paper of fetal heart rate

- Potentially diagnostic in assessing pathophysiological

events affecting the fetus

① Electronic fetal heart rate monitoring provided accurate

information

② The information was of value in diagnosing fetal

distress

③ It would be possible to intervene to prevent fetal death

or morbidity

④ Continuous electronic fetal heart rate monitoring was

superior to intermittent methods


Ch 14 intrapartum assessment

INTERNAL ELECTRONIC

FETAL HEART RATE MONITORING

◎ Measured by attaching a bipolar spiral electrode

directly to the fetus

- the wire electrode penetrate the fetal scalp and the

second pole is the metal wing on the electrode

- vaginal body fluids create a saline electrical bridges

that completes the circuits and permits measurement

of the voltage differences between two poles

◎ The electrical fetal cardiac signal – P wave, QRS

complex, and T wave – is amplified and fed into a

cardiotachometer for heart rate calculation


Ch 14 intrapartum assessment

INTERNAL ELECTRONIC

FETAL HEART RATE MONITORING

◎ Electrical cardiac complexes detected by electrodes

include those generated by mother

- maternal ECG signal is approximately five times stronger

than fetal ECG

- but, its amplitude is diminished when it is recorded

through fetal scalp electrode

① In a live fetus

- this low maternal ECG signal is detected but masked

by the fetal ECG

② If the fetus is dead

- the weaker maternal signal will be amplified by the

automatic gain control circuitry in the fetal monitor

and displayed as “fetal” heart rate


Ch 14 intrapartum assessment

INTERNAL ELECTRONIC

FETAL HEART RATE MONITORING

Standard fetal monitor tracing of heart rate using fetal scalp electrode shown at top. Bottom two tracings represent cardiac electrical complexes detected from fetal scalp and maternal chest wall electrodes. Spiking of the fetal rate in the monitor tracing is due to the premature atrial contractions. (F=fetus; M=mother; PAC=fetal premature atrial contraction.)


Ch 14 intrapartum assessment

INTERNAL ELECTRONIC

FETAL HEART RATE MONITORING

Placental abruption: The fetal scalp electrode detected heart rate first of the dying fetus. After fetal death, the maternal ECG complex is detected and recorded.


Ch 14 intrapartum assessment

EXTERNAL (INDIRECT) ELECTRONIC

FETAL HEART RATE MONITORING

◎ External detectors to monitor

fetal heart and uterine action

⇒ the necessity for membrane

rupture and uterine invasion

may be avoided

◎ FHR (fetal heart rate)

⇒ detected through the

maternal abdominal wall

using the ultrasound Doppler

principle


Ch 14 intrapartum assessment

EXTERNAL (INDIRECT) ELECTRONIC

FETAL HEART RATE MONITORING

◎ Consist of the unit

① transducer - emits ultrasound

② sensor - detect a shift in frequency of the reflected

sound

• transducer

⇒ placed on the maternal abdomen at a site where fetal

heart action is best detected

• coupling gel must be applied

(∵ air conducts ultrasound poorly)

• the device is held in position by a belt

• care should be taken that maternal aortic ulsations are not

confused with fetal cardiac motion


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

◎ Scaling factors (by the workshop)

- 30 bpm per vertical cm (range, 30 to 240 bpm)

- 3 cm/min chart recorder paper speed

# Baseline fetal heart activity

1) Rate

• with increasing fetal maturation

→ the heart rate decreases

• baseline FHR decreased

an average of 24 bpm (between 16 weeks and term)

approximately 1 bpm/week

• 16 weeks : 160 bpm

40 weeks : 150 bpm


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

• during 3rd trimester, normal mean FHR is between 120

and 160 bpm

baseline FHR less than 110 bpm

⇒ bradycardia

baseline FHR greater than 160 bpm

⇒ tachycardia

sympathetic system

⇒ accelerator influence

parasympathetic system

⇒ decelerator factor mediated via vagal slowing

of heart rate


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

A. Bradycardia

• mild bradycardia

: 100 ~ 119 bpm

- observed in 2% of monitored pregnancies, averaged

about 50 minutes in duration

- attributed to head compression from occiput posterior

or transverse positions, particularly during 2nd stage

labor

• moderate bradycardia

: 80 ~ 100 bpm

• severe bradycardia

: less than 80 bpm


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

• other cause

: congenital heart block and serious fetal

compromise

Fetal bradycardia measured with a scalp electrode in a pregnancy complicated by placental abruption and subsequent fetal death.


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

B. Tachycardia

• mild : 161 ~ 180 bpm

severe : 181 bpm or more

• cause

maternal fever from amnionitis (m/c)

fetal compromise

cardiac arrhythmias

parasympathetic (atropine) or sympathomimetic

(terbutaline) drugs

• fetal compromise with tachycardia

⇒ concomitant heart rate deceleration (key point)


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

2) Beat-to-beat variability

• an important index of cardiovascular function

• regulated largely by the autonomic nervous system

A. Short-term variability

• instantaneous change in FHR from one beat to the next

• time interval between cardiac systoles


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

B. Long-term variability

• the oscillatory changes that occur during the course

of 1 minute

- result in waviness of the baseline

- normal frequency : 3 ~ 5 cycle/min


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

• physiological and pathological processes

(affect or interfere with beat-to-beat variability)

① fetal breathing

② fetal body movements

③ advancing gestation

- after 30 wks,

fetal inactivity

→ diminished variability

activity

→ variability increased


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

④ maternal acidemia

- cause decreased fetal beat-to-beat variability

⑤ analgesic drugs given during labor

- diminished variability

(narcotics, barbiturates, phenothiazines,

tranquilizer)

- MgSO4

: decrease variability only in the third hour of

the infusion

: be deemed clinically insignificant

: blunted the frequency of acceleration


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

Grades of baseline fetal heart rate variability. (1) Undetectable, absent variability; (2) minimal≤5 bpm variability; (3) moderate (normal), 6 to 25 bpm variability; (4) marked,>25 bpm variability; (5) sinusoidal pattern.


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

3) Cardiac arrhythmia

◎ first suspected signs

- baseline bradycardia

- tachycardia

- abrupt baseline spiking (m/c)


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

4) Sinusoidal heart rates

◎ true sinusoidal pattern

- observed with serious fetal anemia

• from D-isoimmunization

• ruptured vasa previa

• fetomaternal hemorrhage

• twin to twin transfusion

◎ insignificant sinusoidal pattern

• administration of meperidine, morphine, alphaprodine,

and butorphanol

• amnionitis, fetal distress, and umbilical cord

occlusion


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

◎ definition

① stable baseline heart rate of 120 ~ 160 bpm with

regular oscillations

② amplitude of 5 ~ 15 bpm (rarely greater)

③ frequency of 2 ~ 5 cycles/min long-term variability

④ fixed or flat short-term variability

⑤ oscillation of the sinusoidal waveform above or

below a baseline

⑥ absence of accelerations


Ch 14 intrapartum assessment

FETAL HEART RATE PATTERNS

◎ pathophysiology of sinusoidal patterns is unclear

Sinusoidal fetal heart rate pattern associated with maternal intravenous meperidine administration. Sine waves are occurring at a rate of 6 cycles/min.


Ch 14 intrapartum assessment

감사합니다.


  • Login