CTG

Introduction

Aboubakr Elnashar

Benha university, Egypt

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1. Fetal response to hypoxia

2. Fetal monitoring in labor

3. Indications

4. Types of CTG monitoring

5. Important considerations

6. Why care about CTG

7. Steps

8. Components of CTG paper

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1. FETAL RESPONSE TO HYPOXIA

Hypoxia ← ↓ Blood Flow

↓↓

↓ PO2 ↑PCO2

↓ ↓

Metabolic acidosis ← Respiratory acidosis

⇓

Redistribution of blood flow to vital organs

Bradycardia, and slightly ↓cardiac output

↓oxygen consumption

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↓ ↓

FHR, variability FHR,↓ variability,

retained / ↑ rate, decelerations

⇓⇓ Compensated State Decompensated State

(Normal cortical functions (Decrease cerebral

cerebral oxygenation oxygenation, eventual

maintained cellular damage

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Important definitions

Hypoxia: Decreased po2 level in tissues.

Hypoxima: Decreased po2 level in blood.

Acidosis: Decreased PH in tissues.

Acidemia: Decreased PH in blood.

Ashyxia: Hypoxia + acidosis.

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2. FETAL MONITORING IN LABOR

1. Intermittent auscultation

2. CTG Fetal electrocardiography

Scalp stimulation

Vibroacoustic stimulation

3. Fetal scalp sampling PH determination

4. Fetal pulse oximetry

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1968:

Hammacher and Hewitt-Packard, developed 1st

commercial fetal monitor.

Assessment of fetal well being during late

pregnancy and labor.

Expectations at the time

it would lead to a decreased incidence of perinatal

death and cerebral palsy.

Reality

has fallen very short of these expectations

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3. INDICATIONS OF CONTINUOUS EFM

1. High-risk pregnancies where there is an

increased risk of perinatal death, cerebral palsy

or neonatal encephalopathy.

2. Where oxytocin is being used for induction or

augmentation of labour.

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The admission CTG test

Commonly used screening test consisting of a short

(usually 20 minutes) recording of FHR and uterine

activity performed on the mother's admission to the labour

ward.

Admission CTG not be used for women who are low risk

on admission in labour. (Cochrane SR, 2012)

{:an increase in the incidence of CS without evidence of

benefit}.

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4. TYPES OF CTG MONITORING

External monitoringInternal monitoring

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CTG is best regarded as a screening tool (not

diagnostic)

High negative predictive value (Specificity=

Healthy, 98%)

>98% of fetuses with a normal CTG will be OK

Poor positive predictive value (Sensitivity) with

unnecessary operative intervention for f distress.

50% of fetuses with an abnormal CTG will be

hypoxic and acidotic but 50% will be OK

CTG should always be interpreted in its clinical

context and backed by fetal blood sampling PRN

5. IMPORTANT CONSIDERATIONS

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Normal CTG indicate that there were

no abnormalities

no indication for intervention.

CTG could be viewed as part of Defensive Medicine (permanent record)

Abnormal/suspicious CTG may provide:

an evidence that inappropriate or lack of tt: litigation

In spite of it is poor indicator of overall fetal status but it remains The best we have

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Disadvantages

Insufficient understanding of the (patho-)physiologic background

Confusion due to the many influences on the FH rhythm

Lack of agreement on how, when, and whom to monitor

Lack of uniform classification systems

Poor positive predictive value (Sensitivity): unnecessary operative intervention for f distress.

Substantial intra- and inter-observer variation regarding the interpretation

Contributes to medico-legal vulnerability

Primarily qualitative information (pattern recognition)

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7. STEPS

External monitoring

• Explain the processes and reasons for the CTG, verbal

consent

Ask to empty her bladder

Ascertain the lie, presentation and position of the fetus

Place and secure the FHR ultrasound transducer over the

fetal anterior shoulder

Place and secure the toco-transducer on the fundus

Position the woman: comfortable: sitting upright or laterally

Ensure ultrasound contact is maintained

Document on the FHR pattern: date and time, gestation,

indication for monitoring, maternal pulse/30 min

Record the FHR pattern at the rate of 1cm or 3cm/min

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Internal monitoring

Membranes: absent

Cervix: dilated enough.

1. Fetal scalp electrode:

A device that monitors FHR.

consists of a small clip that is placed on the

fetal scalp.

The electrode is attached to a cable.

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2. Intrauterine pressure catheter (IUPC):

directly measures the strength of contractions

and resting tone in millimeters of Hg.

It provides more accurate information as to the

strength of contractions than an external monitor

(tocodynameter).

can also be used to instill an amnioinfusion.

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8. COMPONENTS OF FETAL HEART

RATE PAPER

Date

Time

Paper speed: 3 cm/minute. There are 6 in one minute between the dark lines so each little box represents ten (10) seconds.

Dark red lines are one minute apart

Maternal vital signs

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LITIGATIONTraces:

not done.

Unsatisfactory or

Missing: EFM traces should be kept up to 25 ys

Abnormal CTG: ignored or not recognized

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EDUCATION AND TRAINING

If you are going to use the CTG You must be

able to Interpret the trace & respond accordingly

Improves Knowledge/clinical skills for all staff

Training should include

instructions on documenting traces and

storage

appropriate clinical responses to suspicious or

pathological traces

local guidelines

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Thank You

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