• Composition of Meconium:

1. Small dried amniotic fluid debris

2. Bile pigment

3. The residue from intestinal secretions.

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• Mechanisms of Meconium passage:

(1) Physiologic maturational event,

(2) Response to acute hypoxic events

(3) Response to chronic intrauterine hypoxia.

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12% to 16% of all deliveries

(Cleary &Wiswell, 1998)

<5 % of pre term pregnancies

Up to 20% of term gestations

Up to 50 % of post-mature infants

INCIDENCE

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AETIOIOGY

Hypoxia and acidemia:

a. Relaxation of anal sphincter

b. increasing the production of motilin, which

promotes peristalsis.

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RISK FACTORS (Gregory et al, 1985)

• Small-for-gestational-age

• Postmature infants.

• Cord complications

• Chronic medical conditions , which can

compromise the uteroplacental circulation.

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CONSISTENCY OF MECONIUM

• Visually diagnosed thin meconium can be thick

meconium when examined objectively and visual

diagnosis is not always reliable and should be

replaced with a new objective method.

• All labors with meconium-stained amniotic fluid (either

thin or thick) should be continuously monitored

(Holtzman et al,1989)

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• Thin meconium:

• Yellow to light green and is watery (Hagemanet al, 1988).

• 10% to 40% of the cases of meconium passage.

• Passed as a maturational event in most cases

• infants are more likely to be healthy at birth.

• 10% to 20% of cases of MAS occur with thin

meconium.

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• Thick or particulate meconium:

• is pasty or granular

(Meis et al,1978).

• The risk of perinatal death is increased

(5-7times).

• Early in labor generally reflects:

a. Oligohydramnios

b. risk factor for neonatal morbidity and mortality.

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Meconium aspiration

• The presence of meconium below the vocal cords (Wiswell & Bent, 1993).

• 20% to 30% of all infants with meconium-stained

amniotic fluid.

Meconium aspiration syndrome (MAS)

1-5 % of deliveries with MSL

History of MSL

Respiratory distress that develops shortly after birth,

Radiographic evidence of aspiration pneumonitis

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SEQUELE

1. Persistent pulmonary hypertension related to

meconium.

2. Pneumothorax.

3. 4 -10 % neonatal death.

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PATHOPHYSIOLOGY

• Aspiration of meconium can occur either

antenatally or postnatally but in the majority of

cases the exact timing is not clear.

a. Antenatally, as meconium has been found in the

lungs of stillbirths and in infants delivered by

elective caesarean section without evidence of

fetal distress.

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b. Postnatal inhalation can occur:

late in the second stage or

immediately after delivery if the infant gasps or makes

breathing movements while the oropharynx,

nasopharynx or trachea contains MSL

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Meconium:

1. Causes mechanical blockage of the airway,

2. Acts as a chemical irritant causing pneumonitis,

alveolar collapse and cell necrosis

3. Although initially sterile, predisposes to

secondary bacterial infection

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PREVENTION

A. Antenatal

B. Intrapartum

C. Postnatal

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A. Antenatal therapies

1. Amnioinfusion

2. Delivery by C.S.

3. Maternal sedation

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1. Amnioinfusion

• Meconium will be diluted.

• A meta-analysis showed that this therapy has a

role in the prevention of MAS.

• But,it requires further evaluation, as it is associated

with a number of complications, (higher incidence

of instrumental delivery and endometritis)

(Hofmeyr GJ. 2002, Cochrane Review).

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2. Delivery by C.S.

• Although most studies suggest that infants with

meconium-stained liquor are more likely to be

delivered by C.S. {suspicion or confirmation of fetal

distress}.

• There is currently no evidence that MAS would be

prevented by elective C.S. {neither the conditions

for, nor the timing of aspiration can be predicted}.

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3. Maternal sedation

• Administration of narcotics to laboring women will

prevent fetal gasping in utero by suppressing fetal

breathing

(RCOG GRADE C).

• Although there has been success in the prevention

of MAS in animal models, there are no data to

support this therapy in humans.

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B. Intrapartum management

1. Oropharyngeal suctioning

2. Physical manoeuvres

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1. Oropharyngeal suctioning

• Suction of the oropharynx and nasopharynx before

delivery of the shoulders and trunk is a well-

established practice that has been used since the

1970s.

• Oropharyngeal suctioning would minimize the

amount of meconium in the upper airway and thus

reduce the amount aspirated during the onset of

respiration (American Academy of Pediatrics, 2000).

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• Routine intrapartum oropharyngeal and

nasopharyngeal suctioning of term-gestation,

does not prevent MAS or its complication

(Vain et al,2004).

• The evidence relating to routine suctioning of the

oropharynx as a preventative measure is

conflicting

(Cochrane library, 2004)

• What is clear, is that meticulous cleaning of the

upper airway after delivery is beneficial in

reducing MAS. Aboubakr Elnashar

2. Physical manoeuvres

• MAS may be prevented if the infant is prevented

from breathing after delivery.

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a. Thoracic compression

thoracic cage of the infant is compressed to

prevent respiration and subsequent aspiration of

the contents of the upper airway

b. Cricoid pressure

external pressure is applied to the cricoid, thus

preventing aspiration.

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• It is suggested that these interventions be continued

until a second resuscitator undertakes oral and/or

endotracheal suctioning.

• There is no evidence supporting the use of either of

these methods in preventing MAS.

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C. Postnatal intervention

1. Intratracheal suctioning

2. Aspiration of gastric contents

3. Saline lavage

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1. Intratracheal suctioning

• Until relatively recently, all infants with MSL

underwent endotracheal intubation and suction, as

this was known to reduce the incidence of MAS.

More recently, evidence has suggested a change

in practice depending on whether an infant is

vigorous or not.

• Vigorous infant is with (Good muscle tone,

HR>100/m, strong respiratory effort) (American Academy of Pediatrics, 2000)

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• Routine intubation of vigorous term infants in order

to aspirate the lungs should be abandoned

(Cochrane library, 2003)

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2. Aspiration of gastric contents

To remove swallowed meconium is still done in many

centers

(American Academy of Pediatrics, 2000).

• The passage of an orogastric tube is likely to cause

apnoea and/or bradycardia and is potentially harmful.

• This practice should be abandoned

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3. Saline lavage

• is used in order to loosen meconium in the distal

airways.

• It is potentially harmful, as it will displace

endogenous surfactant, which could worsen the

respiratory illness.

• Infants developed respiratory distress secondary

to 'wet lung'.

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DELIVERY ROOM MANAGEMENT OF INFANTS

BORN WITH MECONIUM-STAINED LIQUOR

• It is important that a person experienced in neonatal

resuscitation attends the delivery of all infants

in whom thick meconium-stained liquor

is noted.

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• If an infant is vigorous after delivery:

1. No tracheal suctioning should be undertaken,

2. Secretions should be cleared from the mouth and

nose using a wide-bore suction catheter,

3. Routine care should be given (American Academy of Pediatrics International Guidelines for Neonatal

Resuscitation 2000).

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• If an infant is not vigorous afterbirth ,

1. Do not stimulate

2. Direct endotracheal suctioning should be

undertaken as soon as possible,

3. Suction should be applied for no more than 5

seconds and the tube withdrawn.

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• If meconium is aspirated from below the cords,

the infant should be reintubated and the process

repeated,

• If there is profound bradycardia :

1. Resuscitation should proceed with intermittent

positive pressure ventilation (IPPV) without

suctioning

2. Further suctioning can be attempted at a later

stage.

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• If after the first suctioning no meconium is

aspirated:

1. No further suctioning should be attempted and

2. The infant should be resuscitated using IPPV via

an endotracheal tube.

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IS MECONIUM PRESENT

CONTINUE WITH RESUSCITATION

CLEAR MOUTH AND NOSE FROM SECRETIONS

DRY,STIMULATE AND REPOSITION

GIVE OXYGEN AS NECESSARY

NO YES

SUCTION MOUTH,NOSE AND POSTERIOR PHARYNX AFTER DELIVERY OF HEAD BUT BEFORE DELIVERY OF SHOULDERS

IS THE BABY VIGOROUS?

YES NO

SUCTION MOUTH AND

TRACHEA Aboubakr Elnashar

CONCLUSIONS

• The evidence relating to routine suctioning of the

oropharynx as a preventative measure is conflicting.

• Intratracheal suctioning should be reserved for the

non-vigorous baby.

• In the prevention of MAS, there is no evidence

supporting the use of:

1. Saline lavage,

2. Gastric aspiration or

3. Thoracic & or cricoid compression Aboubakr Elnashar

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