Download - MECONIUM STAINED LIQUOR
• 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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