MeconiumMeconium
Dr .Ashraf Fouda
Ob/Gyn. Consultant
Damietta General Hospital
E. mail : [email protected]
INTRODUCTIONINTRODUCTION
The detection of meconiumThe detection of meconium stained amniotic fluid during stained amniotic fluid during
labour often causes labour often causes anxiety in the delivery roomanxiety in the delivery room because of its association with because of its association with increased perinatal mortality increased perinatal mortality
and morbidity and morbidity..
Meconium is composed ofMeconium is composed of : :
1.1. Small dried amniotic fluid debris, Small dried amniotic fluid debris,
2.2. Bile pigment and Bile pigment and
3.3. The residue from intestinal The residue from intestinal secretionssecretions. .
It is a sterile compound made up It is a sterile compound made up primarily ofprimarily of water water ((75 %75 %)), with , with mucous glycoproteins, lipids and mucous glycoproteins, lipids and proteasesproteases. .
INTRODUCTIONINTRODUCTION
Although meconium is Although meconium is sterile, its passage into sterile, its passage into
amniotic fluid is important amniotic fluid is important because of the because of the
risk of risk of meconium aspiration meconium aspiration
syndrome syndrome ((MASMAS)) and its sequelae and its sequelae. .
INTRODUCTIONINTRODUCTION
Infants delivered through Infants delivered through meconiummeconium--stained amniotic stained amniotic fluid are more likely to be fluid are more likely to be
depressed at birthdepressed at birth and to require and to require resuscitation and resuscitation and neonatal intensive care neonatal intensive care..
INTRODUCTIONINTRODUCTION
INCIDENCEINCIDENCE
Meconium-stained liquor is rareMeconium-stained liquor is rare in in premature infants premature infants
(<5 % of preterm (<5 % of preterm pregnancies);pregnancies); if it does if it does occur, there is an association occur, there is an association
with with infection and infection and chorioamnionitis. chorioamnionitis.
Passage of meconium is Passage of meconium is increasinglyincreasingly common in infants common in infants >37 weeks>37 weeks' gestation and occurs ' gestation and occurs in up to in up to 50 %50 % of post-mature of post-mature infants infants ( >42 weeks).( >42 weeks).
The incidence of MAS varies The incidence of MAS varies between between 1 and 5 %1 and 5 % of of all deliveries where there has all deliveries where there has been meconium-stained liquor. been meconium-stained liquor.
INCIDENCEINCIDENCE
There are a number of factors associated with There are a number of factors associated with an increased risk of developing MAS; these an increased risk of developing MAS; these include ainclude a: :
1.1. LLack of antenatal care, ack of antenatal care, 2.2. BBlack race, lack race, 3.3. MMale fetus, ale fetus, 4.4. AAbnormal fetal heart rate monitoring, bnormal fetal heart rate monitoring, 5.5. TThick meconium, hick meconium, 6.6. OOligohydramnios, ligohydramnios, 7.7. OOperative delivery, perative delivery, 8.8. PPoor Apgar scores, oor Apgar scores, 9.9. NNo oropharyngeal suctioning and o oropharyngeal suctioning and 10.10.TThe presence of meconium in the trachea.he presence of meconium in the trachea.
INCIDENCEINCIDENCE
Many theories have been proposed to explain Many theories have been proposed to explain the passage of meconium in utero; however, the passage of meconium in utero; however, the the precise mechanisms remain unclearprecise mechanisms remain unclear. .
The The fetal bowelfetal bowel has has little peristaltic actionlittle peristaltic action and and the the anal sphincter is contractedanal sphincter is contracted. .
It is thought that It is thought that hypoxia and academiahypoxia and academia cause cause the the anal sphincter to relaxanal sphincter to relax, whilst at the same , whilst at the same time increasing the production of time increasing the production of motilinmotilin, , which promotes peristalsis. which promotes peristalsis.
AETIOIOGYAETIOIOGY
PATHOPHYSIOLOGYPATHOPHYSIOLOGY
Meconium aspiration syndrome is a Meconium aspiration syndrome is a disease of term and postdisease of term and post--term infantsterm infants and its severity is linked to coand its severity is linked to co--existing existing fetal asphyxiafetal asphyxia. .
Aspiration of meconium into Aspiration of meconium into the distal airways can occur either the distal airways can occur either antenatally or postnatallyantenatally or postnatally, , but in the majority of but in the majority of affected infants affected infants the exact timing is not clear.the exact timing is not clear.
Aspiration is known to occur Aspiration is known to occur prior to deliveryprior to delivery, as meconium , as meconium has been found in the lungs of has been found in the lungs of
stillbirths and in infants stillbirths and in infants delivered pre-labour by delivered pre-labour by
caesarean sectioncaesarean section without without evidence of fetal distress. evidence of fetal distress.
PATHOPHYSIOLOGYPATHOPHYSIOLOGY
Postnatal inhalationPostnatal inhalation can occur can occur
late in the second stage or late in the second stage or immediately after deliveryimmediately after delivery if the infant if the infant
gasps or makes breathing gasps or makes breathing movementsmovements while the while the
oropharynx, oropharynx, nasopharynx or tracheanasopharynx or trachea
contains meconium-stained liquor.contains meconium-stained liquor.
PATHOPHYSIOLOGYPATHOPHYSIOLOGY
Meconium has a number of Meconium has a number of adverse effects on adverse effects on the neonatal lung the neonatal lung, ,
which may which may ultimately lead to ultimately lead to the the
respiratory failure (and respiratory failure (and hypoxaemia)hypoxaemia) which characterizes MAS.which characterizes MAS.
PATHOPHYSIOLOGYPATHOPHYSIOLOGY
Meconium:Meconium:1.1. Causes Causes mechanical blockagemechanical blockage of the of the
airwayairway, ,
2.2. Acts as a Acts as a chemical irritantchemical irritant causing causing pneumonitis, alveolar collapse and pneumonitis, alveolar collapse and cell necrosiscell necrosis
3.3. Although initially sterile, Although initially sterile, predisposes to predisposes to secondary bacterial secondary bacterial infectioninfection
PATHOPHYSIOLOGYPATHOPHYSIOLOGY
PREVENTION OF MECONIUM PREVENTION OF MECONIUM ASPIRATION SYNDROMEASPIRATION SYNDROME
Because of potential morbidity Because of potential morbidity and mortality from MAS, and mortality from MAS, prevention would prevention would
clearly be beneficial.clearly be beneficial. This has led to a number of This has led to a number of
antenatal, intrapartum and antenatal, intrapartum and postnatal preventative therapiespostnatal preventative therapies, ,
with a varying with a varying degree of success. degree of success.
1.1. AmnioinfusionAmnioinfusion
2.2. Delivery by caesarean Delivery by caesarean sectionsection
3.3. Maternal sedationMaternal sedation
Antenatal therapiesAntenatal therapies
The idea behind amnioinfusion The idea behind amnioinfusion is that by increasing the liquor is that by increasing the liquor volume, volume, meconium will be diluted.meconium will be diluted.
In addition, in cases of oligohydramnios, In addition, in cases of oligohydramnios, the increased volume will the increased volume will preventprevent : :
1.1. cord compression, cord compression,
2.2. subsequent hypoxia, subsequent hypoxia,
3.3. fetal gasping and fetal gasping and
4.4. passage of meconiumpassage of meconium. .
AmnioinfusionAmnioinfusion
AmnioinfusionAmnioinfusionA meta-analysis of amnioinfusion A meta-analysis of amnioinfusion
trials showed that this therapy has trials showed that this therapy has a a role in the prevention role in the prevention of MAS. of MAS.
However, the use of amnioinfusion However, the use of amnioinfusion requires further evaluation, as the requires further evaluation, as the therapy is associated with a number therapy is associated with a number of complications, including a of complications, including a higher incidence of instrumental higher incidence of instrumental delivery and endometritisdelivery and endometritis..
Delivery by caesarean Delivery by caesarean sectionsection
Although most studies suggest Although most studies suggest that infants with MAS are more that infants with MAS are more
likely to be delivered by likely to be delivered by caesarean section than by caesarean section than by
vaginal delivery, this is largely vaginal delivery, this is largely due to the due to the suspicion or suspicion or
confirmation of fetal confirmation of fetal distress. distress.
There is currently There is currently no evidence to no evidence to suggest that MAS would be prevented by suggest that MAS would be prevented by elective delivery by caesarean sectionelective delivery by caesarean section of of infants with meconium-stained liquor; infants with meconium-stained liquor;
Perhaps this is not surprising, as neither Perhaps this is not surprising, as neither
1.1. The conditions for The conditions for nornor
2.2. The timing of aspiration The timing of aspiration can be predicted can be predicted..
Delivery by caesarean Delivery by caesarean sectionsection
Maternal sedationMaternal sedation It has been suggested that the It has been suggested that the
administration of narcotics to laboring administration of narcotics to laboring women will women will prevent fetal gasping in prevent fetal gasping in utero by suppressing fetal breathingutero by suppressing fetal breathing. .
Although there has been success in Although there has been success in the prevention of MAS in the prevention of MAS in animal animal modelsmodels, there are no data to , there are no data to support this therapy support this therapy in humansin humans. .
Moreover, the likely Moreover, the likely maternal and neonatal maternal and neonatal complicationscomplications would preclude its use .would preclude its use .
Intrapartum/Intrapartum/postpartum postpartum
managementmanagement
1.1. Oropharyngeal Oropharyngeal suctioningsuctioning
2.2. Physical manoeuvresPhysical manoeuvres
Oropharyngeal Oropharyngeal suctioningsuctioning
Suction of the oropharynx Suction of the oropharynx and nasopharynx before and nasopharynx before
delivery of the shoulders delivery of the shoulders and trunk is a and trunk is a
well-established well-established practicepractice that has been used that has been used
since the 1970s. since the 1970s.
It seems reasonable that It seems reasonable that suctioning in this way would suctioning in this way would
minimize the amount of minimize the amount of meconium in the upper airwaymeconium in the upper airway
and thus reduce and thus reduce the amount aspirated the amount aspirated
during the onset of during the onset of respiration.respiration.
Oropharyngeal Oropharyngeal suctioningsuctioning
The evidence relating to The evidence relating to routine routine suctioning of the oropharynxsuctioning of the oropharynx as a as a preventative measure is preventative measure is conflicting.conflicting.
What is clear, is that What is clear, is that meticulous meticulous cleaning of the upper airway cleaning of the upper airway after delivery is beneficial in after delivery is beneficial in reducing MASreducing MAS
Oropharyngeal suctioningOropharyngeal suctioning
EVIDENCE l aEVIDENCE l a
Physical manoeuvresPhysical manoeuvres
It has been suggested It has been suggested that MAS may be that MAS may be
prevented if prevented if the infant is the infant is prevented from breathing prevented from breathing
after deliveryafter delivery. .
Methods advocated include:Methods advocated include:
1.1.Thoracic compressionThoracic compression, in which the , in which the thoracic cage of the infant is thoracic cage of the infant is compressed by a healthcare compressed by a healthcare professional in order to prevent professional in order to prevent respiration and subsequent aspiration respiration and subsequent aspiration of the contents of the upper airway, and of the contents of the upper airway, and
2.2.Cricoid pressureCricoid pressure, in which external , in which external pressure is applied to the cricoid, thus pressure is applied to the cricoid, thus preventing aspiration. preventing aspiration.
Physical manoeuvresPhysical manoeuvres
It is suggested that if used, these It is suggested that if used, these interventions be continued until interventions be continued until a second resuscitator a second resuscitator undertakes oral and/or undertakes oral and/or endotracheal suctioning. endotracheal suctioning.
There is no evidence supporting There is no evidence supporting the use of either of these the use of either of these methods in preventing MAS. methods in preventing MAS.
Physical manoeuvresPhysical manoeuvres
In fact, both In fact, both Thoracic compression Thoracic compression
and and Cricoid Cricoid pressurepressure are are
potentially dangerous potentially dangerous and cannot be and cannot be recommendedrecommendedEVIDENCEEVIDENCE IVIV
Physical manoeuvresPhysical manoeuvres
Postnatal Postnatal interventionintervention
Intratracheal Intratracheal suctioningsuctioning
Intratracheal suctioningIntratracheal suctioning
Until relatively recently,Until relatively recently, all infants with meconium all infants with meconium--
stainedstained amniotic fluid underwent amniotic fluid underwent endotracheal intubation endotracheal intubation and suctionand suction, ,
as this was known to as this was known to reduce the incidence of MASreduce the incidence of MAS. .
More recently, evidence More recently, evidence has suggested a has suggested a
change in practicechange in practice depending on whether depending on whether
or not an infant is or not an infant is deemeddeemed vigorousvigorous..
Intratracheal suctioningIntratracheal suctioning
A recent metaA recent meta--analysis analysis suggests that suggests that
routine intubation of routine intubation of vigorous term infants in vigorous term infants in
order to aspirate the lungs order to aspirate the lungs should be abandonedshould be abandoned
EVIDENCE l aEVIDENCE l a
Intratracheal suctioningIntratracheal suctioning
Suctioning of the oropharynx Suctioning of the oropharynx may be beneficial, but may be beneficial, but
endotracheal suctioning should endotracheal suctioning should be reserved forbe reserved for: :
1.1. Depressed Depressed oror
2.2. Non-vigorous infants Non-vigorous infants or or
3.3. Those who deteriorate following Those who deteriorate following initial assessment.initial assessment.
Intratracheal suctioningIntratracheal suctioning
Aspiration of gastric contents to remove Aspiration of gastric contents to remove swallowed meconium is still done in swallowed meconium is still done in many centers. many centers.
The passage of an The passage of an orogastric tubeorogastric tube is is likely to cause likely to cause apnoea and/or apnoea and/or bradycardia and is potentially harmful. bradycardia and is potentially harmful.
This practice should be abandonedThis practice should be abandoned
EVIDENCEEVIDENCE IVIV
Aspiration of gastric Aspiration of gastric contentscontents
Saline lavage is Saline lavage is used in order to loosen used in order to loosen meconium. meconium.
Saline lavage is potentially harmfulSaline lavage is potentially harmful, , as saline will displace endogenous as saline will displace endogenous surfactant, which could in turn surfactant, which could in turn worsen the respiratory illnessworsen the respiratory illness. .
In cases where saline lavage has been In cases where saline lavage has been used, infants developed respiratory used, infants developed respiratory distress secondary to distress secondary to 'wet lung'.'wet lung'.
Saline lavageSaline lavage
It is important that a It is important that a person experienced in person experienced in neonatal resuscitationneonatal resuscitation attends the delivery of all attends the delivery of all infants in whom infants in whom thick meconium-thick meconium-
stained liquor is notedstained liquor is noted, , particularly if accompanied by particularly if accompanied by suspected fetal compromise.suspected fetal compromise.
DELIVERY ROOM MANAGEMENT OF DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED INFANTS BORN WITH MECONIUM-STAINED
LIQUORLIQUOR
The Neonatal Resuscitation Program of the The Neonatal Resuscitation Program of the American Academy of PediatricsAmerican Academy of Pediatrics incorporates incorporates guidelines for the management of these guidelines for the management of these infants infants
If an infant is vigorous after delivery:If an infant is vigorous after delivery:
1.1. No tracheal suctioning should be undertaken,No tracheal suctioning should be undertaken,
2.2. Secretions should be cleared from the mouth Secretions should be cleared from the mouth and nose using a wide-bore suction catheter, and nose using a wide-bore suction catheter,
3.3. Routine care should be given.Routine care should be given.
DELIVERY ROOM MANAGEMENT OF DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-INFANTS BORN WITH MECONIUM-
STAINED LIQUORSTAINED LIQUOR
DELIVERY ROOM MANAGEMENT OF INFANTS DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED LIQUORBORN WITH MECONIUM-STAINED LIQUOR
However, if an infant is However, if an infant is not vigorousnot vigorous afterbirth afterbirth (defined as :(defined as :
depressed respirations, depressed respirations, decreased muscle tone and/or decreased muscle tone and/or
heart rate < 100 beats per minute):heart rate < 100 beats per minute):
1.1. Direct endotracheal suctioningDirect endotracheal suctioning should be should be undertaken as soon as possible,undertaken as soon as possible,
2.2. Suction should be applied for Suction should be applied for no more no more than 5 seconds and the tube withdrawnthan 5 seconds and the tube withdrawn..
If meconium is aspirated from below If meconium is aspirated from below the cords, the cords, the infant should be the infant should be reintubated and the process repeatedreintubated and the process repeated, ,
Unless the infant has a profound Unless the infant has a profound bradycardia, in which case:bradycardia, in which case:
1.1. Resuscitation should proceed with Resuscitation should proceed with intermittent positive pressure intermittent positive pressure ventilation ventilation (IPPV)(IPPV) without suctioning, without suctioning,
2.2. Further suctioning can be attempted Further suctioning can be attempted at a later stage.at a later stage.
DELIVERY ROOM MANAGEMENT OF INFANTS DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED LIQUORBORN WITH MECONIUM-STAINED LIQUOR
If after the first suctioning If after the first suctioning no meconium is no meconium is aspirated : aspirated :
1.1. No further suctioning should be No further suctioning should be attempted and attempted and
2.2. The infant should be The infant should be resuscitated using IPPV via an resuscitated using IPPV via an endotracheal tube.endotracheal tube.
DELIVERY ROOM MANAGEMENT OF DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED INFANTS BORN WITH MECONIUM-STAINED
LIQUORLIQUOR
IS MENONIUM PRESENTYESNO
SUCTION MOUTH,NOSE AND POSTERIOR PHARYNX AFTER DELIVERY OF HEAD
BUT BEFORE DELIVERY OF SHOULDERS
IS THE BABY VIGOROUS?
SUCTION MOUTH AND
TRACHEA
CONTINUE WITH RESUSCITATION
CLEAR MOUTH AND NOSE FROM SECRETIONS
DRY,STIMULATE AND REPOSITION
GIVE OXYGEN AS NECESSARY
NOYES
KEY POINTSKEY POINTS
Meconium-stained liquor is Meconium-stained liquor is associated with associated with increased increased morbidity and mortalitymorbidity and mortality in babies. in babies.
MAS is MAS is linked to perinatal linked to perinatal asphyxiaasphyxia. .
Good neonatal resuscitation skills Good neonatal resuscitation skills reduce the incidence of MAS reduce the incidence of MAS
In the prevention of MAS , there In the prevention of MAS , there is is no evidence supportingno evidence supporting
the use of: the use of:
1.1. Saline lavage, Saline lavage,
2.2. Gastric aspiration or Gastric aspiration or
3.3. Thoracic compressionThoracic compression
KEY POINTSKEY POINTS
The evidence relating to The evidence relating to routine suctioning of the routine suctioning of the oropharynxoropharynx as a preventative as a preventative measure is conflicting.measure is conflicting.
Intratracheal suctioningIntratracheal suctioning should be reserved for the should be reserved for the non-vigorous babynon-vigorous baby..
KEY POINTSKEY POINTS