Meconium Aspiration Syndrome

 

Meconium Aspiration syndrome

By Krishnadas.A 

 

INTRODUCTION 

Meconium is the earliest stools of an infant.  

The term Meconium  derives from meconium-arion , meaning "opium "opium-like", -like", in reference either to its tarry appearance or to Aristotle's belief that it induces sleep in the fetus



Meconium is almost sterile, unlike later feces, is viscous and sticky like tar, and has no odor. It should be completely passed by the end of the first few days of life 

 

INTRODUCTION 

Meconium is composed of : of :

1.

Small dried amniotic fluid debris,

2.

Bile pigment and The residue from intestinal secretions.

3. 

It is a sterile compound made up primarily of  water (75 %), with mucous glycoproteins, lipids and proteases.

 

INTRODUCTION Although meconium is sterile, its passage into amniotic fluid is important because of the risk of 



meconium aspiration syndrome (MAS)  (MAS)  and its sequelae.

 

INTRODUCTION Infants delivered through meconium-stained meconium-st ained amniotic fluid are more likely to be depressed at birth  birth 



and to require resuscitation and neonatal intensive care. care.

 

INCIDENCE 

Meconium-stained liquor is rare  in premature infants (<5 % of preterm pregnancies)  pregnancies) 

 

INCIDENCE 

Passage of meconium is increasingly  common in infants >37 weeks' weeks' gestation and occurs in up to 50 %  %  of post-mature infants ( >42 weeks).

 

Definition Meconium aspiration syndrome is a  serious condition in which a newborn breathes a mixture of  meconium and amniotic fluid into the lungs around the time of delivery.  

 

Risk factors There are a number of factors associated with an increased risk of developing MAS; these include a: a: 1. Lack of antenatal care, 2. Black race, 

3. Male fetus, 4.  A bnormal bnormal fetal

heart rate monitoring, 5. Thick meconium, 6. 7.

Oligohydramnios, Operative delivery, 8. Poor Apgar scores, 9. No oropharyngeal suctioning and 10.The presence of meconium in the trachea.

 

Riskfactors Decreased oxygen to the infant while in .11 the uterus Diabetes in the pregnant mother .12 Difficult delivery or long labor .13 High blood pressure in the pregnant .14 mother Passing the due date .15  

 

Etiology 

Many theories have been proposed to explain the passage of meconium in utero; however, the precise mechanisms remain unclear .



The fetal bowel has little peristaltic action and the anal sphincter is contracted. contracted.



It is thought that hypoxia and academia cause the anal sphincter to relax, relax, whilst at the same time production of motilin of motilin,, whichincreasing promotesthe peristalsis.

 

PATHOPHYSIOLOGY   

 

PATHOPHYSIOLOGY  Meconium: 1.

Causes mechanical blockage of the

airway, airway, 2. Acts as a chemical irritant causing pneumonitis, alveolar collapse and cell necrosis 3. Although initially sterile, predisposes to secondary bacterial infection

 

Clinical findings Bluish skin color (cyanosis) in the infant  Breathing problems  Difficulty breathing (the infant needs to  work hard to breathe) No breathing  Rapid breathing  Limpness in infant at birth   

 

Clinical findings Cyanosis  End-expiratory grunting   Alar flaring  Intercostal retractions  Tachypnea  Barrel chest in the presence of air trapping   Auscultated rales and rhonchi (in some  cases

 

PREVENTION OF MECONIUM  ASPIRATION SYNDROME 

Because of potential morbidity and mortality from MAS, prevention would clearly be beneficial.   beneficial.

This has led to a number of  antenatal, intrapartum and postnatal preventative therapies, therapies, 

with a varying degree of success.

 

 Antenatal therapies therapies 1.

Amnioinfusion

2.

Delivery by caesarean section

3.

Maternal sedation

 

 Amnioinfusion 

The idea behind amnioinfusion is that by increasing the liquor volume, meconium will be diluted.  diluted. 



In addition, in cases of oligohydramnios, the increased volume will prevent :

1. 2.

cord compression, subsequent hypoxia,

3.

fetal gasping and

4.

passage of meconium. meconium.

 

Maternal sedation 

It has been suggested that the administration of narcotics to laboring women will prevent fetal gasping in utero by suppressing fetal breathing. breathing.

 

Intrapartum/postpartum management 1. 2.

Oropharyngeal suctioning Physical manoeuvres

 

Postnatal intervention

Intratracheal suctioning

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DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED LIQUOR 

It is important that a person experienced in neonatal resuscitation  resuscitation  attends the delivery of all infants in whom thick meconium-stained liquor is noted, noted, particularly if accompanied 

by suspected fetal compromise.

 

DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED LIQUOR  

The Neonatal Resuscitation Program of the American Academy of Pediatrics incorporates guidelines for the management of these infants



If an infant is vigorous after delivery:

1. 2.

No tracheal suctioning should be undertaken, Secretions should be cleared from the mouth and nose using a wide-bore suction catheter,

3.

Routine care should be given.

 

DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED LIQUOR  

However, if an infant is not vigorous  vigorous  afterbirth (defined as :

 

depressed respirations, decreased muscle tone



heart rate < 100 beats per minute):

1.

Direct endotracheal suctioning should be undertaken as soon as possible,

2.

Suction should be applied for no for no more than 5 seconds and the tube withdrawn. withdrawn.

and/or 

 

DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED LIQUOR 

If meconium is aspirated from below the cords, the infant should be reintubated and the process repeated, repeated, Unless the infant has a profound  bradycardia, in which case: 1. Resuscitation should proceed with intermittent positive pressure ventilation (IPPV) without suctioning, 2. Further suctioning can be attempted at 

a later stage.

 

DELIVERY ROOM MANAGEMENT OF INFANTS BORN WITH MECONIUM-STAINED LIQUOR 



1. 2.

If after the first suctioning no meconium is aspirated : No further suctioning should be attempted and The infant should be resuscitated using IPPV via an endotracheal tube.

 

IS MENONIUM PRESENT  YES

NO

SUCTION MOUTH,NOSE AND POSTERIOR  PHARYNX AFTER DELIVERY OF HEAD BUT BEFORE DELIVERY OF SHOULDERS IS THE BABY VIGOROUS?  YES CONTINUE WITH RESUSCITATION  CLEAR

MOUTH AND NOSE FROM SECRETIONS 



DRY,STIMULATE AND REPOSITION

NO SUCTION MOUTH  AND TRACHEA  TRACHEA 



GIVE OXYGEN AS NECESSARY 

 

General • Sedation Analgesia • Muscle Relaxants • Alkalinizatio Alkalinization n

Infection &  Inflammation • Antibiotics • Anti-inflammatory Anti-inflammatory agents

Pharmaco therapy

Pulmonary care • Surfactant treatment • Surfactant lavage • Ventilator support

 

Pulmonary hypertension • Vasodilators • Hemodynamic stabilizers