Major disorders of newborns

3. MECONIUM ASPIRATION
SYNDROME
PRESENTED BY:
REENA BHAGAT
MN 1ST YEAR, 2017
LNC, PAHS

4. PRE-TEST

5. Objectives:
 Introduction of meconium
 Definition of MAS
 Incidence
 Causes
 Pathophysiology
 Clinical Features
 Diagnostic Evaluation
 Prevention
 Management
 Complication
 Prognosis

6. Introduction of meconium
 The first intestinal discharge from newborns is
meconium, which is a viscous, dark-green substance
composed of intestinal epithelial cells, lanugo, mucus
and intestinal secretions( eg. bile).
 Meconium is typically passed for 2-3 days after birth.
 Sometimes, the fetus passes the meconium while it is
still in the womb.
 Intestinal secretions, mucosal cells and solid elements
of swallowed amniotic fluid are the major solid
constituents of meconium.

8. Definition of MAS
 Meconium aspiration syndrome( MAS) is a
respiratory distress in a newborn who has
breathed( aspirated) meconium into the lungs
before or around the time of birth.

10. Incidence:
 A study conducted in Australia and New Zealand in
infants who were intubated and mechanically ventilated
with a primary diagnosis of MAS between 1995 and 2002
showed that MAS occurred in 0.43 of 1,000 live births.
 The possibility of inhaling meconium occurs in about 5-
10% of births.
 Not all infants with meconium aspiration will develop
MAS. Features of MAS develop immediately after birth
only in 5-10% infants.( Dutta 2006)

11.  Finding from a study at Manipal College of Medical
Science, Pokhara, Nepal showed that: incidence of
meconium stained amniotic fluid( MSAF) was 13.97%
and that of MAS was 8.57%.
 Most common and significant risk factor associated with
MAS were increased gestational age, increased cesarean
section(LSCS) and low apgar score at 1min & 5 min.
( Swain & Thapalial, 2008)

13. Causes of MAS
 Hypoxia in distressed baby
 Meconium Stained Liquor
 Uterine Infections
 Difficulty during labour process

14. Factors that promote the passage of meconium in utero
includes the following:
 Placental insufficiency
 Post dated pegnancy
 Maternal hypertension
 Pre-eclampsia
 Oligohydramnios
 Maternal drug abuse, especially of tobacco and cocaine
 Maternal infection/ chorioamnioitis
 Fetal gasping secondary to hypoxia( fetal distress)
 Inadequate removal of meconium from the airway prior to
the first breath.

15. Pathophysiology of MAS

16. Airway Obstruction
 Complete obstruction of lungs may result in
atelectasis.
 Partial obstruction cause: air trapping and
hyperdistension of alveoli, commonly called ball-valve
effect.

18. Clinical features:

19.  History
 Presence of meconium in amniotic fluid.
 Green urine may be observed in newborns with
meconium aspiration syndrome less than 24 hours
after birth. (Meconium pigments can be absorbed
by the lungs and can be excreted in urine).
 Signs:
Severe respiratory distress may be present.

20.  Symptoms include the following:
 Cyanosis
 End-expiratory grunting
 Nasal flaring
 Breathing problems like( difficulty in breathing,
no breathing and rapid breathing)
 Intercostal retractions
 Tachypnea
 Barrel chest in the presence of air trapping
 Auscultated rales and rhonchi ( in some cases).
 Yellow-green staining of fingernails, umbilical cord
and skin my be observed.

21. Diagnosis of MAS
 High risk infants may be identified by
fetal tachycardia
 bradycardia or
 absence of fetal accelerations (upon CTG ) in utero
At birth, the infant may look cachexic and show signs
of yellowish meconium staining on skin, nail and the
umbillical cord.
These infants usually progress onto Infant Respiratory
distress syndrome within 4 hours.

22.  Investigations which can confirm the diagnosis are :
 Fetal chest x-ray, which will show hyperinflation,
diaphragmatic flattening, cardiomegaly, patchy
atelectasis and consolidation.
 ABG samples, which pH, partial pressure of
oxygen( p02), partial pressure of CO2 ( pCO2) and
continuous measurement of oxygenation by pulse
oximetry are necessary for management.

23.  Complete blood count: hemoglobin & hematocrit
level must be sufficient to ensure adequate oxygen-
carrying capacity.
 Serum electrolytes: obtain sodium, potassium and
calcium concentration when the infants with MAS
aged 24 hrs because the syndrome of inappropriate
secretion of antidiuretic hormone( SIADH) and
acute renal failure are frequent complications of
perinatal stress.

24. Preventive measures of MAS
 MAS is difficult to prevent.
 When there is meconium stained liquor, careful suctioning
of posterior pharynx after delivery of head decreases the
potential for aspiration of meconium.
 When aspiration occurs, intubation and immediate
suctioning of airway can remove much of aspirated
meconium.
 Do not perform the following harmful techniques in an
attempt to prevent aspiration of meconium- stained liquor:
- Squeezing of the chest of baby
-Inserting a finger into the mouth of baby.

25. Management of MAS
Prenatal:
1. Identification of high risk pregnancies
- recognition of predisposing maternal factors
- post dates pregnancy inductions as early as 41 weeks
2. Monitoring
- careful observation and fetal monitoring during labour
- corrective measures should be undertaken in identifies
compromised fetus.
3. Amnioinfusion
- relieved umbilical cord compression during labor ->
reducing occurrence of variable fetal heart rate decelerations
- efficiency not well demonstrated.

26. Delivery room management
Anticipate the worst….
Be prepared…

27. Immediate Management
The American Academy of Pediatrics Neonatal Resuscitation
Program Steering Committee guidelines are as follows
If the baby is not vigorous:
 Suction the trachea immediately after delivery
 Suction for no longer than 5 seconds
 If no meconium is retrieved, do not repeat intubation and suction
 If meconium is retrieved and no bradycardia is present, reintubate
and suction
 If the heart rate is low, administer positive pressure ventilation and
consider suctioning again later.
If the baby is vigorous:
 Do not electively intubate
 Clear secretions and meconium from the mouth and nose with a
bulb syringe or a large-bore suction catheter.
Dry, stimulate, reposition, and administer oxygen as necessary.
Transfer ill newborns with respiratory distress to NICU

28. General management
Continued care in the neonatal ICU (NICU)
 Maintain an optimal thermal environment
 Minimal handling to reduce agitation thus pulmonary
hypertension and right-to-left shunting causing hypoxia and
acidosis
 Insert umbilical artery to monitor blood pH and blood gases
without agitating the infant.
 Continue respiratory care: oxygen therapy via hood or positive
pressure is crucial in maintaining adequate arterial
oxygenation. Oxygen saturation ( 90-95%) should be
maintained.
 Newborns are treated with antibiotics because of risk of
infection( eg. Gentamycin)

29. Supportive treatment
o IV Dextrose to prevent hypoglycemia.
o Fluid restriction (60-70 mL/kg/d) to prevent cerebral
and pulmonary edema
o Electrolytes to correct metabolic acidosis
o Protein, lipids, and vitamins to prevent deficiencies
For treatment of persistent pulmonary
hypertension of newborn( PPHN), inhaled nitric
oxide is the pulmonary vasodilator of choice.

30. Surfactant Therapy: Replace displaced or inactivated
surfactant and as a detergent to remove meconium, may reduce
the severity of disease, progression to extracorporeal
membrane oxygenation and decrease length of hospital stay.
 May decrease respiratory failure with MAS within 6 hrs of 3
doses
ECMO: Extracorporeal membrane oxygenation is the last
option focused on the function of oxygenation and CO2
removal. Effective but associated with a high incidence of poor
neurologic outcomes.
 ECMO is done using only cervical cannulation, which can be
performed under local anesthesia used for longer-term support
ranging from 3-10 days.Allow time for intrinsic recovery of the
lungs and heart. Survival rate 93-100%

31. EXTRACORPOREAL MEMBRANE
OXYGENATION

32. Complications of MAS
 In mild cases, respiratory distress usually subsides in
2-4 days although tachypnea can persist for longer.
 Cerebral hypoxia may lead to long term neurological
damage.
 Aspiration pneumonia
 Brain damage due to lack of oxygen
 Collapsed lung
 Persistent pulmonary hypertension of newborn.

33. Prognosis of MAS
 The mortality rate of meconium-stained infants is considerably
higher than that of non-stained infants.
 Meconium aspiration accounts for a significant proportion of
neonatal deaths.
 Residual lung problems are rare but include symptomatic
cough, wheezing, and persistent hyperinflation for up to five to
ten years.
 The ultimate prognosis depends on the extent of CNS injury
from asphyxia and the presence of associated problems such as
persistent pulmonary hypertension.
 Mortality rate is approx 5%.

36. References:
 Ranabhat, R.D & Niraula, H.(2017) A textbook of midwifery
& reproductive health (1st ed.). Kathmandu, Page no: 580-
582
 Tuitui, R. (2016) Manual of midwifery III (11th ed.). Vidyarthi
Pustak Bhandar, Kathmandu, Page no: 227-231
 Dutta, D.C. (2011). A textbook of obstetrics including
perinatology and contraception (7th ed.). A central book
agency(P) ltd., Hyderabad, page no: 476