meconium-stained amniotic fluid (msaf) pediatrics point of view

Meconium-stained Meconium-stained amniotic fluid (MSAF)amniotic fluid (MSAF)

Pediatrics point of viewPediatrics point of view

M&M PresentationM&M Presentation

Darinka Shaw MDDarinka Shaw MDPediatrics ResidentPediatrics Resident

February 2009February 2009

ObjectivesObjectives

DefinitionDefinition Epidemiology Epidemiology EtiologyEtiology PathophysiologyPathophysiology Clinical featuresClinical features ManagementManagement Morbidity&MortalityMorbidity&Mortality

DefinitionDefinition

Meconium aspiration syndrome Meconium aspiration syndrome (MAS)(MAS) is a respiratory disorder in is a respiratory disorder in

an infant born throughan infant born through Meconium stained amniotic fluidMeconium stained amniotic fluid

whose symptoms cannot be whose symptoms cannot be otherwise explained.otherwise explained.

MASMAS

Cleary&Wiswell proposed severity Cleary&Wiswell proposed severity criteria to define MAS:criteria to define MAS:

Mild: requires <40%O2 for <48hrsMild: requires <40%O2 for <48hrs Moderate: >40%O2 for >48hrs, no Moderate: >40%O2 for >48hrs, no

air leak.air leak. Severe: assisted ventilation for Severe: assisted ventilation for

>48hrs often with PPH.>48hrs often with PPH.

EpidemiologyEpidemiology

MSAF observed in 13% of all live MSAF observed in 13% of all live births.births.

MAS occurs in 5% of newborns MAS occurs in 5% of newborns delivered through MSAF.delivered through MSAF.

25,000 to 30,000 cases and 1,000 25,000 to 30,000 cases and 1,000 deaths related to MAS annually in US.deaths related to MAS annually in US.

EpidemiologyEpidemiology

More frequently in infants who are More frequently in infants who are postmature and small for gestational postmature and small for gestational age. age.

Decline from 5.8% to 1.5% (1990–Decline from 5.8% to 1.5% (1990–1997), attributed to a 33% reduction 1997), attributed to a 33% reduction in the incidence of births >41 weeks in the incidence of births >41 weeks gestation.gestation.

PhysiologyPhysiology

The passage of meconium from the fetus into The passage of meconium from the fetus into amnion is prevented by lack of peristalsis amnion is prevented by lack of peristalsis (low motilin level), tonic contraction of the (low motilin level), tonic contraction of the anal sphincter, terminal cap of viscous anal sphincter, terminal cap of viscous meconium.meconium.

MSAF may be a natural phenomenon that MSAF may be a natural phenomenon that doesn’t indicate fetal distress but mature GI doesn’t indicate fetal distress but mature GI tract in post term fetus with increased motilin tract in post term fetus with increased motilin level.level.

Vagal stimulation by cord or head Vagal stimulation by cord or head compression may be associated with passage compression may be associated with passage of meconium in the absence of fetal distress.of meconium in the absence of fetal distress.

Risk factors for MSAFRisk factors for MSAF

Maternal HTMaternal HT Maternal DMMaternal DM Maternal heavy cigarette smokingMaternal heavy cigarette smoking Maternal chronic respiratory or CV DxMaternal chronic respiratory or CV Dx Post term pregnancyPost term pregnancy Pre-eclampsia/eclampsiaPre-eclampsia/eclampsia OligohydramniosOligohydramnios IUGRIUGR Poor biophysical profilePoor biophysical profile Abnormal fetal HR patternAbnormal fetal HR pattern

PathophysiologyPathophysiology

The pathophysiology of MAS is complex. The pathophysiology of MAS is complex. Intrauterine fetal gasping, mechanical Intrauterine fetal gasping, mechanical

airway obstruction, pneumonitis, airway obstruction, pneumonitis, surfactant inactivation, and damage of surfactant inactivation, and damage of umbilical vessels: all play roles in the umbilical vessels: all play roles in the pathophysiology of meconium aspiration. pathophysiology of meconium aspiration.

There is also a strong association between There is also a strong association between MAS and persistent pulmonary MAS and persistent pulmonary hypertension of the newborn (PPHN). hypertension of the newborn (PPHN).


TheThe timingtiming of the initial insult of the initial insult resulting in MAS remains controversial. resulting in MAS remains controversial.

Chronic in-utero insult may be Chronic in-utero insult may be responsible for most cases of responsible for most cases of severe severe MAS.MAS.

In contrast to these severe cases, the In contrast to these severe cases, the vigorous infant who aspirates vigorous infant who aspirates meconium-stained fluid from the meconium-stained fluid from the nasopharynx at birth usually develops nasopharynx at birth usually develops mild to moderatemild to moderate disease. disease.


The traditional belief was that meconium The traditional belief was that meconium aspiration occurs aspiration occurs immediatelyimmediately after birth. after birth.

Aspirated particulate or thick meconium Aspirated particulate or thick meconium can be carried rapidly by the first breaths can be carried rapidly by the first breaths to the distal airways. to the distal airways.

Studies of neonatal puppies with tantalum-Studies of neonatal puppies with tantalum-labeled meconium instilled into the trachea labeled meconium instilled into the trachea before the first breath have confirmed that before the first breath have confirmed that the distal migration of particulate matter the distal migration of particulate matter can occur within 1 hour of birth. can occur within 1 hour of birth.


Several investigators have suggested that Several investigators have suggested that most cases of meconium aspiration occur most cases of meconium aspiration occur in in uteroutero when fetal gasping is initiated when fetal gasping is initiated before before deliverydelivery..

Meconium has been found distally as far as Meconium has been found distally as far as the alveoli in some stillborn infants and in the alveoli in some stillborn infants and in some infants that die within hours of some infants that die within hours of delivery.delivery.

There is currently There is currently no wayno way to distinguish to distinguish between the infant who has developed MAS between the infant who has developed MAS by intrauterine respiration or gasping and the by intrauterine respiration or gasping and the infant who has developed MAS by inhalation infant who has developed MAS by inhalation of meconium at the first breaths after of meconium at the first breaths after delivery. delivery.

Mechanism of injuryMechanism of injury

1.Mechanical Obstruction of the Airway1.Mechanical Obstruction of the Airway It is commonly thought that the initial and most It is commonly thought that the initial and most

important problem of the infant with MAS is important problem of the infant with MAS is obstruction caused by meconium in the airways. obstruction caused by meconium in the airways.

Complete obstruction of large airways by thick Complete obstruction of large airways by thick meconium is an uncommon occurrence.meconium is an uncommon occurrence.

The exact incidence of large-airway obstruction The exact incidence of large-airway obstruction is unknown, though Thureen et al, in an autopsy is unknown, though Thureen et al, in an autopsy study of infants who died of MAS, foundstudy of infants who died of MAS, found no no evidence of such obstruction. evidence of such obstruction.


Usually, small amounts of meconium Usually, small amounts of meconium migrate slowly to the peripheral airways. migrate slowly to the peripheral airways.

This mechanism can create a This mechanism can create a ball valve ball valve phenomenonphenomenon, in which air flows past the , in which air flows past the meconium during inspiration but is meconium during inspiration but is trapped distally during expiration, leading trapped distally during expiration, leading to increases in expiratory lung resistance, to increases in expiratory lung resistance, functional residual capacity, and anterior functional residual capacity, and anterior posterior diameter of the chest.posterior diameter of the chest.


Regional atelectasis and V/P mismatches can Regional atelectasis and V/P mismatches can be developed from total obstruction of the be developed from total obstruction of the small airways. small airways.

Adjacent areas often are partially obstructed Adjacent areas often are partially obstructed and over expanded, leading to pneumothorax and over expanded, leading to pneumothorax and pneumomediastinum air leaks. and pneumomediastinum air leaks.

Pulmonary air leaks are 10x more likely to Pulmonary air leaks are 10x more likely to develop in infants with MAS than those without, develop in infants with MAS than those without, and leaks often develop and leaks often develop during during resuscitation.resuscitation.


2. Pneumonitis2. Pneumonitis Pneumonitis is a usual feature of MAS, Pneumonitis is a usual feature of MAS,

occurring in about ½ of the cases.occurring in about ½ of the cases. Meconium has a direct toxic effect Meconium has a direct toxic effect

mediated by inflammation.mediated by inflammation. An intense inflammatory response in An intense inflammatory response in

the bronchi and alveoli can occur the bronchi and alveoli can occur within hours of aspiration of within hours of aspiration of meconium.meconium.

The airways and lung parenchyma become The airways and lung parenchyma become infiltrated with large numbers of infiltrated with large numbers of polymorphonuclear leukocytes and polymorphonuclear leukocytes and macrophages.macrophages.

Produce direct local injury by release of Produce direct local injury by release of inflammatory mediators-cytokines (TNF-inflammatory mediators-cytokines (TNF-αα, , IL-1IL-1ββ, IL-8), IL-8) and reactive oxygen species. and reactive oxygen species.

Lead to vascular leakage, which may Lead to vascular leakage, which may cause toxic pneumonitis with hemorrhagic cause toxic pneumonitis with hemorrhagic pulmonary edema.pulmonary edema.



Meconium contains substances such as Meconium contains substances such as bile acids that also can cause direct injury.bile acids that also can cause direct injury.

Clinicians should maintain a high index of Clinicians should maintain a high index of suspicion for suspicion for bacterial pneumoniabacterial pneumonia in in infants with MAS.infants with MAS.

Presence of fever, an abnormal WBC or a Presence of fever, an abnormal WBC or a decline in respiratory function are decline in respiratory function are indications of bacterial pneumonia and/or indications of bacterial pneumonia and/or sepsis and should prompt the clinician to sepsis and should prompt the clinician to obtain relevant cultures and initiate obtain relevant cultures and initiate antimicrobial therapy.antimicrobial therapy.


3.Pulmonary vasoconstriction3.Pulmonary vasoconstriction The release of vasoactive mediators, such The release of vasoactive mediators, such

as eicosanoids, endothelin-1 and as eicosanoids, endothelin-1 and prostaglandin E2 as a result of injury from prostaglandin E2 as a result of injury from meconium seems to play role in the meconium seems to play role in the development of persistent PH.development of persistent PH.

The pulmonary vasoconstriction is, in part, The pulmonary vasoconstriction is, in part, the result of the underlying in utero the result of the underlying in utero stressors. stressors.


4. Surfactant inactivation4. Surfactant inactivation Recognized in the early 1990.Recognized in the early 1990. Meconium displaces surfactant from the Meconium displaces surfactant from the

alveolar surface and inhibits its surface alveolar surface and inhibits its surface tension lowering ability.tension lowering ability.

A full term baby born with a sufficient A full term baby born with a sufficient quantity of surfactant may develop quantity of surfactant may develop surfactant deficiency by inactivation that surfactant deficiency by inactivation that leads to atelectasis, decreased lung leads to atelectasis, decreased lung compliance/volume and poor oxygenation.compliance/volume and poor oxygenation.

CLINICAL FEATURESCLINICAL FEATURESHistoryHistory

Infants with MAS have a history Infants with MAS have a history of MSAF.of MSAF.

They often are postmature or They often are postmature or small for gestational age. small for gestational age.

Many are depressed at birth. Many are depressed at birth.

CLINICAL FEATURES CLINICAL FEATURES Physical examinationPhysical examination

Evidence of postmaturity: peeling skin, Evidence of postmaturity: peeling skin, long fingernails, and decreased vernix. long fingernails, and decreased vernix.

The vernix, umbilical cord, and nails may The vernix, umbilical cord, and nails may be meconium-stained, depending upon be meconium-stained, depending upon how long the infant has been exposed in how long the infant has been exposed in utero. utero.

In general, nails will become stained after In general, nails will become stained after 6 hours and vernix after 12 to 14 hours of 6 hours and vernix after 12 to 14 hours of exposure.exposure.


Affected patients typically have respiratory Affected patients typically have respiratory distress with marked tachypnea and distress with marked tachypnea and cyanosis. cyanosis.

Reduced pulmonary compliance and use of Reduced pulmonary compliance and use of accessory muscles of respiration are accessory muscles of respiration are evidenced by intercostal and subcostal evidenced by intercostal and subcostal retractions and abdominal (paradoxical) retractions and abdominal (paradoxical) breathing, often with grunting and nasal breathing, often with grunting and nasal flaring.flaring.


The chest typically appears barrel-shaped, The chest typically appears barrel-shaped, with an increased anterior-posterior diameter with an increased anterior-posterior diameter caused by overinflation. caused by overinflation.

Auscultation reveals rales and rhonchi -Auscultation reveals rales and rhonchi -immediately after birth.immediately after birth.

Some patients are asymptomatic at birth and Some patients are asymptomatic at birth and develop worsening signs of respiratory develop worsening signs of respiratory distress as the meconium moves from the distress as the meconium moves from the large airways into the lower tracheobronchial large airways into the lower tracheobronchial tree.tree.

DiagnosisDiagnosis

MAS must be considered in any MAS must be considered in any infant born through MSAF who infant born through MSAF who

develops symptoms of RD.develops symptoms of RD.

DiagnosisDiagnosis

The diagnosis of MAS is confirmed by The diagnosis of MAS is confirmed by chest radiograph.chest radiograph.

The initial CXR may show streaky, linear The initial CXR may show streaky, linear densities similar in appearance to densities similar in appearance to transient tachypnea of the newborn (TTN). transient tachypnea of the newborn (TTN).

As the disease progresses, the lungs As the disease progresses, the lungs typically appear hyperinflated with typically appear hyperinflated with flattening of the diaphragms. flattening of the diaphragms.

Diffuse patchy densities may alternate Diffuse patchy densities may alternate with areas of expansion. with areas of expansion.

Coarse focal consolidation with Coarse focal consolidation with emphysema.emphysema.

Hyperinflation and patchy Hyperinflation and patchy asymmetric airspace disease that asymmetric airspace disease that is typical of MAS.is typical of MAS.

Coarse interstitial infiltrates +L side Coarse interstitial infiltrates +L side

pneumothoraxpneumothorax

Areas of opacification due to Areas of opacification due to atelectasis bilaterally. atelectasis bilaterally.

Close up of left lung demonstrating the streaky Close up of left lung demonstrating the streaky lucencies of the air in the interstitium lucencies of the air in the interstitium (red arrows)(red arrows) complicated by a pneumothoraxcomplicated by a pneumothorax (yellow arrow).(yellow arrow).

DiagnosisDiagnosis

In infants with severe disease who require In infants with severe disease who require high concentrations of supplemental oxygen high concentrations of supplemental oxygen and mechanical ventilation, the lungs may and mechanical ventilation, the lungs may develop an appearance of homogeneous develop an appearance of homogeneous density similar to respiratory distress density similar to respiratory distress syndrome (RDS). syndrome (RDS).

Radiographic changes resolve over the course Radiographic changes resolve over the course of 7 to 10 days but sometimes persist for of 7 to 10 days but sometimes persist for several weeks. several weeks.

Air leak occurs in 10 to 30 percent of infants Air leak occurs in 10 to 30 percent of infants with MAS. with MAS.

Homogeneous density similar to respiratory Homogeneous density similar to respiratory distress syndrome (RDS). distress syndrome (RDS).

DiagnosisDiagnosis

Arterial blood gas measurements Arterial blood gas measurements typically show hypoxemia and typically show hypoxemia and hypercarbia. hypercarbia.

Infants with pulmonary hypertension and Infants with pulmonary hypertension and right-to-left shunting may have a right-to-left shunting may have a gradient in oxygenation between gradient in oxygenation between preductal and postductal samples. preductal and postductal samples.

2D Echocardiogram for evaluation of 2D Echocardiogram for evaluation of PPH.PPH.

Management Management

ManagementManagement

Sept 2007 the ACOG revised Sept 2007 the ACOG revised recommendations and recommended that recommendations and recommended that ““all infants with MSAF should not longer all infants with MSAF should not longer receive intrapartum suctioning. If meconium receive intrapartum suctioning. If meconium present and the newborn depressed, the present and the newborn depressed, the clinician should intubate the trachea and clinician should intubate the trachea and suction meconium from beneath the suction meconium from beneath the glottis”.glottis”.

Intrapartum suctioning not effective in Intrapartum suctioning not effective in removing meconium aspirated by the fetus removing meconium aspirated by the fetus into the lungs prior delivery. into the lungs prior delivery.


Skilled resuscitation team should be Skilled resuscitation team should be present at all deliveries that involve MSAF.present at all deliveries that involve MSAF.

Pediatric intervention depends on whether Pediatric intervention depends on whether the infant is vigorous.the infant is vigorous.

Vigorous infant is if has:Vigorous infant is if has:1.1. Strong resp. effortsStrong resp. efforts2.2. Good muscle toneGood muscle tone3.3. Heart rate >100b/mHeart rate >100b/m

When this is a case-no need for tracheal When this is a case-no need for tracheal suctioning, only routine management.suctioning, only routine management.


When the infant is not vigorous:When the infant is not vigorous:1.1. Clear airways as quickly as possible.Clear airways as quickly as possible.

2.2. Free flow 0Free flow 02.2.

3.3. Radiant warmer but drying and stimulation should be Radiant warmer but drying and stimulation should be delayed.delayed.

4.4. Direct laryngoscopy with suction of the mouth and Direct laryngoscopy with suction of the mouth and hypopharynx under direct visualization, followed by hypopharynx under direct visualization, followed by intubation and then suction directly to the ET tube as intubation and then suction directly to the ET tube as it slowly withdrawn.it slowly withdrawn.

5.5. The process is repeated until either ‘‘little additional The process is repeated until either ‘‘little additional meconium is recovered, or until the baby’s heart rate meconium is recovered, or until the baby’s heart rate indicates that resuscitation must proceed without indicates that resuscitation must proceed without delay’’.delay’’.

Postnatal ManagementPostnatal Management

Apparently Apparently well childwell child born through born through MSAFMSAF

Most of them do not require any Most of them do not require any interventions besides close interventions besides close monitoring for RD. monitoring for RD.

Most infants who develop symptoms Most infants who develop symptoms will do so in the first 12 hours of life.will do so in the first 12 hours of life.

Postnatal ManagementPostnatal Management

Approach to the Approach to the ill newbornsill newborns:: Transfer to NICU.Transfer to NICU. Monitor closely.Monitor closely. Full range of respiratory support should Full range of respiratory support should

be available.be available. Sepsis w/up and ABx indicated.Sepsis w/up and ABx indicated. Transfer to ECMO center may be Transfer to ECMO center may be

necessary.necessary.

Treatment in NICUTreatment in NICU

Goals:Goals: Increased oxygenation while minimizing Increased oxygenation while minimizing

the barotrauma (may lead to air leak) by the barotrauma (may lead to air leak) by minimal MAP and as short IT as possible.minimal MAP and as short IT as possible.

Prevent pulmonary hypertension. Prevent pulmonary hypertension. Successful transition from intrauterine to Successful transition from intrauterine to

extrauterine life with a drop in pulmonary extrauterine life with a drop in pulmonary arterial resistance and an increase in arterial resistance and an increase in pulmonary blood flow.pulmonary blood flow.


Severe MAS can spiral into Severe MAS can spiral into vicious cyclevicious cycle of of hypoxemia that leads to acidosis, which hypoxemia that leads to acidosis, which together cause pulmonary vein constriction. together cause pulmonary vein constriction.

May lead to persistent pulmonary May lead to persistent pulmonary hypertension. hypertension.

The resultant right-to-left shunting at the The resultant right-to-left shunting at the level of the ductus arteriosus, the atrial level of the ductus arteriosus, the atrial level, or both causes further cyanosis and level, or both causes further cyanosis and hypoxemia, which perpetuate the cycle. hypoxemia, which perpetuate the cycle.

Treatment in NICUTreatment in NICU Ventilatory supportVentilatory support depends on the amount of depends on the amount of

respiratory distress:respiratory distress:

OO22 hood hood Mechanical ventilation (40%). Mechanical ventilation (40%). CPAP (10%). CPAP (10%). Observational study showed worse outcome for Observational study showed worse outcome for

infants treated with hyperventilation.infants treated with hyperventilation. High-frequency ventilators should reduce air leak High-frequency ventilators should reduce air leak

syndromes in MAS, but animal and clinical models syndromes in MAS, but animal and clinical models have yielded conflicting results.have yielded conflicting results.

High-frequency ventilators may slow the High-frequency ventilators may slow the progression of meconium down the progression of meconium down the tracheobronchial tree and allow more time for tracheobronchial tree and allow more time for meconium removal.meconium removal.


SurfactantSurfactant Two randomized controlled studies have evaluated Two randomized controlled studies have evaluated

the efficacy of exogenous surfactant administration. the efficacy of exogenous surfactant administration. Results showed decreased number of infants Results showed decreased number of infants requiring ECMO and possible reduction of requiring ECMO and possible reduction of pneumothorax, but no difference in mortality.pneumothorax, but no difference in mortality.

A Cochrane meta-analysis of 4 randomized trials A Cochrane meta-analysis of 4 randomized trials confirmed that surfactant replacement showed no confirmed that surfactant replacement showed no effect on mortality but reduce the use of ECMO effect on mortality but reduce the use of ECMO (RR (RR 0.64, 95% CI, 0.46-0.91).0.64, 95% CI, 0.46-0.91).

Lavage with dilute surfactant-increases oxygenation Lavage with dilute surfactant-increases oxygenation and decrease the need of MV and decrease the need of MV (need additional trials).(need additional trials).


Inhaled NO

NO causes selective pulmonary vasodilation by NO causes selective pulmonary vasodilation by acting directly on the vascular smooth muscle-acting directly on the vascular smooth muscle-activates guanylate cyclase and increases cGMP.activates guanylate cyclase and increases cGMP.

By dilating blood vessels in well ventilated areas of By dilating blood vessels in well ventilated areas of lung, NO decreases the V/P mismatch and improved lung, NO decreases the V/P mismatch and improved oxygenation in infants with PPH. oxygenation in infants with PPH.

Decreases need for ECMO Decreases need for ECMO (RR 0.61, 95%CI 0.51, (RR 0.61, 95%CI 0.51, 0.72)0.72)

but no difference in mortality.but no difference in mortality. In a large randomized multicenter trial infants with In a large randomized multicenter trial infants with

MAS responded well to the combination of inhaled MAS responded well to the combination of inhaled nitric oxide and HFOV, likely because of improved nitric oxide and HFOV, likely because of improved lung inflation and better delivery of the drug.lung inflation and better delivery of the drug.

ECMOECMO

40% of infants with MAS treated with 40% of infants with MAS treated with inhaled NO fail to respond and inhaled NO fail to respond and require bypass.require bypass.

35% of ECMO patients are with MAS.35% of ECMO patients are with MAS. Survival rate after ECMO 93-100%.Survival rate after ECMO 93-100%.

Morbidity & MortalityMorbidity & Mortality

Pulmonary morbidity Pulmonary morbidity Pulmonary outcome evaluated in 35 Pulmonary outcome evaluated in 35

infants with MAS and 70 controls. infants with MAS and 70 controls. During the first 6mo after birth, the infants During the first 6mo after birth, the infants

with MAS were significantly more likely to with MAS were significantly more likely to have one or more episodes of wheezing have one or more episodes of wheezing and/or coughing lasting ≥3 days and/or coughing lasting ≥3 days (49% vs. (49% vs. 20%)20%) and receive bronchodilator therapy and receive bronchodilator therapy (23% vs. 3%)(23% vs. 3%) compared to controls. compared to controls.


Pulmonary function testing was performed at Pulmonary function testing was performed at 8y of age in 11 children who had MAS and 9 8y of age in 11 children who had MAS and 9 controls. controls.

The MAS group had evidence of mild airway The MAS group had evidence of mild airway obstruction, hyperinflation, and increased obstruction, hyperinflation, and increased closing volumes compared to controls, and closing volumes compared to controls, and had more exercise-induced bronchospasm had more exercise-induced bronchospasm (4 (4 vs. 0 children).vs. 0 children).

However, during graded exercise stress tests, However, during graded exercise stress tests, MAS children had normal maximal oxygen MAS children had normal maximal oxygen consumption and anaerobic threshold without consumption and anaerobic threshold without significant hypoxemia or hypercarbia.significant hypoxemia or hypercarbia.


Respiratory symptoms, pulmonary function tests, and Respiratory symptoms, pulmonary function tests, and chest radiographs evaluated in 18 children age 6-11y chest radiographs evaluated in 18 children age 6-11y who had MAS. who had MAS.

7 children had recurrent cough and wheezing 7 children had recurrent cough and wheezing consistent with asthma, and 5 of these had exercise-consistent with asthma, and 5 of these had exercise-induced bronchospasm that responded to induced bronchospasm that responded to bronchodilators. bronchodilators.

Of the 11 asymptomatic children, 2 had mild Of the 11 asymptomatic children, 2 had mild expiratory airflow limitation, 1-exercise-induced expiratory airflow limitation, 1-exercise-induced bronchospasm, and 8 had normal pulmonary function. bronchospasm, and 8 had normal pulmonary function. Chest radiographs were normal in all the children. Chest radiographs were normal in all the children.


Neurologic outcomeNeurologic outcome Outcome is good in uncomplicated Outcome is good in uncomplicated

MAS with no underlying disorder. MAS with no underlying disorder. Most cases of severe MAS are Most cases of severe MAS are

associated with intrauterine asphyxia associated with intrauterine asphyxia and/or infection and neurologic and/or infection and neurologic outcome depends upon these outcome depends upon these conditions. conditions.


In retrospective comparison, perinatal In retrospective comparison, perinatal mortality significantly higher in singleton mortality significantly higher in singleton pregnancies with/ than without MSAF pregnancies with/ than without MSAF (1.5 vs. (1.5 vs. 0.3/1000).0.3/1000).

The mortality rate for MAS resulting from The mortality rate for MAS resulting from severe parenchymal pulmonary disease and severe parenchymal pulmonary disease and pulmonary hypertension is as high as 20%.pulmonary hypertension is as high as 20%.

Severe fetal acidemia-cord arterial pH<7.0 Severe fetal acidemia-cord arterial pH<7.0 was significantly more common with was significantly more common with meconium-stained fluid meconium-stained fluid (7 vs. 3/1000).(7 vs. 3/1000).

Cesarean delivery was doubled in the Cesarean delivery was doubled in the meconium group meconium group (14 vs. 7%).(14 vs. 7%).

SummarySummary

Optimal care of an infant born Optimal care of an infant born through MSAF involves close through MSAF involves close collaboration between OBs and collaboration between OBs and Pediatricians.Pediatricians.

Effective communication and Effective communication and anticipation of potential problems is anticipation of potential problems is a corner stone of the successful a corner stone of the successful partnership.partnership.

References:References:

1. Meconium Stained Fluid: Approach to the Mother and the Baby Michele C. Walsh, MD, MS; Jonathan M. Fanaroff, MD, JD Clin Perinatol 34 (2007) 653–665

2. The epidemiology of meconium aspiration syndrome: incidence, risk factors, therapies, and outcome. Dargaville PA; Copnell B Pediatrics. 2006 May;117(5):1712-21.

3. Delivery room management of the apparently vigorous meconium-stained neonate: results of the multicenter, international collaborative trial. Wiswell TE; Gannon CM; Jacob J; Goldsmith L; Szyld E; Weiss K; Schutzman D; Cleary GM; Filipov P; Kurlat I; Caballero CL; Abassi S; Sprague D; Oltorf C; Padula M Pediatrics 2000 Jan;105(1 Pt 1):1-7.

4. Defecation in utero: a physiologic fetal function. Ramon y Cajal CL; Martinez RO Am J Obstet Gynecol 2003 Jan;188(1):153-6.

5. Surfactant and surfactant inhibitors in meconium aspiration syndrome. Dargaville PA; South M; McDougall PN J Pediatr 2001 Jan;138(1):113-5.

meconium-stained amniotic fluid (msaf) pediatrics point of view

Documents

thick meconium

inhalation of meconium

cases of meconium aspiration

meconiumstained fluid

cases of severe mas

mas clearywiswell

severe cases

intrauterine fetal gasping