1 Meconium Aspiration Syndrome Meconium MSAF Prenatal

Meconium Aspiration Syndrome
Rita M. Ryan, MD
Chief, Division of Neonatology
Professor of Pediatrics, Pathology and Anatomical
Sciences, and Gynecology-Obstetrics
Meconium
y
first intestinal discharge from newborns is meconium
◦ a viscous, dark green substance composed of intestinal epithelial cells,
lanugo, mucus, and intestinal secretions, such as bile.
◦ Intestinal secretions, mucosal cells, and solid elements of swallowed
amniotic fluid are the 3 major solid constituents of meconium.
◦ Water is the major liquid constituent, making up 85-95% of meconium.
y
Intrauterine distress can cause passage of meconium into the
amniotic
i i flfluid.
id
◦ Factors that promote the passage in utero include placental
insufficiency, maternal hypertension, preeclampsia, oligohydramnios, and
maternal drug abuse, especially of tobacco and cocaine.
y
y
Meconium-stained amniotic fluid may be aspirated during labor and
delivery, causing neonatal respiratory distress.
Because meconium is rarely found in the amniotic fluid prior to 34
weeks' gestation, meconium aspiration chiefly affects infants at term
and postterm.
Dave Clark emedicine 2004
Pediatric Grand Rounds October 3, 2008
Meconium Aspiration Syndrome - More Than Intrapartum Meconium
[Editorial]
Ross, Michael G.
New England Journal of Medicine. 353(9):946353(9):946-8, 2005 Sep 1.
Harbor--UCLA Medical Center
Harbor
Meconium, the fecal material that
accumulates in the fetal colon throughout
gestation, is a term derived from the Greek
mekoni,
k i meaning
i poppy juice
j i or opium.
i
Beginning with Aristotle's observation of the
association between meconium staining of
the amniotic fluid and a sleepy fetal state or
neonatal depression, obstetricians have been
concerned about fetal well-being in the
presence of meconium-stained amniotic
fluid.
MSAF
y
The passage of mec in utero accompanies 8% to 20%
(average 12-13%) of all deliveries
◦ <37 weeks Æ 2%
◦ >42 weeks Æ 44%
◦ seen predominantly in infants who are SGA and postmature,
cord complications or other factors compromising the in
utero placental circulation
MSAF is usually considered to be indicative of fetal
distress.
y Many MSAF babies exhibit no signs of depression, etc.,
but some brief period of asphyxia could have induced
the passage of mec before delivery.
y MAS seen in 4% of MSAF deliveries
y
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
Avery 1991, Hansen and Corbet
Prenatal Management
y
presence of MSAF is not always an
indication of fetal distress in all infants
◦ MSAF may signal fetal hypoxia, but if FHR, pH
remain normal then outcome usually
favorable
y
combination of MSAF and ominous FHR
tracing is often associated with significant
fetal and neonatal asphyxia with
accompanying morbidity
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
Pathophysiology
y
passage of meconium in utero:
◦ we think it is associated with asphyxia but data
actually are weak
◦ ? result of transient parasympathetic stimulation from
cord compression in a neurologically mature fetus
◦ ? natural phenomenon that reflects the maturity of
the GI tract
◦ most agree that MSAF plus FHR abnormalities are a
marker for fetal distress and associated with
increased perinatal morbidity
Avery 1991, Hansen and Corbet
1
Pathophysiology
y
y
y
Mec in the AF may stain the umb cord, placenta
and fetus
when fetal distress is present, gasping may be
initiated in utero Æ AF and particulate matter
contained therein may be inhaled into the large
airways
Î mec aspiration may occur antenatally
mec inhaled by the fetus may be present in the
trachea or larger bronchi at delivery Æ after air
breathing has commenced Æ rapid distal
migration of mec within the lung
Pathophysiology
y
If aspiration of meconium stained
amniotic fluid before, during, and after
birth occurs, there can be 3 major
pulmonaryy effects:
p
◦ airway obstruction
◦ surfactant dysfunction
◦ chemical pneumonitis
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
Ball--Valve Phenomenon
Ball
Dave Clark emedicine 2004
Pathophysiology
areas of atelectasis, resulting from total airway
obstruction, adjacent to
y areas of overexpansion, from gas trapping in regions
with partial obstruction
y Î “salt and pepper” appearance on CXR
y air leaks
y
◦ pneumomediastinum
◦ pneumothorax
chemical inflammation Æ pneumonitis
in vitro: concentration-dependent inhibition of
surfactant
y animal models: influx of inflammatory cells and protein,
inactivation of surfactant, decrease in surf proteins
y
y
during inspiration, lower
airways open Æ air can go
into the alveolar air space
however, during expiration, the lower
airways collapse and with the
meconium present air cannot leave Æ
air trapping Æ hyperinflation, PTX
Clinical Findings
postmaturity
mec staining – nails, skin, umbilical cord
y often perinatal depression
y
y
◦ neurologic, resp depression secondary to hypoxia (which
precipitated the passage of mec in the first place)
y
Severe respiratory distress may be present:
◦
◦
◦
◦
◦
◦
◦
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
Cyanosis
End-expiratory grunting
Alar flaring
Intercostal retractions
Tachypnea
Barrel chest in the presence of air trapping
Rales
Dave Clark emedicine 2004
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
2
PPHN in MAS
Clinical Manifestations
clinical symptoms progress over 12-24
hours as mec migrates to the periphery
y mec ultimately has to be removed by
phagocytosis
p
agocytos s Æ resp
esp distress
st ess and
a resp
esp
support may be persist for days or even
weeks
y
y
y
can be a major problem in infants with MAS
both prenatal and postnatal maladaptation of the
pulmonary circulation may contribute to the
development of PPHN in infants with MAS
◦ anatomic abnormalities
x evidence of injury to the vascular bed of the lung that dates back
several weeks prior to birth.
x Vasc smooth muscle extends into the walls of normally nonmuscularized intra-acinar arterioles Æ bad PPHN
◦ active vasoconstriction
x directly or may cause plt aggregation Æ release of thromboxane, a
potent pulm vasoconstrictor
Avery 1991, Hansen and Corbet
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
Avery 1991, Hansen and Corbet
CXR
coarse, irregular densities with areas of
diminished aeration and consolidation
y pneumomediastinum, PTX
y hyperinflation
y cardiomegaly at times, due to perinatal
asphyxia
y “salt and pepper”
y
Meconium Aspiration
Air trapping and
yp
p
from
hyperexpansion
airway obstruction
Dave Clark emedicine 2004
Left pneumothorax with
depressed diaphragm
and minimal mediastinal
shift because of
noncompliant lungs
Dave Clark emedicine 2004
3
Treatment
y
Diffuse chemical
pneumonitis
from constituents
of meconium
let them breathe fast in hood oxygen
◦ arterial line – frequent ABGs
◦ minimal stimulation
◦ try to avoid intubation
y
if intubate – no longer aggressive in hyperventilation /
alkalosis but avoid hypercarbia / acidosis
◦ no consensus on “optimal”
optimal vent strategy
◦ if a lot of parenchymal disease Æ HFOV
y
target normal blood pressure
y
not a big fan of nasal CPAP
y
if intubate, use sedation generously
y
nothing on this slide has been well-studied
◦ avoid hypotension Æ PPHN
◦ just makes them mad
◦ may need paralysis (no data)
Dave Clark emedicine 2004
Treatment
Surfactant
r/o sepsis but not automatic commitment
to a full course Abx
y steroids are not recommended –
textbook
te
tboo recommendation
eco
e at o but this
t s may
ay
be changing….
y
y
meconium may inhibit surf function Æ
role for exogenous surf
y multicenter RCT of term infants with
severee resp
seve
esp failure,
a u e, 50% of
o whom
w o had
a
MAS as primary dx Æ surf decr need for
ECMO
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
Lotze et al, (J Pediatr 1998;132:401998;132:40-7)
y
y
y
Need for ECMO (%)
A multicenter (n = 44), randomized, doubleblind, placebo-controlled trial was conducted.
Infants > 2000g and > 36 wks, OI* 15-39,
n=328
stratified:
◦ by diagnosis (MAS, sepsis, or idiopathic PPHN) and
◦ oxygenation index (15 - 22, 23 - 30, 31 - 39)
y
four doses of surfactant (Survanta) 100 mg/kg
or air placebo, every 6 hours before ECMO
treatment and four additional doses during
ECMO, if ECMO was required.
*OI = FiO2 x MAP
pO2
The need for ECMO therapy was significantly less in the surfactant group than in
the placebo group (p = 0.038)
4
Need for ECMO (%)
this effect was greatest within the lowest oxygenation index stratum
(15 to 22; p = 0.013).
Steroids in MAS - Cochrane Review - 2003
Steroid therapy for meconium aspiration syndrome in
newborn infants
Cochrane Reviews
Ward, M; Sinn, J
Date of Most Recent Update: 25-August-2003
At present, there is insufficient evidence to assess the effects of steroid
therapy in the management of meconium aspiration syndrome. A further
large randomized controlled trial assessing potential benefits and harm would
be required to determine its role.
role.
(85 patients in 2 trials)
Modes of action to explain efficacy of
steroids
inhibition of prostaglandin and leukotriene
synthesis
y removal of excess edema fluid
y suppression of cytokine mediated
inflammatory reaction
y inhibition of nitric oxide production
y
5
y
y
y
y
y
y
y
Sultantate of Oman
pilot study, case series, not RCT
all ventilated, all OI >25, all PPHN
average age starting dex 80hrs
dex 0.5/kg/day div q12h x3d, 0.3 x3d, 0.125 x3d
steroids started if not weaning on vent or OI worsening over
16h
RCT, 3 arms
◦ placebo
◦ 0.5 mg/kg/d Methylprednisilone div q12h
◦ 50 ug q12h budesonide
y
blinded
y
not sure if ventilated population
2006
Steroids
Results
2 deaths, both in placebo group (one with
massive PTX, one with sepsis/DIC)
y no baby in steroids group needed MV
y
y
y
RCT, n=99, 3 arms, not blinded
placebo, methylprednisilone 0.5mg/kg/d q12h x7d,
budesonide 50ug q12h x7d
6
Steroids for MAS
Need larger studies
y Need long term follow up
y
◦ Effects on brain / neurodevelopment
x Need reallyy large
g studies
y
Inflammation in MAS
11 neonatal patients with MAS, 16 neonates without
MAS, and 9 healthy children.
y 6 cytokines higher in MAS compared with non-MAS
neonates:
Could be useful for sickest babies
Steroids in MAS
y
◦ IL-6, IL-8, GM-CSF, G-CSF, interferonγ, MIP-1, and TNF
y
y
y
Tripathi et al, Ind J Med Microbiology (2007) 25
(2):103-7
RCT, blinded, 3 groups
◦ Placebo, methylprednisilone, inhaled budesonide
IL-10 (anti-inflammatory cytokine) also was higher in
the MAS group
x Steroids given for 7 days
◦ Tracheal aspirates on day 1, 3, 4
y
y
Decreased TNFα in steroid treated groups
TNFα levels correlated with LOS
Controversies in the treatment of meconium
aspiration syndrome
Controversies in the treatment of
meconium aspiration syndrome
y
25,000-30,000 cases per year in US
Gelfand, J Fanaroff, Walsh, Clinics in Perinat
2004;31,445-452
y
13% of live births have MSAF
•
•
•
Amnioinfusion
intrapartum suctioning
tracheal suctioning
◦ 1000 deaths annually
◦ onlyy 5% of these babies have MAS
y
MAS defined as “resp distress in an
infant born through MSAF whose
symptoms cannot be otherwise
explained”
Gelfand, J Fanaroff, Walsh, Clinics in Perinat 2004;31,445-452
7
Amnioinfusion
Fraser WD et al, N Engl J Med 2005;353: 909-17
Average BW 3.4 kg
dilutes meconium
relieves cord compression Æ relieving
hypoxia Æ decreasing gasping
y does it reduce MAS? – meta-analysis of
13 studies suggests that both fetal
distress and MAS are decreased:
y
y
x Hofmeyr, GJ et al, Cochrane review, 2001, 2004
update
Gelfand, J Fanaroff, Walsh, Clinics in Perinat 2004;31,445-452
Table 3 continued…
Amnioinfusion – Fraser WD et al
N Engl J Med 2005;353: 909909-17
y
Conclusions: For women in labor who
have thick MSAF, amnioinfusion did not
reduce the risk of moderate or severe
meconium aspiration
p
syndrome,
y
perinatal
p
death, or other major maternal or
neonatal disorders.
DeLee and tracheal suctioning
y
preventive approach
◦ thorough suctioning of nose and pharynx by
OB after delivery of head but before thorax
is delivered and the infant can take a breath
◦ if infant depressed Æ tracheal suctioning to
remove residual mec
Amnioinfusion does not prevent meconium aspiration syndrome.
ACOG Committee Opinion No. 346.
American College of Obstetricians and Gynecologists.
Obstet Gynecol 2006;108:1053–5.
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
8
Intrapartum suctioning
y
considered standard for 25 years
y
Wiswell et al Peds 2000;105:1-7
x Carson et al Am J Ob Gyn 1976;126:712-5
Fanaroff
and Martin
2002,
Miller,
Fanaroff
and Martin
◦ RCT studyy to examine tracheal suctioningg 2094 infants
◦ MAS increased in those who did not receive
intrapartum oropharyngeal suctioning before
delivery of the shoulders (8.5% vs. 2.7%, OR
3.35, CI 1.55-7.27)
Gelfand, J Fanaroff, Walsh, Clinics in Perinat 2004;31,445-452
Intrapartum Suctioning – NRP
2005
y
y
y
y
Aspiration of meconium before delivery, during birth, or
during resuscitation can cause severe aspiration pneumonia.
One obstetrical technique to try to decrease aspiration has
been to suction meconium from the infant’s airway after
delivery of the head but before delivery of the shoulders
(intrapartum suctioning).
Although some studies (LOE 3) suggested that intrapartum
suctioning might be effective for decreasing the risk of
aspiration syndrome, subsequent evidence from a large
multicenter randomized trial (LOE 1) did not show such an
effect.
Therefore, current recommendations no longer advise
routine intrapartum oropharyngeal and nasopharyngeal
suctioning for infants born to mothers with meconium
staining of amniotic fluid (Class I).
Circulation 2005
y
y
Circulation 2005
Recommendations were generally labeled Class IIb when the
evidence documented only short-term benefits from the therapy
or when positive results were documented with lower levels of
evidence.
Class IIb recommendations fall into 2 categories:
◦ (1) optional and
◦ (2) recommended by the experts despite the absence of high-level
supporting evidence.
◦ Optional interventions are identified by terms such as “can be
considered” or “may be useful.” Interventions that the experts
believe should be carried out are identified with terms such as “we
recommend.”
Vain et al, Lancet 2004;364;597-602
9
Intrapartum suctioning
Infants were randomly allocated to either suctioning
of the oropharynx and nasopharynx (including the
hypopharynx) before delivery of the shoulders
(suction group), or no suctioning (no-suction group).
y 10-Fr to 13-Fr connected to a negative pressure of
150 mm Hg.
Hg
y Oropharyngeal suctioning was done first, followed by
bilateral nasopharyngeal suctioning, when possible.
y Thereafter, care was given according to NRP
y
◦ tracheal suctioning for non-vigorous infants
Vain et al, Lancet 2004;364;597-602
Vain et al, Lancet 2004;364;597-602
Intrapartum suctioning
y
y
The primary outcome was incidence of MAS.
Diagnosis of the syndrome was defined by
(1) respiratory distress (tachypnea, retractions, or
grunting) in a neonate born through MSAF;
(2) need
d ffor supplemental
l
l oxygen to maintain
i i oxygen
saturation levels at 92% or greater;
(3) oxygen requirements starting during the first 2 h of
life and lasting for 12 h or longer; and
(4) absence of congenital malformation of the airway,
lung, or heart.
Vain et al, Lancet 2004;364;597-602
Vain et al, Lancet 2004;364;597-602
DeLee and tracheal suctioning
y
preventive approach
◦ thorough suctioning of nose and pharynx by
OB after delivery of head but before thorax is
delivered and the infant can take a breath
◦ if infant depressed Æ tracheal suctioning to
remove residual mec
Fanaroff
and Martin
2002,
Miller,
Fanaroff
and Martin
Fanaroff and Martin 2002, Miller, Fanaroff and Martin
10
Tracheal Suctioning – NRP
2005
Traditional teaching recommended that meconiumstained infants have endotracheal intubation
immediately following birth and that suction be applied
to the endotracheal tube as it is withdrawn.
y Randomized controlled trials have shown that this
practice offers no benefit if the infant is vigorous (Class
I). A vigorous infant is defined as one who has strong
respiratory efforts, good muscle tone, and a heart rate
100 beats per minute (bpm).
y Endotracheal suctioning for infants who are not
vigorous should be performed immediately after birth
(Class Indeterminate).
y
Circulation 2005
Circulation 2005
Tracheal suctioning
y
Linder et al – Israel – J Peds 1988 – n>500
◦ no morbidity in infants with Apgar scores of 8 or
higher at 1 minute who had been deLee suctioned
y
Wiswell et al Peds 2000;105:1-7
◦ prospective RCT of vigorous infants with MSAF
◦ 2094 iinfants
f t att 12 centers,
t
vigorous
i
bbaby
b
◦ 149 (7.1%) of enrolled infants Æ resp distress
x 62 (3%) dx with MAS
x 87 (4.2%) other (TTN, delayed transition, sepsis, PPHN)
◦ no diff whether tracheally suctioned or not
x MAS 3.2% intubated vs. 2.7% non-intubated
◦ no diff in other resp disorders
Meconium Aspiration Syndrome
Is Surfactant Lavage the Answer?
John P. Kinsella, AJRCCM, 2003;168:4132003;168:413-4
commentary
y method to enhance removal of particulate meconium
from the airway using bronchoalveolar lavage with a
dilute bovine surfactant preparation.
y 2 week old piglets
y They found that a 30-ml/kg lavage volume of dilute
surfactant was associated with increased meconium
removal, improved post-lavage lung function, and less
lung injury as compared with perflourocarbon emulsion
or multiple, smaller aliquots of dilute surfactant.
Endotracheal intubation at birth for preventing
morbidity and mortality in vigorous, meconium
meconium-stained infants born at term
Halliday, HL; Sweet, D; Cochrane review, 2000, 2005
4 RCTs
y Meta-analysis of these trials does not support routine
use of endotracheal intubation at birth in vigorous
meconium-stained babies to reduce mortality, MAS,
other resp symptoms / disorders,
disorders PTX,
PTX O2 need,
need stridor,
stridor
HIE and convulsions.
y Conclusions: Routine endotracheal intubation at birth in
vigorous term meconium-stained babies has not been
shown to be superior to routine resuscitation including
oro-pharyngeal suction.
y This procedure cannot be recommended for vigorous
infants until more research is available.
y
y
Dargaville, Morley et al, Melbourne, AJRCCM 2003; 168:456–463
controls
perfluorocarbon
y
dilute surf lavage
11
dilute surf lavage
Therapeutic lung lavage in meconium
aspiration syndrome: A preliminary report
perfluorocarbon
y
Dargaville, Morley et al (Australia)
y
Infants with severe MAS, HFOV
Lavaged infants typically stablized but not improving, still on high
FiO2 with an alveolar-arterial oxygen difference (AaDO2) of >400
mm Hg
◦ Journal of Paediatrics and Child Health 43 (2007) 539–545
y
◦ Lavage not performed if arterial pH < 77.20,
20 sat < 75%
75%, or mean bp <35
mm Hg
◦ Lavage performed in sedated muscle-relaxed infants
y
y
1/5 dilution of Survanta, mixed gently in sterile NS and warmed to
37°C, delivered via catheter protruding approximately 0.5 cm
below ETT
Lavage aliquot volumes were increased through the case series,
aiming to deliver two aliquots of 15 mL/kg 3-5 minutes apart
Dargaville, Morley et al, Melbourne, AJRCCM 2003; 168:456–463
Surfactant lavage
y
8 babies enrolled
◦ median age of 23 h (range 8–83 h)
◦ 88% nitric oxide, 3 on adrenalin infusion
◦ lavage was associated with significant
desaturation but not bradycardia or hypotension
y
y
3 in “Therapeutic lavage group”Æ subgroup
of infants who received at least 25mL/kg
within 24h age
34 babies in non-lavaged group
No lavage
all lavaged infants
P=0.03 repeated measures ANOVA
“Tx” lavage
◦ Comparable, if anything, lavaged babies sicker
Surfactant lavage
efficacy deserves further investigation in a
randomized controlled trial
y About 10 prior human studies
y RCT – Surfaxin ongoing
◦
y “lessMAS”
y Lavage with Exogenous Surf Suspension in MAS
ECMO usage
iNO
HFOV
y surfactant
y less post-term pregnancies
Æ less ECMO
y
y
Gelfand, J Fanaroff, Walsh, Clinics in Perinat 2004;31,445-452
12
Decreased Use of Neonatal Extracorporeal Membrane
Oxygenation (ECMO): How New Treatment Modalities
Have Affected ECMO Utilization
1993-4
1996-7
Patients were included if:
y
◦
◦
◦
◦
*OI >15 x 1 within the first 72 hours
of admission
>35 weeks
dx MAS, PPHN or sepsis/pneumonia
<5 days of age on admission
Pre-ECMO surfactant
iNO
3 (6.1%)
0
18 (44.7%)
*OI = FiO2 x MAP
pO2
Hintz S et al, Pediatrics 2000;106:1339– 1343
Neonatal Respiratory ECMO
Conrad SA et al, ASAIO Journal 2005;51:4-10
Hintz S et al, Pediatrics 2000;106:1339– 1343
Neonatal Respiratory ECMO
Conrad SA et al, ASAIO Journal 2005;51:4-10
From the Departments of Pediatrics and Obstetrics/Gynecology,
Wilford Hall Medical Center, Lackland AFB,Texas
Obstet Gynecol 2002;99:731–9
CONCLUSION: Reduction in post-term
delivery was the most important factor in
reducing meconium aspiration syndrome.
Yoder et al, Obstet Gynecol 2002;99:731–9
13
Yoder et al, Obstet Gynecol 2002;99:731–9
Yoder et al, Obstet Gynecol 2002;99:731–9
Yoder et al, Obstet Gynecol 2002;99:731–9
Yoder et al, Obstet Gynecol 2002;99:731–9
Yoder et al, Obstet Gynecol 2002;99:731–9
Yoder et al, Obstet Gynecol 2002;99:731–9
14
Results
y
MASINT
◦ 1061of 2,490,862 live births (0.43 of 1000)
◦ decrease in incidence from 1995 to 2002
Pediatrics 2006;117;1712-1721
May 2006
Data were gathered on all of the infants in Australia and New Zealand who
were intubated and mechanically ventilated with a primary diagnosis of
MAS between 1995 and 2002, inclusive. Information on all of the live births
during the same time period was obtained from perinatal data registries.
y
MASINT
◦ 34% > 40 weeks’ gestation
◦ 6.5% > 41 weeks’ gestation
g
y
total birth population
◦ 16% > 40 weeks’ gestation
◦ 2.0% > 41 weeks’ gestation
y
y
P < .001 in both cases
Associated with MASINT:
◦ low 5-minute Apgar score
◦ maternal ethnicity Pacific Islander or indigenous Australian
◦ planned home birth
MASINT = intubated for MAS
Possible etiology of lower MASINT
Compared with 1995, in 2002, there were
fewer deliveries beyond 41 weeks’
gestation (1.6% vs 2.8%; P .001) and
y fewer infants with a 5-minute Apgar score
<7
7 (1.4%
(1 4% vs 1.7%;
1 7% P .001).
001)
y These factors combined account for 62%
of the reduction in MAS incidence noted
in this time period.
y
15
Yoder et al, Ob Gyn,
Gyn, March 2008
Is there a trade-off?
Logistic regression Æ
5 factors
independently related
to resp morbidity:
GA, C/S, male, FHR,
low 5 min Apgar
Change in GA distribution from 1990 to 1998
Yoder et al, Ob Gyn March 2008
Summary
y
y
y
y
y
y
MSAF is often associated with in utero fetal distress and
hypoxia.
The pathophysiology of MAS includes airway obstruction,
surfactant inactivation and a chemical pneumonitis leading to
air trapping, atelectasis and PPHN.
Standard therapy for MAS includes supplemental oxygen,
mechanical ventilation, surfactant, nitric oxide and ECMO.
The use of ECMO for MAS-PPHN patients is decreasing due
to the increased use of other therapies such as HFV,
surfactant and iNO.
Preventive measures such as amnioinfusion, intrapartum oroand naso-phayngeal suctioning, and tracheal suctioning are
now controversial and no longer recommended as routine.
The incidence of MAS is decreasing, primarily related to
fewer post-mature infants and less intrapartum fetal distress.
16