Clinical Approach to Respiratory Distress in Newborn
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Transcript of Clinical Approach to Respiratory Distress in Newborn
Clinical approach to Respiratory Distress in Newborn. Indian J Pediatr (Supplement- optimum pulmonary care of neonates) 2003;70: S53 – S59
CLINICAL APPROACH TO RESPIRATORY DISTRESS IN NEWBORN
K. K. Diwakar MD.
Head, Neonatal Division,
Professor, Department of Pediatrics,
Kasturba Medical College, Manipal,
Karnataka – 576119.
Correspondence:
K. K. Diwakar MD.
Head, Neonatal Division,
Professor, Department of Pediatrics,
Kasturba Medical College, Manipal,
Karnataka – 576119
Tel: 08252 – 571201 ext 22466
FAX: 08252 – 570061 attn: KK Diwakar, NICU.
e-mail: [email protected]
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ABSTRACT
Respiratory distress is a common reason for a neonate seeking medical attention. The
clinical features of tachypnea, intercostals retractions, grunting or cyanosis could be the
manifestations of a variety of etiological causes. Both pulmonary and extrapulmonary
causes could present as tachypnea and respiratory distress. While conditions like Hyaline
membrane disease (HMD) is seen more in premature infants, others like Meconium
Aspiration Syndrome (MAS) considered a disease of the more mature infant. Infections
and structural anomalies like Tracheo-esophageal fistula (TEF)and Congenital
Diaphragmatic Hernia (CDH) are common in both term and preterm infants. Stabilization
of the infant and early recognition of the etiology helps in minimizing complication and
ensuring appropriate definitive therapy. An overview of a few common cause of
respiratory distress in the newborn is being discussed in this article.
Key words: Respiratory Distress, Newborn.
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Respiratory distress is a common cause of admission of a Neonate in the intensive care
unit. 1, 2 .The clinical picture of a neonate with varied combination of tachypnea,
retractions, nasal flaring, grunting and cyanosis constitute a familiar scenario in a
neonatal intensive care unit. When faced with a neonate with respiratory distress it
becomes necessary to compartmentalize the management into an initial phase focusing on
the degree of respiratory compromise, resuscitation of the neonate and optimizing its
tissue oxygenation, and a planned subsequent phase to clarify the nuances of etiology,
definitive management and follow up.
The weight and gestation of the infant and the degree of respiratory compromise would
be the key factors to decide the level of care the infant would require. While infants of
lower weight and gestation would require more advanced facilities, larger infants can
often be managed at smaller centers. Simple clinical scores like the Downes’s score 3 if
meticulously documented at 30 – 60 minutes intervals are very useful to determine the
progression of the respiratory distress. The importance of such an evaluation would be
invaluable to plan referrals in the resource-limited environment of developing countries,
where structured neonatal transportation facilities are unavailable. A clinical evaluation
should whenever possible include oxygen saturation (SaO2) assessment by Pulse
Oximetry. SaO2 below 88 % would indicate hypoxia. While SaO2 between 88 – 94 %
would be normal in the more premature neonates, higher SaO2 values are the norm in
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term infants. Increasing requirement of inspired oxygen, to maintain ‘normal’ SaO2
would therefore be an ominous sign.
While the clinical presentation could be similar, the etiology, prognosis and management
of the patients presenting with respiratory distress could be varied and diverse. The
‘distress’ of the infant could be attributed to pulmonary or extra-pulmonary disorders.
A functionally normal lung could be at times called upon to work at a capacity far
exceeding natural level, in order to compensate for abnormalities of other systems. eg. In
the presence of metabolic acidosis, cardiac disease or abdominal distension. The extra
effort required of lungs enclosed in a compliant rib-cage could manifest as tachypnea,
chest retraction, prominence of accessory muscles of respiration and resultant fatigue
leading to further de-compensation. The definitive management of such an infant would
naturally be based on the treating the primary ‘extra-pulmonary etiology.
It must be reinforced that the initial management of all infants presenting with respiratory
distress is aimed at preventing hypoxia, hypercapnia and acidosis in the newborn. The
methods adapted for this could vary from oxygen supplementation to various strategies of
mechanical ventilation.
Despite a relatively uniform approach to the initial management, one must realize that
procrastination and delay in instituting definitive therapy would result in adverse
outcome. For example, an infant with tension pneumothorax could rapidly deteriorate
despite the transient improvement of initial therapy, if the pneumothorax is not
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evacuated. Similarly, repeated aspiration pneumonia would contribute to poor surgical
outcome in patients with delayed diagnosis of tracheoesophageal fistula (TEF). Therefore
a definite diagnosis is mandatory for successfully managing infants with respiratory
distress.
The cause of for neonatal respiratory distress could be broadly classified as
1) Causes affecting respiration at alveolar level: HMD, Pneumonia, Meconium
Aspiration Syndrome, Pneumothorax, pulmonary hemorrhage, PPHN, TTN
2) Structural anomalies of respiratory tract: eg Choanal Atresia, Tracheo-esophageal
fistula, Congenital Diaphragmatic hernia, Congenital Lobar Emphysema.
3) Extrapulmonary causes: eg. Bone defects of the chest wall, Congenital heart
disease, Metabolic acidosis.
Is the respiratory distress and cyanosis due cardiac or pulmonary problems? Is the
distress an effect of metabolic acidosis due to some other cause?
Differentiating a cardiac from pulmonary cause is often easier said than done. The
radiological picture of total anomalous pulmonary venous connection (TAPVC) or that of
a hypoplastic left heart with pulmonary edema would often resemble that of common
pulmonary causes for neonatal respiratory distress. Radiological differentiation becomes
even more difficult in the presence of an under expanded lung or a rotated view! It used
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to be believed that ‘hyperoxia test’ done by ventilating the infant for 20 minutes in 100%
oxygen would help differentiate the pulmonary from cardiac causes. While an arterial
oxygen concentration (PaO2) greater than 200 - 250 torr favours a pulmonary cause,
lower values do not positively indicate a cardiac etiology. The availability of
Echocardiography has thankfully made the diagnosis of a cardiac disease immeasurably
easier.
Tachypnea and ‘respiratory distress’ could be a presentation of metabolic acidosis. Renal
disease, inborn errors of metabolism (IEM) and late metabolic acidosis are forerunners of
a long list of causes for metabolic acidosis. While a history of oligohydraminios,
poor urine output or urine stream could suggest a renal disease, a history of sibling death
or sibling with similar clinical presentation would favour IEM. A low birth weight infant
on ‘cow’s milk’ supplementation should arouse the suspicion of late metabolic acidosis.
Chest X-ray unexplainably normal to justify the degree of tachypnea should alert one to
the possibility of metabolic acidosis being the cause for the distress. SaO2 is usually
normal in these patients. Arterial blood gases would confirm metabolic acidosis.
Biochemical evaluation for renal failure, renal tubular acidosis (RTA) and IEM constitute
an essential part of managing such patients.
Pulmonary disorders that manifest in the newborn are usually related to immaturity of the
lung, events that occurred in the perinatal period, or a result of congenital
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malformations 4 . The role of history in diagnosing the disease can never be
overestimated. It could be confidently said that the pulmonary causes for respiratory
distress are far commoner than the ‘extra pulmonary’ ones.
The gestation of the infant is probably the single most important factor that influences our
clinical outlook. While structural anomalies and pneumonia are common in both term and
preterm infants, conditions like Hyaline membrane disease is almost an exclusive disease
of the premature infant. Meconium aspiration on the other hand is almost always seen in
term infants. (Table 1). Some of these conditions are being briefly discussed.
HYALINE MEMBRANE DISEASE
This is the commonest respiratory problem of a premature infant . Nearly 80 % of infants
less than 28 weeks develop RDS compared to about 20 % among those between 33 – 34
weeks gestation. 4 . The increased use of antenatal corticosteroids, have definitely shown
to decrease the incidence and severity of HMD 5 .
Factors like poorly controlled diabetes in the mother, fetal or perinatal asphyxia,
anterpartum hemorrhage in mother and multiple pregnancies 6 increase the chances of
RDS in the neonate.
The picture of rapidly progressing respiratory distress, manifesting with tachypnea,
expiratory grunt, intercostals recession, active accessory muscles of respiration and
cyanosis in a premature infant would highlight a diagnosis respiratory distress syndrome.
Often the infant is born with a good cry. This forced expiration thru a partially closed
glottis generates significant distending pressures to open up most of the alveoli. The
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inadequacy of surfactant however results in progressive alveolar collapse. The rapidity of
the collapse and the efficacy of respiratory efforts of the infant determining the
progression and severity of the clinical features. It is therefore easy to understand the
reason for very premature or inadequately resuscitated infants and neonates with severe
surfactant deficiency to present immediately after birth with cyanosis and often as
respiratory failure.
By 72 to 96 hrs of postnatal age the infant would start generating its own surfactant to
increase the compliance of the lung, thereby resulting in natural recovery. Preventing the
progression of alveolar collapse during this intervening period therefore forms the basis
of all treatment. A heavier less premature infant could probably sustain its alveolar
surface area by its own respiratory effort till this dramatic natural turn about of events
occur by 72 to 96 hrs of life. More often than not mechanical ventilator support and
surfactant replacement are required to tide over the tumultuous initial days of this
surfactant deficiency state.
PNEUMONIA
Indian literature attributes pneumonia as the commonest cause for neonates presenting
with respiratory distress. 2, 7 . Pneumonia could be acquired due to a transplacental spead
of virus or bacteria, or acquired in the perinatal or post natal period. A detailed history to
seek out maternal infection or Premature rupture of membranes would therefore be
invaluable 8 .
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One must always hasten to rule out pneumonia in an infant presenting beyond the 1st few
days of life with Tachypnea and difficulty to feed. A decrease in the normal activity of
the infants as noticed by the mother would most certainly reinforce this suspicion. Early
onset pneumonia is very difficult to distinguish from conditions like HMD – more so in
the premature infant. While radiological evaluation could help differentiate pneumonia
from other conditions, in some cases like group B streptococcal pneumonia even this
becomes virtually impossible. Its this authors personal observation systemic features like
poor perfusion, metabolic acidosis and altered glucose homeostasis are more common in
pneumonia than in hyaline membrane disease. Another clue could be the excessive and
thick endotracheal secretion in the 1st day of life --- a feature that is almost never seen in
infants being ventilated for hyaline membrane disease.
Early antibiotic therapy with a ‘Penicillin + Aminoglycoside’ combination, still
continues to be the most accepted line of therapy. It must be reinforced that intravenous
antibiotics must be commenced without delay. It’s the practice to collect blood samples
for investigations including blood culture as soon as the infant is admitted and thereof
immediately give the first dose of antibiotics as per the policy of the treating unit.
Antibiotics can subsequently be tailored according to the culture and sensitivity pattern of
the isolates. Supportive therapy with inotropes and ventilator support must be initiated
based on the clinical condition of the infant. These play very significant role in the
survival of the infant.
MECONIUM ASPIRATION SYNDROME:
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Any infant who passes meconium in-utero is at risk for developing meconium aspiration
syndrome (MAS). While 10 – 15 % of all babies could pass meconium before birth, its
rare before 37 weeks 9. The passage of meconium could at occasions be an effect of fetal
hypoxemia. Occasionally pre-term infants over 34 wks of gestation may pass meconium
inutero. The clinical features of these infants are the same as those seen in term infants 4.
Therefore a history of meconium stained amniotic fluid is mandatory before attributing
the respiratory distress of the neonate to meconium aspiration syndrome.
The consistency of the meconium, adequacy of oro-pharyngeal suction before delivery of
shoulder, associated perinatal asphyxia warranting active resuscitation have all been
shown to influence the severity of meconium aspiration syndrome 9. The aspirated
meconium can completely or partially block the conducting airways leading to segmental
or sub-segmental collapse of the lung. The partial block could function as a ‘ball-valve’
leading to emphysematous changes in the area distal to the obstruction. Rapidity of the
resultant distention could lead to airleaks manifesting as pneumothorax.
The immediate respiratory distress seen in an infant who has aspirated meconium can
therefore easily be attributed to the ‘mechanical’ effects of meconium. However over the
next few hours, diffuse inflammatory responses occur throughout the lung leading to a
picture of ‘chemical pneumonitis’ 9. We have, not uncommonly, noticed such a picture
developing even in infants born through thin MSAF who were asymptomatic in the initial
period after delivery.
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The progressive ventilation /perfusion mismatch and inflammatory responses of MAS
can lead pulmonary vasoconstriction resulting in persistent pulmonary hypertension of
the newborn (PPHN), with its additional morbidity.
The approach to management would be to anticipate MAS in all infants with MSAF.
At Delivery: A good suction of the pharynx before delivery of the shoulders would
significantly reduce the chances of meconium aspiration. It was the recommendations of
the American Academy of Pediatrics and American Heart Association 10 to undertake
endotracheal suction in all infants if there was a (1) Evidence of in utero fetal distress (2)
Neonate is depressed or requires positive pressure ventilation in the delivery room (3)
Meconium is thick, including moderately thick or particulate in nature (4) if obstetric
pharyngeal suction was not performed. However reservations have been expressed about
undertaking endotracheal suction in a vigorously crying infant, even in the presence of
thick meconium 11.
Subsequent management: This phase of management is to evaluate the progression of
MAS and to detect and treat promptly the complications like pneumothorax and PPHN.
An X-ray of the chest might show patchy non-homogeneous opacities often confluencing
towards the mid-zone, with evidence of segmental or subsegmental collapse and areas of
hyperaeration. The presence of a pneumothorax must always be looked for. Occasionally
the X-ray taken immediately after birth could look apparently normal, but a subsequent
film taken over the next 12 – 24 hours might show diffused haziness, non-homgeneous
opacity --- probably reflecting the occurrence of ‘chemical pneumonitis’. Infants are
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more often than not symptomatic during this period. Irrespective of the controversies of
endotracheal suction, its best not to forget that even a vigorously crying infant can
develop all the meconium associated morbidity. It has therefore been our practice to
observe all infants born thru MSAF for at least 24 hrs, keeping an hourly record of the
Downe’s score 3 and continuously monitoring the SaO2 by pulseoximetry.
An increasing respiratory distress would imply that the pulmonary functions have been
compromised by the ‘mechanical’ effects of meconium or due to the development of
chemical pneumonitis. Occurrence of pneumothorax must always be anticipated. Efforts
to rule out pneumothorax must be undertaken especially when, an apparently normal
infant with minimal tachypnea, shows increasing respiratory distress, often after an
episode of vigorous and active crying. A fibre optic source of light is often used to detect
pneumothorax by transilluminating the chest. While a positive transillumination is
suggestive of pneumothorax, one must remember that this test could be negative in term
infants with ‘thicker’ skin. A chest X-ray would confirm the presence of pneumothorax.
A progressive increase in the clinical score would undoubtedly be the most practical and
cost effective way for continuous evaluation. Increasing oxygen demand and a worsening
Downes’ score are ominous signs of a progressive disease.
Fluctuations in the oxygen saturation with the same Fi02, in a quiet infant should arouse
the suspicion of pulmonary vascular instability. Such infants must be monitored more
carefully, with arterial blood gases from an indwelling arterial catheter. A higher ambient
Fi02 could reduce the chances of hypoxemia with its accompanying risk of pulmonary
vasoconstriction. 4. Progressive hypoxia, increasing oxygen demands, metabolic or
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respiratory acidosis, or hypercapnia, should be taken as indications for initiating
mechanical ventilation. Its best to prevent an infant from progressing to established
PPHN.
Antibiotics are usually not warranted. It is however a common practice of doctors to
commence antibiotics, in the presence of abnormal chest-X-ray or respiratory distress 6.
This is probably done keeping in mind the differential diagnosis congenital pneumonia.
Antibiotics are discontinued with in 48 – 72 hrs if the respiratory distress settles or if
investigations are not suggestive of infection.
An uncomplicated MAS normally recovers over 48 – 72 hrs, rarely being symptomatic
beyond the 1st week of life.
PNEUMOTHORAX
Pneumothorax can occur in 1 % of all newborns 12 though only 10 % of these are
symptomatic. 15 – 20 % of pneumothoraces are bilateral.
An infant with lung disease like MAS & HMD, or those given positive pressure
ventilation are more to develop a pneumothorax. The compression of the underlying lung
and progressive mediastinal shift to the opposite side pressure result in pulmonary and
hemodynamic changes. A sudden increase in cerebral blood flow corresponding to the
changes systemic hemodynamics, could cause or increase the bleed in to the germinal
matrix or cerebral ventricles 12, especially in premature infants.
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The occurrence of a pneumothorax must be frequently evaluated in all at risk infants.
The clinical presentation could varied. It maybe dramatic with severe respiratory distress,
hyperinflated chest, shift in cardiac apex, unilateral decrease in breath sounds, and a
positive transillumination. Not uncommonly an infant under treatment for other cause of
respiratory distress would develop a pneumothorax. The progression could be fairly
gradual. An unexplained increase in heart rate, or gradual drop in blood pressure in an
infant with respiratory distress should arouse the suspicion of pneumothorax. More so if
the infant is on mechanical ventilator support or required positive pressure resuscitation.
Screening for pneumothorax by transilluminating the chest of an at-risk infant at regular
intervals have been incorporated in the standard protocol of most neonatal intensive care
units.
A chest-Xray would confirm the diagnosis. While the incidentally detected asymptomatic
pneumothorax requires no treatment other than close observation, immediate
decompression is the rule in all symptomatic patients. Aspiration thru a 21G or 22 G
‘scalp-vein’ needle inserted in to the 2nd intercostals space in the mid-clavicular line or 5th
/ 6th inercostal space in the mid-axillary line would temporarily abate symptoms while
awaiting preparations for intercostals drain insertion. Insertion of the intercostals catheter
under local anesthesia in the 6th intercostals space in the mid-axillary line, connected to
an under water sealed drain would satisfactorily drain out the airleak. A negative suction
of 10 – 15 cms of water is often applied to the drainage bottle. In the absence of
availability of controlled suction, a ‘vacuum breaker’ bottle with a 10 – 15 cm water
level can be connected between the ICD bottle and the suction apparatus. If the infant
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continues to be symptomatic, despite a ‘bubbling’ ICD, think of a pneumothorax on the
opposite side! It must be remembered that if all the clinical features are exclusively due
to the pneumothorax, the recovery would also be quite dramatic. However in the presence
of an underlying lung disease, improvement in symptoms are significantly influenced by
the extent of the primary disease.
It is worthwhile to maintain an hourly chart to document the bubbling of the ICD.
The catheters are clamped when the ICD has not bubbled for 24 hours. Should the infant
deteriorate, the clamp is release to see if there had been any fresh accumulation of
pneumothorax.. If there is no clinical worsening, the infant is observed for a 6 -12 hr
period and the clamped catheters are removed.
PULMONARY HEMORRHAGE
Pulmonary hemorrhage or massive pulmonary hemorrhage in the newborn is not an
uncommon manifestation. In majority of cases it’s a manifestation of massive pulmonary
edema. Its seen more often in low birth weight infants. A shunt thru a persistent ductus
arteriosus or fluid load could be the main cause of pulmonary hemorrhage in premature
infants. We have seen SGA and growth retarded infants presenting with pulmonary
hemorrhage. Multiple factors could be contributing to pulmonary hemorrhage in the
severely growth retarded infant. Hypothermia, hypoglycemia, thrombocytopenia and
sepsis are a commonly encountered combination. The clinical presentation could range
from mild tachypnea to severe respiratory distress depending of the severity of the
hemorrhage and the ability of the infant to generate distending pressure. A grunt in a
growth retarded infant often manifesting beyond the first few hours of life should always
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arouse the clinical suspicion of pulmonary hemorrhage. The relatively normal activity of
the infant and “ability to suck at the breast” in the near term infant, often contributes to
the complacency seen in detecting this condition.
Early management with ventilator support with a continuous positive airway pressure
(CPAP) of 6 – 8 cm or intermittent positive pressure ventilation with high PEEP, would
effectively control the hemorrhage. More severe the hemorrhage more complicated and
less gratifying becomes the ventilator management, with mortality being proportionate to
the severity of the bleed and general condition of the infant.
If the hemorrhage is due to conditions like PDA, definitive treatment of medically or
surgically closing the ductus must be undertaken. .
TRANSIENT TACHYPNEA OF THE NEWBORN (TTN)
This is a well recognized entity, attributed to delay in fetal lung fluid clearance. This is a
transient phenomenon usually lasting for 6 – 24 hrs, 4 manifesting with increased
respiratory rate, occasionally accompanied by other features of respiratory distress like
grunt and cyanosis. Infants rarely require more than 40% Oxygen.. Occasionally the
clinical features could persist for 2- 5 days. However under such circumstances it would
be more prudent to search for other cause for the respiratory distress. The radiographic
findings are non-specific and include prominent vascular markings, pleural and
interstitial fluid and prominence of the interlobar fissure 6. The final diagnosis of TTN is
always considered after EXCLUDING all other cause for a similar presentation.
PERSISTENT PULMONARY HYPERTENSION OF THE NEWBORN (PPHN)
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Persistent pulmonary hypertension of the newborn is one of the most challenging
conditions of neonatal care. The in-utero status of high pulmonary vascular resistance
starts to drop the first cry of the normal infant, a rapid drop seen with in the first minute
of birth. The drop in pulmonary pressures continues to occur at a fast pace over the first
24 hrs and then at a more gradual pace up to the 7th – 10th post natal day 13. Any factor
(TABLE 2) hampering this drop in pulmonary vascular resistance could ensure that the
infant continues to retain ‘in-utero’ features of circulation with its ‘right to left’ shunt
with the resultant associated hypoxemia and cyanosis.
PPHN should be always considered when an at-risk neonate presents with cyanosis often
being referred from a peripheral hospital as ‘congenital cyanotic heart disease’. Often the
clinical presentation could be dominated by the features of the precipitating causes like
MAS or Pneumonia. This author feels that under such conditions, hypoxemia
disproportionate to the radiological picture would be a good clue to suspect PPHN.
Echocardiography could confirm the suspicion.
Once a diagnosis of PPHN is made, the significance of this labile condition and the high
associated mortality must be recognized and respected. A dictum of minimal handling,
continuous measurement of oxygen saturation (SaO2) by pulse-oximetry or
trancutaneous PO2 (TcPO2) monitoring, high ambient oxygen, and arterial blood gas
assessment thru an indwelling catheter, maintenance of blood pressure and fluid and
electrolyte balance, form the sheet anchor of management. Occasionally SaO2 difference
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greater than 10% between the right hand and the lower limbs is seen if the PPHN results
in a right to left shunt thru a persistent ductus ateriosus.
High Fi02 4, 13 contributes to the gradual reduction of the pulmonary vascular resistance.
Swings in SaO2 or TcPO2 in a quiet infant without any changes in FiO2 is a good
indicator of significant pulmonary vascular lability. Such a labile vasculature could
rapidly constrict to an ‘irreversible’ state under adverse circumstances. Its must therefore
be remembered that the FiO2 would have to be weaned very slowly, often at 1-2 % every
one – two hours. A more rapid or erratic weaning strategy could lead to a
disproportionate drop in the PaO2, due to the extremely labile pulmonary vascular
physiology. The resultant hypoxemia would further worsen the vasoconstriction and
elevate the pulmonary pressure --- leading to a progressive deterioration of the infant.
If the oxygenation of the infant continues to deteriorate varied ventilator strategies,
addition of inhaled Nitric Oxide (iNO) or ECMO might have to be resorted to. Specifics
of these methods would be beyond the purview of this article. Infants would often have to
be transported to advanced centers for these modes of treatment.
Transporting a sick infant is a specialized task undertaken by trained neonatal transport
teams. In most developing countries such transport facilities are unavailable. It is
therefore best to anticipate this eventuality and prepare oneself in advance. This author
recommends a dictum of COME for transporting these infant.. Communicate with the
referral hospital well before transferring the patient; Ensure appropriate Oxygen delivery
to the infant during transport; Minimal handling of infant during transport; Evaluate the
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clinical condition during transport, preferably with pulseoximetry and cardio-respiratory
monitors.
It should be appreciated that adequate ambient oxygen 4 could significantly prevent the
labile pulmonary vasculature of the at-risk infant from progressing to an established stage
of PPHN.
While an infant treated for PPHN often has normal pulmonary functions at one year of
age, the over all outcome is influenced by the etiological cause, duration and mode of
therapy required.
STRUCTURAL ANOMALIES
Most of these conditions would come under the purview of surgical management. Early
recognition of these entities would undoubtedly ensure better management.
Choanal atresia: Bilateral choanal atresia warrants mention here due to its interesting
presentation. A infant who is normal and pink when it cries but rapidly develops
respiratory distress becomes cyanosed when it stops crying should be evaluated for
bilateral choanal atresia. Residents attending the delivery would be the first to be exposed
to this perplexing presentation. As neonates are obligate nasal breathers, bilateral choanal
obstruction results in their becoming cyanosed when they stop crying. An oral airway
would often immediately alleviate the symptoms. Occasionally the presentation would be
as respiratory distress while attempting to breast feed.
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Diagnosis is suspected when one is unable to introduce a nasopharyngeal catheter. CT
scan would confirm the diagnosis.
Surgical intervention to alleviate the membranous or bony obstruction to the choanae
would have to be undertaken with out delay.
Tracheo-esophageal Fistula: (TEF)
While a detailed discussion would be beyond the purview of this article, it must be
remembered that an early recognition of this condition would dramatically influence the
therapeutic outcome. An antenatal history of polyhydraminos may be occasionally
available. A clinical suspicion of TEF must be aroused in an infant who continues to
‘pour out oral secretion’ warranting repeated oral suction. Esophageal atresia associated
with the proximal tracheo esophageal connection, would result in the inability of the to
swallow its oral secretions. While there is a high chance of the infant aspirating these
oropharyngeal secretion, aspiration of gastric secretion through the lower tracheo-
esophageal communication and resultant pneumonia would further contribute to the
morbidity. If undetected at the time of delivery presentation could be as cyanotic episodes
associated with feeding, respiratory distress, abdominal distension in the presence of
fistula, and a scaphoid abdomen in the presence of pure esophageal atresia.14 .
Radiographic evaluation with a ‘gastric’ tube would demonstrate the absence of the tube
in the stomach with the tube getting coiled up at the point of obstruction. Instilling about
5 – 10 ml of air thru the tube would make it easy to observe these coils of the tube against
the air in the esophageal pouch – obviating the necessity of a radio-opaque dye. The
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presence of a ‘gastric bubble’ is due to the movement of air into the stomach thru the
lower tracheo-esophageal connection.
The infant should be kept nil by mouth, with nutrition, fluid and electrolytes requirements
being maintained intravenously. The baby should be nursed in a 15 – 30 degrees head
elevated prone or lateral position. The upper pouch should be continuously drained,
preferably with minimal continuous suction. Once stabilized the infant must be
transferred to the surgical team for further management. The surgical management could
vary between an immediate definitive correction OR a feeding gastrostomy with
exteriorization of the upper pouch followed by corrective surgery after a few months.
These options are based on the anatomy of the anomaly, the general condition of the
infant and policies of individual surgical units.
It is not uncommon for other VACTERL group of congenital anomalies to be associated
with TEF.
CONGENITAL DIAPHRAGMATIC HERNIA (CDH)
Survival of patients with Congenital diaphragmatic hernia have gradually improved over
the years. Antenatal diagnosis of CDH has made anticipatory management at delivery
and a planned subsequent management a welcome reality. It has been the traditional
teaching to rule out “diaphragmatic hernia” in all neonates presenting with respiratory
distress at birth with a cardiac impulse better felt in the right hemithorax. The only
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differential diagnosis would be a left sided pneumothorax, as rarely does a complex
congenital heart disease with dextrocardia present in such a manner. Radiograph of the
chest would confirm the diagnosis.
If warranting resuscitation at the time of delivery, this is one of two conditions, the other
being MSAF, where positive pressure ventilation thru a mask is discouraged and
ventilation is commenced after directly intubating the infant. The associated hypoplasia
of the ipsilateral lung, compression of the contralateral lung, and the associated
hypoxemia, acidosis and hypercapnia result in these infants having a significant degree of
PPHN. No longer is immediate emergency surgery recommended. Instead a period of
stabilization with adequate fluid support, maintenance of blood pressure, control of
PPHN and ventilatory stability have ensured better surgical outcome. The primary aim of
respiratory management is to ensure adequate oxygenation and avoiding acidosis.
Various strategies of conventional and high frequency ventilation are adapted for
attaining this. It was the aim to try and lower the PaCO2 to acceptable low values by
hyperventilation, providing adequate FiO2 and Mean Airway pressure (MAP) for
oxygenation. An oxygenation index (OI) greater than 20 at 6 hrs of life, was associated
with higher mortality. A modified ventilation index (MVI) greater than 70, (MVI =
Respiratory Rate X Peak Inspiratory Pressure X PaCO2/ 1000) was seen to predict 93%
mortality with 98 % specificity and 67 % sensitivity 15. However a more gentle way of
ventilation with permissive hypercapnia has been shown to be very effective, ensuring
survival with minimal pulmonary morbidity 16.
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Surgical correction is mandatory, though the major determinants of the final outcome
would be prenatal factors that affect the development of pulmonary parenchyma,
pulmonary vascular bed and surfactant system15.
Postoperative care would involve continued ventilator support, strategies to manage the
associated PPHN and if warranted extracorporeal membrane oxygenation (ECMO).
Follow-up of the survivors is necessary to evaluate and manage respiratory problems and
tackle issues of those of feeding, growth and development.
CONGENITAL LOBAR EMPHSEMA:
This is a rare but well recognized cause for an infant presenting with respiratory distress
anytime within the neonatal period 17. The infant would present with tachypnea,
recessions, cyanosis and hyperinflation of the affected side. Breath sounds on the affected
side may be diminished. A differential diagnosis of pneumothorax may be considered. A
chest X-ray would show hyperinflation of the affected lobe, mediastinal shift to the
opposite side and on closer examination would reveal the lung markings --- thus
differentiating this from pneumothorax. Definitive surgical treatment of lobectomy
should be undertaken without delay.
Intranasal tumours, laryngeal webs, laryngeal cysts, laryngomalacia are few of the
anomalies of the upper airway that could present as respiratory distress in the neonatal
period. Other rare developmental anomalies like cystic adenomatoid malformation of the
lung, congenital pulmonary lymphangectasia etc. could present as neonatal respiratory
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distress, warranting surgical intervention . The outcome of these conditions depends on
the extent of lung involvement and association of other congenital anomalies.
Conclusion
Respiratory distress could be a clinical presentation of both pulmonary and non-
pulmonary causes. While HMD and congenital pneumonia would be the first differential
diagnosis in a preterm infant presenting with these features, pneumonia and meconium
aspiration syndrome form a bulk of the respiratory problems in term infants. Its
imperative that surgical causes like TEF and CDH be detected early, to optimize the
effect of surgical intervention. It must be recognized that the entity of PPHN could
complicate all pulmonary conditions presenting during the early first week of life. Early
detection and appropriate management is essential to ensure better outcome in all infants
presenting with respiratory distress. A systematic approach would useful to confirm the
diagnosis and cause for the respiratory distress. (table 3).
24
References
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disorders, In: Neonatology – Pathophysiology & Management of the newborn
Eds. Avery GB, Fletcher MA, Macdonald MG. 4th edn. JB Lippincott Company,
Philadelphia 1994, 429 – 452.
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respiratory distress in New born. Indian pediatr 1979; 26.1121-26.
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ascending infection. Br J Obster Gynecol 1982; 89:793 – 801.
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Pediatr clinics North Am1993; 40 : 955 – 981.
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10. Committee on neonatal ventilation/ meconium / chest compressions: Guidelines
proposed at 1992 National Conference on Cardiopulmonary Resuscitation and
Emergency cardiac care, Dallas, 1992. JAMA 1992; 268:2276.
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D, et al. Delivery room management of apparently vigorous meconium stained
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12. Greenough A, Morley CJ, Roberton NRC. Acute respiratory Diseases in the
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13. Spitzer AR, Davis J, Clarke WT, Bernbaum J, Fox WW. Pulmonary hypertension
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atresia and tracheo-esophageal fistula : A review. Indian J Pediatr 1999; 66: 759 –
772.
15. Bohn DJ, Pearl Are, Irish MS, Glick PL, Postanatal Management of Congenital
diaphragmatic Hernia. Clinics in Perinatol 1996; 23: 843 – 872.
16. Boloker J, Bateman DA, Wung JT, Stolar CJH. Congenital Diaphragmatic Hernia
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26
(Table 1) RESPIRATORY DISTRESS IN NEWBORN(adapted with permission from Neonatal Handbook by Elizabeth John 4)
Respiratory Distress in Newborn
At birth or soon after birth Hours to days later
Term Preterm Term and Preterm
MAS HMD PPHN PPHN Immature Lung Obstructed airways
Asphyxia Laryngo tracheomalacia Congenital Pneumonia Pneumonia & Sepsis
Transient Tachypnea of the newborn Cardiac Failure Diaphragmatic hernia Diaphragmatic hernia
Choanal Atresia Pulmonary Hemorrhage Aspiration of other matter
(eg. Blood or mucus)Pulmonary Hypoplasia Skeletal Anomalies
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Table 2. Classification Based on PathophysiologyPulmonary Vasoconstriction
Perinatal Asphyxia / Hypoxia
Pulmonary Parenchymal Disease
Premature in – utero ductal closure
Decreased Pulmonary Vascular BedCongenital Pulmonary Hypoplasia
Secondary pulmonary hypoplasia eg. Diaphragmatic hernia, Oligohydramnios
Increased Pulmonary blood flow associated with congenital heart disease
Decreased pulmonary blood flow as in Hyperviscosity syndrome
Pulmonary Venous hypertension associated with pulmonary venous obstruction, LVF etc. (with permission from Elizabeth John- Neonatal Handbook 4)
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Table 3: Approach to Evaluation
ANTENATAL Polyhydramnios or oligohydramnio, Cervical incompetenceMaternal Illness: Diabetes, PIH, Infections, Maternal medications, antenatal SteroidsAntenatal Ultrasound suggestive of anomalyHistory of Sibling death / similar clinical presentation in sibling.
DELIVERY Prolonged / Premature rupture of membranesMSAF, Asphyxia
CLINICAL Term or PretermTime of presentation and progression of Respiratory DistressExternal congenital anomalies, shape of the chestTachypnea, Grunt, Cyanosis, Acces. Muscles of Respiration, excessive oral secretions, Hyperinflation of chest,Position of cardiac apex, Breath sounds, TransilluminationNormal passage of nasogastric tubeClinical monitoring by Downe’s score ;
INVESTIGATION Pulseoximetry : SaO2, Fluctuations of SaO2, Differential SaO2Chest – Xray (with gastric tube in place)Arterial Blood gas.Echocardiography & CT scan if required.
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