newborn resp probs

8/22/2019 Newborn Resp Probs

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Respiratory Distress in Newborn

Leena ManePGY 3 Resident

Emory Family Medicine

Rhea ManeSpecialist



Question

A male infant weighing 3000 g (6 lb 10 oz)

is born at 36 weeks' gestation, with normal

Apgar scores and an unremarkable initialexamination. At 48 hours of age he is noted

to have dusky episodes while feeding, and

does not feed well. On repeat examination

the child is tachypneic, with subcostal

retractions. Lung sounds are clear and

there is no heart murmur.



What Next ?



Tests & labs…

Pulse oximetry on room air is 82%.

Arterial blood gases on 100% oxygen show a pCO2

of 26 mm Hg (N 27-40), a pO2 of 66 mm Hg (N 83-

108),

blood pH of 7.50 mg/dL (N 7.35-7.45), and a base

excess of -

2 mmol/L (N -10 to-

2).



Labs…

Hemoglobin- 22.0g/dl (N13.0-20.0)

Hematocrit- 66 % (N 42- 66)

WBC- 19,000/mm3 (N9000-30,000)

Blood cultures- Pending.

Chest X-ray- Increased vascularmarking, Large thymus.



Most likely diagnosis

1- Transient tachypnea of newborn

2- Congenital heart disease

3- Hyaline membrane disease

4- Neonatal sepsis

5- Hyperviscosity syndrome



Transient Tachypnea of Newborn

Most common cause of respiratory distress.

40% cases.

Residual fluid in fetal lung tissues.

Risk factors- maternal asthma, c- section, male sex,macrosomia, maternal diabetes



TTN

Tachypnea immediately after birth or withintwo hours, with other predictable signs of

respiratory distress.

Symptoms can last few hours to two days.

Chest radiography shows diffuse

parenchymal infiltrates, a “ wet silhouette”around heart, or intralobar fluidaccumulation



X-ray

Fluid in the

fissure



Respiratory Distress Syndrome

Also called as hyaline membrane disease

Most common cause of respiratory distress in

premature infants, correlating with structural &functional lung immaturity.

1/3 infants born between 28 to 34 weeks, butless than 5% of those born after 34 weeks.

Pathophysiology- surfactant deficiency-increase in alveolar surface tension- decrease incompliance.



RDS

Hyaline membrane- combination of sloughed

epithelium, protein & edema.

Diagnosis of respiratory distress should be

suspected when grunting, retraction or other

typical distress symtoms occur in premature infant.

CXR- homogenous opaque infiltrates & airbronchograms.



Meconium Aspiration Syndrome

Incidence- 1.5- 2 % in term or post terminfants.

Meconium is locally irritative, obstructive &medium for for bacterial culture

Meconium aspiration causes significant

respiratory distress. Hypoxia occurs becauseaspiration occurs in utero.

CXR- Patchy atelectasis or consolidation.



Infections

Pneumonia & Sepsis have various manifestations

including typical signs of distress as well as

temperature instability.

Common pathogen- Group B Streptococcus, Staph

aureus, Streptococcus aureus, Streptococcus

Pneumoniae,Gm neg rods



Infections ctd.

Risk factors- prolonged rupture of membranes,

prematurity,& maternal fever.

CXR- bilateral infiltrates suggesting in utero

infection.



Other causes-

Congenital malformations-Pulmonary hypoplasia,congenital emphysema, esophageal atresia &diaphragmatic hernia.

Neurological causes- hydrocephalus & intracranialhemorrhage.

Metabolic derangements-hypoglycemia,

hypocalcaemia, polycythemia.



Congenital Heart disease

Cyanotic Heart Disease-

Tetralogy of fallot- ( VSD, Pulmonary stenosis,

overriding aorta, RVH)

Tricuspid atresia

Transposition of great vessel

Total anamolous pul. venous return

Truncus arteriosus.



Hyperoxia Test

Obtain ABG –> Then place the patient

on 100% O2 for 10 minutes then

repeat ABG , If the cyanosis is

pulmonary , the PaO2 should be

increased by 30 mm of Hg. If the cause

is cardiac , there will be minimalimprovement in PaO2.



Treatment

Can be generalized & disease specific

Oxygenation can be enhanced by blow by

oxygen, nasal canula or mechanical ventilationin severe cases.

Surfactant administration may be required.

Antibiotics are often indicated if bacterialinfection is suspected clinically or because of leucocytosis, neutropenia or hypoxia.



Treatment

Fluids should be restricted in acute phase

Fluids should be limited for insensible losses &

replacement of Urine output.

Mortality & morbidity is lower in premature infants

who were fluid restricted as compared to similar

infants



Transient Tachypnea of Newborn

Rx is supportive because the condition is usuallyself limited.

Oral lasix has not shown to significantly improvestatus.

Prenatal administration of steroids 48hrs beforeelective C- section @ 37- 39 weeks gestation

reduces TTN but this has not become commonpractice.



Respiratory distress Syndrome

General intervention for oxygenation.

Prenatal administration of corticosteroidsbetween 24- 34 wks gestation reduces risk

of respiratory distress when risk of preterm

delivery is high.

Post natal steroids may decrease mortality

but may increase risk of cerebral palsy.



Meconium Aspiration Syndrome

Use minimal stimulation & keep head downto prevent breathing of meconium

Standard practice of suctioning the mouth &nares upon head delivery before bodydelivery is not recommended.

Amnioinfusion does not decrease theincidence of meconium aspiration syndrome& perinatal death.



Algorithm



Evaluation

Detailed history

Differential diagnosis changes with EGA, GBS status& prophylaxis, duration of rupture of membrane,color of amniotic fluid, maternal temperature,maternal tachycardia, fetal heart tracing

Physical signs- look for apnea, tachypnea orcyanosis, cardiac auscultation for murmur.

Lung auscultation - asymmetrical chestmovements- in pneumothorax ,crackles inpneumonia, clear in TTN, & persistent pulmonaryHTN.



Algorithm



Treatment

Mild distress- observation & pulse oximetry

Severe distress- immediate resucitation, CXR, and

laboratory tests

Tests- blood culture, blood gas, blood glucose, CBC

with Diff,lumbar puncture if indicated, pulse

oximetry.



Answer

Cyanotic congenital heart disease can appear at the timeof ductus closure. A heart murmur is not usually audible,and murmurs heard this early are usually not due toheart disease. The failure to correct hypoxemia with100% oxygen is diagnostic for abnormal mixing of bloodfrom the right and left circulations.

Transient tachypnea presents earlier, and the hypoxiacorrects with supplemental oxygen.

Hyaline membrane disease can occur at 36 weeks, butwould cause problems in the first hours of life. It canmake oxygenation difficult, but would cause extremedistress with CO2 retention in such cases.



Answer

This patient has the energy to hyperventilate and hasslight respiratory alkalosis as a result. Neonatal sepsiscan cause V/Q mismatching and hypoxia, and can have adelayed presentation. Concern would be high enough in

this case that the patient would probably receive broad-spectrum antibiotics while awaiting culture results. Onthe other hand, the clinician would not want to bedistracted from the evidence for congenital heartdisease.

The baby is polycythemic from poor intake in the first 2

days of life. The hyperviscosity syndrome can occurwhen the hematocrit is over 65%. It can cause poorfeeding, tachypnea, and sluggishness, but does notcause hypoxia.



Thank You …

newborn resp probs

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