8.Infant Respiratory Distress Syndrome

Question 1

what is Infant Respiratory Distress Syndrome

Answer 1

hypoxia and hypercapnea d/2 inadequate lung surfactant in infants

Question 2

IRDS pathogenesis

Answer 2

• Inadequate surfactant production causes
• air sacs to collapse on expiration and leads to
• drastically reducing lung compliance and difficulty breathing
• development of interstitial oedema worsens the condition and causes

.-hypoxia and

• hypercapnea and
• CYANOSIS- d/2/ RIGHT TO LEFT SHUNT

Question 3

what are the 2 possible types of R-L shunts in IRDS

Answer 3

occurs
through collapsed lung (intrapulmonary)

if pulmonary hypertension is severe, across the ductus arteriosus and
foramen ovale (extrapulmonary).

Question 4

surfactant

Answer 4

produced after 30 weeks of gestation.

by type II pneumocytes

to lower surface tension

Question 5

what determines the incidence/severity of IRDS

Answer 5

inverse relationship w/ gestational age

affects 50% of infants at 28-32wks gestation

Question 6

RF for IRDS

Answer 6

Premature delivery.
Male infants.
Caeserean 
Hypothermia.
Perinatal asphyxia. Maternal diabetes. Multiple pregnancy.
Family history of IRDS.

Question 7

prophylactic factors against IRDS

Answer 7

use of antenatal steroids.

Pregnancy-induced/ chronic maternal hypertension.

Prolonged rupture of membranes.

Maternal narcotic addiction.

Question 8

what can cause secondary surfactant deficiency in infants

• parenchymal damage,
• atypical growth
• oxygen excess/insuff

Answer 8

Intrapartum (birth) asphyxia.

Pulmonary haemorrhage.

Pulmonary infection
(group B beta-haemolytic streptococci)

pulmonary hypoplasia.

Meconium aspiration pneumonia.

Question 9

classic presentation

Answer 9

Usually preterm delivery.

swift postbirth presentation of
respiratory distress: tachypnoea, expiratory grunting, subcostal and intercostal
retractions, diminished breath sounds, cyanosis and nasal flaring.

rapidly progress to fatigue, apnoea and hypoxia.

Question 10

sx of respiratory distres in infants

Answer 10

tachypnoea,
expiratory grunting,

subcostal and intercostal
retractions,

diminished breath sounds,

cyanosis

nasal flaring.

Question 11

dx of IRDS are other causes of respiratory distress in infants other than inadequate surfactant

Answer 11

Pulmonary air leaks
(eg, pneumothorax , pneumomediastinum, pneumopericardium).

puilmonary infection

Congenital lung anomalies
-diaphragmatic hernia, -chylothorax,
-

Congenital heart anomalies.

Primary persistentpulmonary hypertensionof
-dg of exclusion

Question 12

investigation in IRDS

Answer 12

Blood gases: respiratory and metabolic acidosis along with hypoxia.
- Metabolic acidosis results from poor tissue
perfusion.

 Pulse oximetry: non-invasive tool to monitor oxygen saturation, which should be maintained at 85-93%.

 CXR.

 Monitor FBC (anemia) electrolytes, glucose, renal and liver function.

 Echocardiogram:

• diagnose PDA
• determine the direction and degree of shunting,
• diagnose of pulmonary hypertension
• excluding structural heart disease.

 Cultures to rule out sepsis.

Question 13

management of IRDS

Answer 13

Surfactant replacement therapy via endotracheal tube:

Oxygen:

Supportive therapy:

Question 14

Supportive therapy:

Answer 14

Temperature regulation: .

Fluids, metabolism and nutrition:

 Circulation and anaemia: monitor heart rate, peripheral perfusion and blood pressure

 Antibiotics:
cultures. Discontinue antibiotics after three to five days if blood cultures are negative.

Question 15

acute complications of IRDS

Answer 15

Alveolar rupture: pneumothorax, pneumomediastinum, pneumopericardium, interstitial emphysema.

Intracranial haemorrhage: the risk is increased in those who require mechanical ventilation.

pulmonary haemorrhage after surfactant therapy

Question 16

Chronic complications

Answer 16

Retinopathy of prematurity

Neurological impairment d/2/ hypoxia and infection

bronchopulmonary dysplasia d/2/ trauma during mech vent

Question 17

prognosis pf IRDS

Answer 17

baby’s over 1500g have increased prognosis

Question 18

how to prevent IRDS

Answer 18

Antenatal corticosteroids (dexamethasone) - 40% irds reduct d/2 accelerate fetal surfactant production and lung maturation.

delaying premature births

• use of tocolytics
  e. g. atosiban, nifedipine allows time for corticosteroids to be given

avoid hypothermia

Question 19

what is retinopathy of the newborn

Answer 19

normally, the retinal vessels grow in an environment of relative hypoxia.

In phase I, after premature birth, the retina is relatively hyperoxic (exposed to increased oxygen), resulting in reduced levels of vascular endothelial growth factor (VEGF)

reduced VEGF stops vascular growth from the optic disc but the eye carries on growinng causing preipheral ischemia and hypoxia in the reitna

peripheral hypoxia increases VEGF in phase 2

effects of increased vegf in phase 2

• tortuous vessels
• growth of fibrous vessels and retinal detatchment