2.2 Respiratory disorders

Question 1

Surfactant’s role

Answer 1

• 22 week to 23 weeks - before can not sustain life
• effective ongoing and effortless respiration is facilitated by an abundance of surfactant covering the alveolar surface within the newborn lungs
• surfactant is a substance primarily of phospholipids and proteins which is secreted mainly by the type II pneumocytes
• type II pneumocystis cells being to appear during the saccular stage
• availability of surfactant is directly linked to the gestational age
• preterm <26 there isn’t enough surfactant to sustain ventiliatiion
• pulmonary surfactant reduces the lung surface tension on the alveoli surface preventing the collapse of the alveoli on exhalation
• other roles
  
  • aids in lung fluid clearance following birth
  • immune response via antimicrobial activity
• soapy in texture that forms film over the alveolar surface (makes the lung less stiff)
  *

Question 2

Respiratory Distress Syndrome (RDS)

Answer 2

• occurs in preterm infants
• immature lung anatomy and physiology
• anatomically - preterm lungs cannot support oxygenation and ventilation
• because alveolar sacs not developed so there is decreased surface area for gas exchange
• volume of surfactant is insufficient to prevent collapse of unstable alveoli
• because of alveoli collapse there is insufficient o2 and ventilation exchange which causes increased energy output
• surfactant production is limited and stores a quickly depleted

Question 3

what infants are at risk of low levels of surfactant

Answer 3

• preterm
• mec aspirations
• GDM type 1 or 2

Question 4

Respiratory Distress Syndrome (RDS)

Question 5

Transient tachypnoea of the newborn (TTN)

Answer 5

• delayed reabsorption of normal lung fluid
• Lasts less than 24 hours
• infants include term or late term infants whom were born via:
  
  • c-section
  • precipitous delivery
  • prenatal exposure to methamphetamines
  • or other abnormalities of labour and transition
• signs of TTN
  
  • tachypnoea
  • mild retraction
  • grunting
  • nasal flaring
  • cyanosis may be present
• treatment and management of TTN
  
  • o2 monitoring
  • xray
  • bloods especially blood gases to see what ph level and bicarb
    *

Question 6

Meconium Aspiration Syndrome (MAS)

Answer 6

• affects term and post term infants
• is a chemical irritant
• rarely occurs in preterm infants less than 34 week (gut is not as mature)
• how it occurs
  
  • meconium found in the amniotic fluid
• hypoxic event occurs during birth stimulates the intestinal peristalsis and the relaxation of the anal sphincter
• respiration post birth draws meconium into the major airways and then subsequently into the smaller airways causing
  
  • obstruction
  • atelectasis
  • air trapping
  • pneumothrorax
• meconium can cause chemical pneumonitis and inactivation of the surfactant which further impairs gas exchange
• can lead to respiratory distress
• secondary persistent pulmonary htn due to pulmonary atelectasis
  
  • right to left shunting (due to the increased pressure in the lungs
  • patent dutus arteriousus
• Symptoms:
  
  • meconium stained amniotic fluid
  • not vigorous at birth
    
    • poor tone
    • respiration
    • < 100 hr
    • requiring tracheal intubation for suctioning

Question 7

Apnoea

Answer 7

• common in preterm but can occur in term infants
• central apnoea:
  
  • is caused by the decreased CNS stimuli to respiratory muscles
• Obstructive apnoea:
  
  • caused by pharyngeal instability or collapse
  • neck flexon
  • nasal obstruction
• Mixed Apnoea
  
  • is a combination of central and obstruction apnoea where there is persisting airway obstruction leads to CNS depression due to hypoxia and acidosis
• Causes:
  
  • prematurity
    
    • head and neck poorly positioned
    • drugs
    • metabolic
    • respiratory
    • gastrointestinal
    • CNS
    • infections
    • cardiovascular
    • pain
      *

Question 8

uncommon causes of respiratory distress in neonate

Answer 8

• congenital diaphragmatic hernia
• oesophageal atresia
• trachea-oesophageal fistula
• chronic lung disease
• bronchopulmonary dysplasia
  *

Question 9

mentimeter

Question 10

At Birth, fetal shunts close due to

Answer 10

decrease in pulmonary vascular resistance

Question 11

Meconium aspiration syndrome is most commonly seen in

Answer 11

post term infants

Question 12

RDS is most commonly seen in

Answer 12

preterm babies

Question 13

PPHN is most commonly associated with

Answer 13

MAS

blockage increase pressure

Question 14

surfactant is produced in the

Answer 14

Type pneumocytes

Question 15

Apnoea is defined as a cessation of breathing for

Answer 15

more than 20 seconds

more than 10 seconds with bradycardia

Question 16

In neonatal resuscitation, the o2 sats monitor should be placed on the

Answer 16

right hand