Meconium aspiration

Question 1

What is meconium aspiration?

Answer 1

Spectrum of respiratory distress in neonates born through meconium stained liquor

Question 2

What severity can meconium aspiration be

Answer 2

Mild respiratory distress to severe repiratory failure

Question 3

What can meconium cause in resp tract?

Answer 3

Inflammatory response through cytokine release

Question 4

What is meconium release into amnitoic fluid related to?

Answer 4

Increased vaginal outflow - umbilical cord compression or hypoxia

Question 5

Risk factors for meconium asporation

Answer 5

2-10% neonates born in meconium stained liquor
MAS risk increases with postdates gestation and small for gestational age

Question 6

What are the clinical features of MAS?

Answer 6

Meconium-stained liquor
Respiratory distress at or shortly following birth
Typical radiographic features on CXR, hyperinflation, patchy opacification and consolidation
Increased O2 requirements - mechanical ventilation may be required for severe cases

Question 7

Different ways meconium can affect repiratory system

Answer 7

Respiratory distress
Pneumonitis
Bacterial pneumonia
Pneumothorax

Question 8

How is respiratory distress caused by medonium?

Answer 8

Damages surfactant and metabolism
Severe effects due to reduced surfactant ef increased surface tension, reduced lung volume, compliance and oxygenation

Question 9

How does meconium cause pneumonitis?

Answer 9

-> irritation and local inflammation -> exudatice and inflammatory pneumonitis

Question 10

How does meconium cause bacterial pneumonia?

Answer 10

Meconium stained liquor - bacterial infection in utero - E.coli esp -> increased morbidity

Question 11

How does meconium cuase pneumothorax?

Answer 11

Thich meconium -> AW obstruction in distal small AWs
Plugging and distal gas trapping can lead to distention of dital lung and pneumothorax

Question 12

What does meconium in AW mechanisms cause ?

Answer 12

Hypoxic and repiratory distress

Question 13

Differntial diagnosis for meconium aspiration

Answer 13

Transient tachypnoea of newborn
Delayed transition form foetal circulation
Sepsis
Congenital oneumonia
Persistent pulmonary HPTN of newborn
Pneumothorax
Hypovolaemia

Question 14

TTN vs MAS

Answer 14

Infants with TTN present initially similar but recover quickly

Question 15

Why treat infants iwth MAS withantibiotics?

Answer 15

Presents v similarly to pneumonia - treat until blood cultures return

Question 16

How differentiate MAS with penumothorax

Answer 16

Transillumination of chest wall and CXR

Question 17

Bedside investigations for MAS

Answer 17

Pre and post ductal saturations
Capillary gas or venous gas

Question 18

Pre and post ductal sats why do it with MAS?

Answer 18

assess resp involvement and detect congenital cardiac lesions

Question 19

Why do capillary gas or venous gas in MAS?

Answer 19

Assess degree of respiratory compromise and assist in decisions regarding respiratory support and systemic involvement

Question 20

Lab investigations for MAS

Answer 20

FBC - raised WCC
CRP
Blood cultures - bactaraemia suggestive of sepsis and pneumonia

Question 21

What imaging should be done with MAS?

Answer 21

CXR - local guidelines

Question 22

Why would you wait 4 hours to do a CXR in sus MAS? When would you not?

Answer 22

TTN will resolve after this time, eliminating the need for X ray
Acutely unwell or mechanically ventialted CNAT DELAY

Question 23

CXR findings in MAS

Answer 23

Hyperinflated lungs from distal air trapping, patchy pulmonary changes and may show pneumothorax or pneumomediastinum due to raised alveolar tension

Question 24

Intrapartum measures prevent MAS

Answer 24

Foetal hypoxia
Prevent postdates gestation

Question 25

Vigorous vs non vigorous infant management

Answer 25

Vigorous infant - no oropharyngeal suctioning despite meconium-stained liquor (doesnt reduce risk)
Non-vigorous infant - May need oropharyngeal suctioning if meconium obstructing AW - rapidly initiate intervention
No routine endotracheal suction

Question 26

What APGAR score infants do not require additional monitoring (except for sepsis)

Answer 26

> 9

Question 27

What should be done with infants with respiratory distress after birth?

Answer 27

4-6 hours in neonatal unit to ensure successful transition

Question 28

Management for MAS

Answer 28

Supportive - avoid morbidity and mortality ass with MAS
Oxygen therapy needed
Assisted ventialtion if required

Question 29

Why is CPAP used with caution in MAS?

Answer 29

May exacerbate air trapping

Question 30

What does surfactnat use reduce the need for in MAS?

Answer 30

Extracorpereal mebrane oxygenation in ventilated infants

Question 31

Short term complications form MAS

Answer 31

Ongoing O2 requirements
Seizures
Necrotising enterocolitis
Increased reactive airwyas disease
Good long term prognosis