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Flashcards in RM Week 11 Deck (47)
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0
Q

What does relative hyperventilation of mother help with?

A

Aids clearance of fetal co2

1
Q

List the two hormones in pregnancy that alter respiratory function?

A

Increased estrogen: causes fluid retention and edema throughout the airway mucosa and stimulates mucous gland hyperplasia, also increases blood volume (increases oxygen delivery)

Increased progesterone: sensitises Central chemoreceptors resulting in decreases pulmonary carbon dioxide and increased pH

2
Q

Is there any significant change in PaO2 in the mother?

A

No

3
Q

What can happen in pregnancy in regards to asthma?

A

Altered hormone levels may affect asthma control. (Can improve, worsen or stay the same). Airway hyperactivity can be increased but generally returns to pre-pregnancy levels with red months postpartum

4
Q

What affects respiratory mechanics in mother in the last trimester? Also how is loss of lung function this partially offset?

A

Enlarging of the uterus. Diaphragm is displaced by the chephalad which decreases RV , decreases ERV, decreases IRV, decreases FRC.

Partially offset by increased anterior-posterior and transverse diameters of the chest and widening of subcostal angles

5
Q

What’s happens to VC and FEV1 in pregnancy?

A

Stay the same

6
Q

When in weeks does an infant have a chance of surviving if premature?

A

26-27 weeks and over. This is during transition from canalicular to saccular

7
Q

What secretes lung fluid?

A

Alveolar epithelial cells

8
Q

What is the primary role of lung liquid?

A

To flush out debris out of lung and prevent developing tissues from collapsing. Appears to maintain a positive pressure relative to amniotic fluid, resulting in lung expansion responsible for stimulating cell division and lung growth

9
Q

When do attempted respiratory movements begin to take place in the fetus?

A

By the end of first trimester . Increase in frequency from 22-35 weeks gestation

10
Q

When are respiratory movements inhabited in the fetus and what is the point of this?

A

During last 7 days - helps to prevent lungs filling with fluid as well as debris from the meconium(first stool). Excreted into amniotic fluid

11
Q

What type of Hb makes up 70% of all the Hb in a newborn?

A

Fetal Hb - HbF

12
Q

Which has a higher oxygen affinity? Adult or fetal Hb?

A

Fetal Hb - designed to operative at a lover PO2

13
Q

When is HbF replaced by adult Hb?

A

By 6 months of age

14
Q

When do the majority of babies take their first breath?

A

Within the first 20s and have established a normal rhythm by 90 seconds

15
Q

What allows air to be drawn into the lungs in birth?

A

Thoracic compression during vaginal delivery followed by elastic recoil of rib cage.

16
Q

What are the major stimuli to breathing in newborns?

A

Largely unknown but cooling of skin and mechanical stimulation (via respiratory centre)

17
Q

At birth where does fluid in lungs go?

A

Epithelial cells in lungs switch from secreting the lung fluid to absorption of fluid

18
Q

How much pressure is required to oppose surface tension and open the alveoli for the first time?

A

25mmHg negative pressure

19
Q

Why is it important that infant doesn’t expel all their air in first expiration?

A

May cause alveoli to collapse and be retained like that by dynamic airway compression

20
Q

How is surface tension created in the alveoli?

A

Attraction of water molecules in the alveolar fluid . h2O is more attracted to eachother than to air,

21
Q

Where is surface tension directed towards in the alveoli?

A

The centre - acts to prevent alveoli being overstretched

22
Q

What would happen if alveoli were lined by water alone?

A

Airway collapse as water attractive forces so strong

23
Q

What’s does surfactant do regarding surface tension?

A

Reduces surface tension by physically getting in the way of water molecules

24
Q

What is surfactant made up of?

A

90% lipids, rest is proteins and carbohydrates

25
Q

What is the most important lipid in surfactant and what is it responsible for?

A

DPPC- responsible for surfactants effect on surface area

26
Q

Where is surfactant synthesized?

A

Type 11 alveolar cells

27
Q

Half life of surfactant?

A

15-30 hours

28
Q

Other roles of surfactant ?

A

May have a role in lung defence (antiviral/bacterial), protein component may increase phagocytosis of bacteria and viruses . May assist with mucocillary escalator

29
Q

What do preterm lungs look lime?

A

Smaller, less developed

30
Q

What’s is the percentages of babies getting IRDS if born in the 34-37 weeks

A

15%

31
Q

What’s is the percentages of babies getting IRDS if born in the 30-34 weeks

A

50%

32
Q

What’s is the percentages of babies getting IRDS if born in the 30 weeks

A

70 %

33
Q

What is infant respiratory distress syndrome also called

A

Hyaline membrane disease

34
Q

What is the pria ray cause of IRDS?

A

Lack of pulmonary surfactant leading to decreased compliance and an increased surface tension

35
Q

Explain mechanical ventilation for IRDS and some risks?

A
  1. CPAP and PEEP:
    Physically moving oxygen into lungs via a device.
    Can decrease alveolarizarion, increased collagen deposition and bronchial smooth muscle,
  2. Exogenous surfactant: good but 30% cases don’t respond to treatment
36
Q

List some pulmonary complications with IRDS ?

A

Alveolar rupture: pneumothorax, interstitial emphysema

Persistent pulmonary hypertension

Pulmonary haemorrhage ↑risk ↓gestational age, esp. post surfactant therapy

Apnoea of prematurity is common, ↑ incidence with surfactant therapy

37
Q

List other complications with IRDS ?

A

Trauma to vocal cords from tracheal intubation
•Intracranial haemorrhage: ↑risk with mechanical ventilation
•PDA especially if weaned rapidly after surfactant therapy
•Necrotising enterocolitis and/or gastrointestinal perforation

38
Q

What is bronchi pulmonary displasia?

A

When oxygen is required at a corrected gestational age 36 weeks and over. Due to injury from mechanical ventilation

39
Q

Other chronic problems with IRDS?

A

Retinopathy,neurological impairment

40
Q

What is Cheney stokes breathing?

A

Periodic breathing of hyper, hypo estimation and the apnea. Common in premature a

41
Q

When is a respiratory pause termed as an apnea?

A

Over 20 seconds

42
Q

Why does sudden unexplained death in infancy usually occur

A

During sleep

43
Q

What is sudden infant death syndrome?

A

Death of a baby under 1 year of age, remains vs unexplained forever even after autopsy

44
Q

She is peak incidence for SIDS?

A

2-3months

45
Q

Due to a public health campaign in Australia, what was the percentage reduction in SIDS in australia?

A

83% reduction.

46
Q

What causes SIDS?

A

Multi factorial