2.1 Fetal Lung Developnment Flashcards
1
Q
EXAM ?
Lung development
A
2
Q
EXAM ?
explain the stages of lung development
Every premature child takes air
Embryonic
Psuedoglandular
Canalicular
Terminal sac
Alveolar
A
- Embryonic
- 0-6 week
- bronchi
- trachae
- psuedoglandular
- 7 - 16 weeks
- bronchioles
- lung circulation
- terminal bronchioles
- Canalicular
- 17 - 24 weeks
- primitive alveoli
- respiratory bronchioles
- about 22-24 weeks of pregnanc
- terminal sac
- 25 - 36 weeks
- alveolar ducts
- primitive alveoli
- thin walled alveolar sacs
- Alveolar
- >37 weeks
- definitive alveoli and mature type 2 cells
3
Q
EXAM ?
Signs of respiratory distress
A
- tachypaena
- grunting - expiration
- nasal flaring
- use of accessory muscles. intercostal space
- low O2 sats
- change in colour
4
Q
At what gestation does the fetus begin to produce surfactant
A
- about 22-24 weeks of pregnancy.
- If a baby is premature (born before 37 weeks of pregnancy), they may not have made enough surfactant yet
- When there is not enough surfactant, the tiny alveoli collapse further with each breath.
5
Q
EXAM ?
Explain the concept of respiratory distress and identify common respiratory diseases in the newborn period
A
- grunting
- nasal flaring
- low o2 sats
- poor tone
- low hr <100
- use of intracoastal muscles
- common respiratory disease
- TTN
- meconium aspiration
- RDS
6
Q
Transition at Birth - what is the relevance to respiratory disorders?
A
- transition is caused by
- cooler environmental temperature
- tactile stimulation
- changes in partial pressures of O2 and carbon dioxide during birth
- high pressures in the lungs in the uterus
- for successful transition:
- The initiation and sustained regular respiration
- Fluid-filled air spaces cleared of excess fluid to air-filled for effective gas exchange,
- Redirect blood flow towards the fetal lungs and close fetal shunts
- Spontaneous labour triggers fetal catecholamines:
- noradrenaline and adrenaline
- facilitates the mobilisation of lung fluid
- about ⅓ of total amniotic fluid volume maybe removed with the remains fluid slowly reasborbed;
- by the lymphatic system
- Pulmonary circulation
- sodium channels drive by adrenaline released during labour
- c-section deliveries may have a slower transition with th amniotic fluid shunted via the lymphatic systems
- The release of catecholamines during spontaneous labour ensures an availability of surfactant for the preparation of respiration post birth
*
7
Q
EXAM ?
Meconium Aspiration Syndrome (MAS)
A
- parasympathetic activity from fetal stress
- Mainly affects term and post term infants
- (rarely occurs in preterm infants less than 34 weeks)
- Hypoxic event occurs before birth
- stimulates the intestinal peristalsis
- relaxes the anal sphincter
- Respiration post birth is that meconium is draw into the major airway
- Meconium visible in trachea
- subsequently into the smaller airways
- causing
- Obstruction
- atelectasis
- air trapping
- pneumothorax
- chemical pneumonitis (meconium is a chemical irritant)
- inactivation of the surfactant impairs gas exchange
- In severe cases
- leads to respiration distress
- secondary persistent pulmonary hypertension due right to left ductal shunting due to increased pressure
- patent ductus arteriosus
- Risk factors
- fetal distress
- mec stained liquor
- post dates
- prolonged labour
- gestational htn
- cord compression
- hypoxic event
- SGA
- cigarette smoking
- management key
- Ventilation may be required
- O2 management
- antibiotics
- chest xray
- maintenance of optimal thermal environment
warmer - nurse baby upright
- small frequent feeds
- orogastric tube
8
Q
EXAM ?
Apnoea
A
- common occurrence in preterm infants
- is cessation of breathing for 20 secs or longer
- cessation of breathing for 10 sec with cyanosis or/and bradytcardia
- types of apnoea
- Central Apnoea
- decreased central nervous system stimuli to respiratory muscles
- Obstructive apnoea
- pharyngeal instability
- collapse
- neck flexion
- nasal obstruction
- Mixed Apnoea
- combination of both
- persistence obstructive apnoea leads to CNS depression due to hypoxia and acidosis
- Central Apnoea
- Apnoea of prematurity
- poorly positioned head and neck
- drugs
- gastrointestional
- metabolic
- CNS
- Infection
- cardiovascular
- pain
9
Q
EXAM ?
Transient Tachypnoea of the newborn (TTN)
A
- delayed reabsorption of normal lung fluid
- precipitous birth
- c-section births
- term or late gestation
- prenatal exposure to methamphetamine
- Onset usually two to six hours after birth
- Respiratory distress is evident
- Tachypnoea
- mild retraction
- grunting
- nasal flaring
- cyanosis may be present
- Management
- CPAP
- HiFlow
- ?treat with abx until cultures come back
- Risk factors
- term infant - c section
- precip labour
- me
- bradycardic event during labour
- reduced catacohmines
- prenatal exposured to methampetine
10
Q
EXAM ?
Describe the treatment and management of respiratory distress in the neonate
A
RDS:
- Resp monitoring
- Sats RR
- HFNP/CPAP
- prevention
- administer antenatal corticosteroids
MAS
- Ventilation may be required
- O2 management
- antibiotics
- chest xray
- maintenance of optimal thermal environment
- warmer
- nurse baby upright
- small frequent feeds
- orogasric tube
11
Q
EXAM ?
Explain the term respiratory distress
A
- progressive impairment of the lungs to exchange gas at the alveolar level
- having to work harder to breath and getting enough oxygen,
12
Q
EXAM ?
Respiratory distress syndrome (RDS)
A
- RDS
- consequence of immature lungs anatomy and physiology
- Cannot support oxygenation ad ventilation
- alveolar sacs are not developed
- decreased surface area for gas exchange
- volume of surfactant is insufficient to prevent collapse of unstable alveoli
- Alveoli collapses with each breath
- therefore Normal Functional residual capacity is not established
- (very similar to spesis)
- RISK factors
- prematurity
- size and gestation of neonate
- maternal diabetes
- c-section
- Management
- monitoring
- HFNP/CPAP
- administer of corticosteroids antenatal
13
Q
Pneumonia
A
Early onset - within 3 days of birth
- MAS
- GBS positive (maternal long term PPROM)
- genital herpes
- chicken pox
- Rubella
- mumps
- fungal infections
14
Q
EXAM ?
Describe the role of PIPER
A
15
Q
The following diagram illustrates the changes occurring within the fetal-placental circulation whereby circulation is re-routed via the lungs at birth.
A
