Respiratory Distress Syndrome / Neonatal SOB Flashcards
What happens to the fluid in a neonates lungs before, during and after birth?
- In utero the lungs are full of fluid & pulmonary blood vessels are constricted.
- Shortly before and during labour respiratory fluid secretion is reduced.
- The lung fluid is removed by the squeezing of the foetus’s thorax during vaginal delivery.
What is the normal physiology of a neonates first breath and subsequent breathing?
- Breathing is triggered by
- thermal (keep warm but its cold vs womb)
- tactile (rub them with towel)
- hormonal stimuli
The first breath:
- normally occurs within 6 seconds of delivery.
- remainder of the lung fluid is absorbed into the pulmonary lymphatics and circulation.
Neonatal respiratory rate is 30-50 breaths per minute,
- through the nose (obligate nose breathers)
Is transient tachypnoea of the newborn common, less common or rare as a cause of SOB in a neonate?
Common
are the following conditions common, less common or rare as a cause of SOB in a neonate?
- Respiratory distress syndrome
- meconium aspiration
- pneumonia
- pneumothorax
- persisteny pulmonary HTN of newborn
Less common
are the following conditions common, less common or rare as a cause of SOB in a neonate?
- Diaphragmatic hernia
- pulmonary hypoplasia
- lung anomalies
- airways obstruction e.g. choanal atresia (congenital stenossi of the psoterior nasal apertures blocking the posterior nasal cavity of L or right nostil and nasopharynx)
- pulmonary haemorrhage
- neuromusular disorder
- tracheo-oesophageal fistula
Rare
What do these non-pulmonary (neonatal) conditions all have in common?
- Congenital heart disease
- Heart failure
- Sepsis
- Severe anemia
- Metabolic acidosis
- intracranial birth trauma or encepalopathy
- hypoxic ischaemia encepathopathy
they cause SOB in a neonate!
What is the management of SOB in a neonate?
- ABCDE
- ABG
- CXR
- Blood cultures
- Antibiotics FOR ALL
What antibiotics do you give a neonate if you suspect meningitis?
- For suspected meningitis (they’ll look really sick)
- benpen
- gentamicin
- or cephtriaxone
listeria can cause infection in neonates (<1m old). What antibiotic do you give?
Amoxicillin
if suspect listeria
What bacteria may cause SOB in neonates (<1month)?
- group A strep
- G -ves
- Listeria
What microorg may cause SOB in >1 month olds?
- Strep pneumoniae
- group A strep
- HiB
- meningococcus
- VIRUSES
What is the pathophysiology of Respiratory distres syndrome (RDS)?
- There is a deficinecy of alveolar surfactant
- aka proteins, phospholipids excreted by type 2 pneumocytes
- this leads to alveolar collapse, atelectasis,
- reinflation with each breath exhausts the baby and respiratory failure follows
What does the hypoxia caused by RDS respiratory failure cause?
- hypoxia –>
- decreased cardiac output –>
- hypotension –>
- acidosis –>
- renal failure–>
major cause of death from prematurity
What are the risk factors for RDS?
- prematurity
- especially <28 weeks
- or no maternal antenatal corticosteroids
- maternal diabetes (can occur at term)
- males
- 2nd twin
- caesarians
- preterm prelabour rupture of membranes (PPROM)
What are the signs of respiratory distress seen in neonates and in what timeframe do you see these?
these signs of RDS are seen within 4 hrs after delivery
- increased work of breathing
- tachyponea e.g. >60/min
- grunting
- nasal flaring
- intercostal recession
- cyanosis
What causes transient tachypnoea of the newborn?
(A ddx for RDS in SOB neonate)
How do you Dx and Rx it?
- is due to excess lung fluid
- caused by delayed absorption of the lung fluid
- TF RF: elective C-section!
- normally resolves after a day or 2
Dx: of exclusion, supported by fluid in the horizontal fissure on a CXR
Rx: use O2 for a few days until the symptoms resolve
What causes congenital pneumonia?
(A ddx for RDS in SOB neonate)
Group B strep
What is a characteristic of a neonate having a tracheo-oesophageal fistula?
resp problems after feeds
TF it is ddx for RDS in SOB neonate
What would a CXR of RDS show?
diffuse “ground glass” appearance
that indicates a partial filling of air spaces in the lungs by exudate or transudate)
+/- air bronchograms
What is the prevention of RDS?
Betamethasone or dexamethasone should be offered to all women at risk of pre-term delivery from 23-35 weeks;
(mothers at high risk should be transferred to perinatal centres with experience in managing RDS)
- 2x doses of betamethasone/dex should happen
- the last being at least 24hrs before birth
Delayed cord camping (now normal practice) promotes placento-foetal transfusion (of the steroids?)
What do you do for a baby whos mother has not recieved antenatal steroids (betame/dexa) before 24hrs of the birth?
- Synthetic surfactant given to baby via tracheal tube
- oxygen +/- CPAP via nasal cannulae
- artificial ventilation also via tracheal tube
- continuous monitoring of O2, blood gas and chest wall movements
Why when giving artificial ventilation/oxygen to a newborn should you aim for sats of 85-93%?
to avoid:
- Retinopathy of prematurity
- Bronchopulmonary dysplasia (formerly known as chronic lung disese of infancy)
NB: pneumothorax can be caused by artifical ventilation so it is used as little as possible
What are the complications of RDS?
- Pulmonary or intra-ventricular haemorrhage
- pulmonary infection
- Persistent pulmonary hypertension of the new born
- renal failure (via hypoxia–>acidosis/dc CO & hypotension)
- DEATH
[&retinopathy of prematurity, Pneumothorax caused by artificial ventilation & Bronchopulmonary dysplasia (chronic lung disease of infancy); why keep sats @85-93%}
How does bronchopulmonary dysplasia cause persistent hypoxia?
the pressure & volume trauma caused by artificial ventilation,
–> oxygen toxicity and infection
–> persistent hypoxia +/- difficult ventilator weaning
e.g. Still needed ventilation at 36wks
A CXR of a neonate shows hyperinflation, rounded, radiolucent areas alternating with thin dense lines, what does this show?
Bronchopulmonary dysplasia
Histology shows necrotisin bronchiolitis with alveolar fibrosis. What condition is this related to?
bronchopulmonary dysplasia
What are the complications of bronchopulmomary dysplasia?
- feeding problems (O2 desaturation during feeding),
- severe RSV bronchiolitis,
- GOR,
- Cerebral Palsy /low IQ,
- asthma & exercise limitation
How do you prevent bronchopulmonary dysplasia?
- antenatal and postnatal steroids
- surfactant
- high calorie feeding
(ideally dont put on artificial ventilation / prevent infections too i guess)
Which infection is the most frequent cause of early onset e.g. < 7 days, severe infection in newborn infants?
Group B streptococcus infection
What is a neonates immune system like physiologically?
- Neonates have great macrophages (2x adults)
- but rest is non-existant
- relies on mothers IgG via placenta
- IgA (mucosa) & IgG & maternal lymphocytes (e.g. for specific rxns –>abs) are in milk but not ideal
- TF Rx any sign of infection in neonates aggressively!
Asphyxiation during birth and babies with listeria syndrome are risk factors for what condition?
Rx of this condition?
Meconium aspiration syndrome (MAS)
foetuses can pass meconium in response to hypoxia –> inhaled (sticky & chemically nasty) –> obstruction, pneumonitis, predisposition for infection, inactivates surfactants
TF Rx: w/sufactant, ventilation - inhaled NO (vasodilation) & abx maybe required …
NB: due to it being hard to achieve adequate oxygenation as infants develop pulmonary hypertension
A CXR shows hyper-inflated lungs with areas of collapse and consolidation what condition is this asociated with?
Meconium aspiration syndrome
–> PTX can develop!
(breathed in sticky and chem nasty meconium ~during hypoxic epidose/infection –> incactivated surfactant)
What are the signs and symptoms of a pneumothorax in a neonate?
Causes & Rx?
they can be asymptomatic or respiratory distress
O/E: decreased breath sounds & chest movment on the affected side
- often PTX happen spontaneously
- (babies put a LOT of work into their first breath so PTX happens in 2-4% + increased risk if ventilatied)
or secondary to
- meconium aspiration or
- artificial ventilation
Rx: insertion of a chest drain
What would signs of respiratory distress and STRIDOR in a neonate indicate?
laryngomalacia or bronchomalacia
- stridor = inspirational high pitched whistle/gasping sound –> airway obstruction @/below larynx level e.g. croup or epiglottitis too… requires med management*
- (stertor = snoring-like noise @above level of larynx)*
What are the consequences of having a diaphragmatic hernia, when are they Dx?
What is the Rx?
Diaphragmatic hernia can be diagnosed antenatal w/intestines seen in the thorax or on CXR post-natal
- they are normally left sided –>
- result in left lung hypoplasia from development –>
- & bowel there displaces apex of heart to right
Rx:
- NG tube for suction to prevent distension or intrathoracic bowel (and give lung tissue space to expand)
- surgery once stable
What causes persistent pulmonary hypertension of a newborn?
spontaneous
or secondary to:
- meconium aspiration,
- birth asphyxia,
- diaphragmatic hernia,
- sepsis or
- respiratory distress syndrome.
anything causing increased WOB/SOB(?)
What can a neonate having persistent pulmonary hypertension lead to (the consequences)?
Rx?
- right-to-left shunting of blood (from high pressure in RHS now)
- across a patent foramen ovale or ductus arteriosus
Rx:
circulatory and resp support
vasodilator agent e.g. nitric oxide / sildenafil (viagra lol)
