The Preterm Baby: Flashcards
This is a cranial US of preterm baby
What does it show? [1]
Black holes: cystic change - preterm baby injury
Pre-term brain injury
What are the two types of Pre-term brain injury? [2]
How and when do you monitor for this? [+]
Preterm brain injury:
* intraventricular haemorrhage
* periventricular leukomalacia
Screen cranial US at:
- 1, 3 & 7 days
- 2-4 weekly until discharge
Describe the pathophysiology of intraventricular haem. [2]
When does it typically occur? [1]
In neonatal practice the vast majority of IVH occur in the first 72 hours after birth, the aetiology is not well understood and it is suggested to occur as a result of birth trauma combined with cellular hypoxia, together the with the delicate neonatal CNS.
Occurs due to fragile BV x poor autoregulation of cerebral blood flow
Describe 4 risks for IVH [4]
Reducing GA
Lack of perinatal optimisation
Chorioamnitis
Early haemodynamic instabilty
Describe the pathophysiology of ROM [4]
Retinal blood vessel development starts at around 16 weeks and is complete by 37 – 40 weeks gestation.
The blood vessels grow from the middle of the retina to the outer area.
- This vessel formation is stimulated by hypoxia, which is a normal condition in the retina during pregnancy.
- When the retina is exposed to higher oxygen concentrations in a preterm baby, particularly with supplementary oxygen during medical care, the stimulant for normal blood vessel development is removed.
When the hypoxic environment recurs, the retina responds by producing excessive blood vessels (neovascularisation), as well as scar tissue. These abnormal blood vessels may regress and leave the retina without a blood supply. The scar tissue may cause retinal detachment.
The retina is divided into three zones. What are they? [3]
Zone 1 includes the optic nerve and the macula
Zone 2 is from the edge of zone 1 to the ora serrata, the pigmented border between the retina and ciliary body
Zone 3 is outside the ora serrata
NB: The retinal areas are described as a clock face, for example “there is disease from 3 to 5 o’clock”. The areas of disease are described from stage 1 (slightly abnormal vessel growth) to stage 5 (complete retinal detachment).
“Plus disease” describes additional findings, in ROM, such as: [2]
“Plus disease” describes additional findings, such as tortuous vessels and hazy vitreous humour.
Which babies are screened for ROM? [2]
How often does screening occur? [1]
What does screening involve? [1]
All babies < 1500g or 31/40 are screen
4 – 5 weeks of age in babies born after 27 weeks
Screening should happen at least every 2 weeks and can cease once the retinal vessels enter zone 3, usually at around 36 weeks gestation.
Screening involves monitoring the retinal vessels as they develop and looking for plus disease.
How do you treat ROM? [4]
First line is transpupillary laser photocoagulation to halt and reverse neovascularisation.
Other options are cryotherapy and injections of intravitreal VEGF inhibitors.
Surgery (vitrectomy) may be required if retinal detachment occurs.
What are some longer term complications of being premature? [5]
PDA
Chronic lung disease of prematurity
ROM
Neurodisability: hearing impairment and oral aversion
Neurodiversity
A baby is deemed high risk with chronic lung disease. What management might you consider for them? [1]
RSV prophylaxis
What are risk factors for cot death? [4]
How do you instruct babies to sleep? [1]
Risk factors:
- exposure to tobacco smoke
- late or no antenatal care
- young maternal age
- premature birth
Instruct babies to ‘‘Back to sleep” - sleep on their backs to reduce likelyhood
Describe what is meant by meconium aspiration syndrome (MAS) [1]
What is the clinical consequence of MAS?
When a newborn inhales a mixture of meconium and amniotic fluid during birth
Lead to:
* airway obstruction
* inflammation
* infection
* respiratory distress due to chemical pneumonitis
What are the clinical featuers of meconium aspiration syndrome?
A typical presentation of meconium aspiration syndrome (MAS) may involve a term or post-term neonate displaying signs of respiratory distress shortly after birth:
Tachypnoea:
- Rapid breathing is one of the most common presenting features in MAS. It typically occurs within minutes to hours after birth.
Cyanosis:
- A bluish discoloration of the skin and mucous membranes due to low oxygen levels in the blood.
Decreased breath sounds or rales:
- Auscultation may reveal decreased breath sounds with rales or rhonchi due to airway obstruction by meconium.
Barrel-shaped chest:
- This may be present due to hyperinflation of the lungs from obstructive emphysema as a result of air trapping.
Prolonged expiratory phase:
- This can be noted on physical examination and is indicative of airway obstruction.
NB: It’s important to note that the severity of symptoms and findings can vary significantly between individuals. Some neonates with MAS may present with mild respiratory distress while others may develop severe respiratory failure requiring mechanical ventilation
How do you investigate for MAS?
- First line? [3]
First-line investigations
Chest X-ray:
- A chest radiograph is essential to evaluate the presence of infiltrates, atelectasis, or hyperinflation. Typical findings in meconium aspiration syndrome (MAS) include patchy areas of atelectasis and hyperinflation.
- The presence of air leaks such as pneumothorax or pneumomediastinum should also be assessed.
Arterial blood gas (ABG):
- ABG analysis is critical for assessing the degree of hypoxemia, hypercapnia, and acidosis.
- This helps gauge the severity of respiratory compromise and guides oxygen therapy and ventilation strategies.
Pulse oximetry:
- Continuous monitoring of oxygen saturation provides real-time data on the infant’s oxygenation status and helps in titrating supplemental oxygen levels.
NB: The diagnosis of MAS typically relies heavily on clinical presentation combined with radiographic evidence from chest X-rays. Further investigations are guided by specific clinical indications such as suspected PPHN or concurrent infections.
A baby presents with MAS and PPHN. What is the next appropriate investigation and why? [2]
Echocardiography:
- This investigation is indicated if there are signs suggestive of persistent pulmonary hypertension of the newborn (PPHN), which can coexist with MAS. Echocardiography evaluates pulmonary artery pressures, cardiac function, and excludes congenital heart disease.
Describe the management plan for a baby with MAS [+]
Initial stabilisation:
* Avoid routine intrapartum suctioning.
* If the neonate is vigorous (strong respiratory effort, good muscle tone, heart rate >100 bpm), proceed with standard neonatal care.
* If the neonate is not vigorous: perform direct laryngoscopy and tracheal suctioning to remove meconium from the airway before initiating positive pressure ventilation (PPV).
Respiratory support:
* Administer supplemental oxygen to maintain target oxygen saturation levels as per neonatal resuscitation guidelines.
* Initiate continuous positive airway pressure (CPAP) or mechanical ventilation if indicated by respiratory distress or hypoxaemia.
Surfactant therapy:
* Consider administration of exogenous surfactant in cases of severe respiratory distress or when mechanical ventilation is required.
Antibiotic therapy:
* Initiate empirical antibiotic therapy due to the risk of secondary bacterial infection. Adjust based on culture results and clinical course
Management of persistent pulmonary hypertension (PPHN):
* Employ inhaled nitric oxide (iNO) for infants with significant PPHN unresponsive to conventional ventilation and oxygen therapy.
* If iNO is unavailable or ineffective, consider extracorporeal membrane oxygenation (ECMO) as a last resort in specialised centres.
AVOID routine use of corticosteroids unless there are specific indications such as concurrent conditions requiring their use.
Describe the respiratory changes / process that happens directly at birth [4]
During birth the thorax is squeezed as the body passes through the vagina, helping to clear fluid from the lungs
Birth, temperature change, sound and physical touch stimulate the baby to promote the first breath.
- A strong first breath is required to expand the previously collapsed alveoli for the first time
Adrenalin and cortisol are released in response to the stress of labour, stimulating respiratory effort
The first breaths the baby takes expands the alveoli, decreasing the pulmonary vascular resistance. The decrease in pulmonary vascular resistance causes a fall in pressure in the right atrium
Describe the cardiac changes / process that happens directly at birth [4]
After first breath:
- decrease in pulmonary vascular resistance causes fall in pressure in right atrium
At this point:
- the left atrial pressure is greater than the right atrial pressure, which squashes the atrial septum and causes functional closure of the foramen ovale. The foramen ovale then structurally closes and becomes the fossa ovalis.
Prostaglandins are required to keep the ductus arteriosus open.:
- Increased blood oxygenation causes a drop in circulating prostaglandins. This causes closure of the ductus arteriosus, which becomes the ligamentum arteriosum.
What happens to the ductus venosus after birth? [1]
Immediately after birth the ductus venosus stops functioning because the umbilical cord is clamped and there is no blood flow in the umbilical veins. The ductus venosus structurally closes a few days later and becomes the ligamentum venosum.
Describe in neonatal guidelines for resuscitation [+]
Neonatal resuscitation guidelines
* Birth: Dry the baby, remove any wet towels and cover and start the clock or note the time.
* Within 30 seconds: Assess tone, breathing and heart rate.
* Within 60 seconds: If gasping or not breathing - open the airway and give 5 inflation breaths
* Re-assess: If no increase in heart rate look for chest movement
* If chest not moving: Recheck head position, consider 2-person airway control and other airway manoeuvres, repeat inflation breaths and look for a response.
* If no increase in heart rate look for chest movement
* When the chest is moving: If heart rate is not detectable or slow (< 60 min-1) - start chest compressions with 3 compressions to each breath.
* Reassess heart rate every 30 seconds. If heart rate is not detectable or slow (< 60 beats per minute) consider venous access and drugs
*
Pulmonary hypoplasia is a term used for newborn infants with underdeveloped lungs
Causes include
[2]
Pulmonary hypoplasia is a term used for newborn infants with underdeveloped lungs
Causes include
oligohydramnios
congenital diaphragmatic hernia
