4 - Neonatology Flashcards
What are some cardiorespiratory changes that happen at birth?
- During birth thorax is squeezed 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. Adrenaline and cortisol are released to the stress of labour, stimulating respiratory effort
- The first breaths baby takes expands alveoli, decreases pulmonary vascular resistance so fall in pressure in the right atrium. At this point the left atrial pressure is greater than the right atrial pressure, which closes foramen ovale so becomes foramen ovalis
- Increased blood oxygenation causes a drop in circulating prostaglandins. This causes closure of the ductus arteriosus, which becomes the ligamentum arteriosum.
- Ductus venosus stops functioning because umbilical cord is clamped and no blood flow in the umbilical veins. Closes a few days later and becomes ligamentum venosum
When is surfactant produced in the fetal life?
Between 24 and 34 weeks the type II pneumocytes start to produce surfactant
What is the protocol for neonatal resuscitation?
- Birth
- Dry and warm baby trying to stimulate breathing
- APGAR at 1,5 and 10 minutes
- If gasping or not breathing: open airway, 5 inflation breaths, give oxygen and ECG monitoring
- Reassess heart rate and chest movements
- If chest not moving optimise airway control, repeat 5 inflation breaths
- If no increase in heart rate at this point, re-assess for chest movement and repeat above steps if necessary
- If chest is moving and heart rate <60 bpm, ventilate for 30 seconds
- If heart rate still <60 bpm, commence chest compressions at a rate of 3:1
- Reassess every 30 seconds if heart rate remains <60 bpm, consider venous or osseous access and administering drugs
- Throughout process keep the parents updated, and keep a record
How can we try to stimulate baby to breathe after birth?
- Dry vigorously with towel
- Place baby’s head in neutral position
- Check for meconium in airway and aspirate
What gas should you use for inflation breaths during neonatal resuscitation?
Image is important
For term or near term use air
For pre-term use air and oxygen
Aim for gradual rise in sats, not exceeding 95%
If a neonate has suspected HIE after resuscitation what can be given to them?
Therapeutic hypothermia
What are some issues to recognise in neonatal resuscitation?
What is part of the APGAR score?
Measure at 1,5,10 minutes giving score out of 10
- A score of >7 is reassuring
- A score of 4-6 requires stimulation
- A score of <4 requires resuscitation
What are the benefits of delayed cord clamping and when is this done?
In uncompromised neonates this is done for one minute
- Improved Hb and iron stores
- Improved blood pressure
- Reduction in intraventricular haemorraghe and NEC
- Only negative is risk of neonatal jaundice so need more phototherapy
What care is done for the baby after birth?
- Skin to skin
- Clamp the umbilical cord
- Dry the baby
- Keep the baby warm with a hat and blankets
- Vitamin K IM
- Label the baby, measure the weight and length
- Initiate breast feeding or bottle feeding as soon as the baby is alert
- Newborn examination within 72 hours
- Blood spot test
- Newborn hearing test
Why are newborns given Vitamin K?
- Babies have a deficiency and need it for clotting
- Helps to prevent bleeding, particularly intracranial, umbilical stump and GI
- Usually given IM in thigh, helps them to cry too
- Can give oral but need 3 doses
What is the blood spot screening and when is it done?
Taken on day 5 (to day 8)
Need four drops of blood from heel to test for 9 conditions
Results take 6-8 weeks
What screening tests are done for newborns?
- Blood spot
- Hearing
What is the difference between Caput Succedaneum and Cephalohaematoma?
Caput Succedaneum
Fluid collecting on the scalp, outside the periosteum.
Caused by pressure to specific area of scalp during a traumatic, prolonged or instrumental delivery
Able to cross suture lines
Does not require any treatment and will resolve within a few days
Cephalohaematoma
Collection of blood between the skull and the periosteum, same cause as above
The blood is below the periosteum, therefore the lump does not cross the suture lines of the skull
Blood can discolour skin
Reesolves without treatment within a few months. There is a risk of anaemia and jaundice due to the blood that collects within the haematoma and breaks down, releasing bilirubin
What are some risk factors for early onset neonatal sepsis and what are common organisms causing this?
(Early onset up to 72 hours, Late onset after 72 hours)
Can come from chorioamnionitis, birth canal or external environment
Risk Factors
- Vaginal GBS colonisation
- GBS sepsis in a previous baby
- Maternal sepsis, chorioamnionitis or fever > 38ºC
- Prematurity (less than 37 weeks)
- Premature rupture of membrane
- Prolonged rupture of membranes (PROM)
Common Organisms
- Group B streptococcus (GBS)
- Escherichia coli (e. coli)
- Listeria
- Klebsiella
- Staphylococcus aureus
How is GBS prevented from causing neonatal sepsis?
Give intrapartum IV benzylpenicillin
How may neonatal sepsis present? (inc red flags)
- Fever
- Reduced tone and activity
- Poor feeding
- Respiratory distress or apnoea
- Vomiting
- Tachycardia or bradycardia
- Hypoxia
- Jaundice within 24 hours
- Seizures
- Hypoglycaemia
When should you start treatment for suspected neonatal sepsis?
- If there is one risk factor or clinical feature, monitor observations and clinical condition for at least 12 hours
- If there are two or more risk factors or clinical feature of neonatal sepsis start antibiotics
- Antibiotics should be started if there is a single red flag
What is the initial management of neonatal sepsis?
- Take baseline FBC and CRP
- Blood cultures before antibiotics
- Antibiotics given within 1 hour
- Lumbar puncture if infection strongly suspected or features of meningitis (e.g. seizures)
What antibiotics are used for neonatal sepsis?
Early Onset
- IV Benzylpenicillin and IV Gentamicin
- If Gram -ve add in Cefotaxime IV and remove the Benzylpenicillin
Late Onset
- IV Flucloxacillin and IV Gentamicin
Meningitis
- IV Amoxicillin and IV Cefotaxime
What is the ongoing management of neonatal sepsis once antibiotics have been initiated?
ANTIBIOTIC TREATMENT IS 7 DAYS MAX (stop if well and negative culture, continue if positive)
- Check CRP again at 24 hours and check blood culture results at 36 hours:
- Consider stopping antibiotics if baby is clinically well, blood cultures are negative 36 hours after taking them and both CRP results are less than 10
- Check the CRP again at 5 days if they are still on treatment:
- Consider stopping antibiotics if the baby is clinically well, the lumbar puncture and blood cultures are negative and the CRP has returned to normal at 5 days
- Consider performing a lumbar puncture if any of the CRP results are more than 10
How long is neonatal sepsis treated for?
7 days if culture positive
If meningitis 14-21 days
What is the incidence of HIE and when do we suspect HIE may have occurred?
2 to 5 in 1000 births
- Events that could lead to hypoxia during the perinatal or intrapartum period
- Acidosis (pH < 7) on the umbilical artery blood gas
- Poor Apgar scores
- Features of mild, moderate or severe HIE
- Evidence of multi organ failure.
What are some causes of HIE?
Primary neuronal death from ischaemia and then secondary reperfusion injury
- Maternal shock
- Intrapartum haemorrhage e.g placental abruption
- Twin to twin transfusion syndrome
- Sepsis
- Prolapsed cord, causing compression of the cord during birth
- Nuchal cord, where the cord is wrapped around the neck of the baby
How is HIE graded?
Sarnat Staging
How can HIE be investigated?
EEG monitoring
How is HIE managed?
- Respiratory support
- Anticonvulasant therapy
- Fluid balance, electrolyte monitoring and inotropes
- Therapeutic Hypothermia for secondary reperfusion injury
- Follow up by paediatrician to check for learning disability
How is therapeutic hypothermia carried out for HIE management?
- Babies near or at term
- Baby transferred to neonatal ICU and actively cooled using cooling blankets and a cooling hat
- Target of between 33 and 34°C, measured using a rectal probe.
- Continued for 72 hours then warmed back up over 6 hours
Reduces the inflammation and neurone loss after the acute hypoxic injury. It reduces the risk of cerebral palsy, developmental delay, learning disability, blindness and death
What is the prognosis with HIE?
Assess extent of damage with MRI
- Chronic neurological disability e.g cerebral palsy
- Epilepsy
- Learning disabilities
- Blindness
- Delayed motor skills and speech
- ⅓ are fatal
What is neonatal jaundice and the epidemiology of this?
Jaundice (high bilirubin) that occurs in the first month of life, more common in preterm
May be physiological or pathological
- Term ( ≥ 37 weeks gestation): affects 60% of newborns
- Preterm (< 37 weeks gestations): affects 80% of newborns
What are some risk factors for newborn jaundice?
- Preterm <37 weeks
- Ethnicity: Asian, European, or native American
- Male
- Cephalohaematoma
- Maternal factors: diabetes mellitus, >25 years old, exclusive breastfeeding
- Other: previous sibling needing phototherapy for neonatal jaundice
What is physiological neonatal jaundice?
- More common in breast fed babies
- Neonate has high concentration of RBC and less developed liver function
- Neonate RBCs break down more rapidly than normal releasing lots of bilirubin. Normally this bilirubin is excreted via the placenta, however at birth the foetus no longer has access to a placenta to excrete bilirubin
Mild yellowing of skin and sclera at 2-7 days, resolves by 10 days
What are some pathological causes of newborn jaundice?
Any jaundice that occurs before 24 hours, needs urgent investigations
ALWAYS CONSIDER SEPSIS
Increased production of bilirubin:
- Haemolytic disease of the newborn
- Sepsis
- ABO incompatibility
- Haemorrhage
- Intraventricular haemorrhage
- Cephalo-haematoma
- Polycythaemia
- G6PD deficiency
Decreased clearance of bilirubin:
- Prematurity
- Breast milk jaundice
- Neonatal cholestasis
- Extrahepatic biliary atresia
- Endocrine disorders (hypothyroid and hypopituitary)
- Gilbert syndrome
Why do the following babies often develop jaundice:
- Pre-term
- Breast feed
- Haemolytic Disease of Newborn
Preterm: Immature liver function
Breast fed: Components of breast milk inhibit ability of liver to conjugate bilirubin. Also may be dehydrated so constipated so absorb more from intestines
HDN: haemolysis due to rhesus antibodies on rhesus positive antigens
What is prolonged jaundice?
When physiological jaundice occurs for longer than expected:
- More than 14 days in full term babies
- More than 21 days in premature babies
Should prompt further investigation e.g biliary atresia, hypothyroidism and G6PD deficiency.
What is Kernicterus?
- Unconjugated bilirubin is potentially toxic to neural tissue in newborns and able to cross the blood-brain barrier
- Yellow staining of cerebral tissue, particularly in the deep grey matter of the brain due to bilirubin deposition
- Short term: less responsive, floppy, drowsy baby with poor feeding.
- Long term: cerebral palsy, learning disability and deafness
What are the clinical features of neonatal jaundice?
- Yellowing of skin: check in bright natural light, harder in dark skin
- Irritable baby
- Poor feeding
What investigations are done for neonatal jaundice?
Routine screen:
- Serum bilirubin
- Blood packed cell volume
- Blood group (mother and baby)
- Direct Coombs Test
If clinically indicated:
- Full blood count
- Blood film
- LFTs
- G6PD levels
- Cultures: work up for sepsis
- CRP
How is neonatal jaundice treated?
- Treatment threshold table for newborns > 38 weeks gestation or treatment threshold graphs for preterm newborns
- Phototherapy or Exchange transfusion
Refer to gastro if profound conjugated hyperbillirubinaemia as could mean biliary atresia
- Treatment is to prevent irreversible Kernicterus
What is phototherapy and red cell exchange?
(count in hours on chart)
Phototherapy
- Blue-green light in the range of 460-490 nm, converts unconjugated bilirubin into water soluble molecules isomers that can be excreted without conjugation by liver
- Regular assessment of bilirubin levels every 6 hours
Red cell exchange
Removal of the newborns blood and simultaneously replacing it with a compatible donor. This leads to a dramatic reduction in bilirubin levels.
Done for extremely high levels
What is Crigler Najjar syndrome?
- Mutations within the UGT1A1 gene, which encodes glucuronosyltransferase
- They cause an unconjugated hyperbilirubinaemia
- Similar to Gilbert’s but more severe as it leads to a profound reduction or absence of the enzyme activity,
What are some issues in early life for premature babies?
- Respiratory distress syndrome
- Hypothermia
- Hypoglycaemia
- Poor feeding
- Apnoea and bradycardia
- Neonatal jaundice
- Intraventricular haemorrhage
- Retinopathy of prematurity
- Necrotising enterocolitis (NEC)
- Immature immune system and infections
What are some long term effects of prematurity?
- ROP
- Chronic lung disease of prematurity
- Cerebral palsy
- Developmental delay
What is apnea?
Breathing stops spontaneously for more than 20 seconds, or shorter periods with oxygen desaturation or bradycardia
Happens to all babies before 28 weeks gestation but can also happen at any gestational age
What is the pathophysiology of retinopathy of prematurity?
Usually afters before 32 weeks and low birth weight babies
- Retinal blood vessel development is stimulated by hypoxia and finishes around 37-40 weeks
- 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
How is retinopathy of prematurity assessed?
Retina has 3 zones
- Zone 1: optic nerve and the macula
- Zone 2 : edge of zone 1 to the ora serrata, the pigmented border between the retina and ciliary body
- Zone 3: outside the ora serrata
Stage 1 (slightly abnormal vessel growth) to stage 5 (complete retinal detachment).
What is the aetiology of respiratory distress syndrome of the newborn?
Inadequate surfactant leads to high surface tension within alveoli. This leads to atelectasis (lung collapse), as it is more difficult for the alveoli and the lungs to expands
Results in hypoxia, hypercapnia and respiratory distress
What investigation can help to diagnose respiratory distress syndrome and what does it show?
CXR
Ground glass appearance and air bronchograms
What is chronic lung disease of prematurity?
Bronchopulmonary Dysplasia
Persistent hypoxia and difficult ventilator weaning at 36 weeks’ postmenstrual age. Usually due to oxygen toxicity
Early issues: Feeding problems. O2 desaturation during feeds, severe RSV bronchiolitis, GORD
Late issues: cerebral palsy, asthma and exercise limitation
What are some risk factors for developing NEC?
- Very low birth weight or very premature
- Formula feeds
- Respiratory distress and assisted ventilation
- Sepsis
- Patient ductus arteriosus and other congenital heart disease
How may NEC present?
- Vomiting, particularly with green bile aspirate
- Fresh blood in stools
- Intolerance to feeds
- Generally unwell
- Distended, tender abdomen
- Absent bowel sounds
What may an AXR show in NEC?
- Pneumatosis intestinalis is gas in the bowel wall and is a sign of NEC
- Pneumoperitoneum is free gas in the peritoneal cavity and indicates perforation
- Dilated loops of bowel
- Bowel wall oedema (thickened bowel walls)
- Gas in the portal veins
How is NEC managed?
- Make nil by mouth
- IV fluids and total parenteral nutrition (TPN)
- Triple antibiotics
- NG tube to drain fluid and gas from stomach
- Barrier nurse
NEC is a surgical emergency and requires immediate referral to the neonatal surgical team. Some recover medically, some need surgery to remove dead bowel and have temporary stoma
What are some signs of neonatal abstinence syndrome?
How can we minimise the risk of SIDS?
- Put baby on back when not directly supervised
- Keep their head uncovered
- Place feet at the foot of the bed to prevent sliding down and under the blanket
- Keep cot clear of lots of toys and blankets
- Maintain a comfortable room temperature (16 – 20 ºC)
- Avoid smoking
- Avoid co-sleeping, particularly on a sofa or chair
- If co-sleeping avoid alcohol, drugs, smoking, sleeping tablets or deep sleepers
What are the main causes of neonatal death?
RESPIRATORY DISTRESS OF NEWBORN
- Infections (36%, which includes sepsis/pneumonia, tetanus and diarrhoea)
- Pre-term (28%)
- Birth asphyxia
When is ROP screened for and how?
Need laser therapy for neovascularisation
Risk factors: prematurity and low birth weight
