Neonatology Flashcards
What is neonatology?
The medical care of newborn infants, especially the ill or premature
What do neonatologists deal with?
Prematurity Low birth weight IUGR Congenital malformations Infection Birth asphyxia
When does the CVS begin to develop?
Towards the end of the 3rd week
When does the heart start to beat?
Beginning of 4th week
When is the critical period of heart development?
Day 20 to day 50 after fertilisation
Foetal body saturations
60-70%
What is the biggest organ of the baby when it is born and what is the significance of this?
Liver
Gets most of the oxygenated blood
What are the functions of the Ductus Arteriosus?
Protects lungs against circulatory overload - safety valve
Allows the right ventricle to strengthen
Carries low oxygen saturated blood
What does the ductus venosus do?
Connects the umbilical vein to the IVC
Carries mostly oxygenated blood
What is ductus venosus blood regulated by?
Sphincter
What happens with the first breath?
Breathe with the fluids
Start moving the fluids out
Normal labour forces cause stress and mechanical squeeze
First breath opens the arteries in the lungs - so instead of blood on bypass, it is getting great oxygenation and circulation
Ductus arteriosus, ductus venosus, umbilical veins and arteries become ligaments
Foramen ovale closes and leaves a depression
Normal BP for a 1 hr old newborn
70/44
Normal BP for a 3 day old newborn
77 +/- 12 / 49 +/- 10
RR for full term newborn
30 - 60 / min
What is a feature of breathing of a full term newborn?
Periodical breathing
Normal HR for a full term newborn
120 - 160 b / min
Tachycardia value for a newborn
> 160 b / min
Bradycardia value for a newborn
< 100 b / min
How is thermoregulation done in the foetus?
Maternal thermoregulation in the womb
Metabolic production of heat due to lack of shivering
Brown fat well innervated by sympathetic neurones
Cold stress leads to lipolysis and heat production
Loss of heat occurs by….
Radiation - heat dissipated to colder objects
Convection - heat loss by moving air
Evaporation
Conduction - heat loss to surface on which the baby lies
How is breathing measured in newborns?
Non invasive - Blood gas - Trans cutaneous pCO2 / O2 measurement Invasive - capnography - tidal volume 4-6ml / kg - minute ventilation TV x RR - flow volume loop
What is normal values of PaCO2 and PaO2 in newborns?
PaCO2 = 5-6kPa PaO2 = 8-12 kPa
When does physiological jaundice appear?
DOL 2-3
What does DOL stand for?
Day of life
When does physiological jaundice disappear?
7-10 DOL
up to 21 DOL in premature infants
What % of babies develop visible jaundice?
60% terms
80% premature
How much bilirubin comes from haemoglobin?
75%
What does bilirubin cause at high concentrations?
Irreversible changes in the brain - kernicterus
What does blue light do to jaundice?
Converts bilirubin to water soluble form and increases oxidation of bilirubin
Loss of fluid in the full term newborn is due to what?
Shift of interstitial fluid to intravascular
Diuresis
Loss of fluid in the premature infant is due to what?
Less fat in body composition Increased loss through kidney - slower GFR - reduced Na reabsorption - decreased ability to concentrate or dilute urine Increased insensible water loss (IWL) - immature skin - breathing
How much insensible water loss is normal to lose?
20 - 40 ml / kg / day
Anaemia of prematurity
Reduced erythropoiesis
Infection
Blood letting
Most important cause of anaemia of prematurity
Blood letting
Types of small babies
Small for gestational age (SGA)
IUGR
Hypotrophy
- symmetric / asymmetric
What centile is IUGR?
< 10th centile
What centile is severe IUGR?
< 0.4th centile
Causes of small for dates babies
Maternal - smoking - alcohol - PET Foetal chromosomal e.g. Edwards syndrome Infection e.g. CMV, syphilis Placental - insuffiency - abruption Twins - TTN Normal Mixed
Common problems in small for dates babies
Perinatal hypoxia Hypoglycaemia Hypothermia Polycythaemia Thrombocytopenia Hypoglycaemia GI problems (feeds, NEC) RDS (less surfactant) Infection
Long term problems for small for dates babies
HTN Reduced growth - first 2 - 3 yrs remain small Obesity Ischaemic Heart disease
What gestational age is a baby preterm?
< 37 weeks
What gestational age is a baby extremely preterm?
< 28 weeks
What is considered a low birth weight?
< 2500g
What is considered an extremely low birth weight?
< 1000g
Incidence of prematurity
5 - 12%
What is RDS?
Respiratory distress syndrome
What is IVH?
Intraventricular haemorrhage
What is PVL?
Peri-ventricular leuomalacia
What is NEC?
Necrotising entero-colitis
What is PDA?
Patent ductus arteriosus
What is BPD?
Broncho-pulmonary dysplasia
What is ROP?
Retinopathy of prematurity
What is PHH?
Post haemorrhagic hydrocephalus
What is NAS?
Neonatal abstinence syndrome
What is HIE?
Hypoxic - ischaemic encephalopathy
Pathology of RDS
Alveoli collapse
Become hypercapnic even though have good perfusion
Less surfactant
Prevention of RDS
Antenatal steroids
Treatment of RDS
Early - surfactant
Early extubating
Non invasive support (N-CPAP)
Minimal ventilation (low tidal volume and good inflation)
Pathology of BPD
Overstretch by volubaro trauma Atelectasis infection via ETT O2 toxicity Inflammatory changes tissue repair - scarring
Treatment of BPD
Patience
NUTRITION AND GROWTH
steroids
Minor respiratory problems include
Apnoea
Irregular breathing
Desaturations
Sometimes forget to breathe
Treatment of minor resp problems
Caffeine
N-CPAP
Prevention of IVH
Antenatal steriods
Treatment of IVH
NO TREATMENT
Drainage
Pathology of PVL
white matter surrounding ventricles deprived of O2 and blood leading to malacia (softening) - leading to holes in the brain and abscess
What % of PVL have adverse outcomes?
95%
Pathology of PDA
Over perfusion of lungs - Lung odema
Lung oedema steals from systemic circulation leading to
Systemic ischaemia
Consequences of PDA
Worsening of resp symptoms
Retention of fluids (low renal perfusion)
GI problems (GI ischaemia)
What does NEC involve?
Ischaemic and inflammatory changes
Necrosis of bowel
Treatment of NEC
Surgical often required
Antibiotics
Parental nutrition
Prognosis of prematurity
1 / 3 die
1 / 3 normal life or mild disability
1 / 3 have moderate or severe disability for lifetime
1 in 6 entirely normal at 6 y/o
Treatment of PVL
No treatment
What can IVH lead to?
PHH
What is a risk factor for NEC?
Formula feeding
What is protective of NEC?
Breastfeeding
What is the first step in neonatal resuscitation?
Dry the neonate
Neonatal resus guidelines
- Dry the neonate, remove any wet towels and start the clock / note the time
- within 30 seconds; assess tone, breathing and HR
- within 60 seconds; if gasping or not breathing; open airway and give 5 inflation breaths
- Re-asses; if no increase in HR, look for chest movement
- if chest not moving; recheck head position, consider 2 person airway control and other airway manouvres, repeat inflation breaths and look for a response
- If no increase in HR, look for chest movement
- When the chest is moving, if the HR is not detectable or slow (<60bpm) start chest compressions 3 compressions to each breath
- Reassess HR every 30 seconds. If HR not detectable or slow consider venous access and drugs
What is used to assess the health of a newborn baby?
APGAR score
What is looked at in the APGAR score?
Pulse Resp effort Colour Muscle tone Reflex irritability
What parts of the APGAR score get a score of 2?
Pulse > 100 Resp effort - strong, crying Pink in colour Muscle tone - active movement Reflex irritability - Cries on stimulation/sneezes, coughs
What parts of the APGAR score get a score of 1?
Pulse < 100 Resp effort is weak and irregular Body pink but extremities blue Muscle tone - limb flexion Reflex irritability - grimace
What parts of the APGAR score gets a score of 0?
Pulse absent Resp effort nil Blue all over Muscle tone - flaccid No reflex irritability
Interpretation of APGAR scores
0 - 3 very low score
4 - 6 moderate low
7 - 10 baby in good state
When is a childs hearing first assessed and how?
Newborn
Otoacoustic emissions test
In the first 10 mins of life, what can be expected of O2 sats of neonates?
They may be suboptimal
What are the greater risks associated with neonatal meningitis?
LBW Prematurity Traumatic delivery Foetal hypoxia Maternal peripartum infection
If a baby has a heel prick test done, and it is found to have raised immunoreactive trypsinogen (IRT), what is the next most appropriate test for the baby? What are they looking for?
Sweat test
Tests for CF
Presentation of NEC
Feeding intolerance Abdominal distension Bloody stools Can quickly progress to - abdominal discolouration - perforation - peritonitis
What is the investigation for NEC and what does it show?
AXR
- Dilated bowel loops (often asymmetrical in distribution)
- Bowel wall oedema
- Pneumatosis intesinosis (intestinal gas)
- portal venous gas
- pneumoperitoneum resulting from perforation
- Air both inside and outside of the bowel (rigler sign)
- air outlining the falciform ligament (football sign)
If a baby has an abnormal hearing test at birth, what test are they offered?
Auditory brainstem response test
What is the compression to ventilation ratio in neonates?
3:1
All breech babies at or after 36 weeks gestation require what?
USS for DDH at 6 weeks regardless of mode of delivery
Risk factors for surfactant deficient lung disease of the newborn
Decreasing gestation Male Maternal DM C section Second born of prem twins
Presentation of surfactant deficient lung disease of the newborn
Resp distress of the newborn - tachypnoea - intercostal recession - expiratory grunting - cyanosis CXR - 'Ground glass' appearance with an indistinct heart border
