Paediatrics

Question 1

In England, at what age my a child give consent?

Answer 1

If under 18 they are considered a child. 16 and 17 year olds may make decisions of legal standing, but parents can also give consent for them. Courts may also overrule competent 16 and 17 year olds.
Under 16, a Gillick-competent child may give or withhold consent but again this may be overruled but a parent, guardian or court if in their ‘best interests’

Question 2

Who can consent on behalf of a child?

Answer 2

Mother
Natural father if married, or divorced, from mother
Unmarried father if on birth certificate or in Parental Rights and Responsibilities agreement with mother
Legal guardia
Anyone with court order with right to consent
Person over 16 with care and control of child (limited rights, and not if they are aware that parents would disagree)
Court of Law
The child if appropriate, in extenuating circumstances

Question 3

Can a child be given a life-saving blood transfusion if the parents are Jehovah’s witnesses and refuse?

Answer 3

In an emergency, yes to save or preserve life. Electively the child must be made a ‘ward of court’ with two consultants declaring blood necessary to save life or prevent serious harm.

Question 4

What are the normal RR, HR and SPB in a child <1?

Answer 4

RR 30-40
HR 110-160
SBP 70-90

Question 5

What are the normal RR, HR and SPB in a child aged 1-2?

Answer 5

RR 25-35
HR 100-150
SBP 80-95

Question 6

What are the normal RR, HR and SPB in a child aged 2-5?

Answer 6

RR 25-30
HR 95-140
SBP 80-100

Question 7

What are the normal RR, HR and SPB in a child aged 5-12?

Answer 7

RR 20-25
HR 80-120
SBP 90-110

Question 8

What are the normal RR, HR and SPB in a child aged >12

Answer 8

RR 15-20
HR 60-100
SBP 100-120

Question 9

What is meant by ‘premature’?

Answer 9

Birth before 37 weeks gestation

Question 10

What is a neonate?

Answer 10

a baby up to 28 days old or 44 weeks post conceptional age

Question 11

What is an infant?

Answer 11

A baby up to 1 year

Question 12

What is a toddler?

Answer 12

A child around the early stages of walking 1-3 years

Question 13

What is a child?

Answer 13

Legally, anyone who is not yet 18 years old. Practically, 3 years to puberty

Question 14

What is an adolescent?

Answer 14

Broadly puberty-18

Question 15

What is normal childhood dentition?

Answer 15

First teeth around 6 months, with 20 primary teeth complete by 3 years.
Permanent dentition begins around age 6 and the last primary teeth are usually lost by 14.

Question 16

In what ways is the respiratory system of child different to that of an adult? Why is this relevant?

Answer 16

• Higher airway resistance (narrower airways) therefore partial airway occlusion leads to more dramatic airflow obstruction e.g. secretions, tubes
• Funnel shaped larynx therefore more likely to get subglottic oedema post-extubation
• Neonates have far fewer alveoli and surfactant only begins at 24-26 weeks. Therefore premature infants develop respiratory distress and may require exogenous surfactant
• Ribs are more horizontal, compliant and have no ‘bucket handle’ movement therefore breathing is essentially diaphragmatic. Therefore gastric distension quickly impairs ventilation.
• Higher resting O2 consumption and RR. Minute volume is rate rather than volume controlled. Small FRC and closing volume in a neonate occurs within tidal ventilation. Therefore any small reduction in FRC may lead to lung collapse and they desaturate more quickly than an adult. CPAP may be effective.
• Increased vagal response to upper airway stimulation, more likely to get laryngospasm. Both vagal stimulation and hypoxia may lead to bradycardia.
• High minute volume and metabolic rate mean more rapid onset/offset of volatile anaesthesia.

Question 17

What circulatory changes occur at birth?

Answer 17

With the first breath, pulmonary vascular resistance decreases and as the umbilical cord is clamped and the placenta is taken out of circulation, the systemic vascular resistance increases. These events change the pressure gradient between the right and left atria causing the foramen ovale to close. This happens as the septum primum is pressed against the septum secundum.
The aortic PaO2 then rises, causing the closure of the ductus arteriosus over the next 10h. This is due to local smooth muscle contraction but over the next 3 weeks it fibroses and becomes the ligament arteriosum. The muscle contraction can be reversed initially by hyperaemia or acidosis.

Question 18

In what ways is the cardiovascular system of child different to that of an adult? Why is this relevant?

Answer 18

• Low SVR, high PVR caused by acidosis or hyperaemia can lead to a right-to-left shunt in neonates.
• Cardiac output is increased by increasing HR not SV as the ventricles are small and less compliant than in an adult.
• Bradycardia is a result of hypoxia, Cardiac output is lost below HR of 60.

Question 19

How is the paediatric ECG different to that of an adult?

Answer 19

Right axis deviation

Question 20

What is the circulating volume of a neonate/infant/child?

Answer 20

Neonate 90ml/kg
Infant 80ml/kg
Child 70ml/kg

Question 21

Describe some relevant differences between the neonatal/infant nervous system and adults?

Answer 21

Myelination incomplete in neonates
Parasympathetic system predominates- susceptible
to bradycardia with vagal stimulation
Reduced cerebral auto regulation in the neonate- hypotension may lead to significant brain injury. Sudden increases in pressure may cause intraventricular haemorrhage.
Spinal differences- dural sac ends at S3/4 in neonate (S1-2 in adult), spinal cord ends at L3-4, at 1 year this has moved to L1-2.
Sacral vertebrae are incomplete allowing caudal anaesthesia.

Question 22

Describe some differences of the neonatal GI system compared to adults

Answer 22

Reduces lower oesophageal sphincter tone- may have reflux
Low carbohydrate reserves- prone to hypoglycaemia
Jaundice common in neonates due to immature liver function, higher haematocrit and shorter red cell life. Usually benign but pathological causes must be excluded if prolonged.

Question 23

Why is vitamin K given to newborns?

Answer 23

Neonatal vitamin K stores are low which in turn means vitamin K dependent clotting factors are low. (2, 7 , 9 and 10)
Vitamin K is given to newborns to prevent haemorrhage disease of the newborn.

Question 24

What is a normal neonatal Hb concentration?

Answer 24

18-20g/dL falling to about 10g/dL at 3 months

Question 25

What is fetal haemoglobin?

Answer 25

Fetal haemoglobin in the main oxygen transport protein in the human fetus and it is present in infants up to the age of about 6 months. It has a higher affinity for oxygen than adult haemoglobin and therefore shifts the oxygen dissociation curve to the left and gives a lower P50 kPa. This is beneficial in utero but results in impaired delivery to the tissues in infancy. As HbF declines, the high levels of 2,3 DPG mean that the infant oxygen dissociation curve sits to the right of the adult. What

Question 26

How to babies maintain their temperature?

Answer 26

They lose heat easily due to low body fat stores and a large SA:Vol ratio. They can generate heat through an increase in their metabolic rate, and by non-shivering thermogenesis. This is mediated via B receptors and involves metabolising brown fat, fatty acids and glucose. It is extremely important to minimise heat loss in the infant and child under anaesthesia.

Question 27

What are the limitations of the immature kidney when dealing with excess/insufficient fluid?

Answer 27

Low GFR means high volumes of fluid may not be excreted.

Reduced concentrating ability of the immature kidney means water cannot be efficiently preserved.

Question 28

How does total body water content differ between the neonate and the adult?

Answer 28

Higher in the newborn (80% compared to 60%) Most of this is extracellular with a ratio of extra:intracellular fluid of 1:1

Question 29

What factors should guide postoperative fluid management in children?

Answer 29

• Fluid should be isotonic (ADH release means free water in dextrose/hypotonic saline solutions will be preserved, potentially leading to hyponatraemia.)
• Patient observations/clinical assessment
• Surgical factors e.g. drain losses
• Oral intake

Question 30

What are normal paediatric fasting time?

Answer 30

Solids and milk- 6h
Breast milk -4h
Clear fluids 2h

Question 31

What topical local anaesthetics can be used for cannulation?

Answer 31

EMLA - Eutectic mix of local anaesthetic
2.5% Prilocaine, 2.5% Lidocaine, Takes at least 1h to work, works for up to 60mins. Not recommended <1 month due to risk of methaemoglobinaemia
Ametop gel
4% Tetracaine, takes 30-45mins to work, lasts for 4-6h, causes localised erythema

Question 32

How can midazolam be used as pre-medication?

Answer 32

Dose of 0.5mg/kg PO, max 20mg. Onset time of 20-30mins, lasts around 60mins.

Question 33

In which children should sickle cell trait be considered?

Answer 33

Those of African descent including areas where Africans have migrated to (Caribbean, Americas, some areas of the Mediterranean and middle east)

Question 34

What is the Holliday and Segar formula for maintenance fluid requirement?

Answer 34

0-10kg = 4ml/kg/h
10-20kg = 40ml/h + 2ml/kg/h above 10kg
>20kg = 60ml/h + 1ml/kg/hr above 20kg

Question 35

What formula can be used to estimate a child’s weight?

Answer 35

kg= (3x age) +7

Question 36

What is the dose of ‘reversal’ in a child?

Answer 36

Of 500mcg/ml glycopyrrolate and 2.5mg/ml neostigmine, the dose is 0.02ml/kg which equates to 0.1ml per 5kg. Commonly 1ml of the solution is made up to 10ml and given as 0.2ml/kg.

Question 37

What formula can be used to calculate ETT size?

Answer 37

Age/4 + 4 (cuffed) Age/4 + 4.5 uncuffed for children ages 2-10
For neonates, a 2.5-3.5 tube is used
1-12m would use 3.5-4

Question 38

What formula can be used to calculate ETT length?

Answer 38

Oral = Age/2 +12
Nasal = Age/2 +15

Question 39

What size LMA is used for what patient weights?

Answer 39

Size 1 = <5kg, neonate
Size 1.5 = Infant 5-10kg
Size 2 Child 10-20kg
Size 2.5 Child 20-30 kg
Size 3 Child 30-50kg