Paediatrics

Question 1

How can paediatric population be classified by age?

Answer 1

neonates 0 - 28 weeks
infant - up to 1 year
child - up to 12 years
adolescent 13-16yrs

Question 2

How

what are the physiological difference between an adult and child?

Answer 2

AIRWAY:
* babbies have large head, short neck and small chin - need to be in neutral position to maintain airway for intubation.
* large floppy epiglottis in babies - harder to lift, miller blade
* larynx and pharynx sits higher and more anteriorly in children (C2/3 in babies, C4/6 in adults)
* narrowest part of airway is the cricoid (laryngeal inlet in adults) - risk of tube being too tight as cant see.
* shorter trachea - more at risk of endobronchial intubation.
* babies are obligate nasal breathers

Breathing:
* smaller lung volume
* more at risk of volu/barotrauma
* use respiratory rate to change MV, fixed tidal volumes
* smaller FRC + higher BMR so more at risk of desaturating

circulation
* CO more dependant on HR than SV so HR higher than in adults . tolerate bradycardia poorly.
* more sensitive vagal response - bradycardia with laryngoscopy etc
* total body water of a neonate 80-90ml/kg whereas in adults 60-70ml/kg
* fetal Hb slowly drops from 80% to 3% by 3 months

neuro
* spinal cord ends at L1 by age of 2 (L2/3 in adults)
* sympathetic underdeveloped hence vagal responses.
* immature BBB - risk of kernicterus
* MAC lower in neonate, higher in infants and teenagers.

Other…
thermoregulation
* larger S.A to V ratio - more likely to loose heat. under 3 months cant shiver and use brown fat for thermogenesis
* GI - immature enzymes , poor glycogen stores - risk of hypoglycaemia

Question 3

how does pharmacokinetics vary in children?

Answer 3

adsorption - slower GI emptying, poorer absorption and reduced blood flow

distribution - more water content and less proteins for PB

metabolism - immature enzymes, slower

excretion - underdeveloped renal funciton, so slower.

Question 4

How is fluid deficient in an infant calculated?

Answer 4

10 x body weight in Kg x % dehydration

% dehydration can be calculated clinically/ peripheral temp

Question 5

what are the fasting rules in paediatrics?

Answer 5

can have small sips orally until 1 hour pre op due to risk of dehydration

6hrs for food in over ones
4 hrs milk in under 1s

Question 6

how is maintainence fluid in paediatrics calculated?

Answer 6

100/50/20
100ml/kg for first 10kg
50ml/kg for next 10kg
the rest 20ml/kg

over 24 hr

OR
4:2:1 rule 4ml/kg/hr

Question 7

how is resusitation fluids in paediatrics calculated?

Answer 7

10-20ml/kg STAT

Question 8

how does total body water and its distribution change with age?

Answer 8

TBW in neonates 80-90ml/kg
in adulthood 60-70ml/kg
so gradual drop

initially more in ECF in neonates - this gradually drops over first year
then more in ICF - slowly increases to adulthood.

Question 9

how would you approach an elective paediatric theatre case?

Answer 9

Same way as an adult however few extra things to consider..

pre op
* good rapport with parent and kid. important to gain trust
* assess level of anxiety - premed (midazolam), likelihood of gas induction
* discuss options of IV vs Gas induction
* any recent respiratory illness - risk of bronchospasm and desat higher
* loose teeth.
* EMLA cream

prepping Induction
* pre induction - WET flags calculations
* paediatric dosage of induction agents - quiet environment, no distractions, ask someone to double check
* appropriate airway equipt - Jackson reese circuit, smaller reservoir bag
* appropriate tube size and LMA - often uncuffed , miller blade.

Induction
* parent can be present / play therapist
* good pre oxygenation - more at risk of hypoxia - good rapport make it a game
* IV or gas induction - dont traumatise child too much with IV canula
* dont always need muscle relaxatant
* can use N20 to help with gas induction

maintainance
* appropriate volumes and RR
* appropriate MAC
* buirette for fluid management

emergence
* good oxygenation before
* very awake extubation , more at risk of bronchospasm and hypoxia

Question 10

dose of midazolam in kids for pre-med

Answer 10

0.5mg/kg oral 30mins before
Max 20mg

Question 11

when is a miller vs curved blade used?

Answer 11

miller in babies - straight blade to lift epiglottis. up to 10kg

Question 12

in an arrest, what is the rate of respirations once an ET tube/ secure airway in place?

Answer 12

continous chest compressions

infants = 25 breaths/min
1-8yrs 20breath/min
8-12yrs = 15
>12 = 10-12

Question 13

outlines the ALS algorithm for paediatrics if no response

Answer 13

Intro - check childs response, hello can you hear me, check for pain. call for help and ask for 2222

check for signs of life - head tilt chin, check for obstructions, lift listen/feel for breaths. max 10 second
if no breathing 5 rescue breaths with head tilt/chin lift
adminster 100% O2

check for carotid pulse - 10 sec max
if less than 60bpm, start CPR 15:2 for 1 min at rate of 100bpm.
request defib and attach pads
assess rhythm

ALS
- non shockable -PEA, brady 60bpm, asystole
- continue CPR 15:2, 2 mins
- adreanline 10ug/kg IV or IO - ASAP and every 4 mins
- if treating brady , mention you would consider atropine.

• shockable - VF/ pulseless VT
• shock 4joules/kg
• CPR 2 mins
• adrenaline 10ug/kg after 3 shocks + amiodarone 5mg/kg after 3 shocks
• adrenaline every other shock
• amiodarone repeat once more only

work through reversible causes

Question 14

how do you assess an unwell child that is responding

Answer 14

introduce to child/mum
ask nurse to do full obs whilst you do A to E

Airway - listen for signs of obstruction - visible, stridor, secretions/ vomit

breathing - look and listen - accessory muscle use, tracheal tug, recession, crackles/wheeze/quiet, sats and RR.

circulation - HR, BP, Fluid status - mucus membrane, urine output, cap refil, skin tugor

disability - GCS, temp, glucose, pupils

everything else - rashes, injuries, abdo exam/ neuro exam.

Question 15

after a period of ALS, you get ROSC, what should you do next?

Answer 15

A to E
sats 94-98%
definitive treatment
post arrest care - normoglycaemia, normothermia, normocapnia

Question 16

what is the max dose of adrenaline and amiodarone that can be given to paeds in als?

Answer 16

1mg adrenaline
300mg amiodarone

Question 17

how is weight estimated in paediatrics?

Answer 17

(age x 2) + 8

Question 18

how do you estimate tube size in paeds

Answer 18

length = age/4 + 4
- 0.5 if cuffed
length at teeth= age /2 + 12

Question 19

State the WET FLAGS pneumonic..

Answer 19

W = weight
E = energy 4joule/kg
T= tube size +length
F= fluids 10-20ml/kg
L= lorazepam 0.1mg/kg
A = adenaline 10ug/kg, atropine 0.01-0.02mg/kg
G = glucose 2ml/kg of 10% dex
S = sux 1-1.5mg/kg

Question 20

when is IO performed in kids?

Answer 20

after 3 x IV attempts

Question 21

how much adrenaline can you give via ET tube and IO?

Answer 21

IO is same as IV = 10ug/kg
tracheal = 100ug/kg

Question 22

describe CPR in children

Answer 22

in babys
- 2 finger compressions
- or if 2 people present one can encircle childs chest and use 2 thumbs whilst other gives breaths

in child
lower 3rd of sternum with heal of hand 1/3 depth

Question 23

what is the correct position of defib pads in babies?

Answer 23

one on front in centre over sternum, one of back between shoulder blades.

children that are larger enough - same as adult - one right upper chest and one lower left near armpit

using paediatric sizes

Question 24

when do you use the paediatric algorithm vs adult?

Answer 24

at 15yrs use adult

Question 25

how do you estimate blood volume

Answer 25

neonate = 90ml/kg
infant = 80ml/kg
child = 70ml/kg

Question 26

when would you call the resusitation team in paediatric ALS?

Answer 26

after 1 min of CPR

Question 27

how would you manage a child that has aspirated/ choked?

Answer 27

identify, acute management, definitive managment

identify - signs include coughing/ inability to, desaturating, distress. shout for help.

acute management - encourage coughing
les than 1yr - 5 blows to back , infant held over your arm facing down. then 5 chest blows (infant faced up) and continue
more than 1yrs - Heimlich manoeuvre, kneel child over and wrap arms around them with a fist upward thrust.

CXR and bronchoscopy

later management:
- may require anaesthesia and ventilaiton - avoid N2O, gas trapping and pneumothroax
- ideally avoid PPV and aim for spontaneous. positive pressure can promote gas trapping

Question 28

what are the signs of aspiration on a CXR ?

Answer 28

may see the object
atelectasis
unilateral obstructive emphysema - gas trapping and hyperexpansion behind.
can be normal.

Question 29

where are the aspirated objects likely to go?

Answer 29

right main bronchus - straight and wider

Question 30

Describe the fetal circulation…

Answer 30

ductus venousus
eustachian valve
Foramen ovale
ductus arteriosus - to aorta after the carotid after major branches of aorta (branchiocephalic, left common carotid and left subclavian)

Question 31

sats in different parts of fetal circulation

Answer 31

umbilical vein 80-90%
by time gets to IVC - 70%
to brain - 70%
back via SVC - 25%
descending aorta - 55%

Question 32

what is meant by a transitional circulation?

Answer 32

This refers to the period after birth where the fetal circulation is changing to adult circulation and this is a potentially reversible process.
for example normally the shunts are closing and normal circulation is being estiblished
however there is a risk for this to reverse while it is still maturing and for the shunts to be maintained.

promoted by hypoxia or acidosis or hypercapnia as all these promote pulmonary vasoconstriction, inreased pulmonary pressures and hence right side of heart has increased pressures which can maintain opening of FO.

hypoxia also maintains DA.

can result in viscious cycle as worsening oxygenation.

Question 33

how is transitional circulation treated?

Answer 33

oxygenation
CPAP
surfactant

pulmonary vasodilators - inhaled nitric oxide, prostacyclin.

Question 34

how is SVT managed in a child?

Answer 34

decompensated - DC cardiovert
otherwise valsalva, or ice immersion

or adenosine child 100mcg/kg

Question 35

what rhythm is most common in child arrest?

Answer 35

PEA or brady

shockable are less common

Question 36

what is the dose of paracetamol, ondanset and dexamethasone in paediatrics

Answer 36

paracetamol
15mg/kg QDS
neonates 10mg/kg

ondansetron 0.1mg/kg

dex 0.15mg/kg

Question 37

describe the transition of fetal circulation at birth

Answer 37

first breath - massive negative pressure - fall in PVR + oxygenation

drop in PVR and increase in SVR - increases LA pressures - FO closes

due to changes to SVR and PVR - changes direction of flow in DA
drop in progesterone and rise in O2 - DA closes
closes physiologically within 24 hours but anatomically within 2 weeks

ductus venous - The clamping of the umbilical cord at birth leads to the cessation of placental blood flow. so flowed through the umbilical vein and ductus venosus diminishes.

Question 38

what closes ductus arteriosus and what keeps it open?

Answer 38

closes - O2, indomethacin, bradykinins
open - Prostaglandins, rise in PVR eg. acidosis, hypoxia

Question 39

what is infant respiratory distress syndrome

Answer 39

acute distress seen in infants due to lack of surfactant.

surfactant is normally synthesised from 24 weeks and fully complete by 35 weeks. this is stimulated by maternal corticosteroids

prematurity can result in lack of surfactant and respiratory distress

since alveoli are harder to open without surfactant, the lung compliance is reduced and it result in increased work of breathing, high pressures and hypoxia.

can be treated by giving steroids to mum before birth to stimulate production OR after birth instilling artificial surfactant into neonatal lungs

Question 40

Can you tell me about congenital heart defects..

Answer 40

Congenital HD describe a collection of structural heart defects that are present from birth.

they can be categorised into cyanotic and acyanotic

acyanotic ones describe a left to right shunt i.e. there is no mixing of oxygenated blood with deoxygenated. these include ASD, VSD and PDA. overtime due to excessive blood flow through pulmonary circulation, PVR can rise and right sided pressures rise. can result in right sided hypertrophy and reversal of the shunt. this is known as eisenmengers syndrome

cyanotic ones describe a right to left shunt where there IS mixing of deoxygenated blood with oxygenated blood and therefore reducing saturations of systemic circulation. these include ToF, transposiiton of great vessels, tricuspid atresia.

Question 41

tell me about patent ductus arteriosus

Answer 41

type of acyanotic CHD
resulting from failure of DA to close
results in aortic blood flowing into pulmonary artery

clinically
* wide pulse pressure
* continous murmur

can result in eisenmengers syndrome

Question 42

tell me about ToF

Answer 42

Cyanotic CHD resulting from presence of 4 abnormalities

VSD
overiding aorta
pulmonary artery stenosis
RVH

presents in first month of life and needs surgical intervention

Question 43

when may you need to maintain the PDA?

Answer 43

CHD e.g. transposition of great vessels in not compatible with life unless PDA is maintained.

RA -RV to Aorta
Aorta to PA
PA to PV to LA to LV
LV to PA

Question 44

what are the risk factors to developing CHD?

Answer 44

maternal infections e.g. rubella
fetal genetics e.g. downsyndrome and VSD/ASD
foetal alcohol syndrome
maternal diabetes