1. Paediatric Anaesthesia
4th year MBChB tutorial
UCT

2. Introduction Children are not small adults!
Different physiology, anatomy and pharmacology, therefore they have specific anaesthetic requirements

3. Age-groups Definition Age Prematurity < 37 weeks gestational age
Neonate
days
Infants
1 month – 1 year
Toddlers
1 – 3 years
Children
3 – 7 years
Older children
7 – 12 years
Adolescents
13 – 18 years

4. Anatomy and physiology

5. CVS The differences are most marked in the neonate
Non-compliant and poorly developed myocardium
Fixed stroke volume ∴ CO is HR-dependent
Vagal tone dominant at sino-atrial node→ bradycardias
Immature baroreceptors
Exclude congenital cardiac defects

6. Respiratory Large floppy head, tongue + epiglottis
Anatomic differences
Obligate nasal breathing under 6 months
Small tidal volumes and rapid rate
O2 consumption: 6-9ml/kg/min (adult 3-4ml/kg/min)
↓ed FRC + ↓ed lung compliance
Premature neonates are prone to APNOEAS
Large floppy head, tongue + epiglottis
Narrowest part of the airway at CRICOID
Anterior + cephalad larynx
Short + narrow trachea
Prominent tonsils + adenoids

7. Haematology
Blood volume: ml/kg - adult level (80 ml/kg) by age 1
At birth Hb g/dL + 75% foetal Hb
Physiologic anaemia at 2-3 months
Coagulation may be affected in neonate because of immature hepatic function and reduced levels of Vitamin A, D, E, K.

8. Liver Immature at birth
Metabolism is slow ∴action of anaesthetic drugs may be prolonged
Low glycogen stores in neonates – hypoglycaemia

9. Renal Renal function is immature at birth
Drug clearance may be affected

10. CNS Neonates + small children experience PAIN!
Drug dosages are often reduced in neonates
MAC is normal or ↓ed in neonates, but MAC ↑ed in older children
Propofol dose increased in children

11. Thermoregulation Hyperthermia Hypothermia is a big concern
Rare
Children more prone to MH
Hypothermia is a big concern
Neonates and small babies have large heads with a big surface area and large organs close to the skin
Significant heat loss occurs in theatre if not actively prevented

12. Pre-operative Assessment

13. History Complete medical + surgical Time of last meal – NB Medication
Allergies
Any previous reaction to anaesthesia or FHx of problems
Road-to-Health Cards
Congenital abnormalities or syndromes

14. Examination Airway assessment is tricky Routine general examination
Exclude Upper or Lower Respiratory Tract Infections (common!)

15. Pre-op plan + Premed Discussion with child and parents Verbal consent
If child is old enough to understand, involve them and show them anaesthetic apparatus to allay anxiety
Verbal consent
Premedication
Not for children under 6 months – year old

16. Premedication Tailored to the child and the case
Simple re-assurance and explanation may be sufficient
Drugs (all per os)
Midazolam
Vallergan forte (trimeprazine)
Droperidol
Ketamine
Stopayne syrup (paracetamol, codeine and phenergan)

17. Nil per os
6 hours – solid food or formula milk
4 hours – breast milk
2 hours – clear fluid or juice
Clear fluids are encouraged at Red Cross until 2 hours pre –op
Prevents thirsty, irritable, hypoglycaemic child

18. Preparation of the Paediatric Theatre

19. Paediatric Equipment Magill’s Forceps Breathing circuits LMA’s
Paediatric Ventilators
Face masks
Oropharyngeal airways
Laryngoscopes
Endotracheal Tubes
Introducer
Magill’s Forceps
LMA’s
IV access cannulas, CVPs and arterial lines
IVFluid + giving sets
Nasogastric tubes + urinary catheters
Temperature probes
Warming equipment
Monitors

20. Breathing Circuits Jackson-Rees modification of the Ayre’s t-piece
Light-weight with no valves
Reservoir bag
FGF: 2-3x MV in spontaneous ventilation
Paediatric circle

21. Airway equipment
Paediatric specifications and sizes to meet the different anatomical needs
Facemasks
OPAs
Laryngoscopes
Suction catheters
Introducers + Magill's Forceps
LMAs
ETTs
Size range: 2.0 mm – 6.5 mm i.d.
Uncuffed WHY?
Size: 4 + age / 4 = i.d. ETT (mm)

22. Warming Equipment Forced air warmer – “BAIR hugger”
Overhead radiant heaters
Ambient theatre temperature 22° C
Heated underblankets
Warm IV fluid
Paediatric HMEF (heat moisture exchange filters)
Hats, gamjees, plastic sheets to insulate
“Prevention is better than cure”
when it comes to HYPOTHERMIA

23. The Actual Anaesthetic

24. Induction Choice: inhalational vs. intravenous
At RXH: majority INHALATIONAL
Preferable to young children to getting a drip first!
If EMLA or Ametop cream available, IV Induction is a good option
Older children can be given a choice
Muscle Relaxation not used routinely for intubation

26. Maintenance Choice: inhalational or intravenous NB Points in paeds:
Drug doses in mg/kg
Monitoring and vigilance
Temperature control
IV Fluids → 4:2:1 rule for maintenance; plus remember rehydration for pre-existing deficits and replacement of ongoing losses

27. Analgesia
Babies & children may not express pain clearly, but they do feel pain
Multi-modal approach
Simple analgesics: paracetamol (PR, IV)
NSAIDs: voltaren (diclofenac) (PR)
Not for babies < 1 year
Opiates: fentanyl, morphine, Valoron (tilidene) drops
Ketamine
Regional procedures
Caudals or epidurals • Blocks (multiple)
Wound infiltration with local anaesthesia

28. Emergence & Recovery Potential for many complications at this point
Obstructed airway
laryngospasm
Recovery
Recovery position
Monitoring
Discharge criteria
Awake and maintaining airway
Normal vital signs
Pain free
No PONV
No surgical complications

29. Guidelines for Referral
Doctors not familiar with anaesthetising children should not do so
No child under age of 3 should be anaesthetised by a MO without senior supervision
Must have paediatric equipment, otherwise refer to a centre that does
Refer
Sick kiddies
Anticipated Airway problems
Organ failure
Syndromic – often have multiple congenital abnormalities (CVS!)