1. Paediatric anaesthesia requires modification of standard adult practices due to anatomical and physiological differences in children.
2. Drug dosages must be calculated based on weight in mg/kg and special care taken with airways, ventilation and temperature regulation in small children.
3. Anaesthetists must understand the unique respiratory, cardiovascular and metabolic characteristics of neonates, infants and children to provide safe anaesthesia.
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Paediatric Anaesthesia Essentials
1. M W E B A Z A
VICTORā¢
MBchB 5th year
Ugandan.
Kamapala international university-western
campus @ Jinja site-light
Jinja Regional Referral Hospital
(JRRHosp)
mwebazavictor1997@gmail.com
Presenting:-
PAEDIATRIC ANESTHESIA
(2022/April)
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2. Paediatric anaesthesia
1. Children, infants and neonates differ from
adults both anatomically and physiologically.
2. These differences influence anaesthetic
management.
3. Anaesthetists must be able to modify their
standard adult anaesthetic practice to give safe
anaesthetic for a paediatric case
Children and infants are small!(it is easy to give
too much of a drug or fluid)
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4. Introduction
Adult anaesthetic techniques require
modification for children less than 2 yrs or
weighing less than 15kg.
Children heavier than 15kg can be treated as
small adults as long as dosages of anaesthetic
drugs and volumes of iv fluids are related to
their body weight.
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5. It follows that the weight of all children
presenting for anaesthesia must be known or
estimated.
The size of the trachea is another major
consideration in children below the age of 10
because this alters the management of
intubation
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11. Airway
Infants have a relatively small tongue in a
small mouth and a large floppy epiglottis
with a higher larynx(C3-C4). Normally, they
breathe through their noses, not mouths,
unless they are crying.
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12. Hold the mask carefully without putting
pressure on the soft tissues under the chin.
To avoid using pressure, keep your fingers on
the bone of the mandible.
Use an oral airway, if required, as soon as it is
tolerated.
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13. Beware the child with a blocked nose(e.g.
snuffles) or a nasogastric tube as the
airway maybe difficult.
A small amount of positive airway pressure
will try to open the airway if you are having
difficulties.
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14. For children less than 2yrs:
āIntubate with a straight blade laryngoscope, e.g.
Robertshaw blade or Millerās Blade while
extending the childās neck.
āIn Hydrocephalus children a small pillow under
the shoulders may be helpful.
āIn a child over 2yrs, an adult blade is adequate.
āIn an emergency, a small baby may be carefully
intubated using an adult blade
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20. Airways
ā¢ Lift tongue and epiglottis away from upper
airway
ā¢ Different sizes: measure from centre of incisors
to angle of jaw
ā¢ Nasopharyngeal airways
21. ā¢ The correct ett size may be estimated using the
formula;
(Age divided by 4) + 4.0
Or
You can use a tube which is approximately the width of
the babyās little finger
Always have a tube one size smaller available.
Leave a small leak around the ett in a child, test this by
gently inflating the lungs. If there is no leak, remove
the tube and replace it with a smaller one
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30. Weight chart for children under 10yrs
Age Estimated body weight in kg
Birth 3.4
6months 8.5
1 yrs 11.0
2 yrs 14.0
3 yrs 15.0
4 yrs 17.0
5 yrs 19.0
6 yrs 21.0
7 yrs 24.0
8 yrs 27.0
9 yrs 31.0
10 yrs 34.0
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31. In the developing world, 60% of children will
be as much as 30% below these weights.
Make allowance for this variation when
dealing with a child who seems small for his
age
You must find out the weight or estimate pts
weight.
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32. Calculate drug doses in mg/kg.
Use small needles, canulae and syringes.
Consider whether to dilute your drugs before
starting.
IV access is important.
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33. In an emergency certain drugs can be given
down the endotracheal tube(ETT), i.m or in
the tongue.(double the dose and dilute in
saline for ett)
Inhalation induction is often easier than
intravenous induction
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34. Babies have a high surface area to weight
ratio therefore lose heat very rapidly
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35. Guard against heat loss:
1. Close theatre doors
2. turn off the AC
3. cover the babyās head
4. warm iv fluids,
5. keep the baby dry,
6. use a warming blanket and
7. transport him to the ward in blankets or an
incubator.
Do not anaesthetize hypothermic babies. First
warm them up.
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36. Children under 10 yrs have a relatively narrow
larynx and trachea.
The narrowest point is the cricoid ring
immediately below the vocal cords.
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37. Any swelling in this position following a traumatic
intubation, or the use of an oversized ett, will cause
significant narrowing and very dangerous post
extubation stridor
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38. The infant trachea is short(as small as 2cm at
birth)
Intubation of the right or left main bronchus is
easy in infants. Do not introduce the tube very
far past the cords, secure it firmly in the correct
position and check its position regularly by
auscultation and observation
Trachea
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39. Lungs
Infants have very compliant chest walls making it
difficult for them to increase their tidal volume
markedly.
During anaesthesia, their small airways are more
liable to close than those of adults.
Under anaesthesia particularly when you are
using an ett, spontaneous respiration can become
tiring, resulting to dangerous hypoventilation.
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40. Donāt allow an infant to breathe spontaneously
under anaesthesia except for the shortest of
cases. Assisted and controlled ventilation is
preferable
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41. Respiration is mainly diaphragmatic in neonates
and infants. Any abdominal distension will splint
the diaphragm and may result in respiratory
problems during or after anaesthesia.
Decompress any gastric dilatation early with a
nasogastric tube
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42. Normal respiratory rates
Neonate: 40/min
Infant: 20- 30/min
NOTE: Remember to ventilate at appropriate rates
Tidal volume: 7ml/kg(7-9ml/kg)
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43. Resistance to breathing circuits becomes an
important consideration in children weighing
less than 15kg.
Use a paediatric T- piece circuit in all cases
below 15kg. Above this weight, a paediatric
circle or Magill circuit can be acceptable
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47. INCORRECTLY SIZED MASKS OR
CONNECTORS ADD LARGER AMOUNTS OF
DEAD SPACE TO THE CIRCUIT MAY CAUSE
FURTHER RESPIRATORY EMBARRASMENT
Use paediatric masks and connectors
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48. Premature neonates are particularly prone to
oxygen toxicity which may cause retrolental
fibroplasia resulting in blindness
Whenever possible avoid giving anaesthetics
with 100% oxygen to premature neonates
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49. Cardiovascular system
Normal PR at birth is 120- 160/min, therefore a PR
below 100 is bradycardia
Neonates and infants have a relatively fixed stroke
volume, therefore bradycardia always causes a
marked fall in cardiac output
PR falls to normal by the age of 10 yrs
Normal systolic BP at birth is 90, reaching normal
values by adolescence.
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51. Know these normal values. Use a precordial
stethoscope to monitor heart and breath sounds
during anaesthesia
In major cases, an esophageal stethoscope is
better
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52. Always calculate the blood volume before starting a
major case and more than 10% blood loss requires
transfusion
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53. Renal System
Renal blood flow and glomerular filtration are low in
the first 2 years of life due to high renal vascular
resistance.
Tubular function is immature until 8months, so
infants are unable to excrete a large sodium load.
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54. Dehydration is poorly tolerated. Premature infants
have increased insensible losses as they have a
large surface area relative to weight.
There is a larger proportion of extracellular fluid in
children (40% body weight as compared to 20% in
the adult).
Urine output 1-2 ml/kg/hr
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55. Normal urine output should not be less than
0.5ml/kg/hr
Monitoring urine output is a useful indicator of
the adequacy of circulation during and after a
major case
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56. Children are very sensitive to the vagotonic
effects of anaesthetic agents and bradycardia is
common with halothane and suxamethonium
Always give atropine unless the child is pyrexial
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57. Metabolism
Children, infants and neonates have a high
metabolic rate. Therefore, they become
cyanosed very rapidly if apnoeic.
In addition, infants under the age of 1 year have
a lower reserve of oxygen in the lung- FRC
(worse in abdominal distension)
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58. Immature liver function makes neonates prone
to hypoglycaemia
Neonates and infants are prone to
hypoglycaemia
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59. Practicalities in anaesthetizing children
Pre op visit
Weigh the child
Weight (kg) can be estimated by: (age + 4) x 2. This is less
accurate over 10 years.
Pre op fasting
6 hours for solids and milk if greater than 12 months of
age
4 hours for breast milk and formula feeds if less than 12
months of age
2 hours for unlimited clear fluids (as this decreases
gastric acidity and volume)
There is an increased incidence of nausea and vomiting
with long fasting periods.
60. ā¢ Premedication
Ā» Atropine only: iv injection 5 mins b4 operation
ā¢ Preparation
Ā» Theatre: check temperature
Ā» Check equipment
Ā» Calculate: drugs and dosages, circulating blood
volume
Ā» Establish a reliable drip
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61. ā¢ Induction
Ā» <4weeks: consider inhalational induction
Ā» 4wks ā 2yrs: iv access before anaesthesia. If hard,
inhalational anaesthesia, iv access, sux, intubate
ā¢ Maintenance
Ā» IPPV with nitrous/ oxygen, Halothane 0.5-1%
ā¢ Reversal
Ā» Neostigmine if you used NMBD
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62. Treatment of laryngospasm
1. CPAP with 100% O2
2. Propofol
3. Lignocaine: topical or IV 2mg/kg
4. Suxamethonium: 2mg/kg IV or 4mg/kg IM
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