2. INTRODUCTION
• Dhaka Shishu (Children) Hospital is the largest
children hospital in Bangladesh. It is a
Government supported tertiary level public
hospital for children with 640 beds.
• All indoor facilities including operation
• Two OT complex- General ot and Cardiac ot
4. • Children are not little adults!
– Neonates: 0-30 days old
– Infants: 1 month to 1 year
– Children: older than 1 year
– Full term neonate: born between 37-40 weeks and
aged less than 1 month
– Premature neonate: child born before 37 weeks
gestation
– Extreme preterm neonate: child born less than 28
weeks gestation
• A 10-12 yrs old child thought of anatomically and
physiologically small adult
5. • Different Anatomy
• Different Physiology
• Different Pharmacology
• Different psychology
6. Airways
• Head large
– 1/3 size of adult head
– 1/9 height of adult
– 1/27 weight of adult
• Tongue large
• Nasal passages narrow
• Obligate nose breathers until 5 month
8. • Larynx
– Anterior
– Cephalad
– C 4 level
• Epiglottis long & U shaped
• Trachea short
– Neonates → 2 cm cords to carina
• Cricoid → Narrowest point until 10 yrs
9. More rostral pediatric larynx
Infant’s larynx is higher in neck (C2-3) compared to
adult’s (C4-5)
10. Relatively larger tongue
• Obstructs airway
• Obligate nasal breathers
• Difficult to visualize larynx
• Straight laryngoscope blade
completely elevates the epiglottis,
preferred for pediatric laryngoscopy
Angled vocal cords
• Infant’s vocal cords have more angled
attachment to trachea, whereas adult
vocal cords are more perpendicular
• Difficulty in nasal intubations where
“blindly” placed ETT may easily lodge
in anterior commissure rather than in
trachea
11. Differently shaped epiglottis
• Adult epiglottis broader, axis parallel to trachea
• Infant epiglottis ohmega (Ώ) shaped and angled away from axis
of trachea
• More difficult to lift an infant’s epiglottis with laryngoscope blade
12. Funneled shape larynx
• narrowest part of infant’s
larynx is the undeveloped
cricoid cartilage, whereas in
the adult it is the glottis
opening (vocal cord)
• Tight fitting ETT may cause
edema and trouble upon
extubation
• Uncuffed ETT preferred for
patients < 8 years old
• Fully developed cricoid
cartilage occurs at 10-12
years of age
INFANTADULT
13. Respiratory system
• Alveoli small & limited number
– Lung compliance decreased
• Cartilaginous rib cage
– Chest wall compliance increased
– Chest wall collapse during inspiration and
relatively low residual volume
• Chest is circular shaped with horizontal ribs
14. • Weaker intercostal muscle and the diaphragm
– Fewer type 1 muscle cells
• Abdominal muscle strength undeveloped
• Caliber of airways is relatively narrow
• Large rate of o2 consumption
• Ventilator drive are not well developed, so
hypoxia and hypercapnia depress respiration
15.
16.
17. CVS
In neonates Myocardium less contractile causing the
ventricles to be less compliant & less able to generate
tension during contraction
– Limits the size of stroke volume
– Cardiac output therefore rate dependant
– Infant behaves as with fixed cardiac output state
• Cardiac output
– 300-400 ml/kg/min at birth
– 200 ml/kg/min within few months
18. Vagal parasymphathetic tone is most dominant
which makes neonates & infants more prone to
bradycardias
• Bradycardia:
– Assc with reduced cardiac output
– If assc with hypoxia, should be treated with O2 &
Ventilation initially
– Cardiac compression will be required in neonate
with HR 60 or less OR 60-80bpm with adequate
ventilatio
20. Dehydration:
– Poorly tolerated
– Premature infants have increased insensible losses as
they have large surface area relative to weight
– There is larger proportion of ECF in children (40% BW as
compared to 20% in adult)
• Conclusion:
– Newborn kidneys has limited capacity to compensate
for Volume EXCESS or Volume DEPLETION
22. Thermoregulation
• Greater heat loss
– Thin skin
– Low fat content
– High surface area/weight ratio
• No shivering until 1 yrs
• Thermogenesis by brown fat
• More prone to iatrogenic hypo/hyperthermia
• Optimal ambient temp to prevent heat loss:
– Premature infant: 34⁰C
– Neonates: 32⁰C
– Adults: 28⁰C
23. Pharmacotherapy
• Weight “guesstimate” = 2 x (age) + 9
• Total body water content increased (70-75%)
– Large volume of distribution for water soluble meds
– Increased dose/kg
• Hepatic biotransformation immature
• Protein binding decreased
• Neuromuscular junction immature
• Muscle mass in neonates smaller
– Termination of action by redistribution prolonged
24. Volatile anesthetics
• Minute ventilation to FRC ratio increased
• Blood flow to vessel rich groups increased.
– Rapid rise in alveolar anesthetic concentration
• Blood-gas coefficients lower in neonates
• Inhalation induction rapid
– BP of neonates and infants more sensitive to
hemodynamic effects of volatile agents
– Caution against overdose
25. IV or IM anaesthetics
1- thiopentone sodium
Lower dose in neonates than in infants
Neonates- 3-4 mg/kg
Infants - 5-6 mg/kg
decreased dosage in neonates is due to
-- immature brain
-- decreased plasma protein binding
-- more permeable BBB.
increased requirement in infants due to increased
cardiac output as this would be expected to reduce the
first pass concentration of thiopentone arriving at the
brain.
26. • PROPOFOL
• Children required larger dose of propofol-
– Large vol of distribution
– Shorter elemination half life
– Higher plasma clearance
– 2- 3 mg / kg
27. Opioids
• More potent in neonates than children or adults
– Easier across blood:brain barrier
– Decreased metabolic capability
– Increased sensitivity of respiratory centers
– Caution in neonates
• Hepatic conjugation decreased
• Cytochrome P 450 pathways mature by 1 mo
• Renal clearance of morphine metabolites is
decreased
• Children have high rates of hepatic blood flow
– Increased biotransformation and elimination
28. Neuromuscular blockers
• Shorter onset time (as much as 50%)
– Shorter circulation time
• Depolarizing agent
– Succinylcholine
• Nondepolarizing agents
– Rocuronium
– Cisatricurium
– Vecuronium
29. • Fastest onset → 30-60 secs
• Children → 1-1.5 mg/kg IV, 4-6 mg/kg IM
• Infants → 2-3 mg/kg IV, 4-6 mg/kg IM
• Dysrhythmias
– Bradycardia and sinus arrest
– Atropine 10-20 mcg/kg
• Vecuronium- .1mg/kg
30. Rocuronium
Drug of choice for
intubation
0.6 mg/kg IV
RSI 0.9-1.2 mg/kg IV
May last 90 min
May be given IM
1-1.5 mg /kg
Onset 3-4 min
Cisatricurium
● Consistently
intermediate duration
● 0.05-0.06 mg/kg IV
31. Reversal
• Nondepolarizing blockade can be reversed with
neostigmine (0.03–0.07 mg/kg) or edrophonium
(0.5–1 mg/kg) along with an anticholinergic
agent (glycopyrrolate, 0.01 mg/kg, or atropine,
0.01– 0.02 mg/kg).
32. Preoperative considerations
History and physical
• Comorbid illness
• Recent URI
• Murmur
– Innocent
– New
– Symptomatic
• Anesth problems
• Labs → none routine
33. URI
Symptoms new or chronic?
Infectious vs allergic or vasomotor
Viral infection within 2 - 4 weeks of GA with
intubation increases perioperative risk
Wheezing risk increased 10x
Laryngospasm risk increased 5x
Hypoxemia, atelectisis, recovery room stay,
admissions and ICU admissions all increased
If possible, delay nonemergent surgeries
34. Premedication
• Sedative premedication is generally omitted
for neonates and sick infants.
NPO
● Clears → 2 h
● Breast milk → 4 h
● Formula → 6 h
● Solids → 8 h
35. Monitoring
Age & size appropriate standard monitors
Precordial stethoscope
Heart rate, heart tones, respiratory quality
Preductal pulse oximetry in neonates
Right extremity or earlobe
EtCO2 monitor
Main-stream less accurate in < 10 kg
Side-stream may falsely elevate iCO2 and
falsely lower EtCO2.
Temperature
38. Selection of laryngoscope blade:
Miller vs. Macintosh
• Miller blade is preferred for infants and younger
children
• Facilitates lifting of the epiglottis and exposing the
glottic opening
• Care must be taken to avoid using the blade as a
fulcrum with pressure on the teeth and gums
• Macintosh blades are generally used in older
children
• Blade size dependent on body mass of the patient
and the preference of the anesthesiologist
39. Endotracheal Tube
New AHA Formulas:
Uncuffed ETT: (age in years/4) + 4
Cuffed ETT: (age in years/4) +3
ETT depth (lip): ETT size x 3
Age Wt ETT(mm ID) Length(cm)
Preterm 1 kg 2.5 6
1-2.5 kg 3.0 7-9
Neonate-6mo 3.0-3.5 10
6 mo-1 3.5-4.0 11
1-2 yrs 4.0-5.0 12
40. Cuff vs Uncuffed Endotracheal Tube
• uncuffed ETT recommended in children < 8 yrs old to
avoid post-extubation stridor and subglottic stenosis
• Arguments against cuffed ETT: smaller size increases
airway resistance, increase work of breathing, poorly
designed for pediatric pts, need to keep cuff pressure
< 25 cm H2O
• Arguments against uncuffed ETT: more tube changes
for long-term intubation, leak of anesthetic agent into
environment, require more fresh gas flow > 2L/min,
higher risk for aspiration
• For “short” cases when ETT size >4.0, choice of cuff
vs uncuffed probably does not matter
• Cuffed ETT preferable in cases of: high risk of
aspiration (ie. Bowel obstruction), low lung compliance
(ie. ARDS, pneumoperitoneum) etc.
41.
42.
43.
44.
45. T piece vs closed circuit
•Jackson-Rees modification to Ayres T piece or
Mapleson F circuit
•Simple, lightweight, has an open ended bag which can
be occluded to apply CPAP and PEEP
•Better for children <20kg (varies with anaesthetist)
because easier to assess tidal volume and lung
compliance, has low resistance and dead space
•Disadvantage is pollution and anaesthetic gas wastage
•Bag must be big enough not to restrict tidal volume but
not so large that his visual and tactile monitor is lost
Breathing
46. Paediatric breathing circuit
•Narrow tubing (15mm) which reduces compression
volume and small distal connections to minimise
dead space
•Better conservation of heat and vapour, easy
scavenging and less gas wastage but loss of feel
during hand ventilation due to large compression
volume
47. Perioperative fluid replacement
● 1st 0-10 kg → 4 cc/kg/hr
● 2nd 10-20 kg → 2 cc/kg/hr
● > 20 kg → 1 cc/kg/hr
● Calculate preoperative deficit
– Replace 50% first hour
– Replace 25% second hour
– Replace 25% third hour
● Minor surgery → additional 2 cc/kg/hr
● Major surgery → up to additional 10 cc/kg/hr
48. Regional Anaesthesia
• Most commonly done caudal, SAB and penile
block
• caudal block-
– Penil and anal surgery
– Vaginal surgery
– Orchidoplexy
– Hernia repair
49. • Bupivacain plain 1- 1.5 mg/kg
• Lidocain 2-2.5 mg /kg
• Doses:
0.5cc/kg for perineal surgery
0.75cc/kg for T-10 level
1cc/kg for lower thoracic level
52. CONCLUSION
Pediatric anesthesia involves more than simply
adjusting drug doses and equipment for smaller
patients. Neonates, infants, toddlers, and young
children have differing anesthetic requirements.
Safe anesthetic management depends on full
appreciation of the physiological, anatomic, and
pharmacological characteristics of each group.
Indeed infants are at much greater risk of anesthetic
morbidity and mortality than older children; that
require unique surgical and anesthetic strategies.
