Pediatric Anesthesia

1. Pediatric Anesthesia

2. Changes in cardiovascular system:
Removal of placenta from circulation
Increasing of systemic vascular resistance
Decreasing of pulmonary vascular resistance

3. Changes in pulmonary system:
- Small airway diameter - increased resistance
- Little support from the ribs
- VO2 2x > adults
- Diaphragm and intercostal muscles do not achieve
type-1 adult muscle fibers until age 2y

4. Airway difference:
- Large tongue
- Higher located larynx
- Epiglottis short and , angled over the inlet
- Narrowest portion is cricoid cartilage

5. Chest wall/Respiratory difference:
- Ribs are horizontal in neonates (vertical in adults)
- Chest wall collapse more with increased negative
intrathoracic pressure
- Atelectasis is more common
  FRC
  number of alveoli
- Alveolar ventilation/FRC:
Adults = 1.5:1
Infants = 5:1 ( respiratory rate)

6. Pharmacology/dynamics:
Increased total body water:
- Large initial dose required
- Less fat  longer clinical drugs effect
- Redistribution of the drug into muscle will
increase duration of clinical effect (fentanyl)

7. Volatile anesthetics
Isoflurane:
- Less myocardial depression than Halothane
- Preservation of heart rate
Desflurane:
- Increased incidence of coughing, laryngospasm,
secretions
- Concern of hypertension and tachycardia from
sympathetic activation

8. Volatile anesthetics (2)
Sevoflurane
- Less pungent than Isoflurane
- Most suitable for induction

9. Induction drugs:
Methohexital:
- 1-2 mg/kg i.v or 25-30 mg/kg per rectum
- Side effects:
burning
hiccup
apnea
- Contraindication: temporal lobe epilepsy
Thiopental:
5-6 mg/kg i.v
- Caution in low fat children and malnourished

10. Induction drugs:
Propofol:
3 mg/kg i.v (until >3 years of age)
Pain on injection - 0.2 mg/kg Lidocaine i.v.
Ketamine:
10 mg/kg IM, 1-2mg/kg
Increased salivation mix with atropine 0.02mg/kg
Contraindications: Increased ICP
Open globe injury

11. Induction drugs:
Benzodiazepines:
Diazepam:
0.1-0.3 mg/kg
 contraindicated < 6 months
Midazolam:
0.1-0.15 mg/kg IM
0.5-0.75 mg/kg orally
0.75-1.0 mg/kg rectally

12. Induction drugs:
Narcotics:
Morphine:
Increased permeability of blood/brain barrier
50 mcg/kg IV
Meperidine:
Less respiratory depression than morphine

13. Induction drugs:
Narcotics(2):
Fentanyl:
12.5 mcg/kg IV during induction provides stable
cardiovascular response
1-2 mcg/kg during anesthesia
Stable cardiovascular response

14. Induction drugs:
Muscle relaxants:
Succinylcholine:
1-2 mg/kg IV
Consider Atropine 10-15 mcg/kg given prior SUX
Potential side effects:
bradycardia
Hyperkalemia
Masseter spasm
MH

15. Induction drugs:
Muscle relaxants:
If tachycardia desired - Pancuronium
Rocuronium - useful for child , and can
be administered IM (1 mg/kg)

16. MAINTENANCE DOSE (ED95)
(mg/kg) DURING ANESTHESIA
WITH
N2O/O2 HALOTHANE
SUGGESTED DOSE (mg/kg) FOR
TRACHEAL INTUBATION
(2 × ED95)
Muscle relaxanta
d-Tubocurarine 0.60 0.30 0.80
Pancuronium 0.08 0.06 0.10–0.15
Metocurine 0.34 0.15 0.50–0.60
Atracurium 0.30 0.20 0.50–0.60
Cisatracurium 0.10 0.080 0.10
Vecuronium 0.08 0.06 0.10–0.15
Mivacurium 0.10 0.10 0.20–0.25
Doxacurium 0.030 0.030 0.050–0.060
Pipecuronium 0.080 0.080 0.080–0.120
Reversal agentsb
Edrophonium
(0.3–1.0 mg/kg) +
atropine (0.01–0.02
mg/kg)
Neostigmine
(0.02–0.06 mg/kg)
+ atropine (0.01–
0.02 mg/kg)
Muscle relaxants - Summary:

17. Premedication:
Almost all sedatives are effective
Usually not necessary < 6 months
Most common route used is oral
Side effects:
Oral - slow onset
IM - pain, sterile abscess
Rectal - uncomfortable, defecation, burn
Nasal -irritating
Sublingual -bad taste

18. Pharmacological premedication options
Midazolam (Versed)
• Sublingual: 0.2-0.3 mg/kg as effective as 0.2
mg/kg intranasal
• Rectal: 0.35 to 1.0 mg/kg
• Some effect by 10 minutes, peak effect 20-30
minutes.
• 1.0 mg/kg did not delay PACU discharge.

19. Pharmacological premedication options
Ketamine
• PO: 6 to 10 mg/kg
• May slightly prolong time to discharge after a
short case
• IM: 3 to 4 mg/kg sedation;
• 2 mg/kg did not delay recovery
• 6 to 10 mg/kg = IM induction of general
anesthesia
• 10 mg/kg: as effective as Midazolam 1 mg/kg but
some delay in recovery

20. Pharmacological premedication options
Midazolam + Ketamine:
• PO 0.4 mg/kg + 4 mg/kg respectively
• 100% successful separation
• 85% easy mask induction
• Doubling dose leads to "oral induction of general
anesthesia" in most cases. Lasts 30 to 60
minutes.

21. Pharmacological premedication options
Fentanyl (oral transmucosal Fentanyl)
• 15 to 20 mcg/kg
• Increased volume of gastric contents
• Nausea and vomiting
• Pruritus
• Hypoventilation (SpO2 <90)

22. Pharmacological premedication options
1. Metoclopramide (Reglan) PO or IV: 0.2 mg/kg
2. Ranitidine (Zantac) PO 2.5 mg/kg
3. EMLA cream: Eutectic mixture of Lidocaine and
Prilocaine. For cutaneous application by occlusive
dressing one hour preoperative
4. Glycopyrrolate: consider for selected patients for
planned airway instrumentation; e.g.: fiberoptic
endoscopy, oral or upper airway surgery, cleft
palate)5-10 mcg/kg IV or 10 mcg/kg IM

23. Fasting:
Clear liquids - 2-3 h before the procedure
If infants are breast fed - 4 h before the procedure
For older patients = the adults rule

24. Induction of Anesthesia:
Inhalational induction:
Younger than 12 months
After the induction, place the intravenous catheter
In a case of difficult airway - Fiberoptic intubation

25. Induction of Anesthesia:
Rectal induction:
Methohexital
Thiopental
Ketamine
Midazolam
Technique no more intimidating than rectal
temperature measurement
Usual time of onset ~ 10-15 min

26. Induction of Anesthesia:
Intramuscular induction:
- Most common used Ketamine
- Disadvantage painful needle insertion

27. Induction of Anesthesia:
Intravenous induction:
- The most reliable and rapid technique
- Disadvantage - starting intravenous line
- If patient is older ask the patient
- If you insert IV line:
I. Do not allow the patient to see it
II. Use EMLA cream
III. If use local - ask the patient if there is
any sensation on puncture

28. Patient with full stomach:
Treat the same as adult with full stomach:
- using cricoid pressure
- Tell the patient that will feel “touching on the neck”
- Be aware of  VO2 (desaturation)
- 0.02 mg/kg of Atropine administer before SUX to
avoid bradycardia (usually after 2nd dose)
- Use Rocuronium 1.2 mg/kg
- Use Succinylcholine 1-2 mg/kg  if really need
short duration (difficult airway)

29. Endotracheal tubes:
Recommended Sizes and Distance of Insertion of Endotracheal
Tubes and Laryngoscope Blades for Use in Pediatric Patients
RECOMMENDED
Age Of The
Patient Diameter
(internal)
Size of the
Blade
Distance
Premature
(<1,250 g)
2.5 0 6–7
Full term 3.0 0–1 8–10
1 y 4.0 1 11
2 y 5.0 1–1.5 12
6 y 5.5 1.5–2 15
10 y 6.5 2–3 17
18 y 7–8 3 19

30. Intravenous fluids:
Calculation of Maintenance Fluid Requirements for Pediatric
Patients
Weight
(kg)
Fluids (mL/hour) 24-H Fluids (mL)
<10 4 mL/kg 100 mL/kg
11–20 40 mL + 2 mL/kg > 10 1,000 mL + 50 mL/kg > 10
>20 60 mL + 1 mL/kg > 20 1,500 mL + 20 mL/kg > 20
Include if present: Fluid deficits
Third spaces losses
Hypo/hyperthermia

31. Fluid requirements in neonates:
During the 1st week reduced fluid requirements:
Day 1 - 70 ml/kg
Day 3 - 80 ml/kg
Day 5 - 90 ml/kg
Day 7 - 120 ml/kg
- The volume of extracellular fluids in neonates is
large
- Consider use of radiant warmers, and heated
humidifiers - decrease insensible water loss
- Use LR for replacement, D5% with 0.45 NS

32. Monitoring the Pediatric Patients:
- Must be consistent with the severity of the
underlying medical condition
- Minimal monitoring:
I. 5 ASA monitors
II. Precordial stethoscope
III. Anesthetic agent analyzer
- Use of capnograph and O2 analyzers is associated
with high incidence of false alarms from:
movement artifact
light interference
electrocautery

33. - Intraarterial catheter - most common radial
- Pulmonary artery catheters are rarely indicated
because equalization of the pressure right/left heart
- In a case of rapid fluid replacement peripheral
venous catheter might be very useful
- Short-term cannulation of femoral/brachiocephalic
or umbilical vein may be life-saving
Special Monitoring the Pediatric
Patients:

34. Anesthesia Circuits:
- Nonrebreathing circuits:
1. Minimal work of breathing
2. Speeds-up rate of inhalational induction
3. Compression and compliance volumes are
less (small circuit volume)
- Use of Mapleson D system is recommended in
children < 10 kg
More sensitive to changes in gas flow
More sensitive to humidification
Actual delivered volume is greater than
other systems

35. Mapleson D Circuit:
Gas disposition at end-expiration during spontaneous ventilation
Gas disposition at controlled ventilation

36. Neonatal Anesthesia :
- Children < 1 year old have more complications:
I. Oxygenation
II. Ventilation
III. Airway management
IV. Response to volatile agents and medications
- Stress response is poorly tolerated
- Consider:
1. Organ system immaturity
2. High metabolic rate
3. Large ratio body surface/weight
4. Ease of miscalculating a drug dose

37. Neonatal Anesthesia :
Stress Response:
- Ketamine is excellent choice –stable intraoperative
hemodynamics
- Potent volatile anesthetics are poorly tolerated

38. Regional Anesthesia and Anesthesia:
- Most regional anesthetics are safe to use
- Strict attention to:
Dose
Route of administration
Proper equipment used
- Common:
Caudal blocks