Pediatric Anesthesia Induction
Pediatric Anesthesia · 9 min read
Pediatric induction differs from adult in nearly every dimension — equipment, drug doses, parent presence, anatomy, physiology, behavioral readiness. The technique that works for a calm 7-year-old fails the screaming 2-year-old.
Pre-induction prep
AGE-APPROPRIATE pre-induction. <6 MONTHS — typically not stranger-anxious; mask induction smooth without parent. 6 MONTHS - 5 YEARS — peak stranger anxiety; PARENT PRESENCE often beneficial (depends on child + parent). >5 YEARS — increasing cooperation; verbal explanation helps. CHILD LIFE SPECIALIST — invaluable for anxious or developmentally complex children. PREMEDICATION: midazolam 0.5 mg/kg PO (max 20 mg) 20-30 min preop is workhorse — onset 20 min, anxiolysis + amnesia. Alternative: dexmedetomidine 1-2 mcg/kg intranasal (atomizer) — onset 30-45 min, less paradoxical reaction than midaz, useful for procedural anxiety + premed combined.
Inhalational induction technique (most common 1-5 yo)
MASK INDUCTION: SEVOFLURANE 8% in 70% N2O / 30% O2 (or 100% O2 if N2O contraindicated) — quick onset. ALTERNATIVE: tidal-breathing technique starting at 2% sevoflurane and incrementing q2-3 breaths to 8% — gentler but slower. PARENT PRESENT (institution-dependent) — coaches breathing into mask. SCENT MARKER (chapstick on inside of mask) — helps cooperation. PROGRESSION: child becomes sleepy → loss of consciousness in 30-60 sec → loss of eyelash reflex → eyes roll → MASK SEAL TIGHT to maximize uptake. PLACE IV after LOC. Watch for: laryngospasm (light planes), bradycardia, hypotension, malignant hyperthermia (any unexplained CO2 rise + tachycardia).
Sevoflurane drug entry →IV induction (for older children, full stomach, or family preference)
OLDER CHILDREN (>7-8 yr) often tolerate IV placement awake with EMLA cream applied 60 min preop. RSI with full stomach: PROPOFOL 2-3 mg/kg (children need higher per-kg dose than adults) + ROCURONIUM 1.2 mg/kg or SUCCINYLCHOLINE 2 mg/kg (infants <1 yr need 2 mg/kg vs 1 mg/kg adults due to large Vd). FENTANYL 1-2 mcg/kg or REMIFENTANIL pre-treatment to blunt laryngoscopy response. ATROPINE 0.02 mg/kg (max 0.5 mg, min 0.1 mg) — pre-treat in <1 yr to prevent succ-induced bradycardia. Some institutions skip atropine in routine pediatric induction, give if bradycardia develops.
Equipment selection
ETT SIZE: cuffed (modern preference) (age + 16) / 4 = mm ID for ages 1-8. Older formula: (age/4) + 4 uncuffed, (age/4) + 3.5 cuffed. DEPTH at lip: 3 × ETT size in cm. NEONATE: 3.0 uncuffed or 3.0-3.5 cuffed; depth 9-10 cm at lip. LARYNGOSCOPE: Miller blade preferred <2 yr (lifts floppy epiglottis directly), Mac for older. CIRCUIT: low-compliance pediatric circle for <20 kg (avoid VT loss in compliant adult circuit). LMA SIZE: 1 (<5 kg), 1.5 (5-10 kg), 2 (10-20 kg), 2.5 (20-30 kg), 3 (30-50 kg). Verify equipment available in size BELOW expected — often need to size down for unexpected anterior airway.
Maintenance + emergence
MAINTENANCE: sevoflurane 1-1.5 MAC + opioid + paralytic as needed. PEDIATRIC MAC: peaks at infancy (~3-6 mo) at MAC 3.2% sevoflurane; lower in neonates (~3.0%) and older children (~2.5%). VENTILATOR: pressure-controlled often preferred in <20 kg (compliance changes); volume-controlled OK for older. EMERGENCE: pediatric emergence delirium (PED) common after sevoflurane (30-80% in young children — agitation, thrashing, eyes open but unfocused, lasts 5-15 min). MITIGATION: dexmedetomidine 0.3-1 mcg/kg IV before emergence; propofol bolus 1 mg/kg at end of case; adequate analgesia (don't confuse pain with PED — treat pain first).
Anatomic + physiologic differences (always)
AIRWAY: large tongue, more cephalad larynx (C3-4 vs adult C5), omega-shaped epiglottis, narrowest at cricoid (functional). PHYSIOLOGY: smaller FRC + higher O2 consumption per kg → desaturate FAST (<1 min in neonate, ~6 min adult). Cardiac output is HR-dependent (limited stroke volume reserve) — bradycardia → drop CO. Smaller blood volume — neonate 80-90 mL/kg, infant 75-80, child 70, adult 65-70. Easier to dose-overshoot drugs (small absolute mass × higher Vd often). Higher MAC, faster wash-in/out. Hypothermia rapid — warm OR + warm fluids essential.
Pearl — match the technique to the child
There is no single "best" pediatric induction. The right technique depends on child's age + temperament + medical history + family + setting. Have a primary plan + a backup plan. Premedicate when uncertain. Communicate with parents clearly. The induction is often the highest-stress moment for the family — your calm matters as much as your technique.
References
- · Coté Pediatric Anesthesia 7e Ch 14
- · Smith's Anesthesia for Infants and Children 9e
- · Miller's Anesthesia 9e Ch 77