Anaesthesia for Paediatric Glioma Surgery - 1-Year-Old

CURRENT STATUS - Baby in MRI (Pre-op)

• Continue sedation: propofol infusion (75-150 mcg/kg/min) OR dexmedetomidine (0.5-1 mcg/kg/hr) - MRI-compatible
• Ventilate: target EtCO2 35-40 mmHg (normocarbia)
• Avoid hypoxia: SpO2 >98%, FiO2 adequate
• Temperature: active warming - infants lose heat rapidly
• MRI-compatible equipment only

• Tumour location (supratentorial vs posterior fossa) - changes your entire approach
• Degree of midline shift / mass effect
• Hydrocephalus / EVD planned?
• Peritumoral oedema

PREOPERATIVE CHECKLIST (before going to OT)

Airway

• Confirm ETT size (ideal: (age/4 + 4) = 4.0 uncuffed, or 3.5 cuffed for 1-year-old)
• Confirm depth: (age/2 + 12) = ~12.5 cm at lip
• Secure tube VERY well - repositioning intraoperatively can dislodge it

Vascular Access

• At least 2 large-bore IV lines (22G or 24G in infants)
• Arterial line (radial preferred) - essential for beat-to-beat BP monitoring and ABGs
• Central line if poor access or vasopressors anticipated

Monitors

• ECG, SpO2, EtCO2 (mandatory)
• Arterial line (invasive BP)
• Temperature probe (rectal or oesophageal)
• Urinary catheter
• BIS / depth of anaesthesia monitor if available
• Neurophysiological monitoring (SSEP, MEP) - coordinate with surgical team

Bloods / Labs

• FBC, coagulation (PT, aPTT, fibrinogen)
• Blood group and crossmatch 1-2 units PRBCs - infant brain surgery can bleed rapidly
• Electrolytes, renal function
• Blood glucose baseline (hypoglycaemia is dangerous in infants)

MAINTENANCE OF ANAESTHESIA

Preferred: TIVA (Total IV Anaesthesia)

• Lower ICP and less cerebral swelling at dura opening
• Better cerebral perfusion pressure
• Anti-convulsive properties
• Better controlled regional cerebral blood flow

Note: If using volatile agents, keep sevoflurane ≤1 MAC to minimise ICP rise. Always control ventilation when using volatiles.

ICP MANAGEMENT (Critical)

If ICP spikes intraoperatively:

1. Hyperventilate briefly - reduce EtCO2 to 30-35 mmHg (short-term measure only, causes vasoconstriction)
2. Mannitol 0.25-0.5 g/kg IV over 15-20 min - OR 3% hypertonic saline (preferred in paediatrics, 2-5 ml/kg)
3. Dexamethasone (if not already given) 0.15 mg/kg IV - reduces peritumoral oedema
4. Check head position - ensure 15-30° elevation, no venous obstruction at neck
5. Deepening anaesthesia (propofol bolus)
6. If all else fails: barbiturate (thiopentone 3-5 mg/kg IV)

FLUID MANAGEMENT

• Avoid glucose-containing fluids (risk of hyperglycaemia worsening cerebral oedema)
• Normal saline (0.9%) or Plasmalyte as maintenance
• Maintenance rate: 4 ml/kg/hr for first 10 kg (Holliday-Segar: 40 ml/hr for 10 kg child)
• Monitor urine output: target 0.5-1 ml/kg/hr
• Replace blood loss ml for ml with colloid or PRBCs
• Transfusion threshold: Hb <7-8 g/dL (target >10 g/dL for brain surgery)
• Hypertonic saline doubles as both fluid resuscitation AND ICP treatment

POSTERIOR FOSSA TUMOUR - EXTRA CONCERNS

• Positioning: Prone or lateral - secure airway meticulously before turning
• Venous Air Embolism (VAE): Risk increases in sitting/prone - precordial Doppler or TOE if available; have aspirating CVP line ready
• Brainstem manipulation: Watch for sudden bradycardia, hypertension, arrhythmias - communicate with surgeon
• Cranial nerve nuclei: Damage can cause postoperative apnoea - plan for post-op intubation/ICU
• Obstructive hydrocephalus: Surgeon may place EVD first; coordinate timing

DRUG DOSES (1-year-old, ~10 kg weight)

NEUROTOXICITY CONSIDERATION

EMERGENCE AND POST-OP PLAN

• Plan for ICU admission - almost universal after paediatric craniotomy for tumour
• Do NOT extubate immediately unless brain relaxed, ICP controlled, normal temperature, haemodynamics stable, and neuro assessment possible
• Watch for: seizures, rising ICP, bleeding, hyponatraemia (SIADH after brain surgery)
• Dexamethasone: continue 0.15 mg/kg every 6 hrs post-op for cerebral oedema
• Post-op analgesia: paracetamol + fentanyl; avoid NSAIDs (bleeding risk)
• Scalp block (bupivacaine 0.25%) at incision closure - reduces opioid requirement

SUMMARY CHECKLIST BEFORE KNIFE TO SKIN

• ETT secured and confirmed
• 2 IV lines + art line
• Crossmatch blood available in OT
• TIVA running (propofol + remifentanil)
• EtCO2 35-40, SpO2 >98%
• Mannitol/hypertonic saline drawn up and ready
• Atropine drawn up (bradycardia from brainstem manipulation)
• Temperature probe in place, warming blanket on
• BIS monitoring
• Surgeon briefed on ICP concerns
• ICU bed booked

You've got this. Stay systematic, communicate with the surgical team about ICP status at each step (positioning, dura opening, tumour resection), and have your emergency drugs drawn up before you start. Good luck.