START

❶ Immediate action: Stop any stimulus, Check pulse, rhythm and blood pressure:

• If no pulse or impending arrest: use Box A.
• If narrow complex AND not hypotensive first increase depth of anaesthesia/analgesia.

❷ Adequate oxygen delivery

• Check fresh gas flow for circuit in use AND check measured F_iO₂.
• Visual inspection of entire breathing system including valves and connections.
• Rapidly confirm reservoir bag moving OR ventilator bellows moving.

❸ Airway

• Check position of airway device and listen for noise (including larynx and stomach).
• Check capnogram shape compatible with patent airway.
• Confirm airway device is patent (consider passing suction catheter).

❹ Breathing

• Check chest symmetry, rate, breath sounds, SpO₂, measured VTexp, ETCO₂.
• Feel the airway pressure using reservoir bag and APL valve <3 breaths.

❺ Circulation

• Check rate, rhythm, perfusion, recheck blood pressure, obtain 12-lead ECG if possible.

❻ Consider underlying problems (Box B).

❼ Consider rate control (Box C).

❽ Call for help; consider electrical cardioversion (Box D) if problem not resolving quickly.

❾ Depth:  Consider current depth of anaesthesia AND adequacy of analgesia.

Box A: CRITICAL TACHYCARDIA

If no pulse, delegate one person (minimum) to chest compressions

and → 2-1 Cardiac arrest.

If hypotension worsening or impending arrest, consider electrical cardioversion (Box D).

Box B: POTENTIAL UNDERLYING PROBLEMS

• Stimulation with inadequate depth.
• Consider drug error.
• Also consider: central line/wire; hypovolaemia; primary cardiac arrhythmia; myocardial infarction; electrolyte disturbance; local anaesthetic toxicity (→ 3-10); sepsis (→ 3-14); circulatory embolus, gas/fat/amniotic (→ 3-5); anaphylaxis (→ 3-1); malignant hyperthermia crisis (→ 3-8)

Box C: DRUGS FOR TACHYCARDIA

• Fluid bolus 10 ml.kg^-1 (adult 250 ml)
• Magnesium 50 mg.kg^-1 (adult 2 g) over >10 min, max conc. 200 mg.ml^-1
• Amiodarone 5 mg.kg^-1 (adult 300 mg) over >3 min, NOT in polymorphic VT
• Labetalol 0.5 mg.kg^-1 (adult 25-50 mg), repeat when necessary
• Esmolol 0.5 mg.kg^-1 (adult 25-50 mg)
• Adenosine 0.1 to 0.5 mg.kg^-1 (Adult 3 to 18 mg) – for SVT

Box D: ELECTRICAL CARDIOVERSION

• Attach pads and ECG from defibrillator.
• Ensure adequate depth / sedation / analgesia for cardioversion.
• Engage synchronisation and check for sync spikes on R-waves.
• Start with 1 Jkg^-1 (adult 50-100 J) biphasic.
• Remember to hold shock button until sync shock delivered.