Clinical viva — the inhalational induction technique

The preparation. The sevoflurane vaporiser primed; the mask (scented, appropriately sized); the oxygen flowing; the parent present; the IV equipment, the suction and the airway adjuncts to hand; the standard monitoring applied as soon as feasible — confirm conduct details against local paediatric protocol.^[1]

The method. Two approaches:

• The gradual increment — start low and increase by small steps every few breaths: Epstein's incremental arm used 1% sevoflurane increased by 1% every 2 to 3 breaths, with loss of eyelash reflex at a mean 66 seconds.^[1] Preferred for the younger child and the one who needs acclimatisation.
• The vital-capacity (high-concentration) breath — Epstein's primed-circuit arm used 8% sevoflurane with spontaneous breathing until eyelash-reflex loss at a mean 42 seconds, with similar minor-complication rates (4/20 vs 3/20) and no vital-sign differences.^[1] Preferred for the cooperative older child.

The monitoring of the depth. The loss of the eyelash reflex (the held endpoint), the regular breathing, the relaxation of the limbs, and the acceptance of the mask without resistance mark the onset. The capnography confirms the air movement.^[1]

The IV placement. Once the child is unconscious (the loss of the eyelash reflex — the held endpoint for both methods^[1]), a motionless, vasodilated limb is cannulated. Deepen before instrumentation per local paediatric protocol.

^[2]The management of the complications. The breath-holding, the coughing, and the laryngospasm are managed by the 100 per cent oxygen, the jaw thrust, the CPAP, the deepening, and, if severe, the suxamethonium (confirm dose against local protocol) — succinylcholine produces more intense block in a shorter time at the laryngeal muscles than the alternatives in the held review.^[2] The prevention is the smooth, gradual induction and the avoidance of stimulation during the light plane.