Rapid sequence intubation in children — formative SAQs

SAQ 1 (10)

A 4-year-old, 16 kg child presents with severe viral pneumonia and is now tiring, with oxygen saturations of 86 per cent on high-flow oxygen, reduced air entry, and increasing drowsiness. You decide to perform rapid sequence intubation. ^{[1] [6]}

1. State the endotracheal tube size you would prepare (uncuffed and cuffed) using the age-based formulae, and list three pieces of equipment that must be at the bedside before induction. (4) ^[1]
2. Outline the sequence of drug administration (induction agent, neuromuscular blocker, premedication) with doses for this child, and justify your choice of induction agent. (4) ^[3]
3. Describe how you would confirm correct tube placement and state the immediate action if the child desaturates during laryngoscopy. (2) ^[6]

Model answer

Tube size and equipment. The uncuffed tube internal diameter in mm equals (age/4) + 4 = (4/4) + 4 = 5.0 mm; the cuffed tube equals (age/4) + 3.5 = 4.5 mm. Have a half-size above and below ready. Equipment that must be ready: working suction with a Yankauer tip, high-flow oxygen connected to a bag-mask, a checked laryngoscope with a Macintosh 2 blade and a spare, an exhaled carbon dioxide detector, a bougie or stylet, and a supraglottic airway sized to the child. ^[1]

Drug sequence and induction choice. Preoxygenate with 100 per cent oxygen for three minutes. Give the induction agent and neuromuscular blocker in rapid succession without waiting to observe the induction effect. For this child, who has respiratory but not circulatory failure, a reasonable choice is ketamine 1 to 2 mg/kg IV (about 16 to 32 mg) for its bronchodilator and haemodynamically stable profile, or propofol 2 to 4 mg/kg IV if cardiovascularly stable. Paralyse with suxamethonium 1 to 2 mg/kg IV or rocuronium 1 mg/kg IV. Give atropine 20 micrograms/kg IV (minimum 100 micrograms) as premedication, appropriate for a young child receiving suxamethonium. The choice of ketamine is justified by the need to preserve blood pressure and bronchodilate. ^[3]

Confirmation and desaturation. Confirm placement with exhaled carbon dioxide (capnography or a colour-change detector), supported by bilateral chest rise and air entry and a rise in saturation. If the child desaturates during laryngoscopy, stop, return to bag-mask ventilation with 100 per cent oxygen, reposition, and reattempt — never persist with a blind or prolonged attempt. ^[6]