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Rapid Sequence Induction

General Surgery · Final Professional

Definition & Indication

Rapid sequence induction (RSI) is a technique of inducing anaesthesia and rapidly securing the airway with a cuffed tracheal tube in patients at risk of aspiration (‘full stomach’ — emergencies, trauma, pregnancy, reflux, obstruction), minimising the time the airway is unprotected.

Technique

The classic steps: thorough preoxygenation; a predetermined dose of a rapidly acting induction agent (e.g. Propofol/thiopentone) immediately followed by a rapidly-acting muscle relaxant (suxamethonium, or rocuronium); cricoid pressure (Sellick’s manoeuvre) applied as consciousness is lost; no manual ventilation (to avoid gastric insufflation) until the airway is secured; and prompt intubation with a cuffed tube, confirming placement before releasing cricoid pressure.

CLINICAL PEARL

The essence of RSI is to move from awake to a protected airway as fast as possible — preoxygenate, give induction agent and fast-acting relaxant together, apply cricoid pressure, avoid bag-mask ventilation, intubate and confirm, then release cricoid.

DANGER / REMEMBER

RSI patients are, by definition, at high aspiration risk and may desaturate quickly — have suction, a range of tubes, a bougie and a difficult-airway plan ready, and do not release cricoid pressure until the cuffed tube is confirmed in the trachea.

Cricoid Pressure & Controversy

Cricoid pressure (Sellick’s manoeuvre) applies backward pressure on the cricoid cartilage to occlude the oesophagus against the vertebral body, aiming to prevent passive regurgitation reaching the pharynx during induction. It is applied as consciousness is lost and maintained until the cuffed tube is confirmed, but it is released if it impairs the view at laryngoscopy or if active vomiting occurs (to avoid oesophageal rupture). Its effectiveness is debated and it can distort the airway, so it is now regarded as a helpful but not infallible component of the technique rather than an absolute guarantee against aspiration.

CLINICAL PEARL

The whole point of RSI is to minimise the unprotected interval: preoxygenate well, give the induction agent and a fast relaxant together, apply cricoid pressure, avoid bag-mask ventilation, and intubate — confirming the tube before releasing cricoid pressure.

Used where aspiration risk is high — full stomach, pregnancy.

KEY POINT

Key points TO remember

RSI rapidly secures the airway in aspiration-risk (full-stomach) patients.
Preoxygenate → induction agent + fast relaxant (suxamethonium/rocuronium) → cricoid pressure.
Avoid manual ventilation; intubate with cuffed tube; confirm before releasing cricoid.
Have suction, tubes, bougie & a difficult-airway plan ready.

EXAM TIP

Sources: Morgan & Mikhail’s Clinical Anesthesiology; Miller’s Anesthesia; Ajay Yadav’s Short Textbook of Anaesthesia.

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