Rapid Sequence Intubation

Rapid sequence intubation is the technique of securing the trachea by near-simultaneous administration of a potent induction agent and a rapid-onset neuromuscular blocking agent, designed to create optimal intubating conditions quickly while minimising the time the airway is unprotected. It is the default approach for emergency intubation in patients presumed to have a full stomach and a high risk of aspiration.

Definition

Rapid sequence intubation is an emergency airway technique in which a pre-oxygenated patient receives an induction agent and a fast-acting neuromuscular blocker in rapid succession to achieve unconsciousness and paralysis, allowing prompt tracheal intubation with the aim of reducing the risk of aspiration of gastric contents.

Scope

The topic covers the rationale and component steps of rapid sequence intubation as a concept: pre-oxygenation, induction and paralysis, the historical role of cricoid pressure, and the place of bag-mask ventilation during the apnoeic period. It is presented as reference knowledge and deliberately omits drugs, doses, and procedural decision-making for individual patients.

Core questions

• What problem is rapid sequence intubation designed to solve?
• Why are induction and paralysis given in rapid succession?
• What is the historical and current role of cricoid pressure?
• When is bag-mask ventilation appropriate during the apnoeic period?

Key concepts

• Pre-oxygenation and oxygen reserve
• Induction agent and neuromuscular blockade
• Aspiration risk and the full-stomach assumption
• Cricoid pressure (Sellick manoeuvre)
• Apnoeic period and oxygen desaturation
• Bag-mask ventilation during induction

Mechanisms

The technique exploits a brief window in which a pre-oxygenated patient can tolerate apnoea while drugs take effect. A rapid-onset hypnotic produces unconsciousness and a fast-acting neuromuscular blocker abolishes airway tone and protective reflexes, giving still, optimal intubating conditions within seconds. Pre-oxygenation builds an oxygen reserve that delays desaturation during the apnoeic period. Cricoid pressure was introduced to compress the oesophagus against the cervical spine and reduce passive regurgitation, although its effectiveness and routine use are debated. Whether to provide gentle bag-mask ventilation during induction, traditionally avoided to prevent gastric insufflation, has been re-examined in critically ill patients prone to rapid desaturation.

Clinical relevance

Rapid sequence intubation is a core concept in emergency and critical-care airway practice because it addresses the competing goals of securing the airway quickly and limiting aspiration. This entry explains the rationale and components as reference knowledge; it does not specify agents, doses, or sequences for patient care, which require trained clinicians and local protocols.

Epidemiology

Audit data identify emergency intubation outside the operating theatre as a higher-risk setting for airway complications, reflecting physiological instability and limited reserve. Trial evidence in critically ill adults has examined whether bag-mask ventilation during induction reduces hypoxaemia without increasing aspiration.

History

Cricoid pressure, described by Sellick in 1961, became emblematic of the rapid sequence approach as a means to prevent aspiration during induction. Over subsequent decades the technique was refined, and more recent guidelines and trials have re-examined long-held assumptions, including the routine use of cricoid pressure and the avoidance of mask ventilation before intubation.

Debates

Should cricoid pressure be applied routinely?

Cricoid pressure was long considered standard to reduce regurgitation, but its protective effect is uncertain and it can worsen the laryngeal view, so its routine use is contested.

Is bag-mask ventilation acceptable during induction?

Traditional teaching avoided mask ventilation to limit gastric insufflation and aspiration, but trial evidence in critically ill adults suggests it can reduce severe hypoxaemia, reopening the question for high-risk patients.

Key figures

• Brian Sellick
• Jonathan Casey
• Chris Frerk
• Tim Cook

Seminal works

• sellick-1961
• casey-2019

Frequently asked questions

Why are the induction agent and paralytic given together in rapid sequence intubation?

Giving them in rapid succession produces unconsciousness and muscle relaxation almost simultaneously, creating optimal intubating conditions quickly and shortening the time the airway is unprotected.

Is cricoid pressure still considered essential?

Its routine use is debated; while it was introduced to reduce regurgitation, evidence for benefit is limited and it can impair the view at laryngoscopy, so practice varies.