Rapid Sequence Induction: Indications and the Standard Drugs

Rapid sequence induction is how an anaesthetist secures the airway of a patient who is at risk of aspirating stomach contents: thorough preoxygenation, an induction agent and a neuromuscular blocker given in predetermined doses without a test of mask ventilation, cricoid force, and a tracheal tube confirmed by waveform capnography. The Difficult Airway Society's 2018 guideline for intubation of critically ill adults sets the preparation, the cricoid force and the three-attempt limit; a CT1 at interview is expected to know the indications and the plan for failure, not to perform it unsupervised.

Key takeaways

• The indication is aspiration risk: an unfasted or emergency patient, bowel obstruction, significant reflux, pregnancy beyond the first trimester, or any patient whose stomach cannot be assumed empty.
• The 2018 DAS/ICS/FICM/RCoA guideline recommends preoxygenation with a tight-fitting facemask at 10 to 15 L/min of 100% oxygen for 3 minutes, not a Hudson-type mask, and says a neuromuscular blocking agent reduces intubation complications.
• Cricoid force, where used, is 10 N (about 1 kg) awake rising to 30 N (about 3 kg) once unconscious, and should be reduced or removed if laryngoscopy, tube passage or mask ventilation is difficult.
• Ketamine at 1 to 2 mg/kg produces less cardiovascular instability than propofol or thiopentone in the shocked patient; a 500 mL crystalloid bolus before induction may mitigate hypotension where there is no cardiac failure.
• Failure after a maximum of three intubation attempts should prompt the declaration 'this is a failed intubation' and a move to Plan B or C; a fourth attempt is for an expert.
• The DAS 2025 intubation guideline keeps Plans A to D and prioritises first-attempt success, continuous oxygen delivery and waveform capnography.

Who needs a rapid sequence induction?

Any patient in whom the stomach cannot be assumed empty and whose airway must be secured under general anaesthesia: the emergency laparotomy, the bowel obstruction, the trauma patient who ate an hour ago, the obstetric patient, the patient with severe reflux or a hiatus hernia.

In a CT1 anaesthetics scenario the rapid sequence induction usually arrives disguised: a patient on the ward who needs intubation for respiratory failure, or a theatre case where the surgeon says 'they have not eaten since last night' and the history says otherwise. Spotting the risk is the first mark.

The 2018 DAS critically-ill guideline exists because, in its own framing, intubation outside the operating theatre carries a higher complication rate, and it was a direct response to the Royal College of Anaesthetists' fourth National Audit Project on airway complications. Say that context in one sentence.

How do you prepare for a rapid sequence induction?

With a checklist, a team with named roles, optimised position and thorough preoxygenation. The 2018 DAS guideline recommends a pre-intubation checklist, pre-briefs, and allocation of roles including a cricoid force applier, an equipment assistant and a runner.

• Position: head-up or ramped, on a mattress as firm as possible, which the guideline says optimises cricoid force, head extension and laryngoscopy.
• Preoxygenation: a tight-fitting facemask with 10 to 15 L/min of 100% oxygen for 3 minutes; the guideline explicitly does not recommend a Hudson-type mask with or without a reservoir.
• Haemodynamics: in the absence of cardiac failure a rapid 500 mL crystalloid infusion before or during intubation may mitigate hypotension, and a vasopressor or inotrope should be immediately available.
• Equipment: videolaryngoscope with the screen visible to the team, bougie, working suction, a second-generation supraglottic airway, and the front-of-neck kit opened.
• Time: as induction starts, note the time and allocate someone to call it, because the guideline warns that significant time passes unnoticed in an airway crisis.

For a rapid sequence induction at interview, the preparation is most of the answer. A candidate who says 'I would give the drugs' before saying 'I would preoxygenate for three minutes with a tight seal' has the order wrong.

What are the standard drugs, and how do you choose?

An induction agent chosen for the patient's haemodynamics, and a neuromuscular blocker to give the best intubating conditions. The 2018 DAS guideline recommends a neuromuscular blocking agent because it improves intubating conditions, facemask ventilation and supraglottic airway insertion and reduces the number of attempts.

On the induction agent, the guideline says the choice is dictated by haemodynamics and that ketamine at 1 to 2 mg/kg produces less cardiovascular instability than propofol or thiopentone. Co-induction with a rapidly acting opioid allows lower hypnotic doses.

On the blocker, the guideline notes that succinylcholine has numerous side effects including life-threatening hyperkalaemia and a short duration that can hamper a prolonged attempt, and that rocuronium may be a more rational choice in the critically ill, with sugammadex able to antagonise it though without guaranteeing clinical improvement. A CT1 should state the choice and the reasoning, and check the mg/kg dose on the local guideline rather than guess it.

What does cricoid force involve, and when do you release it?

Cricoid force is pressure on the cricoid cartilage by a trained assistant, applied at 10 N (about 1 kg) while the patient is awake and increased to 30 N (about 3 kg) once unconscious. That is the standard the 2018 DAS guideline recommends, and it describes the technique as a skill needing training and practice.

The guideline is candid that its value is still debated. It says cricoid force should be reduced or removed if there is difficulty with laryngoscopy, passage of the tracheal tube, facemask ventilation, or active vomiting, and that it must be removed before a supraglottic airway is inserted because it occludes the hypopharynx.

For the CT1 rapid sequence induction answer, the point is not to argue the debate but to show you know both the force and the conditions for releasing it. A videolaryngoscope screen visible to the team, the guideline notes, allows cricoid force to be adjusted in real time.

What happens when the first attempt fails?

You optimise, you try again if something has changed, and you declare failure after a maximum of three attempts. The 2018 DAS guideline says failure after three attempts should prompt the declaration 'This is a failed intubation' and a move to Plan B or C, with a fourth attempt reserved for a suitably expert clinician.

• Between attempts: reposition, change the blade or device, use the bougie, adjust or release cricoid force, and maintain oxygenation.
• Plan B or C: a second-generation supraglottic airway or two-person facemask ventilation, with one optimal attempt or a maximum of three at each before declaring failure.
• Plan D: if the patient cannot be oxygenated, front-of-neck access by the scalpel-bougie-tube technique, which the guideline recommends as the default because it is fast, has few steps and a high success rate.

The guideline also says that if an optimal attempt fails and every factor has already been addressed, making no further attempts may be right: three is a maximum, not a target. A CT1 who says 'I would not persist' has understood the lesson of NAP4.

When do you call for help, and who?

Before you start, for any rapid sequence induction outside theatre or in a patient you expect to be difficult, and at the first failed attempt in every case. For a CT1 that means a senior anaesthetist present or on their way before induction, and the difficult airway trolley in the room.

The 2018 DAS guideline's team structure is the escalation plan made concrete: a team leader, an intubator, an assistant, someone on cricoid force, someone monitoring, someone on equipment and a runner. If you cannot fill those roles, that is the reason to wait for help where the patient allows.

Say the phrase the guideline uses. Declaring 'this is a failed intubation' aloud is what moves the room from optimising to rescuing, and assessors listen for it.

What has the DAS 2025 guideline changed?

The Difficult Airway Society published new guidelines for unanticipated difficult tracheal intubation in adults in 2025, in the British Journal of Anaesthesia. Its abstract states 65 recommendations, keeps the linear Plan A to D algorithm, and prioritises continuous oxygen delivery, first-attempt success, waveform capnography, progressing through the algorithm on failure, and multidisciplinary teamwork.

The abstract lists rapid sequence induction, peroxygenation, the physiologically difficult airway, obesity and human factors among the topics covered. The emphasis it describes is on maximising the chance of success rather than on managing failure.

For an interview in the 2027 round, name the 2025 guideline as current and the 2018 critically-ill guideline as the source for the numbers here. A candidate who knows the guideline moved, and in which direction, is showing the currency the assessors' global rating rewards.

What are the human-factors and reflective points?

The scored points are the checklist, the shared plan said aloud before induction, and the willingness to stop. The 2018 DAS guideline names cognitive aids, pre-briefs and checklists as helping decision-making, and says training should include equipment, checklists, algorithms and teamwork.

ANRO's Working Under Pressure descriptor scores 'insight into own limitations within scenario' and being 'flexible and calm when challenged'. A rapid sequence induction is where the CT1 is most tempted to overreach; the mark is for saying 'this is beyond me alone' early.

For reflection, a real airway that was harder than expected is the example to bring: what the plan was, where it drifted, and what you now say aloud before every induction. ANRO's descriptor wants the example and the change in practice.

What are the common mistakes with rapid sequence induction at interview?

The commonest is describing the drugs before the preparation, or reciting a dose you are not sure of. The station is marked on judgement, and a confident wrong number is a safety concern.

• Preoxygenating with a Hudson mask, or for less than 3 minutes, which the guideline specifically advises against.
• No haemodynamic plan: no fluid, no vasopressor available, propofol in a shocked patient.
• Not knowing when cricoid force is released.
• Persisting beyond three attempts, or never saying 'failed intubation'.
• Not naming who is in the room and who has been called.

How this comes up at the CT1 anaesthetics interview

Rapid sequence induction at the CT1 anaesthetics interview is usually framed as a decision, not a procedure: a patient on the ward who needs intubation, and the question of what you do before your senior arrives.

• Clinical judgement and decision-making: recognising the aspiration risk, the preparation sequence, the drug reasoning and the three-attempt limit demonstrates a 'clear plan of action' with a contingency.
• Reflective practice: a difficult airway of your own and what you now do differently meets the 'example they have reflected upon and how' descriptor.
• Working under pressure: calling before induction, declaring failure aloud and not persisting shows 'insight into own limitations' and calm decisions when challenged.

The anaestheticinterview bank of 340 questions includes airway scenarios with AI-marked spoken practice, so the plan-for-failure sentence can be rehearsed until it is reflexive.