The Crash Call: ALS 2021 in the Anaesthetic Context

At a crash call the anaesthetic CT1 confirms the arrest, starts or takes over compressions, and works the Resuscitation Council UK adult ALS algorithm: shock a shockable rhythm, give adrenaline 1 mg as soon as possible in a non-shockable rhythm or after the third shock in a shockable one, then every 3 to 5 minutes. The 2025 republication of the guideline states there are no major changes from 2021, and the anaesthetist's distinctive contribution is the airway, waveform capnography and the search for reversible causes.

Key takeaways

• Resuscitation Council UK published its 2025 adult ALS guideline on 27 October 2025 and states there are no major changes from the 2021 guideline.
• Recognise arrest as unresponsive and not breathing normally; agonal gasping is a sign of arrest, not of life. Call 2222, start compressions at 100 to 120 per minute, 5 to 6 cm deep, and defibrillate a shockable rhythm within 3 minutes in hospital.
• Adrenaline 1 mg IV as soon as possible for a non-shockable rhythm, after the third shock for a shockable rhythm, then every 3 to 5 minutes. Amiodarone 300 mg after three shocks and a further 150 mg after five; lidocaine 100 mg is the alternative.
• Rhythm check every two minutes; keep the pause for a shock under 5 seconds by charging during compressions.
• Tracheal intubation only by someone with a high success rate, which the guideline puts above 95%, and always with waveform capnography; once a tube or supraglottic airway is in, ventilate at 10 breaths per minute without pausing compressions.
• After return of spontaneous circulation, aim for saturations of 94 to 98%, normocapnia, a systolic above 100 mmHg or mean arterial pressure above 60 to 65 mmHg, and a temperature of 37.5 °C or below in a comatose patient.

How do you recognise cardiac arrest at a crash call?

A patient who is unresponsive and not breathing normally is in cardiac arrest until proved otherwise. The Resuscitation Council UK 2025 basic life support guideline says slow, laboured breathing and agonal gasping must be recognised as signs of arrest, and that a short period of seizure-like activity can occur at its onset.

For the anaesthetic CT1 arriving at a crash call, recognition usually means confirming what the ward team has already started: check the patient, check that 2222 has been called, and take the airway position. Do not restart the assessment from scratch while compressions are effective.

The guideline says hospitals should aim to recognise cardiac arrest, start CPR immediately, defibrillate within 3 minutes for a shockable rhythm, and give adrenaline rapidly for a non-shockable one. Those four aims are the timeline your answer should follow.

What do you do in the first two minutes?

Start or continue high-quality compressions, attach the defibrillator, and analyse the rhythm. The Resuscitation Council UK basic life support guideline specifies compressions at 100 to 120 per minute, at least 5 cm deep but not more than 6 cm, with full recoil and as few interruptions as possible.

• Confirm the arrest and that the 2222 call has gone out.
• Compressions at 100 to 120 per minute, 5 to 6 cm, with a ratio of 30 compressions to 2 breaths until an advanced airway is in.
• Pads on, with the lateral pad below the armpit in the mid-axillary line, which the 2025 guideline emphasises.
• Rhythm check: shockable (VF or pulseless VT) or non-shockable (PEA or asystole).
• Remove the oxygen mask or bag-valve mask and place it at least 1 metre from the chest before a shock.

The anaesthetic CT1 at a crash call is usually at the head end. The immediate job is a patent airway and effective bag-mask ventilation with two people if needed, delivering each breath over 1 second to visible chest rise, as the guideline describes.

How do you manage the airway during CPR?

Stepwise, according to skill, and with waveform capnography from the moment an advanced airway goes in. The Resuscitation Council UK 2025 ALS guideline states tracheal intubation should only be attempted by rescuers with a high success rate, which by expert consensus is over 95%, and with continuous waveform capnography.

For a CT1, that sentence is the answer. Say it: 'My intubation success rate is not yet over 95% in this setting, so I would maintain oxygenation with a supraglottic airway or two-person bag-mask ventilation and ask a senior anaesthetist to intubate.' Insight into limitations is a scored descriptor in ANRO's Working Under Pressure domain.

Once a tracheal tube or supraglottic airway is in place, ventilate at 10 breaths per minute and continue compressions without pausing. The guideline says a sustained end-tidal CO2 trace must be used to exclude oesophageal placement, and that videolaryngoscopy is preferable where immediately available.

When do you give adrenaline and amiodarone?

Adrenaline 1 mg intravenously as soon as possible in a non-shockable rhythm, after the third shock in a shockable rhythm, and then every 3 to 5 minutes while ALS continues. That is the Resuscitation Council UK 2025 ALS guideline wording, unchanged in substance from 2021.

• Amiodarone 300 mg IV after a total of three shocks in VF or pulseless VT; a further 150 mg after a total of five shocks.
• Lidocaine 100 mg IV may be used instead if amiodarone is unavailable or a local decision has been made, with an additional 50 mg after five shocks.
• If intravenous access cannot be achieved within two attempts, it is reasonable to use the intraosseous route.
• Give fluids during CPR only if the arrest is caused by hypovolaemia.
• Do not routinely give calcium, sodium bicarbonate or corticosteroids during cardiac arrest.

In the anaesthetic context, the CT1 is often the person drawing up. Say the dose, say the timing, and say that someone is noting the time, because at a crash call minutes disappear and the 3 to 5 minute adrenaline interval is easy to lose.

How do you deliver a shock safely and quickly?

Charge the defibrillator during compressions, stop, deliver the shock, and resume compressions immediately, aiming for an interruption of less than 5 seconds. The Resuscitation Council UK 2025 ALS guideline says to minimise both the pre-shock and post-shock pause and to resume compressions straight after the shock without a pulse check.

The rhythm and pulse check comes every two minutes. The guideline adds that if a defibrillator shows the rhythm with compression artefact removed and it is asystole, there is no need to pause for a rhythm check at all.

Oxygen is the fire risk. Take off the mask or bag-valve mask and put it at least 1 metre from the chest; if a supraglottic airway or tube is in, leave the bag or circuit attached. A CT1 who says this aloud has shown the situational awareness the assessors are marking.

What are the reversible causes, and how does the anaesthetist find them?

The reversible causes are the ones ALS teaches as the four Hs and four Ts: hypoxia, hypovolaemia, hypo- or hyperkalaemia and other metabolic causes, hypothermia; and thrombosis, tension pneumothorax, tamponade and toxins. The Resuscitation Council UK 2025 guideline says to identify and treat them without delay.

The anaesthetist has the tools for several of them. Waveform capnography confirms the tube and monitors CPR quality; a blood gas gives potassium and glucose; and the guideline says point-of-care ultrasound by a skilled operator may identify tamponade and tension pneumothorax, provided it does not prolong interruptions to compressions.

For a suspected pulmonary embolism the guideline says to consider immediate thrombolysis and, in selected patients, to continue CPR for 60 to 90 minutes after giving it. That is a decision for the team leader, but a CT1 who raises it has demonstrated the forward thinking ANRO's descriptors reward.

Who leads, and where does the CT1 fit?

The resuscitation team leads, and the anaesthetic CT1 usually owns the airway and helps with drugs and access. The Resuscitation Council UK 2025 guideline says the hospital resuscitation team should include members who have completed an accredited ALS course incorporating teamwork and leadership, and should meet at the start of each shift to allocate roles.

So the honest interview answer is not 'I would lead the arrest'. It is: 'I would take the airway, confirm capnography, tell the team leader what I have and what I need, and call my senior anaesthetist if intubation is required.' That is a CT1 working within limits and still adding value.

If you are first on scene and no team has arrived, you lead until it does. Say that too, and say that you hand over clearly when the team leader arrives, because the handover is where information is lost.

What happens after return of spontaneous circulation?

Return of spontaneous circulation is the start of post-resuscitation care, not the end of the scenario. The Resuscitation Council UK 2025 post-resuscitation care guideline gives targets: titrate oxygen to saturations of 94 to 98%, ventilate to normocapnia at a PaCO2 of 4.7 to 6.0 kPa, and aim for a systolic above 100 mmHg or a mean arterial pressure above 60 to 65 mmHg.

In a patient who remains comatose, the guideline says to actively prevent fever by targeting a temperature of 37.5 °C or below, and to keep preventing fever for 36 to 72 hours. It also prioritises immediate coronary angiography where there is clear suspicion of coronary occlusion.

For the anaesthetic CT1, the post-ROSC job is the transfer: a secured airway with capnography, monitoring, sedation and a senior escort to critical care or the catheter laboratory. Say who comes with you.

What are the human-factors and reflective points at a crash call?

The scored points are role clarity, closed-loop communication, and a debrief afterwards. The Resuscitation Council UK 2025 guideline recommends data-driven, performance-focused debriefing of rescuers to improve CPR quality and outcomes, which is also what ANRO's Reflective Practice descriptor rewards as 'sharing learning'.

Under pressure, the descriptor that matters reads 'maintained calm perspective throughout, clear task prioritisation'. At a crash call that looks like one voice giving the timings, one person on the drugs, and the CT1 at the airway saying 'capnography trace confirmed' rather than staying silent.

For a reflective example, an arrest you attended as a foundation doctor works well: what your role was, what went badly (a lost adrenaline interval, a confused handover), and what you now do at every arrest because of it.

What are the common mistakes with ALS at interview?

The commonest is the CT1 who intubates in the answer without capnography or a senior, which contradicts the guideline's over-95% success-rate condition and reads as a safety concern.

• Giving adrenaline before the third shock in a shockable rhythm, or forgetting the 3 to 5 minute repeat.
• Pausing compressions to intubate, or for a pulse check straight after a shock.
• Forgetting the oxygen before a shock.
• Never mentioning the reversible causes, which is where the anaesthetist earns their place at the arrest.
• Treating ROSC as the end. The post-resuscitation targets are part of the answer.

How this comes up at the CT1 anaesthetics interview

A crash call at the CT1 anaesthetics interview is usually the second turn of a deteriorating-patient scenario: the ward patient you were assessing stops breathing, and the assessors watch whether the structure survives.

• Clinical judgement and decision-making: naming the rhythm, the drug timings and the reversible causes in order shows 'correct prioritisation with a clear plan'.
• Reflective practice: an arrest you attended, what your role was and what you changed afterwards, plus a debrief, meets the 'example they have reflected upon and how' descriptor.
• Working under pressure: staying at the airway, speaking in closed loops and declining to intubate beyond your competence demonstrates 'insight into own limitations' and calm decisions.

Rehearse the algorithm aloud with the timings until they are automatic; the anaestheticinterview question bank includes arrest scenarios marked against the same three domains.