Perioperative cardiac arrest

[1]

Why this is examined / one-line answer

Perioperative cardiac arrest is the ultimate theatre crisis. Examiners want NAP7-aware epidemiology, a theatre-modified ALS script, the 4 Hs and 4 Ts with anaesthesia differentials named out loud, exact adrenaline and defibrillation behaviour, and special pathways for cardiac surgery and maternal arrest. One-liner: I call for help, start CPR and 100% oxygen, treat shockable rhythms, give adrenaline every 3–5 minutes in non-shockable or refractory cycles, and I search for reversible causes that only exist under anaesthesia while I allocate a leader and a cognitive aid. [1]

NAP7 (RCoA) studied peri-operative cardiac arrest across UK practice. Incidence is on the order of ~3 per 10,000 anaesthetics (~1 in 3,000), with outcomes better than out-of-hospital arrest because of continuous monitoring and immediate help — but still high mortality, especially in neonates, ASA IV–V, emergency, and cardiac cases.[1]

NAP7-aware mental model

What NAP7 emphasises for viva:

• Arrest is rare but not mythical — have a theatre ALS plan before the first case of the day.
• Causes cluster by phase: induction (airway, drug, anaphylaxis, high spinal), maintenance (haemorrhage, embolism, cardiac, hypoxia), emergence/recovery (airway obstruction, residual block, hypovolaemia, PE).
• Human factors dominate: delayed recognition when monitors are silenced or misread, fixation on surgery, no designated leader, no cognitive aid, failure to stop surgery and pack.
• Outcomes improve with early defibrillation, high-quality CPR, ETCO2-guided resuscitation, and cause correction — not heroic drug stacks. [1]

Immediate theatre algorithm (first 60 seconds)

1. Declare the crisis — “Cardiac arrest — call the crash team / additional help.”
2. Note the time. Assign leader (usually senior anaesthetist not deep in a task), CPR, airway, drugs, defibrillator, runner, scribe.
3. Stop surgery that is not immediately life-saving (pack, stop bleeding if that is the cause, remove retractors that impede CPR).
4. Flatten the table, remove/side-arm drapes for access, start external chest compressions (rate ~100–120/min, depth ~5–6 cm adult, full recoil, minimise interruptions).
5. 100% oxygen, confirm ET tube / airway, manual ventilation or ventilator with high FiO2; check circuit disconnect and gas supply.
6. Attach/confirm defibrillator pads. Rhythm check every ~2 minutes.
7. Adrenaline and amiodarone per ALS for the rhythm (see dosing).
8. ETCO2 continuous: low ETCO2 suggests poor CPR or massive dead space (PE); sudden rise suggests ROSC.
9. Consider TEE/TTE early if skilled help available — tamponade, PE, empty heart, severe hypovolaemia, regional wall motion.
10. Deploy cognitive aid (ALS + specialty cards: LAST, anaphylaxis, MH). [1]

Rhythm-directed therapy (say the numbers)

Shockable (VF / pulseless VT)

• Defibrillate immediately (energy per local defibrillator protocol; biphasic typically 150–200 J start — follow machine).
• CPR 2-minute cycles between shocks.
• Adrenaline 1 mg IV after third shock (then every 3–5 min) per standard adult ALS teaching.
• Amiodarone 300 mg IV after third shock; further 150 mg if refractory VF/pVT. [1]

Non-shockable (asystole / PEA)

• Adrenaline 1 mg IV immediately, then every 3–5 minutes.
• High-quality CPR; prioritise reversible cause (often hypovolaemia, hypoxia, PE, high spinal, anaphylaxis, LAST). [1]

Adrenaline nuances examiners love

Do not invent unit-specific microdosing as universal law — state ALS baseline then modify with reason. [1]

4 Hs and 4 Ts — theatre edition

Hs

Ts

Anaesthesia-specific differentials (must name)

1. Anaphylaxis — hypotension/arrest after antibiotic, NMB, chlorhexidine, latex, blue dye; give adrenaline, fluids, stop trigger, take mast-cell tryptase later.
2. High / total spinal — after neuraxial; bradycardia, profound hypotension, apnoea; airway, fluids, vasopressors, atropine; CPR if no output.
3. LAST — after block/top-up; seizures ± collapse; lipid emulsion 20% 1.5 mL/kg lean BW bolus then 0.25 mL/kg/min, LAST-modified ALS.[2]
4. Malignant hyperthermia — late hypercarbia, rigidity, rising temperature, hyperK; stop volatiles/sux, dantrolene, hyperventilate, cool, treat hyperK.
5. Airway loss / CICO — cannot oxygenate; front-of-neck access without delay.[3]
6. Drug error — wrong syringe, relative overdose, sux without airway plan, residual NMB with hypoxia.
7. Massive haemorrhage — surgical bleeding, ruptured AAA, obstetric PPH, trauma.
8. Embolism — venous air (sitting neuro, open veins), fat (long bone), cement (BCIS), amniotic fluid, thrombus PE.[4]
9. Vagal asystole — peritoneal traction, oculocardiac, cervical stretch; stop stimulus, atropine, CPR if needed.
10. Auto-PEEP / dynamic hyperinflation — disconnect circuit briefly in severe asthma/COPD.

Special situations

Cardiac surgery / recent sternotomy

External CPR may not generate adequate coronary perfusion with a rigid chest, tamponade, or graft issues. Follow cardiac arrest after cardiac surgery (CALS) principles used in your unit:

• Early re-sternotomy (often within 5 minutes of arrest if no ROSC) for internal massage and surgical correction.
• Prepare sterile field, surgeon, and internal paddles.
• Pace if asystole/bradycardia with epicardial wires present.
• Avoid large epinephrine stacks that produce catastrophic hypertension on ROSC — use small titrated doses per local CALS card.

Maternal cardiac arrest

1. Call obstetric and neonatal teams immediately.
2. Manual left uterine displacement (or 15–30° left tilt — but CPR quality is better flat with manual displacement).
3. Standard maternal ALS with early advanced airway.
4. Perimortem caesarean if no ROSC by ~4 minutes of arrest (aim delivery by 5 minutes) — primarily to improve maternal venous return and survival; also fetal salvage if viable.[5]
5. Consider AFE, haemorrhage, high spinal, eclampsia/magnesium toxicity, PE, anaphylaxis.

Paediatrics

Weight-based adrenaline 10 microg/kg, defibrillation 4 J/kg, Broselow/cognitive aid, hypoxia and medication error are classic causes.

Laparoscopy / robotics

Deflate abdomen, release pneumoperitoneum, flatten, consider CO2 embolism (mill-wheel, sudden ETCO2 fall, right-heart strain).

Post-ROSC care (exam half-marks)

• Target oxygenation (avoid hyperoxia extremes), normocapnia if possible, support BP (often noradrenaline infusion).
• 12-lead ECG; consider urgent coronary angiography if ischaemic cause.
• Temperature control per current post-arrest guidance (avoid fever; targeted temperature management protocols unit-specific).
• ICU, treat cause, delayed multimodal prognostication (not at the bedside 30 minutes after ROSC).
• Hot debrief + cold debrief; incident reporting; family communication. [1]

CRM that scores marks

• Leader not task-bogged; closed-loop orders (“adrenaline 1 mg IV — give and confirm”).
• Cognitive aids open; runners for blood/lipid/dantrolene.
• Explicit differentials spoken every 2-minute cycle.
• Stop non-essential noise; one person speaks to family later. [1]

SAQ scaffold (10–15 marks)

1. Immediate actions and team roles (3)
2. Shockable vs non-shockable drugs and shocks (3)
3. 4 Hs / 4 Ts with two anaesthesia-specific toxins (4)
4. Maternal arrest / perimortem CS (3)
5. When to open the chest after cardiac surgery (2) [1]

Viva stems with model outlines

Stem 1: “ETCO2 falls to zero, SpO2 crashes, no pulse after induction antibiotic.”
Anaphylaxis until proven otherwise; CPR, adrenaline, fluids, stop trigger, airway, call help. [1]

Stem 2: “Arrest 2 minutes after interscalene bupivacaine.”
LAST: CPR + lipid 1.5 mL/kg; LAST-ALS modifications. [1]

Stem 3: “Asystole on peritoneal traction.”
Stop stimulus, atropine, CPR if needed, short course often. [1]

Stem 4: “VF on cementing a hip hemiarthroplasty.”
BCIS / PE spectrum: CPR, 100% O2, fluids, inotropes, echo, surgeon communication. [1]

Stem 5: “Maternal PEA at CS under spinal.”
High spinal vs haemorrhage vs AFE; left displacement, ALS, perimortem CS timing. [1]

Stem 6: “Cardiac ICU 3 hours after CABG — PEA.”
CALS: early re-sternotomy, internal massage, surgical causes (bleed, tamponade, graft). [1]

Common traps

• Continuing surgery during ineffective CPR.
• Treating LAST or MH with adrenaline alone.
• Forgetting lipid / dantrolene / blood as “drugs.”
• No left uterine displacement in maternal arrest.
• Delayed front-of-neck access in CICO.
• Prognosticating neurological outcome in theatre.
• Silencing alarms that were the only warning. [1]

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Red flags

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References

1. [1]Armstrong RA, et al. Peri-operative cardiac arrest: epidemiology and clinical features of patients analysed in the 7th National Audit Project of the Royal College of Anaesthetists Anaesthesia, 2024.PMID 37972476
2. [2]Neal JM et al. The Third American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity: Executive Summary 2017 Reg Anesth Pain Med, 2018.PMID 29356773
3. [3]Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults Br J Anaesth, 2015.PMID 26556848
4. [4]Donaldson AJ et al. Bone cement implantation syndrome Br J Anaesth, 2009.PMID 19059919
5. [5]Mushambi MC, Kinsella SM, Popat M, et al. Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics Anaesthesia, 2015.PMID 26449292