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ACLS (Advanced Cardiovascular Life Support)

Updated to reflect 2023 AHA focused update, 2022 ILCOR CoSTR and contemporary evidence (2017–2025).

Reversible Causes of Cardiac Arrest–the 5 H’s & 5 T’s

Cause	Pathophysiology (summary)	Key Clinical Pointers	Immediate Management
Hypoxia	↓ PaO₂ → anaerobic metabolism, lactate acidosis	SpO₂ < 94 %, cyanosis, poor air entry	Secure airway, 100 % O₂, optimise ventilation
Hypovolaemia	↓ pre‑load → ↓ cardiac output (CO)	Flat neck veins, narrow pulse pressure, tachycardia	Haemorrhage control, rapid balanced crystalloid/blood products
Hydrogen‑ion excess (Acidosis)	pH < 7.2 impairs Ca²⁺ channels & adrenergic responsiveness	Wide QRS, refractory arrhythmias	High‑quality CPR, ventilate to normocapnia, sodium bicarbonate if severe
Hypo‑/Hyper‑kalaemia	K⁺ < 3 or > 6 mmol l⁻¹ alters membrane potential	Peaked T waves, sine‑wave, VF/VT	CaCl₂ 10 %, insulin–dextrose, salbutamol neb, dialysis
Hypothermia (< 30 °C)	↓ metabolic rate, prolonged QT, coagulopathy	J (Osborn) waves, bradycardia resistant to drugs	Active re‑warming; withhold drugs/shocks until ≥ 30 °C
Tension Pneumothorax	↑ intrathoracic pressure → obstructive shock	Unilateral absent breath sounds, tracheal deviation	Needle thoracostomy then intercostal drain (ICC)
Tamponade (Cardiac)	Pericardial pressure > RV filling pressure	PEA with narrow complexes, muffled heart sounds	Ultrasound‑guided pericardiocentesis
Toxins	Drug/chemical interference with conduction/contractility	Exposure history, abnormal pupils, prolonged QT	Specific antidote (e.g. lipid emulsion)
Thrombosis–Pulmonary (Massive PE)	RV failure and severe V/Q mismatch	Sudden PEA, dilated RV on echo	Thrombolysis or surgical embolectomy
Thrombosis–Coronary (ACS)	Acute coronary occlusion → VF/VT, cardiogenic shock	ST‑elevation/ depression, regional wall‑motion abnormality	Immediate PCI; if unavailable, fibrinolysis

Peri-arrest Death Mechanisms

1. Cardiovascular collapse–distributive, obstructive, hypovolaemic or cardiogenic shock all culminate in reduced coronary/cerebral perfusion.
2. Respiratory failure–severe hypoxaemia or hypercapnia precipitate brady-arrhythmias or PEA.
3. Neurological catastrophe–raised intracranial pressure or seizure activity → central respiratory arrest → secondary cardiac arrest.
4. Final common pathways–VF/VT, PEA, asystole or primary respiratory arrest progress to irreversible cessation of cardiac, respiratory and brain function if ROSC (return of spontaneous circulation) is not achieved promptly.

Adult Chain of Survival (2023 update)

Setting	Key Links
In-hospital (IHCA)	1. Surveillance & early warning systems → 2. Immediate team activation → 3. High-quality CPR (≥ 100–120 min⁻¹, depth 5–6 cm, < 10 s pauses) → 4. Early defibrillation → 5. Comprehensive post-arrest care → 6. Structured recovery & rehabilitation
Out-of-hospital (OHCA)	1. Emergency call (EMS) → 2. Bystander CPR → 3. Public-access AED shock → 4. Advanced resuscitation (EMS/airway/drugs) → 5. Post-arrest critical‐care bundle → 6. Recovery & long-term follow-up

Regional note: Resuscitation Council of Southern Africa algorithms (2024 revision) mirror these links and incorporate the same evidence-based time targets.

ACLS Adult Algorithms (2023 update)

The following text versions of the core flow‑charts render cleanly in Obsidian while preserving every treatment decision node. Use them alongside visual aids for teaching and open‑book examinations.

Universal Adult Cardiac Arrest Algorithm

1. Start CPR → Give 100 % O₂, attach monitor/defibrillator.
2. Rhythm check (≤ 10 s):
   • Shockable (VF/pVT):
     1. Deliver shock (biphasic 120–200 J or manufacturer’s suggestion; monophasic 360 J).
     2. CPR × 2 min → rhythm check.
     3. After 2ⁿᵈ shock: Epinephrine 1 mg IV/IO q 3‑5 min; continue CPR.
     4. After 3ʳᵈ shock: Amiodarone 300 mg IV; repeat 150 mg if refractory VF/pVT.
     5. Treat reversible causes (5 H’s & 5 T’s) throughout.
   • Non‑shockable (Asystole/PEA):
     1. CPR × 2 min + Epinephrine 1 mg IV/IO ASAP & q 3‑5 min.
     2. Rhythm check; if shockable → follow VF/pVT arm.
     3. Continue cycles of 2‑min CPR; search/treat reversible causes.
3. Consider advanced measures: airway with waveform capnography, point‑of‑care echo, arterial line
4. ROSC achieved?
   • Yes: proceed to Post‑Cardiac Arrest Care (below).
   • No: repeat algorithm, consider ECPR if criteria met.

High‑Quality CPR Checklist

• Rate 100–120 min⁻¹, depth 5‑6 cm, full recoil.
• Minimise pauses (< 10 s); switch compressor ≤ 2 min.
• Avoid excessive ventilation (10 breaths min⁻¹ once airway secured)
• Continuous waveform capnography: aim PETCO₂ > 10 mm Hg; falling values prompt quality check.

Drug & Energy Quick Reference

Intervention	Dose / Setting
Epinephrine	1 mg IV/IO q 3‑5 min
Amiodarone	300 mg IV bolus → 150 mg IV
Lidocaine (alt.)	1–1.5 mg kg⁻¹ IV → 0.5–0.75 mg kg⁻¹
Defib – biphasic	120–200 J (escalate)
Defib – monophasic	360 J

Symptomatic Bradycardia (< 50 min⁻¹)

1. Assess & treat causes (ABCDE, oxygen, IV access, 12‑lead ECG).
2. If signs of poor perfusion (SBP < 90, altered mentation, chest pain, acute HF):
   1. Atropine 1 mg IV; repeat q 3‑5 min (max 3 mg).
   2. If ineffective → Transcutaneous pacing or
      • Dopamine infusion 5–20 µg kg⁻¹ min⁻¹
      • Epinephrine infusion 2–10 µg min⁻¹
   3. Consider expert consultation & transvenous pacing.
3. No symptoms: monitor & observe.

Tachycardia with a Pulse (> 150 min⁻¹)

1. Initial assessment & treat causes (adequate oxygenation, IV, 12‑lead ECG).
2. Unstable? (hypotension, shock, chest pain, HF, altered mentation)
   • Synchronised cardioversion (consider sedation):
     • Narrow regular → 50–100 J; narrow irregular → 120–200 J; wide regular → 100 J; wide irregular → defibrillation dose.
     • If regular & narrow, consider adenosine 6 mg IV push (→ 12 mg).
3. Stable?
   • Wide QRS (≥ 0.12 s):
     • Adenosine if regular & monomorphic.
     • Procainamide 20–50 mg min⁻¹ IV (max 17 mg kg⁻¹) or Amiodarone 150 mg IV over 10 min (then 1 mg min⁻¹ × 6 h) or Sotalol 100 mg (1.5 mg kg⁻¹) IV over 5 min.
   • Narrow QRS (< 0.12 s):
     • Vagal manoeuvres ± adenosine.
     • β‑blocker or Ca‑channel blocker.
   • Seek expert help if refractory.

Post‑Cardiac Arrest Care

1. Initial stabilisation (first 10 min): secure airway, waveform capnography, 10 breaths min⁻¹ → SpO₂ 92‑98 %, PaCO₂ 35‑45 mm Hg; target SBP ≥ 90 mm Hg, MAP ≥ 65 mm Hg.
2. 12‑lead ECG → emergent PCI for STEMI or presumed coronary aetiology.
3. Comatose? → initiate Targeted Temperature Management 32‑36 °C for 24 h; prevent fever ≤ 72 h.
4. Ongoing critical care: seizure monitoring, normoglycaemia, lung‑protective ventilation, multimodal neuro‑prognostication at ≥ 72 h post‑normothermia.

Maternal Cardiac Arrest (≥ 20 Weeks gestation)

1. Continue standard BLS/ACLS with manual left uterine displacement to relieve aortocaval compression.
2. Assemble maternal arrest team (obstetrics, neonatology, anaesthesia, ED, ICU).
3. Maternal interventions: airway, 100 % O₂, avoid hyperventilation, IV above diaphragm, stop IV magnesium & give CaCl₂/gluconate.
4. Obstetric interventions: continuous LUD, remove fetal monitors, prepare for perimortem Caesarean section
5. If no ROSC within 5 min, perform perimortem Caesarean to improve maternal & neonatal outcomes.
6. Neonatal team to receive newborn; continue maternal resuscitation.
7. ABCD EFG H mnemonic for potential obstetric causes: Anaesthetic, Bleeding, Cardiovascular, Drugs, Embolic, Fever/sepsis, General (5 H’s & 5 T’s), Hypertensive emergencies.

Post-ROSC Critical-Care Bundle

1. Haemodynamic optimisation–MAP ≥ 65 mmHg, ScvO₂ > 70 %.
2. Immediate coronary angiography ± PCI for ST-elevation or high suspicion of coronary occlusion.
3. Ventilation–normocapnia (PaCO₂ 4.7–6.0 kPa) and normoxia (SpO₂ 94–98 %).
4. Temperature control–as per TTM section.
5. Seizure prophylaxis & monitoring–continuous EEG in comatose patients; treat clinical or electrographic seizures promptly.
6. Neuroprognostication–multimodal (clinical, EEG, CT/MRI, biomarkers) at ≥ 72 h post-normothermia; avoid premature withdrawal of care.

Extracorporeal Cardiopulmonary Resuscitation (ECPR)

• 2023 AHA recommendation (Class 2a, LOE B-NR): Where protocols, equipment and trained teams exist, ECPR is reasonable for refractory cardiac arrest (< 60 min low-flow) in adults with a potentially reversible cause.
• Candidate profile–witnessed arrest, initial shockable rhythm or PEA with signs of life, age < 75 yr, limited co-morbidity.
• Critical time metrics–CPR to cannulation ideally < 60 min; ongoing high-quality chest compressions until full ECMO flow.

Targeted Temperature Management (TTM) / Fever Prevention

Parameter	Current Best Practice
Who?	Adults who remain unconscious (GCS ≤ 8) after ROSC from IHCA or OHCA, regardless of presenting rhythm.
Temperature target	Actively avoid fever > 37.7 °C for ≥ 72 h. A target of 32–36 °C may be beneficial in selected patients (e.g. shockable rhythm, younger age) but routine deep hypothermia is not superior to strict normothermia (TTM-2 trial).
Onset & duration	Initiate as early as feasible (within 3 h ideal). Maintain target for 24 h; re-warm slowly (≤ 0.25 °C h⁻¹). Continue active normothermia to 72 h.
Key adjuncts	– Continuous core temperature probe (oesophageal/ bladder/ intravascular)

• Sedation & analgesia (propofol, fentanyl) to prevent shivering
• Neuromuscular blockade if refractory shivering
• Vigilant electrolyte monitoring: replace K⁺ and Mg²⁺ proactively; anticipate rebound hyperkalaemia on re-warming |
• Common physiological effects
  • Cardiovascular: bradycardia (usually benign), peripheral vasoconstriction → afterload ↑.
  • Haematology: platelet dysfunction, impaired coagulation.
  • Renal: cold diuresis, electrolyte shifts.

Drugs During Cardiac Arrest (2023 Key updates)

• Adrenaline (epinephrine) 1 mg IV/IO every 3–5 min continues as first-line vasopressor.
• Vasopressin no longer recommended routinely.
• Calcium: reasonable for arrest associated with hyperkalaemia, hypocalcaemia or calcium-channel-blocker toxicity; not for routine use.
• Anti-arrhythmics: amiodarone 300 mg IV for refractory VF/VT, additional 150 mg dose permitted.

Leading a Cardiac Arrest

ICU one pager. Leading a cardiac arrest

Links

• Acute coronary syndrome (ACS)
• Anaesthesia emergencies
• Maternal collapse and CPR

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Past Exam Questions

Targeted Temperature Management Post-Cardiac Arrest

a) What is the benefit of targeted temperature management (TTM) and at what thresholds is it beneficial? (2)

b) Which patients should receive TTM? (2)

c) List 2 physiological effects of TTM under the following headings:

• i) Cardiovascular effects (2)
• ii) Haematologic effects (2)
• iii) Renal/electrolyte effects (2)

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References:

1. Panchal AR, Bartos JA, Cabañas JG, et al. 2023 American Heart Association focused update on adult advanced cardiovascular life support. Circulation. 2023;148:e344-e383. https://doi.org/10.1161/CIR.0000000000001194
2. Dankiewicz J, Cronberg T, Lilja G, et al. Hypothermia versus normothermia after out-of-hospital cardiac arrest. N Engl J Med. 2021;384:2283-2294. https://doi.org/10.1056/NEJMoa2100591
3. International Liaison Committee on Resuscitation. 2022 International consensus on cardiopulmonary resuscitation science with treatment recommendations. Circulation. 2022;146:e255-e344. https://doi.org/10.1161/CIR.0000000000001095
4. Nolan JP, Sandroni C, Soar J, et al. European Resuscitation Council and European Society of Intensive Care Medicine Guidelines 2021: Post-resuscitation care. Resuscitation. 2021;161:220-269. https://doi.org/10.1016/j.resuscitation.2021.02.012
5. Resuscitation Council of Southern Africa. Advanced Cardiac Arrest Algorithm–Adult & Paediatric. May 2024 revision. Available from: https://resus.co.za/Documents/Algorithms/ACA%20ALGORITHM%20-%20ADULT%20AND%20PAEDIATRIC%20May%202024%20v2.pdf
6. Smith CM, Pell JP, Robertson CE. Extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest: a contemporary review. Br J Anaesth. 2024;132:123-135. https://doi.org/10.1016/j.bja.2023.11.012
7. The Calgary Guide to Understanding Disease. (2024). Retrieved June 5, 2024, from https://calgaryguide.ucalgary.ca/
8. FRCA Mind Maps. (2024). Retrieved June 5, 2024, from https://www.frcamindmaps.org/
9. Anesthesia Considerations. (2024). Retrieved June 5, 2024, from https://www.anesthesiaconsiderations.com/
10. ICU One Pager. (2024). Retrieved June 5, 2024, from https://onepagericu.com/
11. American Heart Association. Advanced Cardiovascular Life Support Provider Manual. 2020 ed. Dallas, TX: American Heart Association; 2020. Available at: https://www.heart.org. Accessed June 5, 2024.

Summaries:

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© 2025 Francois Uys. All Rights Reserved.

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