Home β€Ί Topics β€Ί ACLS & BLS

❀️ ACLS & BLS β€” Cardiac Arrest

AHA 2025 Official Algorithms ILCOR ERC 2021
High-Quality CPR Shockable vs Non-shockable Hs & Ts Β· Peri-arrest AHA 2025 Guidelines for CPR & ECC β€” official algorithm set Β· ILCOR CoSTR Β· ERC 2021
πŸ“… Last reviewed July 2026 Β· Next review January 2027 Β· Compiled by Dr. Anmol Srivastava Anaesthesia, Emergency Medicine & Critical Care Medicine Β· Reviewed by Dr. Tanya Chawla Anaesthesia & Critical Care
πŸ“• 1 Β· Basic Life Support

BLS β€” The Foundation Is High-Quality CPR

"Survival from cardiac arrest is determined less by any drug than by the quality and continuity of chest compressions and the speed of defibrillation. Every interruption in compressions costs coronary perfusion pressure that takes many compressions to rebuild. The entire ACLS edifice is built on, and must never compromise, the foundation of high-quality BLS."

AHA Guidelines for CPR & Emergency Cardiovascular Care, 2020 (Circulation 2020;142:S336–S604).
High-Quality CPR β€” the Numbers (AHA 2020)
Rate 100–120/min Β· depth β‰₯5 cm (2 in), not >6 cm Β· full recoil each compression Β· minimise interruptions (chest-compression fraction >60–80%; pauses <10 s) Β· avoid over-ventilation. Compression-to-ventilation 30:2 until an advanced airway, then continuous compressions with 1 breath every 6 s (10/min). Switch compressor every 2 min.

⚑ Adult BLS Sequence

C–A–B: Check responsiveness & breathing + pulse (≀10 s) β†’ call for help / activate emergency response & get the AED/defibrillator β†’ start compressions β†’ defibrillate the moment a shockable rhythm is found. For witnessed monitored arrest, immediate defibrillation takes priority.

Chain of Survival

Out-of-hospital: early recognition/activation β†’ early CPR β†’ early defibrillation β†’ advanced resuscitation β†’ post-arrest care β†’ recovery. In-hospital: surveillance/prevention β†’ activation β†’ CPR β†’ defibrillation β†’ post-arrest care. Recovery (survivorship, rehabilitation) is now an explicit link in the chain.

πŸ“‹ 2 Β· Adult Cardiac Arrest Algorithm

Shockable vs Non-Shockable

AHA 2025 Adult Cardiac Arrest Algorithm
AHA 2025 β€” Adult Cardiac Arrest Algorithm. Tap to enlarge β†—
AHA 2025 Cardiac Arrest Circular Algorithm
AHA 2025 β€” Cardiac Arrest Circular Algorithm (the 2-minute CPR cycle view). Tap to enlarge β†—
Shockable β€” VF / Pulseless VT
CPR β†’ defibrillate (biphasic 120–200 J per device; or 360 J monophasic) β†’ immediately resume CPR Γ—2 min β†’ rhythm/pulse check.
Adrenaline 1 mg IV/IO after the 2nd shock, then every 3–5 min.
Amiodarone 300 mg (then 150 mg) IV/IO after the 3rd shock (or lidocaine 1–1.5 mg/kg).
Continue 2-min cycles: CPR β†’ shock β†’ drug/CPR; treat reversible causes throughout.
Non-Shockable β€” PEA / Asystole
CPR β†’ adrenaline 1 mg IV/IO as soon as possible, then every 3–5 min β†’ 2-min CPR cycles with rhythm checks. No defibrillation (not shockable). The priority is excellent CPR + finding and treating the reversible cause (Hs & Ts) β€” PEA/asystole rarely responds to drugs alone.
Throughout the Arrest
Establish IV/IO access (IO if no rapid IV) Β· advanced airway (SGA or ETT) without interrupting compressions, then continuous compressions + 10 breaths/min Β· waveform capnography (confirms tube, monitors CPR quality β€” aim ETCOβ‚‚ >10 mmHg; an abrupt rise often signals ROSC) Β· identify shockable vs non-shockable at each 2-min check.
πŸ’Š 3 Β· Drugs & Defibrillation

ACLS Drug & Energy Reference

DrugIndicationDoseNotes
Adrenaline (epinephrine)All arrests1 mg IV/IO q3–5 minNon-shockable: ASAP. Shockable: after 2nd shock
AmiodaroneRefractory VF/pVT300 mg IV/IO β†’ 150 mgAfter 3rd shock; dilute in D5W
LidocaineAlternative to amiodarone1–1.5 mg/kg β†’ 0.5–0.75 mg/kgEither agent acceptable (AHA)
Magnesium sulphateTorsades / hypomagnesaemia1–2 g IV/IONOT routine in cardiac arrest β€” only for torsades
Calcium / BicarbonateSpecific causes onlyCa for ↑K⁺/↓Ca²⁺/CCB; HCO₃ for ↑K⁺/TCA/acidosisNot routine β€” guided by the reversible cause
NaloxoneSuspected opioid arrest2 mg IM/IN or 0.4–2 mg IVAdjunct to CPR (does not replace it)
Defibrillation

Biphasic 120–200 J (use the manufacturer's recommended dose; if unknown, use the maximum) β€” escalate to maximum for refractory VF. Monophasic 360 J. Minimise the peri-shock pause: charge during compressions, clear, shock, and resume compressions immediately (no post-shock rhythm/pulse check β€” resume CPR for 2 min first). Refractory VF: ensure pad position/contact, consider changing pad position (antero-posterior) and double sequential external defibrillation (DSED) or a vector change (DOSE-VF trial).

πŸ” 4 Β· Reversible Causes β€” Hs & Ts

Find and Fix the Cause (especially in PEA/asystole)

The H's

  • Hypoxia β€” oxygenate, confirm tube (capnography)
  • Hypovolaemia β€” fluids/blood; haemorrhage control
  • Hydrogen ion (acidosis) β€” ventilation; HCO₃ for specific causes
  • Hypo/Hyperkalaemia β€” Ca + insulin/dextrose (↑K); replace (↓K)
  • Hypothermia β€” rewarm; "not dead until warm and dead"
  • Hypoglycaemia β€” check & treat

The T's

  • Tension pneumothorax β€” needle/finger decompression
  • Tamponade (cardiac) β€” pericardiocentesis / thoracotomy
  • Toxins β€” antidotes (naloxone, bicarb for TCA, lipid emulsion, etc.)
  • Thrombosis β€” coronary (MI) β†’ PCI
  • Thrombosis β€” pulmonary (massive PE) β†’ thrombolysis
Point-of-Care Ultrasound
Echo during the rhythm-check pause (≀10 s) can identify tamponade, RV strain (massive PE), severe hypovolaemia, or cardiac standstill β€” but must not prolong compression pauses. Consider thrombolysis for confirmed/strongly-suspected PE arrest (prolong CPR 60–90 min after lysis). ECPR (extracorporeal CPR) in selected refractory arrests at capable centres.

Post-Cardiac-Arrest Care & Special Circumstances (AHA 2025)

AHA 2025 Post-Cardiac Arrest Care Algorithm
AHA 2025 β€” Adult Post-Cardiac-Arrest Care. See the ROSC topic for detail. Tap to enlarge β†—
AHA 2025 Cardiac Arrest in Pregnancy Algorithm
AHA 2025 β€” Cardiac Arrest in Pregnancy (left-uterine displacement; resuscitative hysterotomy by ~4–5 min if no ROSC). Tap to enlarge β†—
AHA 2025 Cardiac Arrest with an LVAD Algorithm
AHA 2025 β€” Cardiac Arrest in the patient with an LVAD. Tap to enlarge β†—
⚑ 5 · Peri-Arrest Algorithms

Bradycardia & Tachycardia (with a pulse)

AHA 2025 Adult Bradycardia Algorithm
AHA 2025 β€” Adult Bradycardia (with pulse) Algorithm. Tap to enlarge β†—
AHA 2025 Adult Tachycardia Algorithm
AHA 2025 β€” Adult Tachycardia (with pulse) Algorithm. Tap to enlarge β†—
AHA 2025 Electrical Cardioversion Algorithm
AHA 2025 β€” Electrical Cardioversion energies & steps. Tap to enlarge β†—
Symptomatic Bradycardia
If unstable (hypotension, altered mentation, ischaemic chest pain, acute heart failure): Atropine 1 mg IV, repeat q3–5 min to max 3 mg. If atropine ineffective β†’ transcutaneous pacing and/or adrenaline 2–10 Β΅g/min or dopamine 5–20 Β΅g/kg/min infusion; prepare for transvenous pacing. Atropine is ineffective in high-grade (Mobitz II / complete) block β€” go to pacing.
Tachycardia with a Pulse
Unstable β†’ synchronised cardioversion. Stable: narrow regular β†’ vagal + adenosine 6 mg β†’ 12 mg; narrow irregular (AF) β†’ rate control (Ξ²-blocker/diltiazem); wide regular β†’ amiodarone (treat as VT if uncertain); wide irregular β†’ expert help (AF + WPW / polymorphic). See the dedicated Arrhythmias topic.
πŸ”„ 6 Β· What Changed Since AHA 2020

Recent AHA / ILCOR Updates (2020 β†’ recent focused updates)

Key Shifts You Should Know
β€’ Early adrenaline in non-shockable rhythms β€” give ASAP (PARAMEDIC-2 showed improved ROSC/survival; emphasised for PEA/asystole).
β€’ Double sequential external defibrillation (DSED) / vector change for refractory VF β€” supported by the DOSE-VF RCT (2022); now a reasonable option after standard shocks fail.
β€’ Opioid-associated arrest β€” naloxone (IM/IN) integrated alongside CPR for suspected opioid overdose (2023/2024 focused updates), reflecting the overdose epidemic.
β€’ Post-arrest temperature β€” shift from mandatory 32–34 Β°C hypothermia to active fever prevention / targeted temperature management ≀37.5 Β°C (TTM2 trial) β€” see the ROSC topic.
β€’ No routine immediate coronary angiography in post-arrest patients without ST-elevation (TOMAHAWK/COACT).
β€’ Recovery & survivorship added as a formal link; structured neuroprognostication delayed to β‰₯72 h, multimodal.
β€’ Emphasis on CPR quality feedback, IO as a fast alternative to IV, and capnography for tube confirmation & CPR quality.
⚠️ Guideline currency

The AHA now publishes annual focused updates rather than one big revision; the comprehensive guidelines remain the 2020 edition with yearly amendments (2023, 2024, and ongoing). The principles above are stable, but always check the most recent AHA focused update for any year-specific change before quoting "the latest" in an exam or protocol.

❌ 7 · Common Mistakes

Common Mistakes in Resuscitation

❌ Mistake 1 β€” Interrupting Compressions Too Much

Long pauses for intubation, pulse checks, or charging the defibrillator destroy coronary perfusion pressure. Keep the chest-compression fraction high, pauses <10 s, charge during compressions, and resume CPR immediately after every shock.

❌ Mistake 2 β€” Over-Ventilating

Excessive ventilation raises intrathoracic pressure, reduces venous return and worsens outcomes. After an advanced airway, give only ~10 breaths/min; avoid bagging fast and hard.

❌ Mistake 3 β€” Defibrillating Asystole / Not Defibrillating VF Fast Enough

Asystole and PEA are NOT shockable β€” focus on CPR + reversible causes. Conversely, in shockable rhythms every minute of delayed defibrillation lowers survival ~10% β€” shock early and minimise the peri-shock pause.

❌ Mistake 4 β€” Ignoring the Hs & Ts in PEA

PEA/asystole rarely respond to adrenaline alone; survival depends on finding the reversible cause (tension pneumothorax, tamponade, PE, hyperkalaemia, hypovolaemia, toxins). Use POCUS and the history β€” but don't prolong compression pauses.

❌ Mistake 5 β€” Stopping Too Early in Special Circumstances

Hypothermia ("not dead until warm and dead"), thrombolysed PE (continue CPR 60–90 min), and toxic/local-anaesthetic arrest may need prolonged resuscitation and specific therapies. Tailor the duration to the cause.

❌ Mistake 6 β€” Neglecting Post-ROSC Care

Achieving ROSC is the beginning, not the end. Targeted temperature/fever control, oxygen & COβ‚‚ targets, haemodynamic support, treat the cause (PCI if indicated) and delayed multimodal neuroprognostication all determine neurological outcome β€” see the ROSC topic.

πŸ“‘ 8 Β· References

References

  1. Panchal AR, Bartos JA, CabaΓ±as JG et al. Part 3: Adult Basic and Advanced Life Support: 2020 AHA Guidelines for CPR and ECC. Circulation 2020;142(suppl 2):S366–S468.
  2. American Heart Association. 2023 & 2024 Focused Updates on Advanced Cardiovascular Life Support / Resuscitation. Circulation (annual focused updates).
  3. Cheskes S, Verbeek PR, Drennan IR et al. (DOSE-VF). Defibrillation Strategies for Refractory Ventricular Fibrillation. N Engl J Med 2022;387:1947–1956.
  4. Perkins GD, Ji C, Deakin CD et al. (PARAMEDIC-2). A Randomized Trial of Epinephrine in Out-of-Hospital Cardiac Arrest. N Engl J Med 2018;379:711–721.
  5. Dankiewicz J, Cronberg T, Lilja G et al. (TTM2). Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest. N Engl J Med 2021;384:2283–2294.
  6. Soar J, BΓΆttiger BW, Carli P et al. (ERC). European Resuscitation Council Guidelines 2021: Adult advanced life support. Resuscitation 2021;161:115–151.