title: "Advanced Life Support Algorithm"
Advanced Life Support Algorithm
Interactive ALS Runner
Practice the ALS algorithm with real-time drug timing, 2-minute CPR cycles, and training scenarios.
Launch ALS Runner →
High-Quality CPR
CPR quality determines survival. Before drugs and shocks, get compressions right: 100-120/min, >5cm depth, full recoil, minimal interruptions.
| Parameter | Target | Why It Matters |
|---|---|---|
| Rate | 100-120/min | Less than 100 or greater than 140 associated with worse survival |
| Depth | >5cm (⅓ chest depth) | Generates coronary perfusion pressure |
| Recoil | Full chest recoil | Allows venous return |
| Interruptions | Under 10 seconds | Every pause drops coronary perfusion to zero |
| Rescuer changes | Every 2 minutes | Fatigue degrades quality within 1-2 min |
Hands-on-chest time is the single biggest modifiable factor in cardiac arrest survival. Aim for >80% chest compression fraction.
Source: ANZCOR (CPR quality guidance).
Rhythm Classification
| Shockable | Non-Shockable |
|---|---|
| VF (Ventricular Fibrillation) | Asystole |
| Pulseless VT | PEA (Pulseless Electrical Activity) |
Asystole check: Before calling asystole, confirm leads attached, gain turned up, and check in 2 leads. "Flat line" can be loose leads or fine VF.
Shockable Pathway (VF/pVT)
Shock energy: 200J biphasic (or manufacturer recommendation). Single shock strategy with immediate CPR resumption.
| Cycle | Action |
|---|---|
| After 1st shock | Resume CPR immediately × 2 min |
| After 2nd shock | CPR + Adrenaline 1mg IV |
| After 3rd shock | CPR + Amiodarone 300mg IV |
| After 5th shock | Consider Amiodarone 150mg IV |
| Ongoing | Adrenaline every 2nd loop (~4 min) |
Why adrenaline after 2nd shock? The first two shocks have the best chance of success. Adrenaline is given after the 2nd shock to augment coronary perfusion for subsequent attempts. Don't delay early shocks for drug access.
Non-Shockable Pathway (Asystole/PEA)
| Action | Timing |
|---|---|
| Adrenaline 1mg IV | As soon as feasible (don't wait) |
| CPR | 2 minutes |
| Rhythm check | After each 2-min cycle |
| Repeat adrenaline | Every 2nd loop (~4 min) |
In ALS, amiodarone is indicated only for shock-refractory VF/pVT.
Drug Summary
| Drug | Dose | Indication | Timing |
|---|---|---|---|
| Adrenaline | 1mg IV | All rhythms | Non-shockable: ASAP. Shockable: after 2nd shock. Then q4min |
| Amiodarone | 300mg IV | Shock-refractory VF/pVT | After 3rd shock |
| Amiodarone | 150mg IV | Refractory VF/pVT | After 5th shock (optional) |
| Lignocaine | 1 mg/kg IV | Alternative to amiodarone | Same timing as amiodarone |
Rhythm Transitions
When rhythm changes between shockable and non-shockable, the new pathway's protocol applies from that point. Shock count resets when entering the shockable pathway.
Non-Shockable → Shockable
If a patient starts in PEA/asystole (adrenaline given immediately) and converts to VF/pVT:
| Rhythm Check | Action |
|---|---|
| VF/pVT detected | Deliver 1st shock (in shockable pathway) → CPR 2 min |
| After 2nd shock | Adrenaline 1mg (even if recently given in non-shockable) → CPR 2 min |
| After 3rd shock | Amiodarone 300mg → CPR 2 min |
The shock count is specific to the shockable pathway. Even if adrenaline was given during non-shockable rhythm, the shockable pathway drug timing (adrenaline after 2nd shock, amiodarone after 3rd) still applies.
Shockable → Non-Shockable
If VF/pVT degenerates to asystole/PEA:
- Give adrenaline 1mg immediately (non-shockable protocol = ASAP)
- No amiodarone — it's only for shock-refractory VF/pVT
- If rhythm converts back to shockable, resume shockable pathway
Do not give amiodarone if rhythm has converted to non-shockable; it only treats shock-refractory VF/pVT.
The 4 H's and 4 T's
4 H's:
- Hypoxia → Check airway, give O₂, consider ETT
- Hypovolaemia → Rapid IV fluids/blood resuscitation (bolus crystalloids)
- Hypo/hyperkalaemia → VBG, calcium gluconate for hyperK
- Hypothermia → Check core temp, warm to 32°C before stopping
4 T's:
- Tension pneumothorax → Chest decompression (needle decompression)
- Tamponade → Pericardiocentesis, thoracotomy
- Toxins → Specific antidotes (naloxone, flumazenil, lipid emulsion)
- Thrombosis (PE/MI) → Consider thrombolysis (PE) or PCI (STEMI)
Special Situations
Thrombolysis in Arrest
If PE is suspected as the cause of arrest, consider thrombolysis (e.g., alteplase; dose per local protocol). Continue CPR for 60-90 minutes before considering termination — thrombolytics take time to work.
Hypothermic Arrest
- Withhold adrenaline if core temp below 30°C
- Increase adrenaline interval to 6-10 minutes if temp 30-34°C
- Consider extracorporeal rewarming (ECMO) for refractory arrest
Post-ROSC Care
Once ROSC is achieved:
- Airway — Secure if not already, confirm ETT position with capnography
- Oxygenation — Target SpO₂ 94-98% (avoid hyperoxia)
- Ventilation — Target normocapnia (PaCO₂ 35-45 mmHg (~4.7-6.0 kPa))
- Circulation — MAP >65 mmHg, consider vasopressors/inotropes
- 12-lead ECG — Look for STEMI → cath lab
- Temperature — Actively prevent fever (≤ 37.5°C) in comatose patients; follow local temperature control protocol
- Glucose — Avoid hypoglycaemia, target under 10 mmol/L
- Cause — Identify and treat underlying cause
Temperature control after ROSC: ANZCOR suggests actively preventing fever by targeting ≤ 37.5°C in patients who remain comatose after ROSC, and continuing fever prevention for at least 72 hours. Whether hypothermia (32–34°C) benefits subgroups remains uncertain.
When to Stop
Consider terminating resuscitation when:
- Refractory to treatment despite correcting reversible causes
- No ROSC after 20+ minutes of ALS with non-shockable rhythm
- Pre-arrest factors suggesting futility (terminal illness, prolonged downtime without CPR)
Do not stop if: hypothermia (until rewarmed), drug overdose (may need prolonged CPR), or if any reversible cause remains untreated.