A 62-year-old man admitted earlier for sudden breathlessness and pleuritic chest pain—thought to have a pulmonary embolism and started on treatment-dose LMWH—is found unresponsive on the ward. The crash team arrives to find CPR already in progress. A supraglottic airway is functioning well. After a full 2-minute cycle, the monitor displays an organised rhythm that looks like normal sinus rhythm, but no central pulse is felt.
What is the most appropriate immediate intervention?
A. Give 500 mL IV crystalloid bolus
B. Give adrenaline 1 mg IV (1:10,000)
C. Give adrenaline 1 mg IM (1:1,000)
D. Administer thrombolysis (e.g., alteplase 50 mg)
E. Deliver an unsynchronised shock
Correct answer → B. Adrenaline 1 mg IV (1:10,000)
Explanation
- The rhythm on the monitor looks normal, but the patient has no pulse → this is Pulseless Electrical Activity (PEA).
- PEA is a non-shockable rhythm → so shocking is NOT helpful.
- According to the ALS algorithm, adrenaline 1 mg IV (1:10,000) should be given as soon as PEA/asystole is identified, then repeated every 3–5 minutes.
Why not the other options?
A. IV fluids
Useful only if the cause is hypovolaemia, but adrenaline is higher priority in PEA.
C. Adrenaline 1 mg IM (1:1,000)
This is the anaphylaxis dose, NOT used in cardiac arrest.
D. Thrombolysis
Could be useful if a massive PE caused the arrest—but first priority is adrenaline and CPR.
E. Unsynchronised shock
Shock is only for VF or pulseless VT. PEA ≠ shockable.
Therefore the correct immediate management is IV adrenaline 1 mg (1:10,000).
Cheat Sheet (ALS – High-yield exam essentials)
1. Rhythm categories
- Shockable → VF, pulseless VT
- Non-shockable → Asystole, PEA
2. Adrenaline
- Dose: 1 mg IV (1:10,000)
- Give immediately in PEA/asystole
- In VF/VT → give after the 3rd shock, then every 3–5 min
3. Amiodarone
- In VF/pulseless VT:
- 300 mg after the 3rd shock
- 150 mg after the 5th shock
- Lidocaine = alternative
4. Key practical rules
- CPR ratio → 30:2 (if airway not secured)
- Continue compressions during defib charging
- Use IV, then IO if no access
- No drug delivery via ETT anymore
5. Reversible causes → 4 Hs + 4 Ts
Hs: hypoxia, hypovolaemia, hypo/hyperkalaemia & metabolic, hypothermia
Ts: thrombosis (PE/MI), tension pneumothorax, tamponade, toxins
6. Thrombolysis
- Consider if PE suspected as cause of arrest
- Continue CPR 60–90 minutes afterwards
7. Special situations
- Pregnancy >20 weeks → left lateral tilt
- Post-ROSC → oxygen target 94–98%
Flashcards (20 total)
- Q: What is the definition of PEA?
A: Electrical activity on ECG without a palpable pulse. - Q: First drug for PEA/asystole?
A: Adrenaline 1 mg IV (1:10,000) immediately. - Q: Adrenaline timing in non-shockable rhythms?
A: Right away, and every 3–5 minutes. - Q: Adrenaline timing in shockable rhythms (VF/VT)?
A: After 3rd shock, then every 3–5 min. - Q: Amiodarone dose after 3rd shock?
A: 300 mg IV. - Q: Amiodarone dose after 5th shock?
A: 150 mg IV. - Q: Alternative to amiodarone?
A: Lidocaine. - Q: Shockable rhythms?
A: VF, pulseless VT. - Q: Non-shockable rhythms?
A: Asystole, PEA. - Q: Compression-to-ventilation ratio?
A: 30:2. - Q: What to do while the defibrillator charges?
A: Continue chest compressions. - Q: Best route for drugs in cardiac arrest?
A: IV, then IO if needed. - Q: Are ETT drugs recommended?
A: No. - Q: When to give thrombolysis during arrest?
A: If massive PE suspected. - Q: CPR duration after thrombolysis?
A: 60–90 minutes. - Q: Four Hs?
A: Hypoxia, hypovolaemia, hypo/hyperkalaemia/metabolic, hypothermia. - Q: Four Ts?
A: Thrombosis, tension pneumothorax, tamponade, toxins. - Q: Oxygen target after ROSC?
A: 94–98%. - Q: Pregnancy modification during CPR?
A: 15° left lateral tilt. - Q: Is atropine used in PEA/asystole?
A: No.
MCQs
MCQ 1
During CPR for asystole, which drug must be given immediately?
A. Amiodarone
B. Adrenaline 1 mg IV
C. Magnesium
D. Lidocaine
Answer: B
MCQ 2
A patient in persistent VF has received 3 shocks. What is the next drug?
A. Adrenaline
B. Amiodarone 300 mg
C. Atropine
D. Lidocaine 50 mg
Answer: B
MCQ 3
A pulseless patient’s rhythm is VF. When should adrenaline be administered?
A. Immediately
B. After the 1st shock
C. After the 3rd shock
D. After 10 minutes of CPR
Answer: C
MCQ 4
Which reversible cause is most consistent with sudden collapse, distended neck veins, and absent breath sounds on one side?
A. Tamponade
B. Tension pneumothorax
C. Thrombosis
D. Hypoxia
Answer: B
MCQ 5
In a cardiac arrest suspected due to massive PE, the recommended action is:
A. Stop CPR and give thrombolysis
B. Give thrombolysis and continue CPR 60–90 min
C. Deliver repeated shocks
D. Use atropine
Answer: B
Summary for Quick Revision
Adult ALS divides cardiac arrest rhythms into shockable (VF/pulseless VT) and non-shockable (asystole/PEA). In non-shockable rhythms, adrenaline 1 mg IV (1:10,000) must be given immediately and repeated every 3–5 minutes. In shockable rhythms, the sequence is one shock, 2 minutes CPR, and adrenaline only after the 3rd shock. Amiodarone 300 mg IV is added after the 3rd shock, with 150 mg after the 5th shock. CPR quality is crucial: 30:2 if airway not secured, minimal interruptions, and continue compressions while the defibrillator charges. IO access is acceptable if IV cannot be established. Drug via tracheal tube is no longer advised. Always search for reversible causes using the 4 Hs and 4 Ts. Thrombolysis should be considered in suspected pulmonary embolism, with prolonged CPR afterwards. In pregnancy over 20 weeks, apply left uterine displacement to improve venous return. Once ROSC is achieved, oxygen saturation should be titrated to 94–98% to avoid hyperoxia. Atropine is not used in PEA or asystole. Remember that PEA means an organised rhythm with no palpable pulse and is treated like asystole. Good CPR, early adrenaline in non-shockable rhythms, and timely defibrillation in shockable rhythms remain the pillars of ALS.