267.1 🎓 醫學生版

267.1.0.1 📌 一頁重點

267.1.0.1.1 Cardiac Arrest Definition

• Cessation of effective cardiac output with hemodynamic collapse
• Pulseless rhythms:
  • VF (ventricular fibrillation) — shockable
  • Pulseless VT — shockable
  • PEA (pulseless electrical activity) — non-shockable
  • Asystole — non-shockable

267.1.0.1.2 Epidemiology

• Out-of-Hospital Cardiac Arrest (OHCA): ~ 350,000/yr USA; ~ 7-9M deaths/yr globally
• In-Hospital Cardiac Arrest (IHCA): > 200,000/yr USA
• Survival rates:
  • OHCA: ~ 10% (better with bystander CPR + AED)
  • IHCA: ~ 25%
• Outcome predictors: time to CPR, time to defibrillation, witnessed arrest, initial rhythm (shockable = better), comorbidities

267.1.0.1.3 Chain of Survival

1. Early recognition + call for help (911)
2. Early CPR
3. Early defibrillation
4. Early advanced life support (ACLS)
5. Post-cardiac arrest care + integrated

267.1.0.1.4 High-Quality CPR Components

• Rate: 100-120 compressions/min
• Depth: ≥ 2 inches (5 cm) adult; at least 1/3 chest depth pediatric
• Full chest recoil between compressions
• Minimize interruptions (< 10 seconds for pulse check, < 5 seconds for defibrillation)
• 30:2 compression to ventilation ratio (adult lay rescuer)
• Continuous compressions + asynchronous ventilation if advanced airway placed

267.1.0.1.5 ACLS (Adult)

267.1.0.1.5.1 Shockable Rhythm (VF/Pulseless VT)

1. Immediate defibrillation (200 J biphasic; 360 J monophasic if available)
2. CPR for 2 minutes + rhythm check
3. Epinephrine 1 mg IV/IO q3-5 min (after second shock)
4. Amiodarone 300 mg IV bolus (after third shock; refractory VF/VT)
5. Repeat shocks + CPR + drugs
6. Treat reversible causes

267.1.0.1.5.2 Non-Shockable Rhythm (PEA/Asystole)

1. CPR for 2 minutes + rhythm check
2. Epinephrine 1 mg IV/IO q3-5 min
3. Treat reversible causes (Hs and Ts)
4. Continue until rhythm change or ROSC

267.1.0.1.6 Reversible Causes (Hs and Ts)

267.1.0.1.6.1 Hs

• Hypovolemia
• Hypoxia
• Hydrogen (acidosis)
• Hyperkalemia / Hypokalemia
• Hypothermia

267.1.0.1.6.2 Ts

• Tension pneumothorax
• Tamponade (cardiac)
• Toxins (drug overdose)
• Thrombosis (PE, MI)
• Trauma

267.1.0.1.7 Drugs in ACLS

267.1.0.1.7.1 Epinephrine

• 1 mg IV/IO q3-5 min during cardiac arrest
• α + β agonist
• Improves coronary + cerebral perfusion
• 2024 evidence: improves ROSC but neurologic outcomes mixed; remains standard

267.1.0.1.7.2 Amiodarone

• 300 mg IV bolus for refractory VF/pulseless VT
• 150 mg IV bolus if recurrent
• After third shock per ACLS

267.1.0.1.7.3 Lidocaine

• Alternative to amiodarone for shockable rhythms
• 1-1.5 mg/kg IV bolus
• 2020 AHA: lidocaine acceptable alternative to amiodarone

267.1.0.1.7.4 Magnesium

• For torsades de pointes (polymorphic VT)
• 1-2 g IV bolus
• Not routine for cardiac arrest

267.1.0.1.7.5 Vasopressin (No Longer Recommended)

• Removed from 2020 ACLS guidelines
• Epinephrine remains standard

267.1.0.1.7.6 Atropine (For Bradycardia, Not Cardiac Arrest)

• No longer recommended in PEA/asystole (removed 2010)

267.1.0.1.8 Defibrillation

• Energy: 200 J biphasic (or device-specific recommendation); 360 J monophasic
• Manual defibrillation vs AED
• AED (Automated External Defibrillator): simplified for lay rescuers; widely deployed in public areas
• Single shock with immediate CPR resumption (no stacked shocks per 2020 guidelines)

267.1.0.1.9 Airway Management

• Bag-valve-mask with 100% O2 initial
• Advanced airway:
  • Supraglottic airway (LMA, i-gel, King LT) — first-line in many cases
  • Endotracheal intubation — definitive
• Compress + ventilate ratio: 30:2 with BVM; continuous compressions with advanced airway + asynchronous breaths (10/min)

267.1.0.1.10 Post-Cardiac Arrest Care

267.1.0.1.10.1 Targeted Temperature Management (TTM)

• Cool to 32-36°C × 24 hr post-ROSC (for comatose patients)
• 2020 AHA: 32-36°C; cool 24 hours then gradual rewarming over 12-24 hr
• TTM2 trial (2021): targeted 33°C vs 36°C — no difference in mortality
• Current: avoid hyperthermia (clearly beneficial); specific target debated; some now recommend “fever avoidance” alone

267.1.0.1.10.2 Hemodynamic Management

• Target MAP > 65 (some > 80 in select)
• Norepinephrine first-line vasopressor
• Avoid hypotension

267.1.0.1.10.3 Coronary Angiography

• Suspected ischemic cause (e.g., ST elevation on post-arrest ECG, regional wall motion on echo, known CAD)
• Without ST elevation but high suspicion: angiography also considered (COACT trial — controversial)
• Early angiography for refractory VF/VT (consider ECPR + angiography)

267.1.0.1.10.4 Neurologic Prognostication

• Delayed (≥ 72 hours post-arrest) — avoid premature withdrawal
• Multimodal: clinical exam, EEG, neuroimaging, somatosensory evoked potentials, neuron-specific enolase, neuroimaging
• Avoid prognostication during sedation / hypothermia

267.1.0.1.10.5 Glucose Control

• Avoid hyperglycemia + hypoglycemia
• Target glucose 140-180 mg/dL typically

267.1.0.1.11 ECPR (Extracorporeal CPR)

• VA-ECMO during cardiac arrest
• For refractory VF/VT or witnessed arrest with appropriate criteria
• Bridge to interventional cardiology + neurologic recovery
• Limited centers + criteria
• Improved outcomes in selected patients

267.1.0.1.12 Pediatric CPR

• Compress depth: 1/3 chest depth
• Rate: 100-120/min
• Compression : ventilation 30:2 (single rescuer) or 15:2 (two rescuers)
• Vagal causes more common (oxygen first)
• Energy for shock: 2 J/kg first, 4 J/kg second + subsequent

267.1.0.1.13 Cardiac Arrest in Special Situations

267.1.0.1.13.1 Pregnancy

• Left lateral displacement of uterus (or supine with manual displacement)
• CPR with chest compressions slightly higher on sternum
• Emergency cesarean delivery within 4-5 minutes if no ROSC (perimortem cesarean)
• Anticoagulation considerations

267.1.0.1.13.2 Hypothermia

• “Not dead until warm and dead”
• Continue CPR + rewarm to 32-35°C minimum
• ECMO for severe

267.1.0.1.13.3 Drug Overdose

• Naloxone for opioid
• Sodium bicarbonate for TCA, salicylate
• Glucagon for β-blocker
• Calcium for CCB
• Toxin-specific approaches

267.1.0.1.13.4 PE Massive

• Consider thrombolysis (alteplase 50-100 mg IV)
• ECMO

267.1.0.1.13.5 Trauma

• Address bleeding + tension pneumothorax + tamponade
• ECMO

267.1.0.1.14 AED + Public Access

• Widely deployed in public areas (airports, schools, gyms, malls)
• Layperson use acceptable + recommended
• Voice-guided + visual instructions
• Improves bystander CPR + survival

267.1.0.1.15 Bystander CPR

• Hands-only CPR acceptable for laypeople (no ventilation needed if uncomfortable)
• Encouraged via dispatcher (telephone CPR)
• Improves OHCA outcomes
• Public education + training campaigns

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267.1.0.2 1️⃣ ACLS Algorithm Detail

267.1.0.2.1 Shockable Rhythm (VF/Pulseless VT)

267.1.0.2.1.1 Round 1

1. CPR + rhythm check + defibrillate (200 J biphasic)
2. CPR for 2 minutes
3. Rhythm check + defibrillate

267.1.0.2.1.2 Round 2

1. Continue CPR
2. Epinephrine 1 mg IV/IO
3. CPR for 2 minutes
4. Rhythm check + defibrillate

267.1.0.2.1.3 Round 3

1. Continue CPR
2. Amiodarone 300 mg IV bolus (or lidocaine 1-1.5 mg/kg)
3. CPR for 2 minutes
4. Rhythm check + defibrillate

267.1.0.2.1.4 Round 4+

1. Epinephrine 1 mg every 3-5 min
2. Amiodarone 150 mg (additional dose)
3. Treat reversible causes (Hs and Ts)
4. Consider extended interventions (ECPR, thrombolysis)

267.1.0.2.2 Non-Shockable Rhythm (PEA/Asystole)

1. CPR
2. Epinephrine 1 mg IV/IO as soon as possible
3. CPR for 2 minutes + rhythm check
4. Continue CPR + epinephrine q3-5 min
5. Treat reversible causes

267.1.0.2.3 Treat Reversible Causes (Hs and Ts) During CPR

Cause	Diagnosis	Treatment
Hypoxia	Pulse ox, ABG	Oxygen
Hypovolemia	History, JVD	IV fluids, blood
Hydrogen (acidosis)	ABG	Sodium bicarbonate (severe), correct underlying
Hyperkalemia	ECG (peaked T), labs	Calcium gluconate, insulin/glucose, bicarb
Hypokalemia	ECG (U waves), labs	KCl IV
Hypothermia	Temperature	Rewarming, ECMO
Tension pneumothorax	Decreased breath sounds, JVD, tracheal deviation	Needle decompression, chest tube
Tamponade	JVD, muffled sounds, pulsus paradoxus, FAST exam	Pericardiocentesis
Toxins	History, examination	Antidote (naloxone, glucagon, calcium, etc.)
Thrombosis (PE)	History, echo (RV strain, McConnell)	Thrombolysis, ECMO
Thrombosis (MI)	ECG, history	Coronary angiography + PCI
Trauma	History, exam	Address bleeding, surgical

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267.1.0.3 2️⃣ Post-Cardiac Arrest Care

267.1.0.3.1 Targeted Temperature Management (TTM)

267.1.0.3.1.1 Indications

• Comatose post-ROSC (initial post-arrest GCS < 8)
• From shockable rhythm initially
• Non-shockable rhythm also (variable)

267.1.0.3.1.2 Procedure

• Cool to 32-36°C × 24 hours
• Cooling methods: surface (cold blankets, ice packs) or invasive (cooling catheters)
• Rewarming over 12-24 hours
• Sedation + neuromuscular blockade to prevent shivering

267.1.0.3.1.3 Updated Evidence

• TTM2 trial (2021): 33°C vs 36°C — no difference in mortality at 6 months
• Many institutions now do “fever avoidance” (37.5°C target)
• Specific 33°C target controversial
• Avoid hyperthermia = clearly beneficial

267.1.0.3.2 Hemodynamic Management

• Target MAP > 65 mmHg
• Norepinephrine first-line vasopressor
• Avoid hypotension during prognostication period

267.1.0.3.3 Coronary Angiography

• Suspected ischemic cause:
  • ST elevation post-arrest
  • Regional wall motion abnormality on echo
  • Known CAD
• COACT trial (2018): early angiography in OHCA without ST elevation — no mortality benefit
• 2024 guidelines: angiography for selected patients with high suspicion

267.1.0.3.4 Neurologic Prognostication

267.1.0.3.4.1 Timing

• Delay ≥ 72 hours post-ROSC (or post-TTM)
• Avoid premature withdrawal
• Multimodal assessment

267.1.0.3.4.2 Methods

• Clinical exam (pupillary reflex, motor response, etc.)
• EEG (status epilepticus, suppression)
• Neuroimaging (CT, MRI — diffusion restriction)
• Somatosensory evoked potentials (SSEPs — bilateral absent N20 = poor prognosis)
• Neuron-specific enolase (elevated = poor prognosis)
• AI / quantitative EEG emerging

267.1.0.3.4.3 Withdraw of Life Support

• After multidisciplinary assessment + family discussion
• Use validated prognostic indicators (most reliable ≥ 72 hr)

267.1.0.3.5 Other Post-Arrest Care

• Glucose control (140-180 mg/dL)
• DVT prophylaxis
• Stress ulcer prophylaxis
• Address other organ dysfunction (renal, hepatic, etc.)

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267.1.0.4 3️⃣ ECPR (Extracorporeal CPR)

267.1.0.4.1 Definition

• VA-ECMO during cardiac arrest (refractory CPR)
• Bypasses heart + lungs

267.1.0.4.2 Indications

• Refractory cardiac arrest (no ROSC within 20-40 min)
• Witnessed arrest
• Initial shockable rhythm
• Younger age
• Reversible cause
• Limited comorbidities
• Specific institutional capability

267.1.0.4.3 Evidence

• ARREST trial (Yannopoulos 2020): ECPR superior in OHCA refractory cardiac arrest
• EuroELSO guidelines: support ECPR for select patients
• Increasing adoption in specialized centers

267.1.0.4.4 Procedure

• Cannulation while CPR continues
• Femoral cannulation common
• Hemodynamic support during interventions (coronary angiography, etc.)
• Bridge to ICU + recovery + transplant

267.1.0.4.5 Outcomes

• Survival 25-40% in select patients
• Significantly better than conventional CPR for refractory arrest
• Important: patient selection critical

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267.1.0.5 4️⃣ Special Situations

267.1.0.5.1 Pregnancy

• Manual left uterine displacement (or 30° tilt)
• Standard CPR + chest compression
• Perimortem cesarean within 4-5 minutes if no ROSC (significant for both mother + baby)
• Anticoagulation considerations
• BLS specific training

267.1.0.5.2 Hypothermia-Induced Arrest

• “Not dead until warm and dead”
• Continue CPR + active rewarming
• ECMO for severe (< 28°C with poor outcome on standard rewarming)

267.1.0.5.3 Drug Overdose

• Naloxone (opioid)
• Sodium bicarbonate (TCA, salicylate)
• Glucagon (β-blocker)
• Calcium (CCB)
• Insulin + euglycemic glucose (CCB severe)
• Toxin-specific approaches

267.1.0.5.4 Massive PE

• Thrombolysis: alteplase 50-100 mg IV
• ECMO if refractory
• Catheter-directed thrombolysis

267.1.0.5.5 Trauma

• ATLS principles
• Address bleeding + tension pneumothorax + tamponade
• ECMO bridge

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