Course 03: Cardiovascular, Vascular and Hematology
Lesson 7 of 12. Read the diagnostic framework and case, then complete the 10-question practice set. All material is original educational content; high-risk presentations require emergency referral.
Recognize shock
- Shock is inadequate tissue perfusion; assess hypotension together with mental status, skin temperature, capillary refill, urine output and lactate trends.
- Distinguish cardiogenic, obstructive, distributive and hypovolemic shock; some patients present before BP falls.
- Cardiogenic shock may follow extensive MI, acute severe valvular dysfunction, arrhythmia or myocarditis.
- Obstructive causes include massive PE, tamponade and tension pneumothorax; each needs immediate cause-specific action.
Initial stabilization
- Activate emergency response, provide high-quality CPR if pulseless, secure airway/oxygenation as indicated and arrange appropriate monitoring.
- Obtain rhythm assessment promptly, but do not delay chest compressions for testing in confirmed arrest.
- Defibrillation is indicated for ventricular fibrillation/pulseless VT; asystole and PEA are nonshockable rhythms.
- Reversible arrest causes include hypoxia, hypovolemia, acidosis, potassium disorders, hypothermia, tamponade, tension pneumothorax, thrombosis and toxins.
Post-arrest and acute instability
- After return of spontaneous circulation, optimize oxygenation, ventilation, BP and identify the underlying cause, including ACS or PE.
- Treatment of unstable tachyarrhythmia versus stable arrhythmia requires trained emergency care and guideline-directed synchronized cardioversion or other measures.
- New chest pain with pulse deficit and abrupt tearing back pain suggests aortic dissection; do not delay transfer or prescribe reflexive anticoagulation.
- Pregnancy, pediatric age and major comorbidities may require distinct algorithms beyond this adult overview.
Anaphylaxis and mimics
- Anaphylaxis with hypotension and airway symptoms is distributive shock; rapid intramuscular epinephrine and emergency activation are first-line.
- Vasovagal faint may cause bradycardia with rapid recovery when supine; persistent dyspnea, wheeze, swelling or hypotension suggests an alternative emergency.
- Obtain help rather than attempting complex procedural management outside scope or available equipment.
Communication and handover
- Use a structured handover: symptoms/onset, vitals, ECG/rhythm, suspected etiology, interventions, response and known medications/allergies.
- Clarify roles for CPR, AED and calling emergency services; document precise time-sensitive events.
- Discuss prognosis and consent with patients/families when appropriate without delaying life-saving interventions.
Applied clinical case
A 61-year-old collapses and is unresponsive, apneic and pulseless; the AED identifies a shockable rhythm.
Show model clinical reasoning and disposition
Start high-quality CPR, deliver an AED shock promptly as instructed and resume CPR according to the 2025 adult resuscitation algorithms while emergency help arrives.
Clinical self-check
- Which arrest rhythms are shockable?
- Name reversible causes of PEA.
- Why is early defibrillation critical?
Guidelines and further learning
- AHA — 2025 Adult Advanced Life Support (external)
- AHA/ACC — 2025 Acute Coronary Syndromes Guideline (external)