Cardiac emergencies (e.g. acute pulmonary oedema, cardiac arrest, cardiogenic shock, cardiac tamponade)for HKMLE according to davidson full important nothing missed full coverage notes with mnemonic and hk high yield also a quick cheat sheet and recent clinical guidelines on management and drawing table and result if necessary

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acute pulmonary edema cardiogenic shock management guidelines

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cardiac arrest resuscitation guidelines 2023 2024

Now let me read the key textbook sections in parallel:

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cardiogenic shock management guidelines 2024

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HKMLE cardiac emergencies high yield 2024 2025 acute pulmonary oedema cardiogenic shock cardiac arrest tamponade

Now let me get more specific Davidson's content and the cardiogenic shock management section:

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AHA ERC 2021 2023 CPR cardiac arrest algorithm BLS ACLS guidelines summary

Finding Sources

Searching the Web

2025 AHA cardiac arrest post-cardiac arrest care guidelines summary ROSC targeted temperature management

Now I have all the data needed. Let me compile the comprehensive HKMLE notes:

🫀 CARDIAC EMERGENCIES — HKMLE Complete Notes

Based on Davidson's Principles | Braunwald's | Goldman-Cecil | Rosen's EM | Harrison's 22E | 2025 Guidelines

📋 QUICK CHEAT SHEET — HKMLE HIGH YIELD AT A GLANCE

Emergency	Key Triad/Mnemonics	First Drug	Definitive Rx	Mortality
Acute Pulmonary Oedema	CPAP + Nitrate + Furosemide	GTN IV	Treat cause	~10–15%
Cardiac Arrest	4H + 4T reversible causes	Adrenaline 1mg IV	Defibrillation (VF/pVT)	~90% OOH
Cardiogenic Shock	SBP <90, CI <2.2, PCWP >18	Noradrenaline	PCI/revascularisation	30–50%
Cardiac Tamponade	Beck's Triad	IV fluids (temporise)	Pericardiocentesis	<10% in-hospital

1. ACUTE PULMONARY OEDEMA (APO)

🔵 Definition

Acute accumulation of fluid in the pulmonary interstitium and alveoli, causing severe respiratory failure. Most commonly cardiogenic (acute LV failure).

🔵 Causes — Mnemonic: "CHAMP"

Letter	Cause
C	Cardiac (ACS, hypertensive emergency, acute valvular regurgitation, arrhythmia)
H	Hypertension crisis (SCAPE = Sympathetic Crashing APO)
A	Acute MI / Aortic/Mitral regurgitation
M	Myocarditis / Mechanical complication of MI
P	Pulmonary causes (ARDS, neurogenic, high altitude, fluid overload)

🔵 Pathophysiology

↑ LV filling pressure → ↑ PCWP (>18–25 mmHg) → ↑ hydrostatic pressure in pulmonary capillaries → transudation across alveolar membrane → alveolar flooding → ↓ PaO₂ → hypoxia → further myocardial ischaemia → vicious cycle

🔵 Clinical Features — Mnemonic: "PAWNS"


P	Pink frothy sputum (pathognomonic)
A	Acute dyspnoea, orthopnoea, PND
W	Wheeze ("cardiac asthma"), crackles basal→apical
N	Nausea, sweating, cold/clammy skin
S	S3 gallop, tachycardia, ↑JVP

🔵 Investigations

Investigation	Finding
CXR	Cardiomegaly, upper lobe diversion, Kerley B lines, bat-wing shadowing, pleural effusions
ECG	LVH, ST changes, arrhythmia; identify precipitant
Echo	Assess LV function, wall motion, valves
Bloods	FBC, U&E, Troponin, BNP/NT-proBNP (↑↑), ABG
ABG	Type I respiratory failure initially (↓PaO₂, ↓/normal PaCO₂); Type II in severe/fatigue

🔴 HK High Yield: BNP >100 pg/mL = heart failure; NT-proBNP >300 pg/mL = decompensated HF. Used to distinguish cardiac vs. respiratory dyspnoea.

🔵 Management — Mnemonic: "LMNOP" (Classic Davidson's/HKMLE favourite)

Letter	Treatment
L	Lasix (Furosemide) 40–80 mg IV → reduce preload
M	Morphine 2–4 mg IV (↓ anxiey/preload — use with caution, ↓ respiratory drive)
N	Nitrates (GTN SL or IV infusion) — powerful venodilator; avoid if SBP <90 mmHg
O	Oxygen (high-flow) / CPAP/BiPAP (NI-PPV — Grade A evidence, ↓ intubation)
P	Posture (sit upright) + Pressure monitoring (arterial line, consider PA catheter)

2025 Evidence-Based Nuances:

SCAPE (hypertensive APO): GTN is first-line (bolus 600–1000 µg IV over 1–2 min or infusion 100–400 µg/min); furosemide is secondary
Normotensive APO: furosemide IV is cornerstone; GTN optional
Hypotensive APO: vasopressors/inotropes; avoid GTN; treat as cardiogenic shock
CPAP/NIPPV: reduces work of breathing, ↑ FRC, ↓ intubation rate — prefer over morphine
Morphine: historically used but 2023 evidence shows ↑ adverse outcomes; use with caution or avoid
If SBP <85 mmHg + APO → inotropes (dobutamine) + vasopressors (noradrenaline)

Specific Scenarios:

BP Status	Key Management
SBP >140 mmHg (SCAPE)	High-dose GTN IV + CPAP
SBP 100–140 mmHg (normotensive)	CPAP + furosemide IV + low-dose GTN
SBP <90 mmHg (shock)	Vasopressors + inotropes; treat as cardiogenic shock

🔴 HK High Yield: ECG + Troponin mandatory to rule out ACS as precipitant. Always check for STEMI — primary PCI takes priority.

2. CARDIAC ARREST

🔵 Definition

Abrupt loss of consciousness due to inadequate cerebral perfusion from failure of cardiac pump function.

🔵 Rhythms

Shockable	Non-Shockable
Ventricular Fibrillation (VF)	Asystole
Pulseless Ventricular Tachycardia (pVT)	Pulseless Electrical Activity (PEA)

🔴 Epidemiology: Most common OOH rhythm now = asystole (50%), VF/pVT ~25%, PEA ~25% (Braunwald's 2024). In-hospital VF/pVT = 33%; asystole + PEA = 61%.

🔵 Chain of Survival (AHA 2020/2025 — 6 Links)

Recognition + call for help
Early CPR (bystander)
Early defibrillation
Advanced life support (EMS/hospital)
Post-arrest care
Recovery (neurological + psychological — NEW 6th link 2020)

🔵 BLS Algorithm

Unresponsive + Not breathing normally
        ↓
Call EMS + Get AED
        ↓
CPR: 30 compressions : 2 breaths
Rate: 100–120/min | Depth: 5–6 cm | Full recoil
        ↓
AED arrives → Analyse rhythm
        ↓
Shockable? → SHOCK → Immediately resume CPR 2 min
Not Shockable? → CPR 2 min → re-analyse

🔵 ALS Algorithm (ACLS)

Cardiac Arrest
        ↓
Shockable (VF/pVT)?
        ↓ YES                    ↓ NO (Asystole/PEA)
Shock (200J biphasic)           CPR 2 min
CPR 2 min                       Adrenaline 1 mg IV ASAP
Adrenaline 1 mg q3–5 min         CPR 2 min
(after 3rd shock)               Re-analyse
Amiodarone 300 mg IV             Continue cycle
(after 3rd shock; 150 mg repeat) ↓
        ↓                    Consider reversible causes
After ROSC → Post-arrest care

🔵 Reversible Causes — Mnemonic: "4H + 4T" ⭐⭐⭐ (Most tested in HKMLE)

4H	4T
Hypoxia	Tension pneumothorax
Hypovolaemia	Tamponade (cardiac)
Hypo/Hyperkalaemia + metabolic	Toxins (drugs overdose)
Hypothermia	Thrombosis (PE or MI)

🔴 HK High Yield: 4H+4T always appears in HKMLE. PEA/Asystole → always think reversible causes.

🔵 Key Drug Doses — ACLS

Drug	Dose	Notes
Adrenaline (Epinephrine)	1 mg IV q3–5 min	All arrest rhythms; early for non-shockable
Amiodarone	300 mg IV bolus (then 150 mg)	VF/pVT after 3rd shock
Lignocaine (alternative)	1–1.5 mg/kg IV	If amiodarone not available
Sodium Bicarbonate	50 mmol IV	Hyperkalaemia, TCA overdose, prolonged arrest
Calcium Gluconate	10 mL 10% IV	Hyperkalaemia, Ca channel blocker OD
Magnesium	2 g IV	Torsades de Pointes, hypomagnesaemia
Atropine	NOT recommended in asystole (2020 guidelines)	Historical only

🔵 Post-Arrest Care (2025 AHA Guidelines — HK High Yield)

Domain	Recommendation
Airway	ETT + ETCO₂ monitoring (target 35–40 mmHg); avoid hyperventilation
Oxygenation	SpO₂ 94–98%; avoid hyperoxia (↑ free radicals); PaO₂ 75–100 mmHg
Blood Pressure	Maintain MAP ≥65 mmHg (2025 update — avoid hypotension)
Temperature Control	≥36 hours temperature control for unresponsive patients post-ROSC; target 32–37.5°C; prevent fever
Coronary Angiography	Immediate if STEMI post-arrest; not routinely for non-STEMI
Neuroprognosis	≥72 hours after ROSC before formal prognostication
Glucose	Maintain 6–10 mmol/L; avoid hypoglycaemia
Seizures	Treat with anticonvulsants; EEG monitoring

🔴 2025 Update: Head-to-pelvis CT post-ROSC is now reasonable to identify clinically significant diagnoses. MAP target simplified to ≥65 mmHg (not higher targets previously recommended).

Survival Predictors (HKMLE favourite)

Favourable	Unfavourable
Witnessed arrest	Unwitnessed arrest
Shockable rhythm (VF/pVT)	Asystole/PEA
Bystander CPR	Prolonged down time (>20 min)
Short time to defibrillation	Advanced age (weak predictor alone)
In-hospital arrest	OOH arrest

3. CARDIOGENIC SHOCK

🔵 Definition (Goldman-Cecil / Braunwald's)

Sustained systemic hypotension + end-organ hypoperfusion due to cardiac pump failure.

Haemodynamic Criteria (must know all 3):

Parameter	Value
Systolic BP	<90 mmHg (or >30 mmHg drop from baseline) for ≥30 min
Cardiac Index (CI)	<2.2 L/min/m²
Pulmonary Capillary Wedge Pressure (PCWP)	>18 mmHg

🔴 Mnemonic: "SBP 90, CI 2.2, PCWP 18" — three haemodynamic criteria

🔵 Causes — Mnemonic: "MATT CAP"


M	MI (large anterior MI — commonest cause; ~75% of cardiogenic shock)
A	Arrhythmia
T	Takotsubo / myocarditis
T	Tamponade (cardiac — obstructive but presents like cardiogenic)
C	Cardiomyopathy (decompensated)
A	Acute valvular (mitral regurgitation, aortic regurgitation)
P	Pulmonary embolism (massive, right heart failure)

Mechanical Complications of MI causing Cardiogenic Shock:

Acute mitral regurgitation (papillary muscle rupture)
Ventricular septal defect (VSD)
Free wall rupture → tamponade
Right ventricular infarction

🔵 Pathobiology — "Downward Spiral"

↓ Myocardial function
        ↓
↓ Stroke volume + ↓ CO + ↓ BP
        ↓
↓ Coronary perfusion pressure
        ↓
↑ Ischaemia → further ↓ myocardial function
        ↓
Death (if uncorrected)

Compensatory mechanisms: sympathetic activation → ↑ HR, ↑ contractility, vasoconstriction — but these increase O₂ demand and worsen ischaemia.

🔵 Clinical Assessment — "Warm/Cold + Wet/Dry" Matrix (Forrester Classification)

	Dry (PCWP normal)	Wet (PCWP ↑, congested)
Warm (perfused)	Normal (Class I)	Fluid overload (Class II)
Cold (hypoperfused)	Hypovolaemia/RV failure (Class III)	Cardiogenic Shock (Class IV)

🔴 HK High Yield: "Cold and Wet" = classic cardiogenic shock profile. "Cold and Dry" = consider RV infarction or tamponade.

Clinical Signs — Mnemonic: "HOCC"


H	Hypotension (SBP <90 mmHg)
O	Oliguria (<0.5 mL/kg/h)
C	Clouded sensorium/confusion
C	Cool, clammy, mottled extremities

🔵 SCAI Shock Classification (2024 ISHLT/ACC Guidelines — HK High Yield)

Stage	Description	Features
A — At Risk	No shock yet	ACS or decompensated HF
B — Beginning	Early shock	Mild hypotension, tachycardia
C — Classic	Clear shock	Hypotension + hypoperfusion (cold limbs, oliguria, lactate ↑)
D — Deteriorating	Worsening	Failing despite vasopressors/inotropes
E — Extremis	Collapse	Cardiac arrest or near-arrest

🔵 Investigations

Test	Findings
ECG	ST elevation, Q waves, arrhythmia
Echo (URGENT)	↓ EF, WMA, mechanical complications, pericardial effusion
CXR	Pulmonary oedema, cardiomegaly
Bloods	↑ Troponin, ↑ BNP, ↑ Lactate, ↑ Creatinine, metabolic acidosis
PA catheter	Haemodynamic confirmation (PCWP ↑, CI ↓)

🔵 Management

Step-by-step (HKMLE framework):

1. ABC + O₂ + IV access + monitoring
2. Identify + treat precipitant (ACS → PCI; arrhythmia → cardiovert)
3. Correct reversible factors (hypoxia, acidosis, hypovolaemia)
4. Vasopressors/inotropes
5. Mechanical Circulatory Support (MCS) if refractory
6. Revascularisation (PCI/CABG)

Pharmacological Support:

Drug	Role	Notes
Noradrenaline	Vasopressor of choice	↑ SVR; preferred over dopamine (↓ arrhythmias)
Dobutamine	Inotrope	↑ CO; use with vasopressor if SBP <70
Dopamine	Historical	Higher arrhythmia risk; less preferred 2024
Adrenaline	Refractory shock	↑ CO + ↑ SVR; risk of ↑ lactate
Vasopressin	Adjunct	Refractory vasoplegia

🚫 Avoid: β-blockers (acutely contraindicated), ACE inhibitors acutely, nitrates (↓ preload)

Mechanical Circulatory Support:

Device	Mechanism	Notes
IABP (Intra-aortic balloon pump)	↑ diastolic BP, ↓ afterload	NOT routinely recommended (IABP-SHOCK II trial)
Impella	Axial flow pump; LV offloading	Better haemodynamics than IABP; mortality benefit uncertain
VA-ECMO	Cardiopulmonary bypass	Refractory shock; "bridge to decision/transplant"
LVAD	Durable device	Destination therapy / bridge to transplant

Revascularisation (2025 ACC/AHA):

STEMI + shock: Immediate PCI regardless of symptom duration (Class I, Level B)
Multivessel PCI: Treat culprit lesion only initially (CULPRIT-SHOCK trial)
CABG: If PCI not feasible; complete revascularisation
Mechanical complications: Emergency surgery (VSD, acute MR, free wall rupture)

🔴 HK High Yield: Only ~25% patients are in shock at MI presentation; most develop shock over hours — early intervention prevents shock.

4. CARDIAC TAMPONADE

🔵 Definition

Compression of the heart by accumulating pericardial fluid → ↓ ventricular filling → ↓ CO.

🔵 Pathophysiology

The rate of fluid accumulation matters more than volume:

Acute (trauma, MI rupture): 150–200 mL can cause tamponade
Chronic (malignancy): 1000–2000 mL before tamponade develops

Three stages: (1) Fluid fills pericardial recesses → (2) Pericardium cannot stretch fast enough → (3) Pericardial pressure exceeds filling pressure → ↓ ventricular compliance → ↓ CO

🔵 Causes — Mnemonic: "MITIAN"


M	Malignancy (32%) — lung, breast, lymphoma, GI
I	Infection (24%) — TB, Staph, HIV
T	Trauma (penetrating > blunt)
I	Iatrogenic (15%) — post-cath, post-cardiac surgery, anticoagulants
A	Autoimmune / Acute MI (wall rupture 7%)
N	Non-specific / Idiopathic (16%) + Uraemic pericarditis

🔵 Clinical Features

Beck's Triad ⭐⭐⭐ (HKMLE favourite)


1️⃣	Hypotension (↓ CO)
2️⃣	Elevated JVP (↑ venous pressure, Kussmaul's sign — JVP rises on inspiration)
3️⃣	Muffled/distant heart sounds

⚠️ Beck's triad is complete in only ~30% of cases — do not rely on it alone.

Other Signs:

Pulsus paradoxus ⭐ (>10 mmHg fall in SBP on inspiration) — pathognomonic when >25 mmHg
Tachycardia (compensatory — last sign to fail before collapse)
Dyspnoea, anxiety, chest tightness
Ewart's sign (dullness beneath left scapula — large effusion)
Reflex tachycardia → hypotension → PEA arrest if untreated

🔵 Investigations

Test	Finding
ECG	↓ Voltage + Electrical alternans (pathognomonic — alternating QRS axis)
CXR	Enlarged cardiac silhouette ("water-bottle" heart) if >250 mL fluid
Echo (POCUS) ⭐	Best test — pericardial effusion + RV diastolic collapse (pathognomonic)
Cardiac cath	Equalisation of diastolic pressures (RA = RV = PCWP = PA diastolic)

ECG in Tamponade:

- ↓ Voltage (all leads)
- Sinus tachycardia
- Electrical alternans (beat-to-beat QRS axis variation) ← PATHOGNOMONIC
- PR depression (if pericarditis co-exists)

🔵 Management — Mnemonic: "FAVO-P"


F	Fluids IV (rapid bolus) — temporising measure to ↑ right-sided filling; limited benefit
A	Avoid mechanical ventilation if possible (positive pressure → ↓ cardiac filling → collapse)
V	Vasopressors (adrenaline/noradrenaline) — bridge to definitive treatment
O	Oxygen
P	Pericardiocentesis — definitive treatment ⭐

Pericardiocentesis:

Indication: haemodynamic compromise + ≥1 cm anterior fluid on echo
Approach: subxiphoid (most common); echo-guided preferred
Minimum: aspirate 15–50 mL → dramatic haemodynamic improvement
Fluid analysis: LDH, protein, cell count, cytology, PCR TB, culture
Indwelling catheter: ↓ recurrence
Surgical options: pericardial window (malignant/recurrent effusion), pericardiectomy

🚫 Avoid: Inotropes (already maximal endogenous adrenergic drive); positive pressure ventilation (unless unavoidable — can precipitate cardiac collapse)

Specific Scenarios:

Cause	Management
Haemorrhagic (trauma/aortic dissection)	Emergency surgery
Bacterial pericarditis	Surgery preferred (diagnostic + therapeutic)
Malignant effusion	Percutaneous balloon pericardial window
Recurrent benign	Pericardial window / pericardiectomy

🔴 Prognosis: In-hospital mortality <10% for non-malignant; ~75% subsequent mortality with malignant effusion

5. DIFFERENTIAL DIAGNOSIS TABLE — All 4 Emergencies

Feature	APO	Cardiac Arrest	Cardiogenic Shock	Tamponade
BP	↑↑ or ↓	Absent	↓↓ (<90)	↓ (narrow pulse pressure)
JVP	↑ (if LVF)	—	↑ (if RVF)	↑↑
Heart sounds	S3 gallop	Absent	S3, S4	Muffled/distant
Lung auscultation	Crackles + wheeze	Absent	Crackles	Clear (usually)
ECG	LVH, ST changes	VF/VT/asystole	ST elevation	Low voltage + alternans
Echo	↓EF, B-lines	No cardiac activity	↓EF, WMA	Effusion + RV collapse
BNP	↑↑↑	—	↑↑	Normal/↑
Pulsus paradoxus	Absent	—	Absent	Present >10 mmHg
Key Rx	CPAP + GTN + Frusemide	CPR + Defib	Vasopressors + PCI	Pericardiocentesis

6. COMPARISON: SHOCK TYPES (HKMLE Must Know)

Parameter	Cardiogenic	Distributive (Septic)	Hypovolaemic	Obstructive (Tamponade/PE)
CO/CI	↓↓	↑ (early), ↓ (late)	↓	↓
SVR	↑	↓	↑	↑
PCWP	↑ (>18)	↓	↓	↓ or ↑
JVP	↑	↓	↓	↑↑ (tamponade)
Skin	Cold, clammy	Warm, flushed	Cold	Cold
Fluid bolus	⚠️ Worsens	May help	Helps	Limited (tamponade)
Inotropes	Yes	Sometimes	No	No
Key Rx	Vasopressors + PCI	Antibiotics + vasopressors	IV fluids + haemostasis	Pericardiocentesis/thrombolysis

7. KEY MNEMONICS SUMMARY

Topic	Mnemonic
APO Treatment	LMNOP (Lasix, Morphine, Nitrates, O₂/CPAP, Position/Pressure)
APO Causes	CHAMP
Cardiac Arrest Reversible Causes	4H + 4T ⭐
Tamponade Clinical	Beck's Triad (hypotension + ↑JVP + muffled sounds)
Tamponade Causes	MITIAN
Tamponade Management	FAVO-P
Cardiogenic Shock Signs	HOCC (Hypotension, Oliguria, Confused, Cold)
Cardiogenic Shock Causes	MATT CAP
SCAI Stages	A B C D E (At-risk → Beginning → Classic → Deteriorating → Extremis)

8. 📊 MANAGEMENT ALGORITHM OVERVIEW

CARDIAC EMERGENCY
        │
        ├─→ CONSCIOUS + dyspnoea + pulmonary oedema?
        │          → APO: CPAP + GTN + Furosemide
        │
        ├─→ NO PULSE / NO BREATHING?
        │          → CARDIAC ARREST: CPR + Defibrillate + Adrenaline
        │          → Check 4H+4T reversible causes
        │
        ├─→ PULSE PRESENT + BP <90 + cold extremities + oliguria?
        │          → CARDIOGENIC SHOCK: Vasopressors + Echo + PCI
        │
        └─→ PULSE PRESENT + ↑JVP + hypotension + muffled sounds?
                   → TAMPONADE: IV fluids → Pericardiocentesis

9. 🎯 HKMLE HIGH-YIELD POINTS

APO: CPAP is Grade A evidence (↓ intubation, ↓ mortality). GTN = cornerstone in hypertensive APO. Morphine increasingly avoided.
Cardiac Arrest: 4H+4T — know all 8 causes; PEA = always think reversible. Adrenaline 1mg every 3–5 min throughout. Amiodarone after 3rd shock for VF/pVT.
Cardiogenic Shock: PCWP >18 + CI <2.2 + SBP <90 — all three criteria. Noradrenaline > dopamine. IABP is not routine (IABP-SHOCK II). PCI = survival benefit for STEMI-CS.
Tamponade: Echo with RV diastolic collapse = diagnostic. Electrical alternans = pathognomonic. Pericardiocentesis = life-saving. AVOID positive pressure ventilation.
Post-arrest care (2025): MAP ≥65 mmHg. Temperature control ≥36 hours. Avoid fever. CT head-to-pelvis now reasonable. Neuroprognostication ≥72h post-ROSC.
SCAI staging (A–E) now guides intensity of cardiogenic shock treatment in 2024–2025 guidelines.
Beck's Triad in tamponade — present in only ~30%; pulsus paradoxus + echo more sensitive.

10. 📐 QUICK REFERENCE TABLE — Drug Doses

Drug	Indication	Dose	Route
GTN	APO (hypertensive)	600–1000 µg bolus or 100–400 µg/min infusion	IV
Furosemide	APO (normotensive/congested)	40–80 mg (2× home dose if on chronic diuretics)	IV
Morphine	APO (use cautiously)	2–4 mg	IV slowly
Adrenaline	Cardiac arrest	1 mg q3–5 min	IV/IO
Amiodarone	VF/pVT (after 3rd shock)	300 mg bolus → 150 mg repeat	IV
Noradrenaline	Cardiogenic shock (vasopressor)	0.01–3 µg/kg/min	IV infusion
Dobutamine	Cardiogenic shock (inotrope)	2–20 µg/kg/min	IV infusion
Sodium bicarbonate	Hyperkalaemia, TCA OD, prolonged arrest	50 mmol (50 mL of 8.4%)	IV
Calcium gluconate	Hyperkalaemia	10 mL of 10%	IV
Magnesium	Torsades de Pointes	2 g over 10 min	IV

11. 📅 RECENT GUIDELINE SUMMARY (2023–2025)

Guideline	Key Update
2025 AHA Post-Arrest Care	MAP ≥65 mmHg; temperature control ≥36 h; head-to-pelvis CT reasonable; no high MAP targets
2025 ACC Expert Consensus — Cardiogenic Shock	SCAI staging guides MCS selection; Level 1 centres for refractory shock; avoid routine IABP
2024 ISHLT Consensus	Cardiogenic shock is a continuum (SCAI A–E); MCS intensity matches stage
2024/2025 ACC/AHA ACS	Primary PCI for STEMI+CS regardless of symptom duration (Class I,B); culprit-only PCI initially
2025 APO Management	SCAPE: GTN bolus first; CPAP/NIPPV preferred over morphine; morphine use cautious/avoid
ERC/AHA 2020 CPR	6-link Chain of Survival; atropine removed from asystole algorithm; early adrenaline for non-shockable

📚 Sources: Braunwald's Heart Disease (2024), Goldman-Cecil Medicine (2024), Rosen's Emergency Medicine (8e), Harrison's Principles 22E (2025), AHA 2025 Post-Cardiac Arrest Care Guidelines, ACC 2025 Cardiogenic Shock Expert Consensus, ISHLT 2024 Consensus, Jordan Cardiac Society APO 2025 GuidelinesHere is your complete, exam-ready coverage of all four cardiac emergencies for HKMLE — synthesised from Braunwald's, Goldman-Cecil, Harrison's 22E, Rosen's EM, and the latest 2025 guidelines.

🫀 CARDIAC EMERGENCIES — HKMLE Complete Notes

Davidson's | Braunwald's | Goldman-Cecil | Harrison's 22E | 2025 AHA/ACC/ISHLT Guidelines

⚡ QUICK CHEAT SHEET

Emergency	Diagnostic Triad/Criteria	First Rx	Definitive Rx	Mortality
Acute Pulmonary Oedema	Dyspnoea + crackles + pink frothy sputum	CPAP + GTN	Treat precipitant (PCI if ACS)	~10–15%
Cardiac Arrest	No pulse + no breathing	CPR + defibrillate	Adrenaline + amiodarone (VF/pVT)	~90% OOH
Cardiogenic Shock	SBP <90 + CI <2.2 + PCWP >18	Noradrenaline	PCI (STEMI-CS)	30–50%
Cardiac Tamponade	Beck's Triad + pulsus paradoxus	IV fluids (temporise)	Pericardiocentesis	<10% in-hospital

1. ACUTE PULMONARY OEDEMA (APO)

Definition

Acute flooding of pulmonary alveoli — most commonly cardiogenic (acute LV failure with PCWP >18–25 mmHg).

Causes — Mnemonic: "CHAMP"


C	Cardiac: ACS (STEMI/NSTEMI), acute valvular regurgitation, arrhythmia
H	Hypertensive emergency (SCAPE = Sympathetic Crashing APO)
A	Acute MI / Aortic or Mitral regurgitation
M	Myocarditis / Mechanical complication of MI
P	Pulmonary causes: ARDS, neurogenic, high altitude, fluid overload

Pathophysiology

↑ LV filling pressure → ↑ PCWP → ↑ pulmonary capillary hydrostatic pressure → transudation into alveoli → ↓ PaO₂ → hypoxia → further myocardial ischaemia → vicious cycle

Clinical Features — Mnemonic: "PAWNS"


P	Pink frothy sputum (pathognomonic)
A	Acute dyspnoea, orthopnoea, PND
W	Wheeze ("cardiac asthma") + bilateral crackles
N	Nausea, diaphoresis, cold/clammy skin
S	S3 gallop, tachycardia, ↑JVP

Investigations

Test	Finding
CXR	Cardiomegaly, upper lobe diversion, Kerley B lines, bat-wing perihilar shadowing, pleural effusions
ECG	LVH, ST changes, arrhythmia — identify precipitant
Echo	↓ EF, wall motion abnormalities, valvular pathology
BNP/NT-proBNP	BNP >100 pg/mL; NT-proBNP >300 pg/mL = acute HF
ABG	Type I RF (↓PaO₂, ↓PaCO₂) initially; Type II in exhaustion
Troponin	Mandatory — rule out ACS

🔴 HK High Yield: BNP differentiates cardiac from respiratory dyspnoea. ECG + Troponin mandatory — STEMI triggers immediate primary PCI (takes priority over other APO management).

Management — Mnemonic: "LMNOP" ⭐⭐⭐

Letter	Treatment
L	Lasix (Furosemide 40–80 mg IV; 1–2× home dose if on chronic diuretics)
M	Morphine 2–4 mg IV — use cautiously (↑ adverse outcomes in recent evidence; prefer CPAP)
N	Nitrates (GTN SL or IV) — venodilator; avoid if SBP <90 mmHg
O	Oxygen (SpO₂ target 94–98%) + CPAP/BiPAP (Grade A — ↓ intubation, ↓ mortality)
P	Posture (sit upright, legs dependent) + Precipitant treatment

2025 Evidence-Based Approach by BP:

BP Status	First-Line	Key Drug
SBP >140 mmHg — SCAPE	CPAP + high-dose GTN	GTN bolus 600–1000 µg IV, then infusion 100–400 µg/min
SBP 100–140 mmHg — Normotensive APO	CPAP + furosemide ± GTN	Furosemide 40–80 mg IV
SBP <90 mmHg — Shock	Vasopressors + inotropes	Noradrenaline + dobutamine; AVOID GTN

🔴 2025 Update: Morphine increasingly avoided (associated with worse outcomes in registry data). CPAP/NIPPV preferred. In SCAPE, GTN is first-line — furosemide is secondary.

2. CARDIAC ARREST

Definition

Abrupt loss of consciousness due to inadequate cerebral perfusion from failure of cardiac pump function.

Arrest Rhythms

Shockable	Non-Shockable
Ventricular Fibrillation (VF)	Asystole
Pulseless VT (pVT)	Pulseless Electrical Activity (PEA)

Epidemiology (Braunwald's): OOH — asystole 50%, VF/pVT ~25%, PEA ~25%. In-hospital — VF/pVT 33%, PEA+asystole 61%.

Chain of Survival — AHA 2020 (6 Links)

Recognition + emergency call
Early bystander CPR
Early defibrillation
Advanced life support
Post-arrest care
Recovery ← NEW 6th link (2020) — physical, cognitive, emotional

BLS Algorithm

Unresponsive + Not breathing normally
        ↓
Call EMS + Get AED
        ↓
CPR: 30 compressions : 2 breaths
Rate 100–120/min | Depth 5–6 cm | Full chest recoil
Minimise interruptions (<10 sec)
        ↓
AED → Analyse
  Shockable → Shock 200J (biphasic) → Immediately resume CPR
  Not shockable → CPR → Re-analyse every 2 min

ALS Algorithm (ACLS)

VF/pVT                              PEA/Asystole
   ↓                                    ↓
Shock (200J biphasic)           CPR 2 min + AIRWAY
CPR 2 min                       Adrenaline 1 mg IV ASAP
Adrenaline 1 mg IV              (repeat q3–5 min)
(after 3rd shock, q3–5 min)     Re-analyse every 2 min
Amiodarone 300 mg               Treat REVERSIBLE CAUSES
(after 3rd shock)
150 mg repeat dose
        ↓
     ROSC → Post-arrest care

Reversible Causes — "4H + 4T" ⭐⭐⭐ (Most tested HKMLE question)

4H	4T
Hypoxia	Tension pneumothorax
Hypovolaemia	Tamponade (cardiac)
Hypo/Hyperkalaemia + metabolic	Toxins (drug overdose)
Hypothermia	Thrombosis (PE or coronary)

PEA or Asystole with no obvious cause → always work through 4H+4T systematically.

Drug Doses — ACLS

Drug	Dose	Notes
Adrenaline	1 mg IV/IO q3–5 min	All arrest rhythms; early for non-shockable
Amiodarone	300 mg IV (then 150 mg)	VF/pVT after 3rd shock
Lignocaine	1–1.5 mg/kg IV	If amiodarone unavailable
Sodium bicarbonate	50 mmol IV	Hyperkalaemia, TCA OD, prolonged arrest
Calcium gluconate	10 mL of 10% IV	Hyperkalaemia, Ca-channel blocker OD
Magnesium	2 g IV over 10 min	Torsades de Pointes, hypomagnesaemia
~~Atropine~~	Removed from asystole algorithm (2020)	No longer recommended

Post-Arrest Care — 2025 AHA Guidelines (HK High Yield)

Domain	2025 Recommendation
Airway	ETT + waveform capnography (ETCO₂ 35–40 mmHg); avoid hyperventilation
Oxygenation	SpO₂ 94–98%; avoid hyperoxia (PaO₂ 75–100 mmHg)
Blood pressure	MAP ≥65 mmHg (new simplified target — higher targets not beneficial)
Temperature control	≥36 hours for unresponsive patients; target 32–37.5°C; prevent fever
Coronary angiography	Immediate if STEMI; not routinely for non-STEMI without ECG evidence
CT scanning	Head-to-pelvis CT post-ROSC now reasonable (new 2025)
Neuroprognosis	≥72 hours post-ROSC before formal prognostication
Glucose	6–10 mmol/L; avoid hypoglycaemia
Seizures	EEG monitoring + anticonvulsants
Survivorship	Structured emotional + psychological support before discharge (new 2025)

Survival Predictors

Favourable	Unfavourable
Witnessed arrest	Unwitnessed
Shockable rhythm (VF/pVT)	Asystole/PEA
Bystander CPR	Prolonged downtime (>20 min)
Short time to defibrillation	Advanced age (weak predictor alone)
In-hospital arrest	OOH arrest

3. CARDIOGENIC SHOCK

Definition

Haemodynamic syndrome — heart unable to maintain adequate tissue perfusion.

Diagnostic Criteria — all 3 required (Goldman-Cecil/Braunwald's):

Parameter	Threshold
Systolic BP	<90 mmHg (or >30 mmHg drop) for ≥30 min
Cardiac Index	<2.2 L/min/m²
PCWP	>18 mmHg

Mnemonic: "SBP 90 / CI 2.2 / PCWP 18"

Causes — Mnemonic: "MATT CAP"


M	MI — large anterior; commonest cause (~75%)
A	Arrhythmia
T	Takotsubo / myocarditis
T	Tamponade (obstructive shock pattern)
C	Cardiomyopathy (decompensated/fulminant)
A	Acute valvular disease (acute MR, aortic regurgitation)
P	Pulmonary embolism (massive, right heart failure)

Mechanical Complications of MI → Cardiogenic Shock:

Acute mitral regurgitation (papillary muscle rupture)
Ventricular septal defect (VSD)
Free wall rupture → tamponade
Right ventricular infarction

Pathobiology — "Downward Spiral"

↓ Myocardial function
        ↓
↓ Stroke volume → ↓ CO → ↓ BP
        ↓
↓ Coronary perfusion + ↑ diastolic LV pressure
        ↓
↑ Ischaemia → further ↓ myocardial function
        ↓
Death (unless cycle interrupted)

Sympathetic compensation (↑HR, vasoconstriction) increases O₂ demand → worsens ischaemia — therapy must interrupt this spiral.

Clinical Features — Mnemonic: "HOCC"


H	Hypotension (SBP <90)
O	Oliguria (<0.5 mL/kg/h)
C	Clouded sensorium
C	Cool, clammy, mottled extremities

Forrester/"Warm-Cold-Wet-Dry" Classification (HK High Yield)

	Dry (no congestion)	Wet (PCWP↑, congested)
Warm (perfused)	Normal	Volume overload — diurese
Cold (hypoperfused)	Hypovolaemia / RV failure	Cardiogenic Shock ←

"Cold + Wet" = classic cardiogenic shock. "Cold + Dry" = think RV infarction or tamponade.

SCAI Shock Staging — 2024 ISHLT/ACC (HK High Yield)

Stage	Description	Features
A — At Risk	No shock yet	ACS / decompensated HF, normal haemodynamics
B — Beginning	Early shock	Mild hypotension/tachycardia, compensated
C — Classic	Overt shock	Hypotension + cold limbs + oliguria + ↑ lactate
D — Deteriorating	Refractory	Failing despite initial vasopressors/inotropes
E — Extremis	Collapse	Cardiac arrest or near-arrest

Investigations

Test	Findings
ECG	ST elevation, Q waves, arrhythmia
Echo (URGENT)	↓ EF, wall motion abnormality, mechanical complications, effusion
CXR	Pulmonary oedema, cardiomegaly
Bloods	↑ Troponin, ↑ BNP, ↑ Lactate (>2 mmol/L), ↑ Creatinine, metabolic acidosis
PA Catheter	PCWP >18, CI <2.2 (confirms diagnosis, guides therapy)

Management

Step-by-Step Framework:

1. ABC + high-flow O₂ + IV access (2 large bore) + continuous monitoring
2. Urgent echo → identify precipitant
3. Correct reversibles: hypoxia, acidosis, arrhythmia, hypovolaemia
4. Vasopressors + inotropes
5. Reperfusion (PCI/CABG) — STEMI: immediate; non-STEMI: urgent
6. Mechanical Circulatory Support (MCS) if Stage C-E
7. Specialist centre transfer if refractory (Level 1 Shock Centre)

Pharmacological Support:

Drug	Role	Dose	Notes
Noradrenaline	Vasopressor of choice	0.01–3 µg/kg/min	↑ SVR; preferred over dopamine (less arrhythmia)
Dobutamine	Inotrope	2–20 µg/kg/min	↑ CO; add if SBP <70 despite vasopressors
Dopamine	Historical	—	Higher arrhythmia risk; less preferred 2024
Adrenaline	Refractory shock	0.05–1 µg/kg/min	↑ CO + ↑ SVR; risk of ↑ lactate
Vasopressin	Adjunct	0.03–0.04 U/min	Refractory vasoplegia

🚫 Avoid: β-blockers (acutely), ACEi/ARB (acutely), nitrates (↓ preload worsens shock)

Mechanical Circulatory Support (MCS):

Device	Mechanism	Current Evidence
IABP	↑ diastolic BP, ↓ afterload	NOT routinely recommended (IABP-SHOCK II trial — no mortality benefit)
Impella	Axial flow pump; LV unloading	Better haemodynamics than IABP; mortality benefit in AMI-CS uncertain
VA-ECMO	Full cardiopulmonary support	Refractory shock; bridge to recovery/transplant; ↑ LV afterload (consider LV vent)
LVAD	Durable mechanical support	Destination therapy / bridge to transplant

Revascularisation — 2025 ACC/AHA:

STEMI + cardiogenic shock: Immediate PCI regardless of symptom duration (Class I, Level B) ← HK High Yield
Multivessel disease: Culprit-only PCI initially (CULPRIT-SHOCK trial); staged PCI later
CABG: If PCI not feasible; provides complete revascularisation; surgical mortality 20–50%
Mechanical complications (VSD, acute MR, free wall rupture): Emergency surgery

🔴 Key stat: Only 25% are in shock at MI presentation — most develop shock over hours. Early treatment prevents shock progression.

4. CARDIAC TAMPONADE

Definition

Compression of cardiac chambers by accumulating pericardial fluid → ↓ ventricular filling → ↓ CO → haemodynamic compromise.

Pathophysiology

Rate of accumulation > volume determines severity:

Acute (trauma, MI rupture): 150–200 mL → tamponade
Chronic (malignancy): 1000–2000 mL before tamponade
Three stages: (1) fluid fills pericardial recesses → (2) pericardium cannot stretch → (3) pericardial pressure exceeds ventricular filling pressure → ↓ CO

Causes — Mnemonic: "MITIAN"


M	Malignancy 32% (lung, breast, lymphoma, GI)
I	Infection 24% (TB, Staph, streptococcus, HIV)
T	Trauma (penetrating: stab wound, catheter; blunt)
I	Iatrogenic 15% (post-cath, post-cardiac surgery, anticoagulants)
A	Autoimmune / Acute MI wall rupture (7%)
N	Non-specific / Nephrotic (uraemic pericarditis 4%); idiopathic 16%

Clinical Features

Beck's Triad ⭐⭐⭐ (present in ~30% of cases)

Hypotension (↓ CO)
Elevated JVP / distended neck veins
Muffled/distant heart sounds

Other Key Signs:

Pulsus paradoxus ⭐ — >10 mmHg fall in SBP on inspiration (normal <10); >25 mmHg is pathognomonic
Tachycardia — compensatory, last sign to deteriorate
Kussmaul's sign — JVP rises on inspiration (also seen in constrictive pericarditis)
Dyspnoea, anxiety, presyncope, chest discomfort
Ewart's sign — dullness beneath left scapula (large effusion)

⚠️ Beck's Triad complete in only ~30%. Rely on Echo + pulsus paradoxus.

Investigations

Test	Pathognomonic Finding
Echo (POCUS) ⭐	RV diastolic collapse (first sign); RA systolic collapse; swinging heart; IVC plethora
ECG	Electrical alternans (beat-to-beat QRS axis change) + sinus tachycardia + ↓ voltage
CXR	"Water-bottle" enlarged cardiac silhouette (only if >250 mL)
Cardiac catheterisation	Equalisation of diastolic pressures (RA = RV = PCWP = PAD)

ECG Features in Tamponade:

✓ Low voltage in all leads
✓ Sinus tachycardia
✓ Electrical alternans ← PATHOGNOMONIC
✓ PR depression (if pericarditis co-exists)

Management — Mnemonic: "FAVO-P"


F	Fluids IV rapid bolus — ↑ right-sided preload, temporises; limited benefit
A	Avoid positive pressure ventilation (IPPV) if at all possible — ↓ cardiac filling → collapse
V	Vasopressors (noradrenaline/adrenaline) — bridge to pericardiocentesis
O	Oxygen
P	Pericardiocentesis — DEFINITIVE TREATMENT

Pericardiocentesis — Technique:

Indication: haemodynamic compromise + ≥1 cm anterior fluid on echo throughout diastole
Approach: subxiphoid (most common); echo-guided preferred (real-time)
Even 15–50 mL aspiration → dramatic haemodynamic improvement
Fluid analysis: LDH, protein, cell count, cytology, PCR TB, culture (bacteria + TB)
Indwelling catheter: ↓ recurrence risk

Specific Scenarios:

Cause	Preferred Treatment
Haemorrhagic (trauma/aortic dissection)	Emergency surgery
Bacterial pericarditis	Surgery (diagnostic + drainage)
Malignant effusion	Percutaneous balloon pericardial window
Recurrent benign effusion	Surgical pericardial window or pericardiectomy

🚫 Avoid inotropes — already maximal endogenous adrenergic stimulation. Avoid IPPV — precipitates acute cardiovascular collapse.

Prognosis: In-hospital mortality <10% (non-malignant); subsequent mortality ~75% (malignant effusion) vs. 3–5%/year (other causes).

5. COMPARISON TABLE — All 4 Emergencies

Feature	APO	Cardiac Arrest	Cardiogenic Shock	Tamponade
Consciousness	Distressed	Absent	Confused/drowsy	Anxious/presyncope
BP	↑↑ or ↓	Absent	↓↓ (<90)	↓ + narrow pulse pressure
JVP	↑	—	↑ (if RV congestion)	↑↑
Heart sounds	S3 gallop	Absent	S3, S4	Muffled/distant
Lungs	Crackles + wheeze	Absent	Crackles	Clear (usually)
ECG	LVH, ST changes	VF/VT/asystole/PEA	ST elevation	Low voltage + electrical alternans
Echo	↓EF, B-lines	No activity	↓EF, WMA	Effusion + RV collapse
BNP	↑↑↑	—	↑↑	Normal/↑
Pulsus paradoxus	Absent	—	Absent	>10 mmHg ← diagnostic
Key Rx	CPAP + GTN + Furosemide	CPR + Defib + Adrenaline	Vasopressors + PCI	Pericardiocentesis

6. SHOCK DIFFERENTIAL TABLE

Parameter	Cardiogenic	Septic/Distributive	Hypovolaemic	Obstructive (Tamponade)
CO/CI	↓↓	↑ early / ↓ late	↓	↓
SVR	↑	↓	↑	↑
PCWP	↑ (>18)	↓	↓	↓
JVP	↑	↓	↓	↑↑
Skin	Cold, clammy	Warm, flushed	Cold	Cold
Fluid bolus	⚠️ Worsens	May help	Helps	Limited
Inotropes	Yes	Sometimes	No	No
Key Rx	Vasopressors + PCI	Antibiotics + vasopressors	Fluids + haemostasis	Pericardiocentesis

7. ALL MNEMONICS SUMMARY

Topic	Mnemonic
APO treatment	LMNOP (Lasix, Morphine, Nitrates, O₂/CPAP, Position/Precipitant)
APO causes	CHAMP
Cardiac arrest reversible causes	4H + 4T ⭐⭐⭐
Tamponade signs	Beck's Triad (Hypotension + ↑JVP + Muffled sounds)
Tamponade causes	MITIAN
Tamponade management	FAVO-P
Cardiogenic shock signs	HOCC (Hypotension, Oliguria, Confused, Cold)
Cardiogenic shock criteria	SBP 90 / CI 2.2 / PCWP 18
Cardiogenic shock causes	MATT CAP
APO presentation	PAWNS
SCAI staging	A B C D E (At-risk → Beginning → Classic → Deteriorating → Extremis)

8. DECISION ALGORITHM

CARDIAC EMERGENCY
        │
        ├─→ CONSCIOUS + dyspnoea + crackles + pink sputum?
        │           → APO: CPAP + GTN (if BP>90) + Furosemide
        │           → ECG → STEMI? → Primary PCI
        │
        ├─→ NO PULSE + NO BREATHING?
        │           → CARDIAC ARREST
        │           → CPR + Defibrillate (if VF/pVT)
        │           → Adrenaline 1mg q3–5 min
        │           → Amiodarone 300mg after 3rd shock (VF/pVT)
        │           → Work through 4H + 4T
        │
        ├─→ PULSE PRESENT + SBP <90 + cold limbs + oliguria?
        │           → CARDIOGENIC SHOCK
        │           → Echo URGENT → identify cause
        │           → Noradrenaline ± Dobutamine
        │           → PCI if STEMI-CS
        │
        └─→ PULSE PRESENT + ↑JVP + hypotension + muffled sounds?
                    → CARDIAC TAMPONADE
                    → IV fluid bolus (temporise)
                    → Echo-guided pericardiocentesis

9. DRUG DOSES — Quick Reference

Drug	Indication	Dose	Route
GTN	APO (hypertensive/normotensive)	600–1000 µg bolus → 100–400 µg/min infusion	IV
Furosemide	APO (congested)	40–80 mg (2× home dose)	IV
Morphine	APO (caution)	2–4 mg slowly	IV
Adrenaline	Cardiac arrest	1 mg q3–5 min	IV/IO
Amiodarone	VF/pVT (post 3rd shock)	300 mg → 150 mg	IV
Noradrenaline	Cardiogenic shock	0.01–3 µg/kg/min	IV infusion
Dobutamine	Cardiogenic shock (inotrope)	2–20 µg/kg/min	IV infusion
Sodium bicarbonate	Hyperkalaemia / TCA OD	50 mmol	IV
Calcium gluconate	Hyperkalaemia / Ca-blocker OD	10 mL of 10%	IV
Magnesium	Torsades de Pointes	2 g over 10 min	IV

10. RECENT GUIDELINES — 2023–2025 Summary

Guideline	Key Updates
2025 AHA Post-Cardiac Arrest Care	MAP ≥65 mmHg; temperature control ≥36 h; head-to-pelvis CT reasonable; no benefit to higher MAP targets; structured survivorship support
2025 ACC Expert Consensus — Cardiogenic Shock	SCAI staging guides MCS selection; Level 1 centres for refractory shock; avoid routine IABP; "Shock Team" concept
2024 ISHLT Consensus	Shock is a continuum (SCAI A–E); match MCS intensity to shock stage; anticoagulation mandatory with Impella/ECMO
2025 ACC/AHA ACS Guidelines	Primary PCI for STEMI+CS regardless of symptom duration (Class I, B); culprit-only PCI initially; β-blockers contraindicated in shock
2025 APO Management	SCAPE: GTN bolus first; CPAP/NIPPV preferred over morphine; morphine use cautious
AHA/ERC 2020 CPR	6-link Chain of Survival; atropine removed from asystole algorithm; early adrenaline for non-shockable rhythms; IV access preferred over IO

Sources: Braunwald's Heart Disease (2024), Goldman-Cecil Medicine (2024), Harrison's Principles 22E (2025), Rosen's Emergency Medicine (8e), Tintinalli's Emergency Medicine, AHA 2025 Post-Cardiac Arrest Care (Circulation), ACC 2025 Cardiogenic Shock Expert Consensus (JACC), ISHLT 2024 Consensus, Jordan Cardiac Society APO 2025 Review

I feel it’s double the content am I right please fix it if so.

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