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

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

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

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

Here 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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