EM Notes – Acute Heart Failure / Cardiogenic Shock

Definition

Cardiac index < 1.8L/min/m2

Classification

Killip ranking of heart failure originally done for 30-day mortality post-MI

  1. Asymptomatic 5% mortality
  2. Mild–mod (S3/creps) 15-20% mortality
  3. APO 40% mortality
  4. Moribund/shocked 80% mortality

New York Heart Association (NYHA)

  1. I – Symptoms on abnormal exertion
  2. II – Symptoms on ordinary activity
  3. III – Symptoms on less-than-usual activity
  4. IV – Symptoms at rest

Causes

High output (Rare)

  1. Fever, anaemia, AV fistula or malformation, thyrotoxicosis, beriberi (Thiamine [B1] deficiency), Paget’s disease

Low output

  1. Mechanical:
    1. Valve lesions, tumours, tamponade. Congenital abnormalities
  2. Myocardial:
    1. Ischaemia/infarct, Toxins (colchicine, alcohol, negative inotropes, metabolic disturbances, chemotherapeutics), cardiomyopathy
  3. Pressure related:
    1. HT, massive PE

Systolic failure (impaired ability to contract, LV Ejection Fraction<0.45):

  1. IHD
  2. Severe systemic HTN
  3. Valve disorders – congenital, 2° to papillary mm. dysfunction, Rh Fever, endocarditis
  4. ASD, VSD
  5. AI, MS
  6. LA tumour
  7. HOCM, other cardiomyopathies

Diastolic failure (impaired ability to fill in diastole):

  1. Mainly HT
  2. Also HOCM, aortic stenosis, restrictive cardiomyopathy, infiltrative disease – sarcoid

Arrhythmias

  1. AF, SVT, VT

Right Ventricular failure

  1. LVF, RV MI, PE/COPD, pulm valve disease, TR, congenital L→R shunts

Assessment

History

  1. Asymptomatic (80%)
  2. Dyspnoea (SOB, SOBOE), orthopnoea/PND, peripheral oedema/RUQ pain/anorexia if RVF
  3. Precipitants – ischaemia, arrhythmias, infection, anaemia, poor compliance, COPD, drug effects, PE, thyrotoxicosis, pregnancy

Examination

  1. Relative tachy, displaced apex, S3/S4, 2° TR or MR
  2. LVF – ↑RR, fine insp creps, rising from base, cardiac asthma, pleural effusions
  3. RVF – ↑JVP, Kussmaul’s sign, hepatomegaly, ascites, peripheral oedema & pleural effusions

Investigations

  1. Bloods:
    1. FBC, UEC, Cardiac markers, BNP (LVF release>RVF, <100pg/ml = HF unlikely, >500pg/ml = likely. Often equivocal. False pos from DDx of HF incl PE, RF, AF & sepsis limits use in ED.)
  2. ECG:
    1. for arrhythmias / IHD / LBBB
  3. Imaging:
    1. CXR (↑CTR, Kerley B’s, pulm oedema). Echo
  4. Special:
    1. Bioimpedance CO monitoring, TFT if indicated

DDx

  1. COPD/Asthma
  2. Non-cardiogenic pulm oedema
  3. Sepsis

Management

Priorities

  1. Pulm oedema – maintain oxygenation
  2. Hypotension – fluid Mx & inotropes
  3. Ischaemia – reperfusion strategies
  4. Treat underlying cause if possible
  5. RVF – non-urgent oedema reduction

Oxygenation

  1. Sit upright (↑lung vent) +/- legs over side of bed (venous return/preload)
  2. High flow O2
  3. CPAP 10mmHg/BiPAP 15/5mmHg
  4. IPPV if NIPPV fails or GCS<9, unprotected airway

Haemodynamic – IVC & consider invasive monitoring if shocked.

  1. NitratesGTN 150-300mcg sl or infusion (start 300mcg/hr & titrate up to 2-12mg/hr). ↓pre- & after-load & coronary dilation/perfusion. Beware ↓BP, RVF, HOCM, AS.
  2. Fluid – restrict in overload; careful challenge if shock & no APO: 100-250ml 0.9% saline.
  3. Inotropes – if BP ok: dobutamine 2-20mcg/kg/min IV. If ↓BP: **dopamine 2-20mcg/kg/min. Even adrenaline or **NA 0.5-30mcg/min (0.02-1mcg/kg/min) but ↑myocardial O2 demand
  4. Diureticsfrusemide 40mg IV or 1-2x usual dose. Not 1st line – consider if fluid overload
  5. PCI – if AMI present (or thrombolysis if PCI not avail/CI)
  6. Treat arrhythmias – medical Rx or DC shock
  7. Mechanical support – intra-aortic balloon pump
  8. Digoxin, ACEI, statin, thrombosis prophylaxis, ±β-blocker (carvedilol) for chronic therapy
  9. Morphine 0.5-2.5mg IV – once a std Rx, now increasingly controversial with questions over haemodynamic effects and reports of poorer outcomes. Considered in low doses as anxiolytic if very agitated, BUT risk of resp depression. Fentanyl a possible alternative.
  10. Nesiritide – recomb DNA BNP – probably useless and ?assoc with ↑mortality

Prognosis

  1. 50% mort post APO episode
  2. F>M
  3. Annual mort NYHA Class II – 10%, III – 20%, IV – 40%
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