Cardiology - Acute Left Ventricular Failure Flashcards
Why does acute left ventricular failure cause pulmonary oedema?
Blood unable to flow efficiently through left side of the heart
Backlog of blood in left atrium, pulmonary veins and lungs
Increased volume and pressure of blood causes there to be fluid leakage
Unable to remove excess fluid from surrounding tissues causing pulmonary oedema
What symptoms do patients with pulmonary oedema experience?
Shortness of breath
Reduced oxygen saturation
Lung tissue and alveoli becomes filled with interstitial fluid, interfering with gas exchange
What is the most common cause of acute left ventricular failure?
Decompensated chronic heart failure
What are some potential triggers of acute left ventricular heart failure?
Iatrogenic (IV fluid too aggressive in frail, elderly patient with impaired LV function)
MI
Arrhythmias
Sepsis
Hypertensive emergency
How does acute LVF present?
Shortness of breath
Exacerbated by lying flat and improved with sitting up
Causes type 1 respiratory failure
Cough with white frothy or pink sputum
What signs on examination will a patient acute left ventricular failure present with?
Raised respiratory rate
Reduced oxygen saturations
Tachycardia
3rd heart sound
Bilateral basal crackles
Hypotensive in severe cases (cardiogenic shock)
How should patients acute LVHF be assessed?
ECG
Bloods (BNP, troponin)
ABG
CXR
Echocardiogram
When is B-type natriuretic peptide released?
When there is distension of the myocardium, released from ventricles
What does it mean that BNP is sensitive but not specific?
Negative result rules out heart failure
Positive result can be due to other causes
What can cause a raised BNP?
Tachycardia
Sepsis
PE
Renal impairment
COPD
What does echocardiography assess?
Function and structural abnormalities in the heart
Why can upper lobe venous diversion be seen in acute left ventricular failure?
In acute LVF back pressure causes upper lobe veins to fill with blood and become engorged
What CXR findings can be found with acute LVF
Upper lobe diversion
Bilateral pleural effusions
Fluid in interlobar fissures
Fluid in septal lines (Kerley B lines)
How should a patient with acute LVF be managed?
SODIUM
Sit up
Oxygen
Diuretics
IV fluids stopped
Underlying causes treated
Monitor fluid balance
Why are patients sat up in acute LVF?
Helps oxygenate lungs
When lying flat fluid in the lungs spreads to a larger area
When upright fluid is at the lung bases allowing middle and upper areas to be clear for gas exchange
