Acute left ventricular failure Flashcards
What is acute left ventricular failure (LVF)?
Acute LVF occurs when an acute event causes the left ventricle to be unable to move blood efficiently through the heart and into the systemic circulation, leading to pulmonary oedema and impaired oxygenation.
What is the formula for cardiac output?
Cardiac output = Stroke volume x Heart rate.
What happens in pulmonary oedema due to acute LVF?
Pulmonary oedema occurs when blood cannot flow efficiently through the left heart, causing fluid leakage in the lungs, impairing gas exchange and causing shortness of breath.
What are some common triggers for acute LVF?
- Iatrogenic factors (e.g., aggressive IV fluids)
- Myocardial infarction
- Arrhythmias
- Sepsis
- Hypertensive emergencies
What is the typical presentation of acute LVF?
Symptoms include shortness of breath (worse lying flat, improves sitting up), cough with frothy sputum, and feeling unwell. Signs include raised respiratory rate, tachycardia, third heart sound, bilateral basal crackles, and hypotension.
What type of respiratory failure does acute LVF cause?
Acute LVF causes Type 1 respiratory failure (low oxygen without increased carbon dioxide).
What are additional signs of right-sided heart failure in acute LVF?
- Raised jugular venous pressure (JVP)
- Peripheral oedema (ankles, legs, sacrum)
What are key assessments in acute LVF?
- Clinical examination
- ECG
- Blood tests (e.g., BNP, troponin)
- ABG
- Chest x-ray
- Echocardiogram
What is the role of B-type natriuretic peptide (BNP) in assessing LVF?
BNP is released when the heart is overloaded. A raised BNP suggests heart failure but can also be elevated in other conditions such as sepsis or COPD.
What is the significance of an echocardiogram in acute LVF?
Echocardiography assesses left ventricular function and structural abnormalities. A key measure is the ejection fraction, with normal being above 50%.
What chest x-ray findings are common in acute LVF?
- Cardiomegaly
- Upper lobe venous diversion
- Bilateral pleural effusions
- Interlobar fissure fluid
- Kerley lines
What is the basic management mnemonic for acute LVF?
‘SODIUM’ – Sit up, Oxygen, Diuretics, Intravenous fluids stopped, Underlying causes treated, Monitor fluid balance.
What is the role of oxygen in acute LVF management?
Oxygen is given to patients with low oxygen saturation (below 95%) to improve gas exchange and oxygen levels.
What is the role of diuretics in acute LVF?
Diuretics like IV furosemide help reduce fluid overload, decreasing the volume of blood in circulation and easing the heart’s workload.
What are the indications for advanced treatments in severe acute LVF?
- Intravenous opiates
- Nitrates
- Inotropes (e.g., dobutamine)
- Vasopressors (e.g., noradrenaline)
- Non-invasive ventilation
- Invasive ventilation
What are inotropes and when are they used in acute LVF?
Inotropes increase the heart’s contractility to improve cardiac output and are used in low-output states like acute heart failure or after myocardial infarction.
What are vasopressors and when are they used in acute LVF?
Vasopressors, like noradrenaline, cause vasoconstriction to increase blood pressure and improve tissue perfusion, typically used in severe hypotension or shock.
