A 78-year-old woman presents with a four-hour history of severe dyspnoea. This is present at rest but worse on lying down and with exertion. She was discharged from the coronary care unit three weeks ago following a myocardial infarction.
On examination, she has fine bibasal crepitus and pitting ankle oedema.
Observations:
Pulse: 104 bpm
BP: 126/88 mmHg
Respiratory rate: 28/min
Temperature: 36.8ºC
Oxygen saturations: 92% on room air
Her chest X-ray shows bilateral fluffy opacification with Kerley-B lines.
You make a working diagnosis of acute heart failure and give her 15L high flow oxygen and IV furosemide. A repeat chest X-ray shows no improvement.
What is the next best management step?
Continuous positive airway pressure (CPAP)