Managing acute pulmonary oedema

Abstract

Acute pulmonary oedema has a high mortality.It requires emergency management and usually admission to hospital.The goals of therapy are to improve oxygenation, maintain an adequate blood pressure for perfusion of vital organs, and reduce excess extracellular fluid.The underlying cause must be addressed.There is a lack of high-quality evidence to guide the treatment of acute pulmonary oedema.The strongest evidence is for nitrates and non-invasive ventilation.Diuretics are indicated for patients with fluid overload.Furosemide (frusemide) should be given by slow intravenous injection.Routine use of morphine is not recommended because of its adverse effects.Oxygen should only be administered in cases of hypoxaemia.Inotropic drugs should only be started when there is hypotension and evidence of reduced organ perfusion.In these cases, dobutamine is usually first-line treatment.The drugs used in treatment include nitrates, diuretics, morphine and inotropes.Some patients will require ventilatory support.A working algorithm for the management of acute pulmonary oedema in the prehospital setting is outlined in the Figure. NitratesDespite the widespread use of nitrates in acute pulmonary oedema, there is a lack of high-quality evidence to support this practice.When nitrates have been compared to furosemide (frusemide) and morphine, or furosemide alone, there has been no difference in efficacy for outcomes such as the need for mechanical ventilation, change in blood pressure or heart rate, and myocardial infarction. 16e mechanism of nitrate action is smooth muscle relaxation, causing venodilatation and consequent preload reduction at low doses. 13Higher doses cause arteriolar dilatation, resulting in reduced afterload and blood pressure.Specifically in the coronary arteries, this dilatation results in increased coronary blood flow. 9These actions collectively improve oxygenation and reduce the workload of the heart. 13 general practice nitrates can be given sublingually.Hospitals may use infusions as intravenous administration is preferred due to the speed of onset and the ability to titrate the dose (Table 1). 8,13trates are associated with hypotension and therefore blood pressure monitoring is essential to ensure the systolic blood pressure is maintained above 90 mmHg. 8,13They should not be given if the