Management of Acute Pulmonary Oedema / Heart Failure
Acute pulmonary oedema may be the first presentation of heart failure or an exacerbation of existing known heart failure. It also may be secondary to another cause e.g. atrial fibrillation (AF), other tachycardias or bradycardia, critical cardiac ischaemia, valvular disease or renal artery stenosis.
General management / drug treatment
- Sit patient upright and give 100% oxygen via facemask unless CO2 retention (see Guidelines for blood gas analysis for interpretation of blood gases).
- Consider slow titrated small increments of intravenous diamorphine or morphine if associated chest pain or severe distress. Also consider antiemetic. Do not give opiate if patient is drowsy, exhausted or hypotensive. Give: furosemide IV 50mg (or in patients already receiving oral diuretics, give, intravenously, double the patient's normal oral dose). Repeat bolus at 30 mins to 1 hour. Double dose at first repeat. If further diuretic required - refer immediately to senior medical staff.
- Glyceryl trinitrate IV. Commence at 0.5 mg/hour. Titrate according to BP but only if systolic BP >90mmHg (see local dosing charts for details).
- Consider continuous positive airway pressure (CPAP - see protocol below) or NIV if acidotic or poor response to furosemide and nitrates.
- Refer to senior medical staff and intensive care for consideration of intravenous inotropes or invasive ventilation.
N.B. Once the acute episode is resolved and the patient is more stable consider long-term management.
CPAP in cardiogenic pulmonary oedema
- CPAP can be considered in patients who have not responded to medical treatment. However, discuss this option with a senior.
- CPAP increases intrathoracic pressure, which reduces preload by decreasing venous return.
- CPAP lowers afterload by increasing the pressure gradient between the left ventricle and the extrathoracic arteries, which may contribute to the associated increase in stroke volume.
- Intubation should be considered in patients with persistent hypoxaemia on CPAP or persistent hypercapnia despite the administration of oxygen, morphine, diuretics, and vasodilators. In addition, intubation is required in the setting of apnoea or profound respiratory depression (respiratory rate <10bpm).
Contraindications to CPAP:
- Reduced conscious level (not responding to pain or unconscious on the AVPU scale: unable to protect airway therefore consider invasive ventilation)
- Dementia resulting in intolerance of therapy
- Systolic blood pressure <90mmHg
- Facial trauma / base of skull fracture
- Type II respiratory failure / severe emphysema
Complications of CPAP:
- Hypotension - CPAP increases mean intrathoracic pressure, reducing systemic venous return and cardiac output
- Aspiration - gastric contents may be aspirated due to large volumes of air being blown into the stomach
- Gastric distension - large volumes of air swallowed can overcome resistance of lower oesophageal sphincter
- Anxiety - hypoxia and tight fitting mask can induce anxiety and panic
When to stop CPAP:
Continue CPAP until chest clear of rales and haemodynamically stable. Initially wean airway pressure then wean supplemental oxygen and change to standard facemask. If there has been no clinical improvement after 30 minutes, CPAP should be stopped.