What is the treatment for acute pulmonary edema?

Treatment for Acute Pulmonary Oedema

Begin immediately with high-dose intravenous nitrates (not low-dose) combined with low-dose furosemide and non-invasive positive pressure ventilation (CPAP or BiPAP), as this combination is superior to high-dose diuretics alone and reduces both mortality and intubation rates. 1

Immediate Respiratory Support (First Priority)

Apply non-invasive positive pressure ventilation (CPAP or BiPAP) immediately as the primary intervention before considering endotracheal intubation. 2, 1

• Both CPAP and BiPAP are equally effective and carry strong evidence for reducing mortality (RR 0.80) and need for intubation (RR 0.60) 2, 1
• These modalities improve oxygenation, decrease left ventricular afterload, and reduce respiratory muscle work 2
• CPAP settings: 5-15 cm H₂O 3
• BiPAP settings: inspiratory pressure 8-20 cm H₂O, expiratory pressure 4-10 cm H₂O 3
• Pre-hospital application of CPAP/BiPAP reduces intubation need even further (RR 0.31) 2, 4
• Avoid CPAP in patients with systolic blood pressure <90 mmHg 4

Initial Pharmacological Treatment

High-Dose Nitrates (First-Line Pharmacotherapy)

Start with sublingual nitroglycerin 0.4-0.6 mg, repeated every 5-10 minutes up to four times, then immediately transition to intravenous infusion if systolic blood pressure remains ≥95-100 mmHg. 2, 1

• Initial IV dose: 20 mcg/min, increase up to 200 mcg/min according to hemodynamic tolerance 1
• Alternative starting dose: 0.3-0.5 μg/kg/min 2, 1
• Titrate aggressively to the maximum hemodynamically tolerable dose, aiming for 10 mmHg reduction in mean blood pressure or systolic blood pressure of 90-100 mmHg 2, 1
• Check blood pressure every 3-5 minutes during titration 1
• Never use low-dose nitrates—this is a critical error that leads to treatment failure 1
• Nitrates relieve pulmonary congestion without compromising stroke volume, particularly beneficial in acute coronary syndrome 5
• Warning: Tolerance develops rapidly within 16-24 hours of continuous high-dose IV infusion 1

Low-Dose Furosemide (Always Combined with Nitrates)

Administer furosemide 40 mg IV as initial bolus (over 1-2 minutes), never as monotherapy. 1, 6

• If inadequate response after 1 hour, increase to 80 mg IV 1, 6
• For patients already on chronic oral diuretics, use a dose at least equivalent to their oral dose 1
• Critical warning: Furosemide transiently worsens hemodynamics during the first 1-2 hours (increases systemic vascular resistance, increases left ventricular filling pressures, decreases ejection fraction) 1
• Never use high-dose diuretics in monotherapy—this is associated with worsening hemodynamics and increased mortality 1
• Aggressive diuresis is associated with worsening renal function and increased long-term mortality 1

Morphine (Adjunctive Therapy)

Consider morphine 3-5 mg IV in the early stage for patients with severe acute heart failure, particularly when associated with restlessness and dyspnoea. 5, 4

• Morphine induces venodilatation, mild arterial dilation, and reduces heart rate 5
• Dosing can be repeated if required 5
• Avoid morphine in patients with respiratory depression or severe acidosis 4

Oxygen Therapy

Administer oxygen only to hypoxemic patients with SpO₂ <90%. 2, 1

• Avoid routine oxygen in non-hypoxemic patients as it causes vasoconstriction and reduces cardiac output 2, 1
• Position patient in upright/semi-upright position to decrease venous return and improve ventilation 2, 4

Invasive Mechanical Ventilation (Reserved for Failure of Above Measures)

Reserve endotracheal intubation only for patients with severe hypoxia not responding quickly to treatment, respiratory acidosis, or respiratory muscle fatigue. 5, 1

• Respiratory muscle fatigue is diagnosed by decreased respiratory rate associated with hypercapnia and confused mental state 5
• Invasive ventilation should not be used to reverse hypoxaemia that could be better restored by oxygen therapy, CPAP, or NIPPV 5

Management of Specific Causes

Acute Coronary Syndrome

Determine early if acute myocardial infarction is present by clinical evaluation and ECG, and consider urgent reperfusion therapy (cardiac catheterization/angioplasty or thrombolysis). 4, 1

Hypertensive Emergency

Aim for rapid initial reduction of systolic or diastolic blood pressure of 30 mmHg during the first few hours using intravenous vasodilators (nitroglycerin or nitroprusside) with loop diuretics. 2, 4

• Sodium nitroprusside may be used for patients not responsive to nitrate therapy, starting dose 0.1 μg/kg/min 2

Hemodynamic Monitoring

Most patients can be stabilized without routine invasive catheters. 1

Consider pulmonary artery catheter if: 5, 1

• Clinical deterioration or recovery does not progress as expected 1
• Need for high-dose vasodilators or inotropes 5, 1
• Diagnostic uncertainty 5, 1

Critical Pitfalls to Avoid

• Never use low-dose nitrates—limited efficacy and potential failure to prevent intubation 1
• Never use high-dose diuretics in monotherapy—worsens hemodynamics and increases mortality 1
• Avoid aggressive simultaneous use of multiple hypotensive agents—can initiate hypoperfusion-ischemia cycle 2, 1
• Avoid beta-blockers in patients with frank cardiac failure evidenced by pulmonary congestion 2
• Avoid excessive reduction of blood pressure as it may compromise organ perfusion 4

Monitoring Requirements

Monitor heart rate, rhythm, blood pressure, oxygen saturation, and urine output continuously until stabilization. 2, 4

• Continue monitoring for at least 24 hours 4
• Evaluate relevant symptoms and treatment-related adverse effects daily 4