Acute heart failure and pulmonary oedema
Sit the patient up, give oxygen, IV furosemide, GTN if the BP is high enough, and CPAP if still hypoxic. Then find out why the heart failed today.
A 68-year-old man with hypertension woke at 3 a.m. gasping for breath. He is sitting bolt upright, sweaty, with pink frothy sputum. RR 34, SpO₂ 82% on air, BP 196/108, pulse 118. Crackles to the mid zones on both sides.
What do you do in the first 15 minutes?
- Sit upright, legs downReduces the blood returning to the heart.
- OxygenAim SpO₂ 94–98% (88–92% if CO₂ retainer).
- Monitor, ECG, cannulaLook for ACS, arrhythmia. Bloods including troponin.
- IV furosemide40 mg IV if not on diuretics. If already on one, at least the usual daily dose IV.
- GTN if systolic BP above 110Sublingual, then IV infusion. Especially useful when BP is high.
- CPAP if still hypoxicOr if working hard to breathe despite the above.
- Catheter and fluid chartHourly urine, daily weight.
- Find the triggerACS, AF, high BP, valve problem, infection, missed tablets, salt and fluid, NSAIDs.
- Systolic BP below 90, cold peripheries
- Chest pain or ischaemic ECG
- Very fast or very slow rhythm
- New loud murmur
- SpO₂ not improving on CPAP
- Rising creatinine with poor urine
- Cardiogenic shock
- ACS causing the failure
- Acute valve problem: papillary muscle rupture, endocarditis
- Hypertensive pulmonary oedema
- Tamponade mimicking failure
- Rheumatic mitral stenosis, especially in pregnancy
| Furosemide | 40 mg IV if not on diuretics. On diuretics: at least the total daily oral dose IV |
| GTN | Only if systolic above 110. Infusion 10–200 micrograms/min, titrated |
| CPAP | 5–10 cmH₂O |
| Urine target | More than 100–150 mL/hour in the first 6 hours. If less, repeat or double furosemide |
| Low BP | Systolic below 90: no GTN, senior now (cardiogenic shock) |
Check every dose against a current drug reference and your hospital protocol.
On this page
What it is
In acute heart failure the heart cannot pump out the blood returning to it, so pressure backs up into the lungs and fluid leaks into the air sacs: pulmonary oedema. The patient is drowning from the inside.
- Good BP and warm hands, but crackles and swelling
- Diuretics and vasodilators (GTN)
- Low BP, cold, confused, little urine, plus congestion
- Cardiogenic shock: senior, ICU, inotropes
- Low output without congestion
- Careful fluid, find the cause, senior review
Causes and triggers to think of in Pakistan: heart attack, uncontrolled high BP, AF, rheumatic valve disease, cardiomyopathy (including peripartum cardiomyopathy in the last month of pregnancy or the months after delivery), infections, anaemia, missed furosemide, salty food, NSAIDs (painkiller injections) and kidney failure.
Recognising it
- Breathlessness, worse lying flat (orthopnoea), waking at night gasping.
- Pink frothy sputum, crackles at both bases (or higher), wheeze ("cardiac asthma").
- Raised JVP, swollen ankles, enlarged liver, a third heart sound.
- Fast pulse, sweating, anxiety, low SpO₂.
Investigations
| Test | Why | What to look for |
|---|---|---|
| ECG | Cause | ST changes, AF, LVH, heart block |
| Chest X-ray | Diagnosis | Upper lobe diversion, bat-wing shadowing, Kerley B lines, effusions, big heart |
| Troponin | ACS as the trigger | A rise needs cardiology input |
| BNP or NT-proBNP | If the diagnosis is unclear | A normal value makes heart failure unlikely |
| Urea, creatinine, electrolytes | Baseline before diuretics | Kidney function, potassium |
| CBC | Anaemia, infection | |
| Blood gas | If SpO₂ is low or the patient is tiring | Acidosis, CO₂ |
| Echo | Heart function and valves | Weak left ventricle, mitral stenosis, regurgitation, effusion |
Treatment
- SpO₂ and work of breathingStill low or tiring: CPAP 5–10 cmH₂O. Not improving on CPAP: senior and ICU.
- BPFalling below 90 systolic: stop GTN, call your senior.
- Urine outputAim for more than 100–150 mL/hour in the first 6 hours. If less, repeat or double the furosemide.
- RhythmFast AF: treat (see Atrial fibrillation).
- Mental stateDrowsy or confused: blood gas, senior review.
- Morphine is no longer given routinely. It may relieve distress but is linked to more ventilation and worse outcomes. Use only on senior advice.
- Continue the beta-blocker unless shocked, the pulse is below 50, or there is heart block.
- Hold NSAIDs, and review drugs that can worsen heart failure (diltiazem, verapamil, pioglitazone).
Cardiogenic shock
Systolic BP below 90, cold and clammy, confused, little urine, rising lactate, with pulmonary oedema.
- Senior and ICU now. Cardiology if from a heart attack: urgent PCI.
- No GTN. Diuretics with caution.
- Inotropes or vasopressors (dobutamine, noradrenaline) in ICU.
- Echo urgently: look for a mechanical cause (ruptured papillary muscle, VSD, tamponade).
Special situations
- Hypertensive pulmonary oedema (often with BP above 180): high-dose IV GTN is the key drug, with CPAP. Diuretics help, but these patients are often not overloaded with fluid.
- Rheumatic mitral stenosis: fast AF or pregnancy can tip them into pulmonary oedema. Slow the heart (beta-blocker), diuretics, and cardiology input. Avoid too much GTN, as these patients depend on filling.
- Peripartum cardiomyopathy: breathlessness in late pregnancy or after delivery. Do not dismiss as "normal in pregnancy". Echo and cardiology with obstetrics.
- Kidney failure: may need dialysis if not responding to diuretics.
Monitoring on the ward
- Fluid balance chart and daily weight (same scale, same time).
- Daily creatinine and potassium while on IV diuretics.
- Fluid restriction (about 1.5 litres a day) and salt restriction if very overloaded.
- Switch to oral diuretic when no longer congested.
Before discharge
- Heart failure medicines as advised by cardiology: ACE inhibitor (or ARNI), beta-blocker, mineralocorticoid antagonist (spironolactone) and SGLT2 inhibitor for a weak heart, plus the lowest diuretic dose that keeps them dry.
- Daily weight at home: gaining more than 2 kg in 3 days means call the clinic.
- Low salt diet. Avoid NSAIDs and painkiller injections.
- Follow-up in cardiology clinic within 2 weeks.
Common mistakes
- Laying a breathless patient flat for the X-ray or the cannula.
- Giving a small furosemide dose to a patient already on a large oral dose.
- Giving GTN with a systolic BP below 90.
- Routine morphine.
- Missing the ACS or the fast AF that caused it.
- Calling breathlessness in late pregnancy "normal" without examining her.
Frequently asked questions
What is the dose of IV furosemide in acute heart failure?
40 mg IV if the patient is not already on a loop diuretic. If they are, give at least their total daily oral dose IV, and repeat or double if urine output is poor after 2 hours.
When is GTN used in acute pulmonary oedema?
When the systolic BP is above 110, especially in hypertensive pulmonary oedema. It is started sublingually and continued as an IV infusion of 10–200 micrograms/min.
Is morphine used in acute pulmonary oedema?
Not routinely. It may increase the need for ventilation. Use it only on senior advice for severe distress.
When is CPAP used in heart failure?
When the patient remains hypoxic or breathless despite oxygen, diuretics and nitrates. Usual pressure is 5–10 cmH₂O.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A 66-year-old has acute pulmonary oedema with BP 210/115. Which treatment matters most, alongside oxygen?
Answer: High-dose IV GTN. In hypertensive acute heart failure, nitrates reduce preload and afterload quickly. Add CPAP if available and IV furosemide.
- IV furosemide alone: Diuretic helps, but afterload reduction is key in hypertensive oedema.
- IV metoprolol: Beta-blockers are not started in acute decompensation.
- Oral amlodipine: Too slow.
- IV fluids: Harmful.
2. A patient on furosemide 80 mg twice daily at home is admitted with fluid overload. What is a suitable IV furosemide dose?
Answer: 160 mg IV per day or more. In patients already on loop diuretics, the IV dose should equal or exceed the total daily oral dose, then be adjusted to urine output and weight.
- Stop diuretics and restrict fluid: Under-treats.
- 500 mg IV bolus: Excessive; ototoxicity risk.
- 20 mg IV once: Too low for a diuretic-treated patient.
- 40 mg IV twice daily: Below the home dose.
3. A 70-year-old has sudden severe breathlessness, frothy pink sputum, bilateral crackles and BP 180/100. SpO₂ is 85%. What is the initial treatment?
Answer: O₂, IV furosemide, nitrate. Acute cardiogenic pulmonary oedema: sit up, oxygen to SpO₂ > 94% (CPAP/NIV if hypoxic despite O₂), IV loop diuretic, IV nitrate if SBP > 110 (reduces preload/afterload), treat the cause (ACS, arrhythmia, hypertension, valve). Avoid routine morphine. Hypotensive patients (cardiogenic shock) need inotropes/vasopressors and specialist support.
- 500 mL IV saline bolus: A saline bolus worsens pulmonary oedema.
- IV metoprolol, oxygen: Beta-blockers are negatively inotropic in acute failure.
- Oral digoxin loading only: Digoxin alone is inadequate.
4. A 70-year-old with breathlessness and ankle oedema has NT-proBNP 2500 pg/mL. What is the next investigation?
Answer: Transthoracic echocardiogram. Suspected heart failure: raised natriuretic peptides (NT-proBNP > 125 pg/mL non-acute; > 300 acute) lead to echocardiography to confirm and classify by ejection fraction — HFrEF (≤ 40%), HFmrEF (41–49%), HFpEF (≥ 50% with structural/diastolic dysfunction). Normal NT-proBNP makes heart failure unlikely. Obesity lowers and renal failure, AF and age raise natriuretic peptides.
- Coronary angiogram first: Angiography is not done before confirming heart failure.
- Repeat NT-proBNP in 6 months: Waiting 6 months delays diagnosis.
- Exercise ECG: Exercise ECG does not assess heart failure.
5. After an extensive anterior MI, a patient has BP 75/45, cold peripheries, confusion, oliguria and pulmonary crackles. What is the key definitive management?
Answer: Urgent PCI. Cardiogenic shock (commonly from large MI): hypotension with hypoperfusion (cold, oliguria, confusion, raised lactate) and congestion. Early revascularisation (PCI of the culprit lesion) improves survival. Support with inotropes (dobutamine) and vasopressors (noradrenaline), oxygen/ventilation, mechanical circulatory support in selected cases. Exclude mechanical complications (VSD, papillary rupture) with echo.
- 2 L crystalloid bolus: Fluids worsen pulmonary oedema.
- IV metoprolol: Metoprolol is negatively inotropic.
- Oral isosorbide: Isosorbide causes hypotension.
6. Ventricular preload is best represented by which measurement?
Answer: LV end-diastolic volume. Preload is the stretch on ventricular muscle before it contracts, best measured as end-diastolic volume (or pressure). It depends mainly on venous return. By the Frank–Starling law, greater preload increases stroke volume up to a point.
- Mean arterial blood pressure: An index of afterload.
- Systemic vascular resistance: Determines afterload.
- Stroke volume per beat: The result of contraction, not preload.
- Aortic diastolic pressure: Related to afterload.
7. A patient on digoxin starts a loop diuretic and develops nausea, yellow vision and arrhythmias. Which electrolyte change made digoxin toxicity more likely?
Answer: Hypokalaemia. Digoxin inhibits the Na⁺/K⁺ ATPase by binding where potassium normally binds. Low potassium lets more digoxin bind, increasing toxicity. Hypercalcaemia, hypomagnesaemia, renal impairment and drugs such as amiodarone and verapamil also raise the risk. Severe toxicity is treated with digoxin-specific antibody fragments.
- Hyperkalaemia: Is a feature of severe acute overdose, not a cause of increased sensitivity.
- Hyponatraemia: Not a main factor.
- Hypocalcaemia: Hypercalcaemia, not hypocalcaemia, increases toxicity.
- Hypermagnesaemia: Low magnesium, not high, increases toxicity.
References and dose sources
- ESC 2021 guidelines for heart failure (2023 focused update)
- NICE CG187: Acute heart failure
- NICE NG106 — chronic heart failure
- Furosemide dosing: Drugs.com: Furosemide dosage (see also our furosemide dose page)
- Glyceryl trinitrate (GTN) dosing: Drugs.com: Nitroglycerin dosage (see also our glyceryl trinitrate (gtn) dose page)
- Enoxaparin dosing: Drugs.com: Enoxaparin dosage (see also our enoxaparin dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.