• Determine the need for emergency admission by assessing the person's blood pressure, pulse, temperature, level of consciousness, peak expiratory flow rate (PEFR), oxygen saturation, and (if possible) electrocardiogram (ECG).
• Arrange emergency admission for people with:
• Respiratory rate of more than 30 breaths per minute.
• Tachycardia greater than 130 beats per minute.
• Systolic blood pressure less than 90 mmHg, or diastolic blood pressure less than 60 mmHg (unless this is normal for them).
• Oxygen saturation less than 92%, or central cyanosis (if the person has no history of chronic hypoxia).
• Peak expiratory flow rate (PEFR) less than 33% of predicted.
• Altered level of consciousness.
• A large respiratory effort (particularly if the person is becoming exhausted).
• Stridor.
• Clinical features of a pulmonary embolus or pneumothorax.
• ECG suggesting a cardiac arrhythmia or myocardial infarction.
• Consider arranging emergency admission, depending on the severity and number of risk factors present, if the person has acute breathlessness associated with any of the following:
• Elevated respiratory rate (but if it is more than 30 breaths per minute, arrange emergency admission).
• Tachycardia (but if it is more than 130 beats per minute, arrange emergency admission).
• Hypotension (but if blood pressure is less than 90 mmHg systolic or 60 mmHg diastolic, arrange emergency admission).
• High temperature (especially if it is higher than 38.5°C).
• PEFR less than 50% of predicted (but if it is less than 33%, arrange emergency admission).
• Older than 65 years of age.

• Sit the person up.
• If the person has an oxygen saturation of less than 92%, give oxygen and continuously monitor their oxygen saturation levels while waiting for transfer to hospital.
• ONLY USE A 28% VENTURI MASK AT 4 L/MIN FOR PEOPLE WITH SUSPECTED CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD), morbid obesity, a chest wall deformity, or a neuromuscular disorder. This is because they are at risk of hypercapnic respiratory failure.
• For other people who are acutely ill, use a simple face mask. Adjust the flow rate to 5–10 L/min to achieve a target oxygen saturation of 94–98%.
• Identify and treat people with clinical features of:
• Silent myocardial infarction: give aspirin 300 mg.
• Pulmonary oedema.
• Give an intravenous diuretic, opioid, and anti-emetic (for example furosemide 40 mg to 80 mg, diamorphine 2.5 mg to 5.0 mg, and metoclopramide 10 mg).
• Also give a nitrate, either sublingual or buccal (for example glyceryl trinitrate [GTN] spray, two puffs).
• Supraventricular tachycardia (SVT). Attempt to terminate the arrhythmia, using a valsalva manoeuvre or carotid sinus massage. For further information, see the CKS topic on Palpitations.
• Valsalva manoeuvre — ask the person to breathe out against a closed nose and mouth.
• Carotid sinus massage — do not attempt this if the person is elderly, or has ischaemic heart disease, a carotid bruit, or a history of stroke or transient ischaemic attack. Only attempt one side at a time. Ensure that a defibrillator is available, as (very rarely) terminating an SVT can provoke other arrhythmias. Ideally, continuously monitor by electrocardiography (ECG), during the procedure as well as afterwards.
• Acute severe asthma (peak expiratory flow rate less than 50% of predicted).
• Give a bronchodilator (for example nebulized salbutamol 5 mg, or repeated doses of a metered-dose inhaler via a spacing device).
• Give prednisolone 30 mg orally (if available).
• Repeat the bronchodilator treatment as necessary.
• For further information, see the CKS topic on Asthma.
• Acute exacerbation of chronic obstructive pulmonary disease.
• Give a bronchodilator (for example nebulized salbutamol 5 mg, or repeated doses of a metered-dose inhaler via a spacing device).
• Give prednisolone 30 mg orally (if available).
• Repeat the bronchodilator treatment as necessary.
• For further information, see the CKS topic on Chronic obstructive pulmonary disease.
• Tension pneumothorax: if the diagnosis is certain, and the person's condition is life threatening, consider inserting a large bore cannula through the second intercostal space in the mid-clavicular line, on the side of the pneumothorax.

If the person does not have an indication for emergency admission:

• Look for clinical features of:
• Acute asthma, especially in people with wheeze or cough that is worse at night, or upon exercise or exposure to allergens.
• An acute exacerbation of chronic obstructive pulmonary disease (COPD), especially in people older than 35 years of age who smoke (or who have smoked), particularly if they have wheeze and a new or worsening cough.
• Pneumonia, especially in people with a cough and at least one other symptom of sputum, wheeze, fever, or pleuritic pain.
• Lung/lobar collapse, especially in people with a history of cancer with lymph node involvement, an inhaled foreign body, or debility causing retained airway secretions.
• Pleural effusion, especially in people with: heart, liver, or renal failure; cancer; tuberculosis; or pleural infection.
• Psychogenic breathlessness, especially in people who have no clinical features of a physical cause for breathlessness.
• Arrange investigations to confirm a suspected cause, or to identify the cause when the cause is uncertain.
• Manage the underlying cause of breathlessness. For people with:
• Acute asthma — see the CKS topic on Asthma.
• Acute exacerbation of COPD — see the CKS topic on Chronic obstructive pulmonary disease.
• Bronchiectasis — see the CKS topic on Bronchiectasis.
• Community-acquired pneumonia — see the CKS topic on Chest infections - adult.
• Lung/lobar collapse — refer the person to a respiratory specialist for investigation of the underlying cause.
• Pleural effusion — refer (or admit) the person, for drainage of the effusion and investigation of the underlying cause.
• Psychogenic breathlessness:
• Explain that the person's symptoms are due to anxiety and hyperventilation.
• Advise the person to try to control their breathing rate (by counting breaths in and out gently), slowing it down.
• Manage any persistent symptoms of hyperventilation, using a bag to re-breathe expired air.
• Consider management of any underlying anxiety disorder.
• Consider referral to a respiratory physiotherapist, so the person can learn methods of controlling breathlessness.
• For people with acute breathlessness that remains of uncertain cause, reassess for risk factors and clinical features of pulmonary embolism. Arrange urgent referral for further investigations if pulmonary embolism is suspected.

• If the person does not have an indication for emergency admission, arrange investigations to identify or confirm the underlying cause of breathlessness.
• Acute breathlessness of uncertain cause
• Chest radiography — to look for signs of heart failure and pulmonary pathology (including pleural effusion).
• Electrocardiogram (ECG) — to look for signs of heart failure, arrhythmia, and pulmonary embolism.
• Spirometry or peak expiratory flow rate — to look for signs of obstructive airway disease.
• Full blood count — to check for anaemia.
• C-reactive protein or erythrocyte sedimentation rate (ESR) — for evidence of infection.
• Other investigations guided by clinical findings.
• Suspected acute asthma or an acute exacerbation of chronic obstructive airways disease (COPD)
• Assess airways obstruction by spirometry. Airway obstruction is confirmed by a forced expiratory volume in 1 second (FEV₁) less than 80% of the predicted value and FEV₁/forced vital capacity (FVC) ratio less than 70%.
• Distinguish asthma from COPD, based on:
• Smoking history — almost always present in people with COPD.
• Age — usually older than 35 years of age for COPD.
• Chronic productive cough — common with COPD, uncommon with asthma.
• Breathlessness — progressive with COPD, variable with asthma.
• Variability of symptoms — common with asthma, uncommon with COPD.
• If asthma and COPD cannot be distinguished based on clinical features:
• Arrange measurements of peak expiratory flow rate (PEFR) — morning and night-time measurements, and during symptoms (to assess variability).
• If doubt still remains, a large response (greater than 400 mL) to bronchodilators or prednisolone (30 mg orally per day, for 14 days) is characteristic of asthma; but not COPD.
• If doubt still remains, refer the person for a specialist's opinion.
• For people with COPD, arrange chest radiography to exclude other serious lung pathology (such as lung cancer).
• Suspected acute exacerbation of bronchiectasis. Arrange chest radiography to exclude other causes for the symptoms. Refer the person to a respiratory specialist for confirmation of the diagnosis (by high resolution computed tomography scanning).
• Suspected pneumonia. Arrange chest radiography if the person is older than 50 years of age and smokes (to exclude underlying cancer). For other people who are well enough to be managed in the community, chest radiography is not required to confirm the diagnosis.
• Suspected lung/lobar collapse. Arrange chest radiography to confirm the diagnosis.
• Suspected pleural effusion. Arrange chest radiography to confirm the diagnosis.