Respiratory conditions

What happens physiologically in an asthma exacerbation?

Bronchoconstriction, airway inflammation and mucus narrow the airways, obstructing airflow.

Why does asthma cause wheeze?

Air moving through narrowed airways creates turbulent airflow, producing a wheezing sound.

Why is a silent chest dangerous in severe asthma?

It may indicate critically reduced airflow and impending respiratory failure.

What does salbutamol do?

It stimulates beta-2 receptors, relaxing bronchial smooth muscle and causing bronchodilation.

What are important adverse effects of repeated salbutamol?

Tachycardia, tremor and potentially hypokalaemia.

What is COPD?

A condition involving persistent airflow limitation, commonly due to small-airway disease and emphysema.

Why can COPD cause CO2 retention?

Inadequate alveolar ventilation can prevent sufficient carbon dioxide removal.

What SpO2 target is commonly used in COPD patients at risk of hypercapnia?

Usually 88–92% initially, following clinical guidance and local protocol.

Why must oxygen not be withheld from a hypoxaemic COPD patient?

Hypoxaemia is dangerous. Give controlled oxygen and titrate to the appropriate target.

What is acute cardiogenic pulmonary oedema?

Raised pulmonary vascular pressure causes fluid to move into lung tissue and alveoli, impairing gas exchange.

Why does pulmonary oedema cause crackles?

Air moving through fluid-affected small airways and alveoli can produce crackling sounds.

Why can pulmonary oedema cause orthopnoea?

Lying flat may increase venous return and worsen pulmonary congestion and breathlessness.

What does GTN do in selected pulmonary oedema patients?

Vasodilation reduces preload and may reduce congestion; monitor blood pressure and check contraindications.

What is a pulmonary embolism (PE)?

An obstruction in the pulmonary arteries, most commonly caused by a blood clot travelling from a DVT.

Why can a large PE cause obstructive shock?

Pulmonary vascular resistance rises, straining the right ventricle and reducing left-heart filling and cardiac output.

What risk factors raise suspicion of PE?

Recent surgery or immobility, previous VTE, active cancer, pregnancy/postpartum status and unilateral leg swelling.

Why can PE cause sudden breathlessness?

Obstructed pulmonary blood flow disrupts ventilation–perfusion matching and impairs gas exchange.

Which observations are priorities in respiratory emergencies?

Respiratory rate, SpO2, work of breathing, air entry, heart rate, blood pressure, mental status and trends after treatment.

What is the difference between oxygenation and ventilation?

Oxygenation transfers oxygen into blood; ventilation moves air and removes carbon dioxide.

Why is falling respiratory rate in an exhausted breathless patient concerning?

It may indicate respiratory muscle fatigue and impending respiratory failure, not improvement.

What is pneumonia?

Pneumonia is an infection of the lung tissue that causes inflammation and may fill alveoli with fluid or inflammatory material, impairing gas exchange.

Why can pneumonia cause crackles?

Inflammation and fluid in the alveoli and small airways can produce crackling sounds as air moves through them.

What signs may suggest pneumonia in a pre-hospital patient?

Cough, fever, breathlessness, increased respiratory rate, crackles, hypoxaemia and sometimes confusion, particularly in older adults.

Why can an older patient with pneumonia present with confusion?

Infection, hypoxaemia, dehydration or sepsis can impair brain function and cause acute confusion or delirium.

What is a lower respiratory tract infection (LRTI)?

An infection affecting structures below the upper airway, such as the bronchi or lungs; it may cause cough, sputum, fever and breathlessness.

What is a pneumothorax?

Air enters the pleural space between the lung and chest wall, disrupting the negative pressure that helps keep the lung expanded.

Why does a pneumothorax cause breathlessness?

The affected lung may partially or completely collapse, reducing ventilation and impairing gas exchange.

What clinical signs may suggest a pneumothorax?

Sudden unilateral chest pain and breathlessness, reduced chest movement and reduced or absent breath sounds on the affected side.

What is a tension pneumothorax?

A pneumothorax in which pressure builds within the pleural space, compressing the lung and impairing venous return to the heart.

Why can a tension pneumothorax cause obstructive shock?

Increasing intrathoracic pressure reduces venous return, lowering cardiac filling and cardiac output.

What signs may indicate a tension pneumothorax in a deteriorating trauma patient?

Severe respiratory distress, unilateral reduced breath sounds, worsening hypoxaemia and hypotension; tracheal deviation is a late and unreliable sign.

What is a pleural effusion?

An abnormal accumulation of fluid in the pleural space, which can compress the lung and restrict its expansion.

How may a pleural effusion present on examination?

Breathlessness, reduced chest expansion and reduced breath sounds over the affected area; percussion may be dull.

What is aspiration?

Entry of material such as vomit, food or liquid into the airway or lungs, potentially causing obstruction, inflammation or infection.

What clues may suggest aspiration in a pre-hospital patient?

A choking or vomiting episode followed by coughing, wheeze, breathlessness, reduced oxygen saturation or altered air entry.

Why is reduced consciousness a risk factor for aspiration?

Protective airway reflexes, such as coughing and swallowing, may be impaired, allowing material to enter the airway.

What is an upper airway obstruction?

Partial or complete blockage of airflow through the nose, mouth, pharynx or larynx.

What signs may suggest upper airway obstruction?

Stridor, noisy breathing, difficulty speaking, increased work of breathing, reduced air movement and deteriorating consciousness.

What is stridor?

A harsh, usually high-pitched sound caused by turbulent airflow through a narrowed upper airway, often heard during inspiration.

How does stridor differ from wheeze?

Stridor usually indicates upper airway narrowing and is often inspiratory; wheeze usually arises from narrowed lower airways and is often expiratory.

Why is suspected epiglottitis an emergency?

Inflammation and swelling near the laryngeal inlet can rapidly obstruct the airway. Avoid unnecessary throat examination or agitation and seek urgent expert support.

What is croup?

A usually viral illness causing inflammation and swelling around the larynx and upper trachea, mainly affecting young children.

What are typical signs of croup?

A barking cough, hoarse voice and inspiratory stridor; severe disease may cause marked work of breathing or exhaustion.

How can anaphylaxis affect breathing?

Airway swelling, bronchoconstriction and sometimes circulatory collapse can rapidly compromise oxygen delivery.

What respiratory signs may occur in anaphylaxis?

Stridor, hoarse voice, tongue or throat swelling, wheeze and increased work of breathing; skin signs may be absent.

What is hyperventilation?

Alveolar ventilation exceeding the body's carbon dioxide production, causing carbon dioxide levels to fall.

Why can hyperventilation cause tingling or light-headedness?

Reduced carbon dioxide causes respiratory alkalosis, which can alter cerebral blood flow and reduce ionised calcium, causing paraesthesia or muscle tightness.

Why must a paramedic not automatically diagnose panic in a breathless patient?

Serious causes such as PE, asthma, ACS, sepsis or pneumothorax can cause anxiety and rapid breathing; assess for underlying illness first.

What is respiratory failure?

Failure of the respiratory system to maintain adequate oxygenation, remove carbon dioxide, or both.

What is type 1 respiratory failure?

Hypoxaemic respiratory failure, characterised by low arterial oxygen with carbon dioxide that is not elevated; the exact definition depends on blood gas criteria.

What is type 2 respiratory failure?

Hypercapnic respiratory failure, in which arterial carbon dioxide is elevated, often with hypoxaemia.

What signs may suggest a patient is tiring and approaching respiratory failure?

Reduced respiratory effort after severe distress, decreasing respiratory rate, poor air entry, exhaustion, confusion or reduced consciousness.

What is ARDS?

Acute respiratory distress syndrome is severe inflammatory lung injury that increases alveolar-capillary permeability, causing fluid leakage and profound hypoxaemia.

Why can ARDS cause severe hypoxaemia?

Fluid-filled or collapsed alveoli impair gas exchange and create areas of lung that are perfused but poorly ventilated.

What is the significance of cyanosis in a breathless patient?

It may indicate significant deoxygenation, but it is a late and insensitive sign; assess oxygen saturation and the whole clinical picture.

Why should respiratory rate be counted rather than estimated?

An accurately measured respiratory rate helps identify deterioration and can be an early indicator of serious illness.

Why is a normal SpO₂ not enough to rule out respiratory failure?

Pulse oximetry estimates oxygen saturation but does not measure carbon dioxide or ventilation; a patient can retain CO₂ despite an apparently acceptable SpO₂.

What should you reassess after an intervention for respiratory distress?

Work of breathing, respiratory rate, SpO₂, air entry, heart rate, blood pressure, mental status and the patient's overall response.