week 3 Respiratory Disorders

Common Respiratory Disorders

• The learning outcomes for this topic include identifying the causes, pathophysiology, clinical features, diagnostic features, and management of acute respiratory disorders such as COPD, pulmonary embolism, pneumonia, and asthma.

Causes of Respiratory Distress

• Respiratory distress can be caused by ventilatory problems, whether obstructive or restrictive, acute or chronic, or impaired pulmonary ventilation or perfusion.
• Infectious processes, impaired CNS drive, heart failure, metabolic problems, and normal responses to increased activity can also cause respiratory distress.

Taking a Good History

• Taking a thorough medical history is essential in assessing patients, not just in the emergency department but in every area of healthcare.
• Important questions to ask include the length of time the symptoms have been present, the onset (gradual or abrupt), and the position of comfort.
• It is also essential to ask about orthopnea, coughing, haemoptysis, pain, and other symptoms.

Focused Assessment

• A focused assessment should include an evaluation of the ABCs (airway, breathing, and circulation) and signs and manifestations of shortness of breath.
• Other essential factors to assess include cough, sputum, fever, chest pain, and haemoptysis.

Dyspnoea Causes

• Dyspnoea can be caused by cardiovascular, respiratory, metabolic, mechanical, or extra-pulmonary disorders.
• Acute dyspnoea without prior heart or lung disease can be particularly challenging to diagnose.

Chronic Lung Disease

• Chronic lung disease can be obstructive (cannot get air out) or restrictive (cannot get air in).
• Examples of obstructive chronic lung diseases include asthma, bronchiectasis, chronic bronchitis, emphysema, COPD, and COAD.
• Restrictive chronic lung diseases include interstitial pulmonary fibrosis, asbestosis, cystic fibrosis, and others.

COPD

• COPD affects 5% of the population and may present as life-threatening respiratory failure.
• It is a common co-morbidity and often combines chronic bronchitis and emphysema, with or without asthma.

Chronic Bronchitis

• Chronic bronchitis is a clinical diagnosis characterized by a chronic cough with sputum production for at least three months per year for two consecutive years.
• It involves long-standing inflammation of the lower airways, mucus production, infections, wheezing, coughing, and mucus for at least three months a year for two years in a row.
• Vital capacity is decreased, tidal volume is normal or decreased, and alveolar ventilation is reduced.

Emphysema

• Emphysema is a pathological diagnosis characterized by the destruction of lung units distal to terminal bronchioles, leading to abnormal permanent airspace enlargement.
• It destroys alveoli, causing loss of recoil, air trapping, and increased residual volume, leading to pulmonary hypertension and cor pulmonale (right heart failure).
• Smokers are at risk, and symptoms include shortness of breath, barrel chest, and blue discoloration.

COPD Treatment

• Relieve hypoxia by titrating oxygen to SpO2 88-92%.
• Position patients in a seated or semi-seated position.
• Administer bronchodilators, such as salbutamol and ipratropium.
• Use non-invasive ventilation (NIV) with BiPAP for ventilatory support and alveolar recruitment.
• Consider corticosteroids and antibiotics.

Pneumonia

• Pneumonia is an acute inflammation of the lung parenchyma, with a 10% mortality rate in Australia.
• It is the second most common hospital-acquired infection, with the highest mortality rate for hospital-acquired infections.
• It is a common cause of death in the elderly.

Pneumonia Classification

• Pneumonia can be classified into community-acquired pneumonia, hospital-acquired (nosocomial) pneumonia, pneumonia in the immunocompromised patient, and aspiration pneumonia.

Community-Acquired Pneumonia

• Community-acquired pneumonia is the largest majority of presentations to the emergency department.
• It can be typical (common bacteria) or atypical (uncommon bacteria), and is mostly managed in the community.

Hospital-Acquired Pneumonia

• Hospital-acquired pneumonia is acquired during a hospital stay, after 72 hours of admission.
• It is the leading cause of death among hospital-acquired infections, with a broad range of causative organisms, some being antibiotic-resistant.

Pneumonia Risk Factors

• Risk factors for pneumonia include advanced age (>65 years), smoking history, stroke or swallowing difficulty, URTI, tracheal intubation, prolonged immobility, immunosuppressive therapy, non-functional immune system, malnutrition, dehydration, and co-morbidities such as CAL, diabetes, CHD.