Part 2… COAD in the Emergency Department

Definitions COPD is a disease state resulting predominantly from smoking tobacco, and is characterised by airflow obstruction, which is generally progressive and is only partially reversible. The diagnosis of chronic bronchitis applies to patients who, in the absence of other recognised causes, e.g. bronchiectasis, have a chronic productive cough for at least 3 months of the year in 2 or more successive years. Emphysema is a pathological diagnosis describing permanent abnormal enlargement of the airspaces distal to the terminal bronchioles, accompanied by destruction of alveolar walls. Most patients with COPD have elements of both chronic bronchitis and emphysema in varying degrees, but some may have one without the other.

What is an exacerbation of COPD? An exacerbation is defined as an increase in symptoms and signs of COPD above the usual day-to-day variation expected by the patient. Exacerbations vary both in severity and frequency.

Symptoms of an exacerbation Increased breathlessness, often accompanied by wheezing, chest tightness and increased cough and sputum. They are often associated with signs of airway infection, increased volume and colour change in sputum (to yellow or green), and fever. Other symptoms are malaise, drowsiness, insomnia, fatigue, depression, confusion and fever.

The most common causes of exacerbations include: tracheobronchial infections environmental (atmospheric) pollution (including cigarette smoke and allergen load) weather changes aspiration associated with gastro-oesophageal reflux.

The role of bacterial infection and the place of antibiotics in the treatment of exacerbations is controversial. Potentially pathogenic bacteria are found in about 50% of exacerbations, and viruses in a further proportion of episodes. In most cases they are likely to be relevant, and reports confirm the benefit of antibiotic treatment on the rate of recovery, morbidity, and even hospital stay, particularly in patients with severe COPD, and those who have severe exacerbations.

Differential Dx of an exacerbation Acute exacerbations must be distinguished from other diseases and complications of COPD, including pneumonia pneumothorax congestive heart failure pulmonary embolism that require alternative treatment. When exacerbations are associated with features of infection (pyrexia and purulent sputum), the presence of pneumonia and other forms of lower respiratory infection must be excluded using chest X-ray. Rosen’s Emergency Medicine 6th Ed

Prevention of exacerbations The following measures have each been shown to reduce the frequency and/or severity of COPD exacerbations: Smoking cessation Prevention of respiratory infections (influenza and pneumococcal vaccination) Bronchodilators: regular dosing with ipratropium bromide, theophylline, long-acting beta2-agonist, tiotropium Oral and high-dose inhaled corticosteroids alone, and in combination with bronchodilators, particularly the long acting varieties.

Management of exacerbations Clinical assessment Determine symptom changes from baseline status including: sputum volume and character, duration and progression of symptoms, dyspnoea severity, exercise limitation and effect on activities of daily living. Look for evidence of respiratory distress, bronchospasm, cor pulmonale and right ventricular failure, pneumonia, haemodynamic instability and altered mentation.

Investigations Arterial blood gas Pulse oximetry Chest radiograph ECG Sputum Blood tests

Rosen’s Emergency Medicine 6th Ed Pulse oximetry and ABG Sats part of monitoring of every patient. Change in baseline or in response to therapy more imp than single value ABG limited value! Considered in those who you are going to admit. A PaO2 < 8.0 kPa (60 mm Hg) and/or SaO2 < 90% with or without PaCO2 > 6.7 kPa (50 mmHg) when breathing room air indicate respiratory failure ABG’S should not be used (alone) to determine whether patient requires intubation or NIVS. Guided rather by clinical state. Rosen’s Emergency Medicine 6th Ed

CXR Primary role – to determine whether there is acute, treatable cause for clinical deterioration, esp pneumothorax or pneumonia. May reveal important co-existant pathology such as effusions, tumours. May just show chronic changes.

Sputum Examination During acute exacerbation sputum may be thicker Sputum culture is of limited value unless you clinically suspect TB

ECG Presence of ECG criteria of RVH suggests established cor pulmonale. In severely ill or those with chest pain should be used to check for dysrhythmias and check for MI

Blood Tests Routine investigation adds little! FBC – reveal polycythemia Elevated WCC non-specific and often related to the hyperadrenergic state of acute dyspnoea. If on theophylline- level should be taken as drug has narrow therapeutic index

PHARMACOLOGICAL TREATMENT: THE ‘‘ABC APPROACH’’ This can be called the ‘‘ABC approach’’, an acronym that reflects the three classes of drugs (antibiotics, bronchodilators and corticosteroids) commonly used for exacerbations of COPD . However, if we consider only the highest levels of evidence, this is only valid for bronchodilators and systemic steroids

Bronchodilators B agonists and anticholinergics 1st line Nebulised anticholinergic agents are as effective as salbutamol in COPD and can be used alone or in conjunction. Recommended that they be given together! Evidence does not support the routine use of Aminophylline for COPD exacerbation!

Anti-inflammatory therapy Corticosteroids should be given, preferably orally. A once-daily dose of 40 mg prednisone is given and continued for 10 – 14 days unless the condition fails to resolve. Tapering is not required. An equivalent dose of an intravenous steroid may be given if the patient is unable to take oral medication.

Antibiotics Prescribed when there is clear evidence or strong suspicion of infection (marked sputum purulence and/or fever), and in those with severe COPD or a severe exacerbation. The organisms most commonly involved are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis Local sensitivity data should be considered when choosing an antibiotic. In areas where there are high levels of resistance to the macrolides and doxycycline, these agents should be avoided. Alternatives such as amoxycillin/clavulanate, cefuroxime, or quinolones may be used. According to GOLD recommendations antibiotics should be given to patients with exacerbations with the three major symptoms (increased dyspnoea, increased sputum volume, and increased sputum purulence).

What about oxygen therapy? Hypoxemia is usually corrected by administration of supplemental oxygen with a goal of sats 90% or >. Excessive supplemental oxygen may cause respiratory arrest secondary two loss of hypoxaemia- induced ventilatory drive. Carefully monitor your oxygen therapy wth ABG’s and sat’s.

Noninvasive mechanical ventilation Noninvasive mechanical ventilation in exacerbations improves respiratory acidosis, increases pH, decreases the need for endotracheal intubation, and reduces PaCO2, respiratory rate, severity of breathlessness, the length of hospital stay, and mortality. Patients who are likely to benefit are those with moderate to severe ventilatory failure and elevated Pco2 but without marker hypoxaemia. Modes of ventilation include CPAP and BiPAP. Rosen’s Emergency Medicine 6th Ed

Indications for hospital admission in patients with COPD: An acute exacerbation associated with one or more of the following features: Sustained failure to improve on outpatient management Inability to walk between rooms (where previously mobile) Family and/or physician unable to manage the patient at home High-risk co-morbid condition, pulmonary (e.g. pneumonia) or non-pulmonary Prolonged, progressive worsening of symptoms before emergency visit Altered mentation Worsening hypoxaemia and new or worsening hypercapnia Newly occurring arrhythmia New or worsening right-sided cardiac failure unresponsive to outpatient management.