Respiratory: COPD III (Acute exacerbations)

Question 1

What are three most common symptoms of worsening / acute exacerbation of COPD? [3]

Answer 1

Most commonly increasing dyspnoea, sputum volume and sputum purulence.

Question 2

Why do acute exacerbations of COPD commonly occur? [1]

How can you group the reasons for acute exacerbations for COPD? [2]

Answer 2

Due to a change in the underlying inflammatory process of stable disease

Triggers:
- respiratory infections (70% of cases)
- non-infective causes

Question 3

Which bacterial [3] and viral infections [3] most commonly cause acute exacerbations of COPD?

Answer 3

Bacterial infections:
- Haemophilus influenzae
- Moraxella catarrhalis,
- Streptococcus pneumoniae

Viral infections:
* Rhinovirus
* influenzae
* respiratory syncytial virus

Question 4

Describe non-infective causes of acute exacerbations of COPD [3]

Answer 4

Non-infective causes:
* Eosinophilic inflammation - (exacerbations caused by this show better response to systemic corticosteroid therapy)
* Environmental factors such as air pollution
* Psychological factors such as anxiety and panic attacks

Question 5

Describe the pathophysiological changes that occur in acute exacerbations of COPD [5]

Answer 5

• Increased inflammation, mucosal oedema and bronchospasm further limit expiratory flow
• Gas trapping worsens, increasing ventilation-perfusion mismatch
• The resulting hypoxia and hypercapnia trigger the neural drive to increase ventilation
• Respiratory muscles fatigue, leading to a ‘neuromechanical decoupling’ that reduces the ventilatory drive
• Existing cardiac dysfunction worsens due to increasing pulmonary vascular resistance

Question 6

What are the major [3] and minor [5] symptoms of acute exacerbation of COPDs

Answer 6

Major symptoms:
- dyspnoea
- increased sputum volume,
- ncreased sputum purulence

Minor symptoms
- cough
- wheeze
- nasal discharge
- sore throat
- pyrexia

Question 7

Describe in detail the signs of acute exacerbations of COPD? [4]

Answer 7

Increased respiratory effort:
- tachypnoea
- nasal flaring
- use of accessory muscles
- paradoxical chest wall movement

Tachycardia (anxiety; hypoxia; increased resp effort)

Worsening airway obstruction on ascultation”
- Reduced breath sounds
- Prolongation of the expiratory phase with wheezing
- Crackles which could indicate an infective component

Indicators of hypoxia:
- New or worsening central cyanosis
- Asterixis
- Altered mentation e.g. confusion, drowsiness

Question 8

Describe which investigations do NICE recommend for all patients admitted with COPD acute exacerbations of COPD? [5]

Answer 8

Blood tests to establish a baseline:
* Full blood count
* Urea and electrolytes
* Theophylline levels if the patient is on it

Serial arterial blood gases (ABGs) to monitor for the development of Type 2 respiratory failure
* A PaO2 of < 7 kPa and a pH level of < 7.35 are indications that the patient should continue to be managed in hospital

Chest X-ray
* overt changes such as opacification and oedema should prompt a reconsideration of the diagnosis

ECG
* helps to exclude acute ischaemia and/or comorbid cardiac dysfunction

Microbiological investigations:
* Sputum sample for microscopy and culture if sputum purulent
* Blood cultures if pyrexia present

Question 9

What are the three key differential diagnoses for acute exacerbations of COPD? [3]

Describe the findings that would indicate the differentials as opposed to COPD

Answer 9

Pneumonia:
- Bronchial breathing
- Increased VR
- Opacification on CXR

PE
- Dysopnea and hypoxia predominate
- Lower limb VTE

Pulmonary oedema (due to MI or acute-on-chronic HF)
- Frothy sputum
- CXR: alveolar and intersitial oedema

Question 10

Treatment of acute exacerbations of COPD:

Answer 10

1 Supplemental oxygen titrated to achieve target saturations of 88-92%

2 Repeat ABG measurements every 30-60 mins

3 Pharmacological managment:
- SABA &/or SAMA initially via inhaler or nebuliser
- LABA, LAMA & ICS continued
- 5-day course of oral prednisolone
- IV theophylline if response inadequate
- Abx (if evidence of infection)

4 Patients with persistent hypercapnia and respiratory acidosis despite optimal medical management need to be started on NIV

5 Escalate to invasive mechanical ventilation

Question 11

State three ways in which supplemental oxygen can be given in treatment of acute excaerbation of COPD [3]

Answer 11

A 24% Venturi mask at 2-3 L/min
A 28% Venturi mask at 4 L/min
Nasal cannulae at 1-2 L/min

Question 12

How does NIV work with regards to treating COPD? [1]

Answer 12

The aim of NIV is to reverse the acidosis by providing pressure support for the airways during inspiration and expiration, leading to an overall improvement in gaseous exchange

Question 13

What are the indicators that NIV is working for tx of acute exacerbations of COPD? [2]

Answer 13

• Improvement in pH
• reduction of the respiratory rate within the first 4 hours

Question 14

BTS recommends that NIV is indicated if WHICH features are present 60 minutes after optimal supplemental oxygen and bronchodilation have been given? [3]

Answer 14

BTS recommends that NIV is indicated if the following features are present 60 minutes after optimal supplemental oxygen and bronchodilation have been given:

Acidosis - pH < 7.35
Hypercapnia - pCO2 > 6.5
Respiratory rate > 23

Question 15

Which Abx [3] are commonly used in treating acute exacerbations of COPD and why [2]?

Answer 15

penicillin e.g. amoxicillin
macrolides e.g. clarithromycin
tetracyclines e.g. doxycyclin

Due to their effectiveness against Haemophilus influenzae and Streptococcus pneumoniae

Question 16

Acute exacerbation of COPD

Which features of a decompensating a patient would indicate moivng to invasive mechanical ventilation? [5]

Answer 16

• Imminent respiratory arrest
• Severe respiratory distress
• Failure of NIV - persistent acidosis (pH < 7.25) and tachypnoea (RR > 35)
• Persistent or worsening acidosis (pH < 7.15)
• Depressed consciousness (GCS < 8)

Question 18

A 73-year-old man presents to the emergency department with a 3-day history of increased dyspnoea and cough. He has a past medical history of severe COPD and uses a Trimbow inhaler daily.

He is admitted and treated for an acute exacerbation with prednisolone 30 mg daily for 5 days and nebulisers. This is his fourth exacerbation in the past 3 months.

What option is most appropriate to reduce the risk of future exacerbations?

Amoxicillin
Carbocisteine
Doxycycline
Long-term oxygen therapy
Roflumilast

Answer 18

Roflumilast

Oral PDE-4 inhibitors such as roflumilast reduce the risk of COPD exacerbations in patients with severe COPD and a history of frequent COPD exacerbations

Question 19

When is NIV indicated in acute exacerbations of COPD? [1]

Answer 19

NIV should be considered in all patients with an acute exacerbation of COPD in whom a respiratory acidosis (PaCO2>6kPa, pH < 7.35 ≥7.26) persists despite immediate maximum standard medical treatment

Question 20

When are O2 sats targets in COPD patients:

88-92% and 94-98%? [2]

Answer 20

pCO2 is known to be normal the target oxygen saturations should be 94-98%.

pCO2 is known to be high the target oxygen saturations should be 88-92%.