A 56-year-old man is admitted with type II respiratory failure secondary to COPD but fails to respond to maximal medical therapy. It is decided that a trial of non-invasive ventilation in the form of bi-level pressure support should be given.
What are the most appropriate initial settings for the ventilator?
Correct Answer A: The 2008 Royal College of Physicians guidelines recommend an initial IPAP of 10 cm H2O. The 2002 British Thoracic Society guidelines had previously advocated starting at 12-15 cm H2O.
Non-invasive ventilation:
The British Thoracic Society (BTS) published guidelines in 2002 on the use of non-invasive ventilation in acute respiratory failure. Following these the Royal College of Physicians published guidelines in 2008.
Non-invasive ventilation - key indications:
Recommended initial settings for bi-level pressure support in COPD:
A 45-year-old woman who is known to have systemic lupus erythematosus (SLE) is referred to the respiratory clinic with increased shortness-of-breath. A number of investigations are ordered including transfer factor of the lung for carbon monoxide (TLCO), which is elevated.
Which one of the following respiratory complications of SLE is associated with this finding?
Correct Answer C:
Transfer factor:
The transfer factor describes the rate at which a gas will diffuse from alveoli into blood. Carbon monoxide is used to test the rate of diffusion. Results may be given as the total gas transfer (TLCO) or that corrected for lung volume (transfer coefficient, KCO).
KCO also tends to increase with age. Some conditions may cause an increased KCO with a normal or reduced.
TLCO:
A 77-year-old man with a history of type 2 diabetes mellitus is admitted to hospital with worsening shortness-of breath. He started a course of amoxicillin given by his GP 5 days ago. On examination blood pressure is 88/60 mmHg with a respiratory rate of 36 / min. A chest x-ray reveals left lower lobe consolidation. Arterial blood gases on air are as follows:
What is the most suitable antibiotic therapy?
Correct Answer C: This patient has a severe pneumonia as the CURB score is 3. He should therefore be treated with a combination of intravenous antibiotics as recommended by the British Thoracic Society guidelines.
Pneumonia: community-acquired:
Community acquired pneumonia (CAP) may be caused by the following infectious agents:
Klebsiella pneumoniae is classically in alcoholics.
Streptococcus pneumoniae (pneumococcus) is the most common cause of community-acquired pneumonia.
Characteristic features of pneumococcal pneumonia:
Management:
The British Thoracic Society published guidelines in 2009:
Which one of the following is the main criteria for determining whether a patient with chronic obstructive pulmonary disease (COPD) should be offered long-term oxygen therapy?
Correct Answer E: COPD - LTOT if 2 measurements of pO2 < 7.3 kPa.
COPD: long-term oxygen therapy:
The 2010 NICE guidelines on COPD clearly define which patients should be assessed for and offered long-term oxygen therapy (LTOT). Patients who receive LTOT should breathe supplementary oxygen for at least 15 hours a day. Oxygen concentrators are used to provide a fixed supply for LTOT.
Assess patients if any of the following:
Assessment is done by measuring arterial blood gases on 2 occasions at least 3 weeks apart in patients with stable COPD on optimal management.
Offer LTOT to patients with a pO2 of < 7.3 kPa or to those with a pO2 of 7.3 - 8 kPa and one of the following:
You are asked to interpret the post-bronchodilator spirometry results of a 56-year-old woman who has been complaining of progressive shortness-of-breath.
What is the most appropriate interpretation of these results?
Correct Answer D:
COPD: investigation and diagnosis:
NICE recommend considering a diagnosis of COPD in patients over 35 years of age who are smokers or ex-smokers and have symptoms such as exertional breathlessness, chronic cough or regular sputum production.
The following investigations are recommended in patients with suspected COPD:
The severity of COPD is categorized using the FEV1*:
Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.
*Note that the grading system has changed following the 2010 NICE guidelines. If the FEV1 is greater than 80% predicted but the post-bronchodilator FEV1/FVC is < 0.7 then this is classified as Stage 1 - mild.
**Symptoms should be present to diagnose COPD in these patients.
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