Respiratory Flashcards
Oxygen toxicity is PCO2 >6 and pH <7.35 and what PaO2? (1)
PaO2 is >10kPa
Which device is used to deliver a fixed or precise oxygen concentration? (1)
Venturi
What conditions are at risk of oxygen toxicity? (2)
Ie chronic CO2 retainers who rely on hypoxic drive.
Chronic hypoxic lung disease- Patients with COPD, severe chronic asthma, bronchiectasis/CF
Obesity hypoventilation syndrome- High BMI,
Neuromuscular disease- Muscular dystrophy
Chest wall disease- kyphoscoliosis
Drugs- opioids
88-92%
Define respiratory failure type 1 (2)
PaO2 < 8kPa
PaCO2 normal or low
Due to V/Q mismatch
Define respiratory failure type 2. (2)
Low PaO2 < 8 kPa
High PaO2 >6 kPa
Caused by ventilation problems.
A patient is severely hypercapnic due to excessive oxygen therapy.
What action do you take? (1)
Reduce to 35% if patient is fully alert
Call critical care for mechanical ventilation if drowsy
Do not stop oxygen suddenly.
A 67 year old man is in A+E with an exacerbation of COPD.
On examination he is on 28% oxygen, sats of 85% and looks distressed.
The ABG shows;
PaO2 6.7
PaCO2 8.3
pH 7.32
What does the blood gas show? (1)
Give 2 ways to improve his oxygen saturations. (2)
Uncompensated respiratory acidosis
Don’t control PaCO2 by reducing O2 if already hypoxic.
Check airway and sit up Beonchodilators Reverse sedation Titrate O2 to get sats up to 90% and rpt ABG (controlled oxygen therapy. Mechanical ventilation
What is the aim of long term oxygen therapy? (1)
Delay death and cor pulmonale
When is long term oxygen therapy indicated? (3)
If PaO2 <7.3kPa
If PaO2 7.3-8kPa AND secondary polycythaemia or evidence of pulmonary hypertension.
Also nocturnal hypoventilation caused by obesity, neuromuscular/spinal/chest wall disease or obstructive sleep apnoea.
In an emergency if sats are 98% do you give supplementary oxygen? (1)
No does not help breathlessness if O2 sats are ok.
Where is the carina of the lungs? (1)
The junction of the manubrium and the 2nd right costal margin. (Level of T5)
Describe the basic structure of the lungs. (4)
The trachea extends from inferior cricoid cartilage(C6) to the carina (T5) where it divides into the left and right bronchi. The bronchi divide by dichromatour branching up to 23 times into secondary, tertiary bronchi and smaller bronchioles and terminal bronchioles and alveoli.
The left lung contains 2 lobes and a cardiac notch whereas the right lobe has 3 lobes.
The lungs are surrounded by double layer of pleura, visceral and parietal pleura, filled with a small amount of fluid.
What epithelium lines the airways? (2)
Ciliated columnar epithelium and mucous (goblet) cells
Describe the mucociliary escalator. (2)
Mucous is secreted by goblet cells (most in larger airways) and traps macrophages, bacteria and inhaled particles. Ciliated columnar epithelium then move the mucous in a cephalad direction, thus clearing the lungs.
Name 4 causes of breathlessness occurring chronically (onset over days or weeks). (4)
Asthma, COPD, ILD, Pleural effusion, cancer of the bronchus/trachea, HF, severe anaemia.
Name 5 causes of breathlessness occurring acutely over minutes or hours. (5)
Acute asthma, Exacerbation COPD, Pneumothorax, PE, Pneumonia, Hypersensitivity pneumonitis (extrinsic allergic alveolitis), Left HF, Cardiac tamponade, Hyperventilation (panic), Upper airways obstruction (foreign body, anaphylaxis)
Describe PND. (3)**
Paroxysmal nocturnal dyspnoea is a symptom of left sided HF. Patient wakes up gasping for breath and finds some relief on sitting up right.
Define orthopnoea. (3)**
Breathlessness that occurs when lying flat and is the result of abdominal contents shifting diaphragm into thorax and redistribution of blood from legs back to lungs.
Describe the epithelium of the alveoli. (2)
Consists of Type I and Type II pneumocytes. Type 1 cover approximate 95% of the alveolar surface (they are very thin and so used for gas exchange) compared to Type II that secrete surfactant and cover the remaining 5%.
The lungs have dual blood flow. Describe this. (2)
Pulmonary circulation (deoxygenated blood from Right side of heart) and Bronchial (systemic) circulation that brings oxygenated blood from the descending aorta to oxygenate the lung tissue (primarily along the larger airways).
Name 3 causes of a persistent cough. (3)
Asthma, Post-nasal drip, GORD*, ACEi, post-viral cough
Lung airway disease: COPD, bronchiectasis, foreign body, tumour.
Lung parenchymal disease: ILD, lung abscess
Name the muscles used in normal inspiration and expiration. (2)
Inspiration: diaphragm (C345), intercostal muscles (sternocleidomastoid and scalenes when in distress)
Expiration: none, it is passive relying on elastic recoil. (internal intercostals and abdominal wall become active during exercise)
A 55 year old man attends A+E with a first episode of sudden onset shortness of breath lasting 3 hours.
He has no PMH and quit smoking 25 years ago.
Name 4 investigations you would like to do initally. (4)
Bedside: Obs: (SATs, BP, RR, Pulse, Temp.) Lung FTs (peak flow, spirometry), ECG*
Bloods: ABGs, FBC, U+Es, blood glucose, Trop T, D-dimer
Imaging: CXR, ?Echo
Name 4 diseases that smoking is a risk factor for. (4)
GI cancer: mouth, oesophagus, stomach, pancreas
Resp cancer: Larynx, bronchus.
Urogenital cancer: Bladder, Kidney, Cervix
COPD
PVD
IHD
Mr Smith requires a bronchoscopy for a biopsy of a mass. He is concerned about the test.
Why might a bronchoscopy be undertaken? Give 3. (3)
Name 3 medications he may recieve during the investigation. (3)
Diagnosis - look or biopsy, Treatment - remove foreign body or growth, BAL - lavage for washings to send for cytology
IV Midazolam, topical lidocaine anaesthesia, anti-muscarinic to reduce bronchial secretions eg atropine
Name 3 causes of haemoptysis. (3)
Define massive haemoptysis. (2)
Give 2 causes of massive haemopytsis. (2)
Bronchiectasis, Bronchial carcinoma, PE, bronchitis, pneumonia (rust coloured), abscess, TB. Rare: Wegener’s granulomatosis, bleeding disorders, Goodpasture’s syndrome.
Massive haemoptysis is more than 200ml in 24 hours.
Pulmonary TB, bronchiectasis, lung abscess or malignancy.
In spirometry what are the 2 most important measurements taken? (2)
What is a normal result? (1)
Give an example of a restrictive lung condition and a obstructive lung condition and the respective values. (4)
Clue: LO HR
FVC1 and FVC (FEV1/FVC)
Normal is 0.7
Restrictive is FEV1/FVC >0.7 eg ILD, scoliosis
Obstructive is FEV1/FVC
When would a pleural aspiration be undertaken? (1)
Name 2 complications of a pleural aspirate. (3)
Sample with fine bore needle to investigate cause of a pleural effusion, or drainage of a pleural effusion for symptom relief.
Pneumothorax, infection, damage to neurovascular bundle in subcostal groove, seeding of malignant cells along the tract with a malignant effusion.
Describe a V/Q scan. (3)
Xenon-133 is inhaled and microaggregates of albumin labelled with Technetium-99m are injected IV.
Pulmonary emboli are detected as “cold” areas on the perfusion scan in relation to the ventilation scan.
However, many lung diseases can affect both values and so V/Q scan is only useful when reported as normal (excluding PE) or reported as high probability of PE.
You suspect a diagnosis of lung fibrosis in a patient. What is the most appropriate imaging test for diagnosis? (1)
High resolution CT.
What is measurement of carbon monoxide transfer factor? (2)
Measurement of the the transfer of a low concentation of carbon monoxide added to inspired air to the hemoglobin.
Gas transfer is reduced in early emphysema and lung fibrosis.
TLCO is the absolute value, whereas KCO is the value adjusted for lung volume.
What does yellow/green sputum indicate? (1)
Infection or allergy
Define Peak Expiratory Flow Rate. (3)
Measure of maximum expiratory flow during a forced expiration after forced inspiration and measured with a peak flow meter.
What does pink frothy sputum indicate? (1)
Heart failure
What does rust coloured sputum indicate? (1)
Pneumonia
Define COPD. (2)
What 2 diseases are encompassed by COPD? (2)
Chronic obstructive pulmonary disease is characterised by poorly reversible airways obstruction thats is usually progressive and associted with persistent inflammatory response of the lungs.
Chronic bronchitis and emphysema
In spirometry, how can COPD and asthma be diagnosed? (2)
Obstructive picture ie FEV1/FVC <0.7%
Post bronchodilator will show more than 20% improvement in asthma.
How does cigarette smoke cause COPD? (2)
Smoking causes mucous cell hypertrophy and increase in neutrophils, macrophages and lymphocytes in the airways which release inflammatory mediators. This leads to amplified inflammatory process, structural changes and connective tissue breakdown (protease-anti-protease imblanace) in lung parenchyma. Emphysema.
Alpha 1 antitrypsin is major protease inhibitor, that is inactivated by cigarette smoke.
Describe the differences between pink puffers and blue bloaters. (2)
These terms describe the extremes of the spectrum.
Pink Puffers have predominantly emPhysema. Increased alveolar ventilation leaves low PaO2 and low PaCO2, they are breathless but not cyanosed.
Blue bloaters have predominantly chronic Bronchitis. Decreased alveolar ventilation leaves low PaO2 and high PaCO2, cyanosed but not breathless. They may be oedematous and have features of CO2 retention. They rely on hypoxic drive, give O2 with care.
Define emphysema. (2)
Emphysema is defined pathologically by dilataion and destruction of the lung tissue distal to the terminal bronchioles. Changes lead to loss of elastic recoil that holds the airways open during expiration and so is associated with air trapping and expiratory airflow limitation.
What underlying condition may cause a 35 year old to show signs of COPD? (1)
alpha 1 anti-trypsin deficiency
Describe the pathophysiology of chronic bronchitis. (3)
Airway narrowing caused by hypertrophy and hyperplasia of the mucous producing cells, bronchial wall inflammation and mucosal oedema. Epithelial layer may ulcerate and on healing, columnar epithelium is replaced by squamous epithelium (squamous metaplasia).
What is the infective agent in a common cold? (1)
Rhinovirus
In allergic rhinitis, what tests can be used to identify triggers? (2)
Skin prick testing RAST testing (serum IgE levels for specific antibodies)
Which groups of patients should be offered the flu vaccine? (3)
Healthy children aged 2, 3 and 4 (live nasal injection)
Children at risk aged 2-17 (live nasal injection)
Children aged 6m-2years at risk of infection (inactive injection)
Pregnancy
Weakened immune system
Long term cardiac or respiratory problems
Over 65 years old
Steve, a 2 year old boy was eating some peanuts and started coughing and wheezing. Apart from inhalation, what other differential is important to consider? (1)
Anatomically where is the peanut most likely to be and why? (2)
How is the peanut best removed in an emergency or non-emergency? (2)
Anaphylaxis
Right bronchus, right is more vertical than the left.
Heimlich manoeuvre or bronchoscopy
What is the common term used to describe acute larynotracheobronchitis? (1)
What is the main infective cause? (1)
What is the management? (3)
Croup
Parainfluenza virus
Oxygen, oral or IM steroids, nebulised adrenaline.
What is the main infective cause of acute pharyngitis? (1)
What are the most common bacterial causes? (3)
How are they treated? (2)
Adenovirus, if more persistent and severe then may have secondary bacterial infection of Group A haemolytic streptococcus, staphylococcus aureus, haemophilus influenzae.
Treat viral causes symptomatically. Treat bacterial causes with phenoxymethylpenicillin 500mg qds for 10 days
What infection is oseltamivir used to treat? (1)
What is its mode of action? (1)
Influenza Neuramidase inhibitor (influenza virus has H and N antigens, N=neuramidase)
What is the most common complication of influenza? (1)
Viral or secondary bacterial pneumonia
Name 2 signs on examination that are associated with CO2 retention. (2)
Warm peripheries, bounding pulse, flapping tremor of outstretched hands, confusion in severe cases.
In a patient with COPD, what can contribute to reduced exercise tolerance apart from decreasing lung function? (2)
Skeletal muscle dysfunction caused by age, malnutrition, systemic inflammation, inactivity and hypoxia)
Describe the spirometry results of a patient with COPD. (4)
FEV1/FVC: <80%) in emphysema
Why might a patient with COPD become polycythaemic? (1)
Hypoxia causes increase in RBC production.
How many stages of COPD are there and how are they distinguished? (4)
What symptoms would you expect at each stage? (4)
4
Mild: FEV1 >80% - chronic cough
Moderate: FEV1 50-80% - SOB on exertion
Severe: FEV1 30-50% - SOB on minimal exertion, may have weight loss and depression
Very severe: FEV1<30% predicted - SOB at rest
What age of onset of COPD would be classed as early onset? (1)
What blood test would then be indicated? (1)
<40 years old
Alpha-1 antitrypsin serum levels
Apart from doctors name 3 other professionals involved in the MDT for a patient with COPD. (3)
Respiratory nurse specialists, physiotherapists, occupational therapists, dietitian, palliative care.
GP and respiratory physician
What bronchodilator therapy may be considered for a patient with COPD? (3)
What vaccinations should a patient receive? (2)
Long acting antimuscarinic (tiotropium) as once daily maintenance
Short acting b2 agonist to reduce acute symptoms
Long acting b2 agonist for persistent dyspnoea
Annual flu and once-off pneumococcal vaccine.
How can reversibility of COPD be assessed clinically? (2)
2 week course of 30mg prednisolone.
Spirometry before and after, if more than 15% reversible then add in inhaled corticosteroid.
Which groups of patients are eligible to consider long term oxygen therapy? (2)
How are patients assessed for LTOT? (1)
PaO2 s made at least 3 weeks apart in a stable patient who is receiving optimum treatment.
