Breathing Flashcards
What are the applications of flexible bronchoscopy?
Therapeutic and Diagnostic
- visualisation of pathology
- sampling eg Bronchoalveolar lavage
- Difficult intubations
- Direct opening eg retrieval or stenting
Why might you pick rigid vs flexible bronchoscopy?
Rigid allows for greater suction and more instrumentation
What is Tidal Volume? and roughly what value is it?
Tidal Volume = volume in and out in one cycle
Roughly 7ml/kg ~500ml
What are inspiratory and expiratory reserve volumes?
This is the volume above and below quiet respiration and tidal volume
IRV is around 3L
ERV is around 1.3L
What is the Inspiratory Capacity?
Inspiratory Capacity = Tidal Volume + Inspiratory Reserve Volume
What is Vital Capacity?
Vital Capacity = Tidal Volume + both inspiratory and expiratory reserve volumes
What is Residual Volume?
Residual Volume = gas remaining after maximum expiration
What is Total Lung Volume?
Total Lung Volume = Vital Capacity + Residual Volume
What is Function Residual Capacity? and what increases it?
Functional residual capacity = Expiratory reserve + respiratory volume ~3L
This is increased in:
1. COPD/Asthma (obstructive)
2. PEEP eg CPAP
How do you differentiate obstructive vs restrictive lung disease
Use spirometry:
Obstructive: FEV1/FVC < 0.8
Restrictive: FEV1/FVC > 0.8
What is atelectasis?
Atelectasis is collapse (loss of gas) in any section of lung
What is absorption atelectasis?
Oxygen is absorbed more readily than nitrogen
over oxygenation causes collapse
What are the causes of post-op atelectasis?
- Increased secretions
- Pain causing reduced tidal volume
- Over oxygenation and absorption atelectasis
- Patient: High BMI, Smoking, COPD
What is Bronchiectasis?
Irreversible dilatation of the bronchi (due to infection) and impaired clearance of secretions
Presents clinically as obstructive
What are the common causes of bronchiectasis and how can they be categorised?
Congenital:
1. Cilliary Dyskinesia (Kartagener’s)
2. Cystic Fibrosis (most common)
3. Immunodeficiency (multiple infections)
Acquired:
1. Repeated acute and chronic inflammation (eg infection)
2. Obstruction (eg tumours/foreign body)
3. Others eg aspergillosis, Rheumatoid, UC
What is the management of bronchiectasis?
- Treat underlying cause (eg infections/airway obstruction)
- Medical (eg bronchodilators and steroids)
- Symptomatic (eg physio)
- Definitive ( eg surgery - RARE)
What is the definition of pneumonia?
Inflammatory condition of the lung, characterised by exudative consolidation
What are the phases of lobar pneumonia?
- Acute congestion (to day 2): hard, firm, lots of exudate
- Red hepatisation (to day 4): firm, red, consolidated with red cells and inflammatory cells
- Grey hepatisation (to day 6): firm, grey, consolidated with fibrin
- Resolution (day 8 to 3 weeks): macrophages break down exudate
What are the common complications of pneumonia?
- Type I respiratory failure
- Pleuritis (extensive adhesions)
- Pleural effusion
- Empyema
- Abscess (local or systemic)
- Sepsis
What is the definition of ARDS?
- Respiratory failure + persistent inflammatory disease
2. Causes: reduced compliance, hyperaemia, pulmonary oedema
What are the phases of ARDS?
- Inflammatory: local complement, immune cells, increased permeability
- Proliferative: increased dead space with fibrosis and scarring
- Progressive: extensive fibrosis and loss of alveolar structure
Which cells produce surfactant?
Type 2 Pneumocytes
How do you manage ARDS?
- Manage initial insult
- Nutritional Support
- Mechanical ventilation to eliminate CO2
- Smaller tidal volumes
- Prone positioning
- Fluid management
- Nitric Oxide for vasodilatation
Define Flail Chest
3 or more ribs broken in 2 or more places
How does a flail segment present?
Paradoxical movement during respiratory cycle
Causes reduced tidal volumes and atelectasis
What is a sucking chest wound?
Open chest wall injury larger than 2/3rds of trachea.
air preferentially enters via this.
causes a large tension pneumothorax
treated with a flutter valve
What are the risk factors for DVT?
Intrinsic: 1. Age 2. Cancer 3. Dehydration and sepsis 4. Haematological 5. Previous thrombotic events 6. Endocrine eg COCP Surgical: 1. Stasis from major surgery and immobilisation
Where do DVTs usually occur?
Deep veins of the calves
venous plexus in soleus.
What are you likely to see in obs and ABG of a PE?
hypoxia - V/Q mismatch due to decreased blood flow
hypocarbia - due to hyperventilation
tachycardia - due to right sided ventricular strain
what is the treatment of a PE?
- LMWH
- Anticoagulation
- Thrombolytic agents
- Catheter dislodge or surgery
What are the normal ranges of PaO2 and PaCO2?
PaO2: 10.6 - 13.3kPa
PaCO2: 4.7 - 6.0kPa
How do you classify Respiratory Failure?
Type 1: low O2 - V/Q mismatch. This causes increased CO2 which leads to hyperventilation. PaO2 <8kPa
Type 2: ventilatory failure. alveolar hypoventilation causing hypercarbia. PaCO2 > 6.7kPa.
Mixed = Type 1 causing tiredness and leading to type 2
Examples of Type 1 Respiratory failure?
Shunting: Eisonmenger’s, congenital shunt
V/Q Mismatch: PE, Pneumonia, Pneumothorax, Oedema, Bronchiectasis, Fibrosis
Examples of Type II Respiratory failure?
Lung parenchyma issues: COPD, asthma, fibrosis, OSA
Neuro issues: stroke, head injury, drugs
Neuromuscular: MND, guillan barré
Outline the equipment and steps for a surgical chest drain.
Equipment:
sterile pack - drapes, swab. Needles, scalpel. curved clamps, suture kit. Local anaesthetic. chest drain, tubing and drainage.
Procedure:
- Mark: based on CXR or 5th IC space
- prep and drape clavicle to pelvis
- Local: anaesthetic lidocaine layer by layer to pleura
- Incision and blunt dissection
- secure the incision
- insert chest drain
- connect to underwater drainage and check for bubbling.
