Acute and critical care Flashcards
What is a pneumothorax? What causes it?
Air in the pleural space (which separates the lung from the chest wall).
Cuases: spontaneous, iatrogenic eg lung biopsy, mechanical ventilation, central line insertion; lung pathology eg infection, asthma, COPD
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How does pneumothorax present?
Young tall thin man, sudden SOB and pleuritic CP (worse on inspiration).
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What investigation would you do for pneumothorax and what would it show?
Erect chest x ray - shows area between lung tissue and chest wall, no lung markings, line demarcating pneumothorax
Need to measure size - horizontally from lung edge to inside of chest wall at level of hilum.
CT thorax can detect smaller pneumothorax
https://zerotofinals.com/medicine/respiratory/pneumothorax/
How is pneumothorax treated?
2010 BTS guidelines:
No SOB, <2cm - self resolving, FU in 2-4 weeks
SOB or >2cm - aspiration.
Aspiration fails twice –> use chest drain.
What is a tension pneumothorax?
When trauma to chest wall creates a one-way valve that lets air in but not out of pleural space. Therefore more air keeps getting drawn in with each breath, increasing pressure in thorax. Risk of arrest.
Give 5 signs that would indicate tension pneumothorax in a person with SOB.
Tracheal deviation away from side of pneumothorax,
reduced air entry to affected side,
Increased resonance to percussion on affected side, tachycardia, hypotension
How would you treat a tension pneumothorax?
Insert a large bore cannula into the second intercostal space in the midclavicular line, then chest drain.
How do you insert a chest drain safely?
Triangle of safety formed by the 5th ICS (inf nipple line), mid-axillary line, and anterior axillary line. Just above rib to avoid neurovascular bundle.
Then get CXR to check positioning.
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Describe the WHO analgesic ladder.
Mild pain - paracetamol, NSAID
Moderate pain - codeine, tramadol
Severe pain - morphine.
How does paracetamol work?
We dont know, the theories are that it works on cannabinoid receptors or is a COX inhibitor
What do you need to be cautious of when prescribing paracetamol?
Liver failure
Low weight eg kids/elderly (<50kg prescribe lower dose)
How do NSAIDs eg ibuprofen work?
Inhibit COX. COX makes prostaglandins. Prostaglandins cause inflammation. There are 2 types of PGs- COX-1 makes protective PGs, which protect GI mucosa against acid and facilitate platelet aggregation. COX-2 makes inflammatory PGs which promote recruitment of inflammatory cells, increases signal transduction from nociceptors.
How does aspirin work?
Inhibits a prostaglandin called thromboxane A2 which stops platelet aggregation, therefore thinning the blood.
What are the side-effects of NSAIDs?
Can worsen asthma (rarely) as NSAIDs reduce COX but increase LOX which makes leukotrienes.
Cause peptic ulcers as the protective PGs which protect the gastric mucosa are inhibited.
Reduce renal blood flow –> AKI
Thin the blood as they inhibit protective PGs which facilitate platelet aggregation.
Give 5 side-effects of opioids.
Sedation, miosis (pinpoint pupils), bradycardia, hypotension, resp depression, N+V, constipation, urinary retention, itching.
