Pneumothorax

Question 1

What happens to pressure in the lungs on inspiration?

Answer 1

• Intrathoracic pressure drops
• Air moves from high pressure (outside body) to low pressure (inside lungs)
• Pleural space is sealed off so no air can move into potential space

Question 2

What happens to pressure in the lungs at the end of inspiration?

Answer 2

• Pressures have equalised between lung and atmosphere
• Larger pressure difference between pleural space and inside of lungs

Question 3

What allows a pneumothorax to form?

Answer 3

• If pleura is broken, air will move into potential pleural space
• Because pleural space has much lower pressure than both inside lung and outside body

Question 4

What happens if a pneumothorax is small?

Answer 4

• If damage to pleura is small, it may seal itself spontaneously
• Especially if there is little pressure difference between pleural space and inside lungs

Question 5

What are the categories of pneumothorax?

Answer 5

• Primary (healthy)
• Secondary (underlying lung pathology)
• Iatrogenic
• Can be simple or tension pneumothorax

Question 6

What symptoms might someone having a pneumothorax experience?

Answer 6

• Sharp and stabbing pain
• Can point to location of pain with a finger
• Pain doesn’t move or worsen
• Normal breathing
• Normal ECG and bloodwork

Question 7

What is an important diagnostic test if a pneumothorax is suspected?

Answer 7

• CXR

Question 8

What is a simple spontaneous primary pneumothorax?

Answer 8

• Small tear in visceral pleura
• Air leaks into pleural space when breathing in
• Pleura seals itself
• Air in pleural space is reabsorbed

Question 9

How are small pneumothoraxes treated?

Answer 9

• If patient is not breathless and pneumothorax is <2cm
• Patient can be discharged home from A&E
• Follow up in 2 weeks with CXR

Question 10

What is a simple spontaneous secondary pneumothorax?

Answer 10

• Underlying lung pathology punctures pleura
• More air escapes into pleural space
• Puncture seals itself once pressure is reduced

Question 11

What might cause a pneumothorax in COPD patients?

Answer 11

• Blebs/Bullae can rupture
• Outpouchings from COPD - they are thin walled

Question 12

How is a simple spontaneous secondary pneumothorax treated?

Answer 12

• Needle aspiration of up to 2.5L
• High flow oxygen + observe for 24 hours
• May need a chest drain

Question 13

Outline how needle aspiration is carried out?

Answer 13

• Using a needle, valve and syringe
• Small amount of water in syringe
• Push through chest wall until air bubbles appear in syringe (indicates that an airspace has been entered
• Can aspirate up to 2.5L

Question 13

How do we know where to insert a needle for aspiration of a pneumothorax?

Answer 13

• Anatomical safe triangle
• Insert into 4th or 5th intercostal space
• No major blood vessels
• Avoid neurovascular bundle

Question 14

What are the borders of the anatomical safe triangle?

Answer 14

• Anterior border of Latissimus Dorsi
• Posterior edge of pectoral major
• Axilla superiorly
• Inferior border is 5th intercostal space

Question 15

What kind of oxygen therapy is used to treat pneumothorax?

Answer 15

• High flow oxygen even if sats are normal
• High concentration of O2 in pleural space
• Oxygen is reabsorbed faster than nitrogen (body can reabsorb O2 in pleural space)
• Significantly better resolution compared to no oxygen therapy

Question 16

What does low pO2 mean in a pneumothorax?

Answer 16

• Concentration of dissolved O2 in blood is low
• Gas exchange significantly impaired due to reduced SA of lung

Question 17

Why does the lung shrink in pneumothorax?

Answer 17

• Lung collapses
• Pleural seal is lost
• No suction holding lung to wall
• Elastic recoil of lung causes it to shrink/collapse

Question 18

What could cause a simple iatrogenic pneumothorax?

Answer 18

• Punctured parietal and visceral pleurae e.g. caused by needle
• If too much of visceral layer tears, air enters pleural cavity
• Harder for pleural cavity to seal itself

Question 19

How are larger simple pneumothoraxes treated?

Answer 19

• Very symptomatic
• Type 1 respiratory failure
• Unlikely to resolve spontaneously
• Will need a chest drain

Question 20

How does a water-sealed chest drain work?

Answer 20

• Inserted in safe triangle
• Tube left in pleural cavity
• Free end submerged in water
• Creates a 1-way valve
• Keep drainage below patient to prevent siphoning
• ‘Swinging and bubbling’ means drain is working

Question 21

What is a tension pneumothorax?

Answer 21

• Sometimes damaged pleura forms a one way valve
• Very bad!
• Each breath fills pleural cavity and increases its pressure
• Air can’t escape on exhalation so pleural cavity is filled with more and more air
• Increased pressure collapses lung and compresses heart
• Squashed heart can’s pump blood

Question 22

How is emergency needle decompression carried out?

Answer 22

• If tension pneumothorax is suspected, decompress before any investigations
• Do not wait to get a CXR
• 2nd intercostal space midclavicular line
• Will buy time for a chest drain
• 30% failure rate

Question 23

What are the signs of a pneumothorax?

Answer 23

• Reduced breath sounds
• Hypoxia
• Hyper resonance
• Flail segment
• Surgical emphysema

Question 24

What are the symptoms of a pneumothorax?

Answer 24

• Pleuritic chest pain
• SOB
• Sudden onset

Question 25

What is a pleural effusion?

Answer 25

• Instead of air, pleural space is filled with fluid
• Haemothorax = blood
• Chylothorax = Lymph
• Empyema = pus
• Fluid settles at bottom of lungs