1. Chest p99-103 (Trauma & Lines/Devices)

Question 1

Diaphragmatic injury - trivia (4)

Answer 1

Left side 3x more common than right (liver = buffer),
Most ruptures are radial, longer than 10cm, posterolateral position.
Collar sign (hourglass sign) - waist like appearance of herniated organ through injured diaphragm
Dependent viscera sign - Absence of interposition of the lungs between the chest wall and upper abdominal organs (Liver on right, stomach on left).

Question 2

Tracheo-bronchial injury - features (3)

Answer 2

Uncommon, usually within 2cm of carina.
Injury close to carina will cause pneumomediastinum rather than pneumothorax.
Tracheal laceration most common at junction between cartilaginous and membranous mediastinum.

Question 3

Macklin effect - features (2)

Answer 3

Commonest cause of pneumomediastinum in trauma.
Alveolar rupture from blunt trauma, air dissects along bronchovascular sheaths into mediastinum

Question 4

Boerhaave syndrome

Answer 4

Ruptured oesophageal wall due to vomiting, resulting in pneumomediastinum/mediastinitis.

Question 5

Flail chest

Answer 5

Defined as 3 or more comminuted rib fractures or >5 adjacent rib fractures.
Paradoxical motion with breathing.

Question 6

Pneumothorax vs tension pneumothorax

Answer 6

Inversion or flattening of the ipsilateral diaphragm suggests tension

Question 7

Malpositioned chest drain (3)

Answer 7

Can be malpositioned into parenchyma, more likely in background lung disease or pleural adhesions.
Blood around tube.
Bronchopleural fistula can occur.

Question 8

Haemothorax

Answer 8

Pleural fluid in trauma is probably blood. Density 35-70HU.

Question 9

Extrapleural haematoma (4)

Answer 9

Injury to chest wall but parietal pleura is still intact (otherwise it’s a haemothorax).
Classic “persistent fluid collection after pleural drain placement”
Buzzword “displaced extrapleural fat”.
Biconvex appearance is more likely arterial, watch for rapid expansion.

Question 10

Pulmonary contusion (4)

Answer 10

Commonest injury from blunt trauma.
Alveolar haemorrhage without alveolar disruption.
Non-segmental ill defined areas of consolidation with sub-pleural sparing.
Should appear within 6hrs and disappear within 72.

Question 11

Pulmonary laceration (3)

Answer 11

Tear in lung, looks like a pneumatocele with gas-fluid level in it.
Can be masked by surrounding haemorrhage early on.
Laceration resolves slowly compared to contusion, can produce nodule or mass persisting for months.

Question 12

Aortic injury (3)

Answer 12

Commonest site is aortic isthmus. Then root, then diaphragm.
Usually obvious on CTA.
Ductus bump (normal variant) can be a mimic.

Question 13

Blunt cardiac injury (2)

Answer 13

Suggested by haemopericardium in setting of trauma.
Correlate with cardiac enzymes and ECG.

Question 14

Fat embolisation syndrome - features (3)

Answer 14

Seen in long bone fractures or IM nail placement.
Fat embolised to lungs, brain and skin (clinical triad of rash, altered mental state and shortness of breath).
Occurs 1-2 days after fracture, better after 1-3 weeks if survive

Question 15

Fat embolisation syndrome - imaging (2)

Answer 15

Lungs have ground glass appearance like pulmonary oedema.
No filling defect like PE.

Question 16

Barotrauma

Answer 16

Positive pressure ventilation can cause alveolar injury, air dissecting into the mediastinum (Causing pneumomediastinum and pneumothorax).
Acute lung injury or COPD have high risk of barotrauma from ventilation.
Pulmonary fibrosis is protective, lungs dont stretch.

Question 17

Central lines - trivia (2)

Answer 17

Abrupt bend at the tip, near the cavo-atrial junction = azygous.
Left side of heart is either arterial or in a duplicated SVC.

Question 18

Hot quadrate sign

Answer 18

Hyperenhancing segment IV of liver, associated with SVC obstruction, consider if central line present.

Question 19

Endotracheal tube positioning (3)

Answer 19

Tip should be 5cm from carina, halfway between carina and clavicles.
Will go up and down with the chin.
Intubation of right main bronchus is common, with left lung collapse.

Question 20

Intra-aortic balloon pump (IABP)

Answer 20

Used in cardiogenic shock for “diastolic augmentation” - provised baclk pressure to help improve perfusion of great vessels of arch

Question 21

Function of IABP

Answer 21

Decreased LV afterload and increased myocardial perfusion.

Question 22

Correct location of IABP

Answer 22

Balloon in proximal descending aorta, just below origin of left SCA.

Question 23

Complications of IABP

Answer 23

Dissection during insertion,
Obstruction of left SCA from malpositioning.