Week 1 - Pleural Space and Mediastinum Disease Flashcards
What is the pleural space?
Two membranes that surround the lungs that contain fluid.
A space between the two pleura which helps the lungs move and expand to fill with air.
How much fluid and what sort of pressure should there be in the pleural space?
0.1 ml/kg of fluid.
Negative pressure - acts as a suction to keep the lungs from collapsing.
What is the mediastinum and what does it contain?
The space between the pleural sac.
Contains blood vessels, nerves, oesophagus, trachea, heart, lymphatic vessels, thymus.
Why can’t patients breathe with pleural disease?
There is a loss of thoracic capacity = less room in the chest for the lungs to expand.
Severity depends on quantity of fluids, air or size of mass.
Known as restrictive disease
How to patients present with pleural space disease?
Restrictive breathing: short, shallow breathes
Tachypnea
Open mouth breathing
Dyspnoea
Orthopnoea
Cyanosis
Muffled heart sounds
Acute or chronic
How do you investigate pleural space disease?
Clinical exam
Percussion
Imagine (FAST, TFAST or radiography)
What can cause the loss of thoracic capacity?
Pleural effusion
Pneumothorax
Neoplasia
Ruptured diaphragm
Abdominal abnormality
Gross cardiomegaly
What is pleural effusion and what causes it?
Fluid in the pleural space (more than normal)
Causes:
- Decreased absorption (from parietal lymphatic vessels)
- Increased production (from parietal pleural vessels)
What are the three types of fluid that causes pleural effusion?
- Transudate
- Modified transudate
- Exudate (with cells)
If a suspected pleural effusion presented, what steps would you take?
- Oxygen supplementation
- Thoracic ultrasound (often too severely dyspneic to radiograph)
- Thoraconcetesis (sample fluid, diagnostic (cytology, cell count, protein, bacterial culture), relief from clinical signs, stabilise)
How is a thoracoentesis performed?
- Aspetic
- Local anaesthesia rarely needed
- Clip area
- Surgically prep skin
- +/- ultrasound guided
- Butterfly needle or catheter into ICS 6-8
- Insert chest drain fro effusions that quickly reappear or that need lavaging (pus present)
What is a transudate and what are the characteristics?
Low protein fluid -> caused by hypoalbuminaemia (low oncotic pressure) -> lead to a leakage of fluid out from the vascular compartment.
- Clear
- Protein <2g/l
- SG <1.018 (low)
- Few cells (if any)
What conditions can cause transudate?
Low protein
- Liver failure (failure of synthesis)
- Protein loosing enteropahty
- Protein loosing nephropahty
- Haemorrhage
- Starvation
- Hyperglobulinaemia (high globulin = low albumin)
What is a modified transudate and what are the characteristics?
High protein fluid -> caused by increased hydrostatic pressure
- Clear
- Protein 2-5 g/dL
- Few cells (if any)
What conditions can cause a modified transudate?
Common - secondary to right sided heart failure
Diaphragmatic hernia (no negative pressure)
Damage to pleural vessels which leak fluid
- Lung lobe torsion
- Neoplasia