CVR - Respiratory failure

Question 1

What are the 3 classifications of respiratory failure?

Answer 1

• Acute
• Chronic
• Acute on chronic

Question 2

What is type 1 respiratory failure?

Answer 2

Hypoxemic:

• Failure of oxygen exchange
• PaO2 < 60 at sea level

Question 3

What is type 2 respiratory failure?

Answer 3

Hypercapnic:

- Failure to remove or exchange carbon dioxide

Question 4

What is type 3 respiratory failure?

Answer 4

Perioperative respiratory failure:

- Increased atelectasis due to low functional residual capacity

Question 5

What is type 4 respiratory failure?

Answer 5

Shock:

- Describes patients who are intubated and ventilated

Question 6

What are the risk factors for chronic respiratory failure?

Answer 6

• COPD
• Pollution
• Recurrent pneumonia
• Cystic fibrosis
• Pulmonary fibrosis
• Neuro-muscular diseases

Question 7

What are the risk factors for acute respiratory failure?

Answer 7

• Infection
• Aspiration
• Trauma
• Pancreatitis
• Transfusion

Question 8

Describe the mechanims of acute respiratory failure

Answer 8

• Injury can cause damage to the interstitium
• When the macrophages in the alveoli are activated by inflammation or infection, they will release cytokines IL-6, IL-8 and TNF-Alpha
• This can lead to fluid build up or protein rich edema in the alveoli
• This can inactivate or degrade surfactant which means the alveoli is less efficient at expanding
• Also, this causes leucocytes to be recruited and when they squeeze into the interstitium they can cause damage on their way to the target site
• These factors increase the distance from the alveolus to the blood vessel, reducing the effectiveness of gas exchange

Question 9

What therapeutic interventions are given to patients with ARDS?

Answer 9

Treat the underlying disease:

• Inhaled therapies
• Steroids
• Antibiotics
• Anti-virals

Respiratory support:

• Physiotherapy
• Oxygen
• Nebulisers
• Mechanical ventilation
• Non-invasive ventilation

Multiple organ support:

• CVR support
• Renal support
• Immune therapies

Question 10

What is the Murray lung injury score system?

Answer 10

A score system used to determine the severity of ARDS, takes into account:

• PaO2 (on 100% oxygen)
• CXR
• PEEP
• Compliance (ml/cmH20)

Question 11

What is ECMO and how does it work?

Answer 11

Extracorporeal mechanical oxygenation:

• A large cannular is passed through the groin and femoral vein usually, can be jugular or femoral vein
• It is then sat just in the IVC, below the right atrium
• Blood is the drawn through tubing and a pump is used to oxygenated the blood drawn
• The blood is them pumped back into the body, oxygenated

Question 12

What are the issues with ECMO?

Answer 12

• Time to access
• Referral system - geographic inequality
• Consideration of referral
• Cost