2.12 - Respiratory Failure

Question 1

What are the two types of respiratory failure?

Answer 1

Type 1: Hypoxaemic respiratory failure

Type 2: Hypercapneic respiratory failure

Question 2

What is the definition of Type 1 respiratory failure

Answer 2

Arterial partial pressure of oxygen (PaO2) < 60mmHg when breathing room air

Question 3

What is the definition of Type 2 respiratory failure

Answer 3

Arterial partial pressure of carbon dioxide (PaCO2) >45mmHg

Question 4

Describe hypoventilation

Answer 4

Total ventilation = tidal volume x respiratory rate

Hypoventilation can be due to inadequate tidal volume or respiratory rate

Question 5

What are some signs of respiratory failure?

Answer 5

The patient is showing signs of respiratory compensation:
• tachypnoea
• use of accessory muscles
• nasal flaring
• intercostal, suprasternal or supraclavicular recession
Increase sympathetic activity:
• Tachycardia
• Hypertension
• Sweating

Question 6

How do you determine if the respiratory failure is chronic or acute?

Answer 6

Is there any compensation?
CO2 +H2O H2CO3 HCO3- + H+
Acute respiratory failure develops in minutes to hours and there is no opportunity for compensation
Chronic RF that has been present for more than 24 hours will lead to compensation
-Increased HCO3- with type 2 respiratory failure
-Decreased HCO3- with type 1 respiratory failure