Respiratory failure

Question 1

What is the definition of type 1 and 2 respiratory failure?

Answer 1

Type 1 respiratory failure is less than 8kPa oxygen

Type 2 respiratory failure is less than 8kPa oxygen and greater than 6kPa carbon dioxide

Question 2

what is the physiology behind type 1 vs type 2 respiratory failure?

Answer 2

Type 1 respiratory failure is caused by a V/Q mismatch for example pneumonia
Type 2 respiratory failure is caused by hypoventilation

Question 3

What are some of the causes of type 1 respiratory failure?

Answer 3

Asthma
Pneumonia
Pulmonary oedema
PE
Asthma
Emphysema
Pulmonary fibrosis

Question 4

What are some of the causes of type 2 respiratory failure?

Answer 4

Chronic pulmonary disease (COPD, Asthma, sleep apnea)
Chest wall deformities
Neuromusclular disease e.g. cervical cord lesion
Reduced respiratoy drive e.g. sedative drugs

Question 5

What are the clinical features of hypoxia?

Answer 5

Dyspnoea
Restlessness
Agitation
central cyanosis
Confusion

Question 6

What are the clinical features of hypercapnia?

Answer 6

Headache
Peripheral vasodilation
tachycardia
Bounding pulse
Retention tremor

Question 7

What is are the saturations to aim for in a patient without chronic respiratory disease?

Answer 7

94-98%

Question 8

What are the saturations to aim for in patients who have chronic respiratory disease?

Answer 8

88-92%

Question 9

What are the causes of restrictive lung defect?

Answer 9

Obesity
Interstitial lung disease
Chest wall deformity
Neuromuscular disoders

Question 10

Why does hypoventilation cause type 2 respiratory failure?

Answer 10

CO2 diffuses 20 times as fast as O2 across the alveoli so the critical part of CO2 movement is ventilation

Question 11

What sort of percentage oxygen is given by nasal cannulae?

Answer 11

Given at a flow rate of 1-4L the percentage O2 is 24 - 40%

Question 12

What percentage oxygen do non rebreathe masks give?

Answer 12

They give 60-90% oxygen and should be used on a flow rate of 15L/min