Respiratory Failure

Question 1

What is respiratory failure?

Answer 1

Defect in pulmonary gas exchange leading to hypoxia

Question 2

What is hypoxia hypoxia?

Answer 2

PaO2 reduced

Question 3

What is anaemic hypoxia?

Answer 3

Reduced Hb

Question 4

What is stagnant hypoxia?

Answer 4

Reduced blood flow

Question 5

What is histotoxic hypoxia?

Answer 5

O2 can’t be used

Question 6

What are signs of respiratory compensation?

Answer 6

Tachypnoea, use of accessory muscles, nasal flaring, intercostal or suprasternal recession

Question 7

What are signs of increased sympathetic tone?

Answer 7

Tachycardia, hypertension, sweating

Question 8

What are signs of respiratory failure? (4)

Answer 8

Bradycardia and hypotension. Cyanosis from Hb desaturation. Flaps and bounding pulse from CO2 retention. End organ hypoxia leading to altered metal status.

Question 9

What is type 1 respiratory failure?

Answer 9

Hypoxaemia. PaO2 < 8kPa

Question 10

What is type 2 respiratory failure?

Answer 10

Hypoxaemia and hypercapnia. PaO2 < 8kPa. PaCO2 > 6.5kPa

Question 11

What are some causes of type 1 respiratory failure?

Answer 11

Pneumonia, pulmonary oedema, asthma, COPD, PE, pneumothorax, obesity, atelactasis, pulmonary confusion

Question 12

What’s the pathophysiology of type 1 respiratory failure?

Answer 12

Alveoli less perfused due to obstructed pulmonary vessels-> inc RH work-> dilation-> tricuspid leaks-> JVP rises

Question 13

How does type 2 respiratory failure develop? (3)

Answer 13

Loss of ventilation capacity, loss of chest wall ability, failure of central control of respiration

Question 14

How does the body respond to a drop in PaO2?

Answer 14

Picked up in aortic and carotid bodies. Nerve output from carotid via vagus to brainstem. O2 sensitive K+ channels and haem based cytochrome enzymes are responsible for local PaCO2.

Question 15

What is Cheyne Stokes breathing?

Answer 15

Alternating hypo and hyperventilation

Question 16

When does Cheyne Stokes happen?

Answer 16

Stage 1 sleep, newborns, altitude hypoxia, HF and uraemia. From inc sensitivity to PCO2 and prolonged lung-brain circulation

Question 17

What are some indications for oxygen therapy?

Answer 17

Respiratory failure, cardiac/ respiratory arrest, tachypnoea, cyanosis, hypotension, metabolic acidosis

Question 18

When would you use oxygen masks or nasal cannulae?

Answer 18

Normal vital signs eg post op

Question 19

When would you use an NRB?

Answer 19

When a higher O2 conc is needed- asthma, pneumonia, sepsis

Question 20

When would you use a venturi mask?

Answer 20

CONTROLLED treatment- long term respiratory failure eg COPD

Question 21

When would you use BiPAP?

Answer 21

Type 2 respiratory failure

Question 22

What are some indications for CPAP (respiratory failure)?

Answer 22

Chest wall trauma, pneumonia, OSA

Question 23

What is an important patient group that require Venturi masks?

Answer 23

COPD drivers that are hypoxia drivers- around 10%. Too much oxygen will cause them to stop breathing.