Respiratory failure

Question 1

What is respiratory failure?

Answer 1

acute or chronic impairment of gas exchange between lungs and blood causing hypoxia with or without hypercapnia
PaO2 <8kPA

Question 2

What are RF for resp failure?

Answer 2

1. Tobacco use
2. Young age
3. Old age
4. Resp system illness
5. Injury or infection
6. Cardiac failure
7. Hypercoaguable states

Question 3

What is T1 resp failure?

Answer 3

hypoxia with normal or low PaCO2

Question 4

What is T1 resp failure caused by?

Answer 4

1. ventilation/perfusion mismatch
2. hypoventilation
3. abnormal diffusion
4. right to left cardiac shunts

Question 5

What are examples of V/Q mismatch?

Answer 5

1. Pneumonia
2. Pulmonary oedema
3. PE
4. Asthma
5. Emphysema
6. Pulmonary fibrosis
7. ARDS

Question 6

What is T2 resp failure?

Answer 6

hypoxia with hypercapnia (PaCO2>6kPA)

Question 7

What is T2 resp failure caused by?

Answer 7

alveolar hyperventilation with or without V/Q mismatch

Question 8

What are 4 key causes of T2 resp failure?

Answer 8

1. Pulmonary disease
2. Reduced resp drive
3. Neuromuscular disease
4. Thoracic wall disease

Question 9

What pulmonary disease causes T2 resp failure?

Answer 9

1. asthma
2. COPD
3. pneumonia
4. end-stage pulmonary fibrosis
5. OSA

Question 10

What causes reduced resp drive?

Answer 10

1. sedative drug

2. CNS tumour or trauma

Question 11

What neuromuscular disease causes T2 resp failure?

Answer 11

1. cervical cord lesion
2. diaphragmatic paralysis
3. poliomyelitis
4. myasthenia gravis
5. GB syndrome

Question 12

What thoracic wall disease can cause T2 resp failure?

Answer 12

1. flail chest

2. kyphoscolisosis

Question 13

What are signs and symptoms of hypoxia?

Answer 13

1. Dyspnoea
2. Restlessness
3. Agitation
4. Confusion
5. Central cyanosis

Question 14

What could long standing hypoxia cause?

Answer 14

1. polycythaemia
2. pulmonary hypertension
3. cor pulmonale

Question 15

What are signs of hypercapnia?

Answer 15

1. Headache
2. Peripheral vasodilation
3. Tachycardia
4. Bounding pulse
5. Tremor/flap
6. Papilledema
7. Confusion
8. Drowsiness
9. Coma

Question 16

What are possible DDx for resp failure?

Answer 16

1. Hyperventilation secondary to metabolic acidosis
2. Hyperventilation secondary to anxiety
3. Sleep apnoea
4. Obesity

Question 17

What bloods are done for resp failure?

Answer 17

1. FBC
2. U+Es
3. CRP
4. ABG

Question 18

What other investigations are done for resp failure?

Answer 18

1. CXR
2. Microbiology sputum and blood cultures (if febrile)
3. Spirometry: COPD, neuromsuclar disease, GB syndrome
4. ABG
5. Pulse OX

Question 19

What is the management for T1 resp failure?

Answer 19

1. Treat underlying cause
2. Give oxygen (24-60%) facemask
3. Assisted ventilation if PaO2<8KPa despite 60% O2

Question 20

How is the resp centre affected in T2 resp failure?

Answer 20

may be relatively insensitive to CO2 and respiration may be driven by hypoxia

Question 21

What is the management of T2 resp failure?

Answer 21

1. Treat underlying cause
2. Controlled oxygen therapy: start 24%
3. Recheck ABG after 20min – if PaCO2 raised >1.5KPA and patient still hypoxic consider assisted ventilation: NIV
4. Consider intubation and ventilation

Question 22

What are possible complications of resp failure?

Answer 22

1. Pneumothorax
2. Endotracheal tube misplacement or dislodgement ]
3. Dental injury with intubation
4. Infection from CPAPA or BIPAP