12. Respiratory Failure

Question 1

What are the two types of respiratory failure?

Answer 1

Hypoxia (<8kPa) with low or normal paCO2- Type 1

Hypoxia (<8kPa) with hypercapnia (>6kPa)- Type 2

Question 2

What causes type 1 respiratory failure

Answer 2

Primarily caused by V/Q mismatch, hypoventialtion, abnormal diffusion, right to left cardiac shunts

Pneumonia
Plmonary oedema
PE
Asthma
Emphysema
Pulmonary fibrosis
ARDS

Question 3

What causes type 2 respiratory failure

Answer 3

Caused by alveolar hypoventialtion. Causes include:

Pulmonary disease
Reduced respiratory drive
Neuromuscular disease
Thoracic wall disease

Question 4

What are the clinical signs of hypoxia?

Answer 4

Dyspnoea, Restlessness, agitation, confusion, central cyanosis, polcythemia, pulmonary hypertension, cor pulmonale, clubbing

Question 5

What are the clinical signs of hypercapnia?

Answer 5

Headache, peripehral vasodialtion, tachycardia, bounding pulse, tremor/flap, papilloedema, confusion, drowsiness, coma

Question 6

What investigations should be done for respiratory failrue?

Answer 6

Blood tests,
Radiology
Microbiology, sputum and blood cultures (if febrile)
Spirometery

Question 7

How do you treat type I respiratory failure?

Answer 7

Treat underlying cause?
Give oxygen up to 60% oxygen
Assisted ventilation if PaO2 <8Kpa despite 60% O2

Question 8

How do you treat type II respiratory failure?

Answer 8

Treat underlying cause
Controlled oxygen therapy (24%)
Re-assess after 20 mins on 24%. If hypercapnia improving then try moving to 28%.
If this fails try alternative ventilation such as NIPPV
If this fails consider intubation and mechanical ventilation

Question 9

When should you consider doing an arterial blood gas?

Answer 9

Any unexpected deterioration in an ill patient
Anyone with an acute exacerbation of a chronic chest condition
Anyone with impaired concioussness or impaired respiratory effort
Signs of CO2 retention (bounding pulse, drowsy, tremor, headache)
Cyanosis, confusion, visual hallucination, low sats

Question 10

What is important to consider about prescribing oxygen?

Answer 10

Titrate the amount guided by the patients SaO2 and clinical condition. Humidification is required with long term oxygen therapy.

Question 11

What are the advantages and disadvantages of delivering oxygen via a nasal cannulae?

Answer 11

Patients prefer it

Causes nasal soreness
Imprecise delivery

Question 12

What is involved when using a venturi mask

Answer 12

Provdies a precise percentage or fraction of oxygen delivery at high flow rates.

Question 13

What is a non-rebreather mask?

Answer 13

Mask with bag on it, used in emergencies.

Not very precise so not used in long term therapy