5) Resp Failure

Question 1

Clinically what is respiratory failure?

Answer 1

• PaO2 of <8KPa

- Roughly sats of <90%

Question 2

Definition of T1 resp failure?

Answer 2

Hypoxaemic Resp Failure

-Pao2 of < 8 kpa with normal or low CO2

Question 3

Definition of T2 resp failure?

Answer 3

Hypercapnic resp failure
-Pao2 of < 8kpa with CO2 over 6.1kpa
(if patient is on o2, the Pao2 may appear normal)

Question 4

Causes of T1 resp failure?

Answer 4

Primarily due to V/Q mismatch

• Stuff going in: Low o2, CO poisoning
• Ventilation issues: airway obstruction (tumour), COPD, Asthma, bronchiectasis
• Alveolar issues: Pneumonia, hemorrhage, pulm. oedema

-ILD
-ARDS
-PE
,

Question 5

Causes of t2 resp failure?

Answer 5

Alveolar hypoventilation, problem anywhere in the chain:

Reduced Drive: sedatives, opiates, CNS tumour/trauma

NMD: Cervical cord lesions, diaphragmatic paralysis, polymyositis, MND, M.G, guillan barre

Chest Wall: Trauma, kyphoscoliosis, fat

Pulm. Disease: asthma, copd, osa, end stage fibrosis

Question 6

Clinical features of resp failure?

Answer 6

Those of underlying cause, hypoxia and maybe hypercapnia

Question 7

Clinical features of hypoxia?

Answer 7

Dyspnoea
restlessness
agitation
confusion
cyanosis

Question 8

Clinical features of longstanding hypoxia?

Answer 8

-polycythaemia
pulmonary HTN
Cor pulmonale

Question 9

Clinical features of hypercapnia?

Answer 9

Headache, bounding pulse, peripheral vasodilation, tachycardia, tremor/flap, papilloedema, confusion, drowsy, coma

Question 10

What causes the headache in hypercapnia?

Answer 10

Cerebral vasodilatation

Question 11

What ix should be done in resp failure?

Answer 11

ABG (VBG often done in A+E)
FBC, U+E, CRP
CXR
If febrile cultures and sputum
Spirometry if COPD, NMD, guillan barre

Question 12

Main differences in ABG and VBG?

Answer 12

CO2 is higher in VBG, O2 lower

Question 13

Management of t1 resp failure?

Answer 13

• Treat cause
• 02 35-60% via mask
• assissted ventilation if <8 despite 60% 02

Question 14

Management of t2 resp failure?

Answer 14

Target sats 88-92%

• treat cause
• start 02 at 24% (blue venturi)
• repeat ABG in 20 mins to see what CO2 is doing, if coming down/stable inc. o2 to 28%
• If risen >1.5 then NIV
• in COPD after 1 hr no improvement NIV
• if nothing is helping then IV (need to be on ITU and sedated)

Question 15

Difference btw NIV and IV clinically?

Answer 15

NIV: on ward, alert
IV: sedated, ITU

Question 16

Indications for ABG?

Answer 16

• Deterioration
• acute exacerbation of chronic condition
• impaired consciousness/resp effort
• CO2 retention signs
• Hypoxic signs

Question 17

when is humidification required in o2 therapy?

Answer 17

• LT
• trache
• can increase expectoration in bronchiectasis

Question 18

Nasal cannulae specs?

Answer 18

flow rate of 1-4L/min
gives 24-40%
useful to maintain o2 when nebs need to be given by air

Question 19

Simple mask use/specs?

Answer 19

VAriable amount of 02, far less precise and risk of co2 accumulation if <5L/min (accumulates in mask)

Question 20

Venturi colours?

Answer 20

24%- blue
28%- white
35%- yellow
40% red
60% green

Question 21

Non rebreath mask use?

Answer 21

high conc o2 (60-90%) at 10-15L. common in emergencies but dont use for controlled therapy

Question 22

Other ways to increase oxygenation without o2?

Answer 22

• treat anaemia
• treat HF and improve CO
• Chest physio for V/Q mismatch