Respiratory failure

Question 1

what is type 1 respiratory failure

Answer 1

hypoxic (PaO2< 8kPa) but with normal or low PaCO2

Question 2

what is type 1 respiratory failure caused by

Answer 2

ventilation/perfusion mismatch

Question 3

give examples of causes of type 1 resp failure

Answer 3

pneumonia, pulmonary oedema, PE, asthma, emphysema, pulm fibrosis, ARDS

Question 4

what is type 2 respiratory failure

Answer 4

hypoxic (PaO2 6kPa) and hypercapnic (PaCO2 > 6kPa)

Question 5

what is type 2 respiratory failure caused by

Answer 5

alveolar hypoventilation with or without ventilation perfusion mismatch

Question 6

examples of causes of type 2 failure

Answer 6

pulmonary (asthma, COPD, pneumonia); reduced respiratory drive (sedative drugs, CNS tumour, trauma); neuromuscular disease (cervical cord lesion, diaphragmatic paralysis, MG); thoracic wall disease (kyphoscoliosis)

Question 7

signs of hypoxia

Answer 7

dyspnoea, restlessness, agitation, confusion, central cyanosis. if longstanding- polycythaemia, cor pulmonale

Question 8

signs of hypercapnia

Answer 8

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

Question 9

investigations

Answer 9

bloods (FBC, U&E, CRP, ABG); radiology CXR, sputum and blood cultures if febrile, spirometry (COPD, neuromusc disease, Guillain Barre)

Question 10

management type 1

Answer 10

treat underlying cause, give O2 (35-60%) by facemask, assisted ventilation if PaO2<8kPa if 60% O2

Question 11

is the respiratory centre more sensitive to O2 or CO2

Answer 11

O2

Question 12

management type 2

Answer 12

treat underlying cause, 24% O2, recheck ABG after 20 mins- if PaCO2 steady or lower incr O2 conc to 28%. if PaCO2 has risen >1.5 and patient still hypoxic consider NIPPV. if fails- intubation, ventilation

Question 13

flow rate of nasal cannulae and % O2 delivered

Answer 13

1-4L/min. conc 24-40%

Question 14

problem with nasal cannulae

Answer 14

imprecise and can cause nasal soreness

Question 15

when do you not use a simple face mask and why

Answer 15

not very precise- don’t use in hypercapnia or type 2 failure. risk of CO2 accumulation if flow rate <5L/min

Question 16

what % do you start COPD patients with the venturi mask

Answer 16

24-28%

Question 17

what colour corresponds to what %O2.

Answer 17

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

Question 18

which type of oxygen administration is used to deliver high concentrations of oxygen

Answer 18

non rebreathing mask (have a reservoir bag)

Question 19

what % of O2 is delivered with a non rebreathing mask and flow rate

Answer 19

60-90%. 10-15ml/min

Question 20

what other ways are there apart from administering O2 to promote oxygenation

Answer 20

treat anaemia, improve cardiac output, chest physio to increase ventilation perfusion ratio

Question 21

when to consider ABG

Answer 21

unexpected deterioration; impaired consciousness/impaired resp effort, acute exacerbation chronic chest condition, signs CO2 retention, cyanosis, confusion