Oxygen and resp failure

Question 1

type 1 resp failure

Answer 1

short of oxygen

Question 2

type 2 resp failure

Answer 2

short of oxygen

too much CO2

Question 3

hypoventilation leads to _____ which leads to _____

Answer 3

hypoxaemia

hypercabia

Question 4

if in doubt regarding type of resp failure what should be carried out

Answer 4

blood gas

Question 5

primary hypoxia bad lungs

Answer 5

low pO2/ high pCO2/ normal HCO3
acidosis
low pO2/ high pCO2/ high HCO3
virus
low pO2/ very high pCO2/ high HCO3
acidosis

Question 6

anaesthetic opinion on giving O2

Answer 6

hypoxia = bad
hypoxia = kills you
hypoxaemia = main cause of hypoxia
reverse all hypoxia
CO2 worry about later

Question 7

chest physician opinion on giving O2

Answer 7

type 2 resp failure = very common
hypercarbia = damaging
O2 poisons
stop O2

Question 8

oxygen in A + E

Answer 8

all O2

Question 9

oxygen in AMU

Answer 9

controlled O2

Question 10

oxygen in ICU

Answer 10

all O2 again

Question 11

prescribing O2

Answer 11

O2 = drug

always ensure = prescribed

Question 12

1st rule =

Answer 12

only give O2 if risk/ benefit ratio is in favour of O2

some people = very sensitive to O2

Question 13

as pO2 rises =

Answer 13

pCO2 rises

• acidosis
• can be severe
• can be life threatening

Question 14

bad lungs =

Answer 14

low pO2/ high pCO2/ normal HCO3
acidosis
low pO2/ high pCO2/ high HCO3
O2 given
high pO2/ very high pCO2/ high HCO3
acidosis

Question 15

COPD patients T2RF

Answer 15

high risk of developing it

1/5 COPD patients

Question 16

Areas of poor ventilation =

Answer 16

reactive vasoconstriction
excess O2 + reactive vasoconstriction = reserves
perfusion = good
ventilation = poor

Question 17

effect of pCO2 on haemoglobin

Answer 17

haldane effect
-O2 can displace CO2 from Hb

bohr effect
-high concn of CO2 = prevent O2 binding to Hb

Question 18

pCO2 Bohr Effect

Answer 18

shifts dissociation curve

Question 19

Theory of Hypoxic Drive

Answer 19

normal respiration = driven by CO2 chemoreceptors
chronic hyperbia = destination of receptors
O2 chemoreceptors = primary respiration drive

Question 20

Treat Hypercarbia

Answer 20

Conservative O2 management 
SaO2 88-92%
increase Vminute
-RR = usually already high
-increase Vt with NIV

Question 21

Severe hypoxaemia

Answer 21

Altered mental state
Cyanosis
Dyspnoea
tachypnoea
Arrhythmias
-tissue hypoxia

pO2<5.3kPa = hyperventilation increases dramatically

4. 3kPa = loss of consciousness
5. 7kPa = death

Question 22

circulatory hypoxia

Answer 22

O2 blood needs to get to tisses

Question 23

global reduction - circulatory hypoxia

Answer 23

heart failure

Question 24

local reduction - circulatory hypoxia

Answer 24

obstruction of vessels
oedema
compression
compartment syndrome

Question 25

types of hypoxia

Answer 25

circulatory hypoxia anaemic hypoxia toxic hypoxia hypoxaemic hypoxia

Question 26

hypoxaemic hypoxia

Answer 26

low inspired O2 concn

Question 27

impaired diffusion

Answer 27

failure of alveolar - endothelial surfaces

Question 28

interstitial thicking

Answer 28

pulmonary fibrosis lymphangitis sarcoidosis

Question 29

vascular dysfuction

Answer 29

pulmonary vasculitis | endothelial malignancy

Question 30

what is required for transfer of O2 from airway to blood

Answer 30

adequate perfusion | adequate ventilation

Question 31

perfusion without ventilation

Answer 31

shunting

Question 32

ventilation without perfusion

Answer 32

dead space

Question 33

lung apex

Answer 33

good v | poor Q

Question 34

lung base

Answer 34

poor V | good Q

Question 35

where should perfusion be directed

Answer 35

areas of best ventilation

Question 36

steps patient = hypoxia

Answer 36

``` which bit = failing cardiac output haemoglobin poisoning then lungs ```

Question 37

patient = hypoxaemia

Answer 37

``` O2 given (not for breathlessness) reversal hypoxaemia = not always beneficial high flow/ concn O2 = rarely beneficial ```

Question 38

high flow, high concn O2 therapy used for

Answer 38

cluster headaches CO poisoning pneumothorax - no chest drain sickle cell crisis

Question 39

If SaO2 greater than or equal to 90%

Answer 39

no O2

Question 40

COPD SaO2

Answer 40

88-92%

Question 41

90-94%

Answer 41

everything bar COPD

Question 42

Vmin =

Answer 42

Vt x RR

Question 43

Vmin @ rest

Answer 43

5-40l

Question 44

Vmin when unwell

Answer 44

400l

Question 45

nasal cannulae

Answer 45

well tolerated low flow only uncontrolled FiO2 Nasal breathing dependent

Question 46

variable performance mask

Answer 46

cheap and simple 5-15l/min uncontrolled fiO2 unable to cope with high flow requirements

Question 47

venturi mask

Answer 47

fixed performance | flows of up to 250 l/min

Question 48

non-rebreathing mask

Answer 48

``` up to 85% FiO2 uncontrolled fiO2 flow limited to outflow of wall beware large Vt Indications for mask = now very few (CO poisoning, PTX, cluster headaches, sickling crisis) ```