O2 delivery + pulse oximetry

Question 1

Anaesthetic agents exert a ?-dependant depression on the sensitivity of central
?, reducing the stimulatory effect of ?, As such, supplementary ? should be delivered for at least ? hours.

Answer 1

dose
chemoreceptors
CO2
O2
72

Question 2

Patients who ? retain CO2 (advanced ?) should be titrated using a ? mask to prevent hypo?, monitored by serial ???.

? occurs when deoxyhaemoglobin exceeds a certain level within the blood.

Answer 2

chronically
COPD
venturi
hypoventilation
ABG
cyanosis

Question 3

Methods of oxygen delivery;
Nasal cannulae: ?-? L/min, plus room air;
o E.g. if breathing 5L/min, ?L of 100% 02 plus ?L 21% 02 room air gives an average of 53% oxygen.
Simple (?) facemask: 5-? L/min.

Answer 3

2-4
2
3
hudson
10

Question 4

Venturi masks;
o Blue: ? inspired ox ? L/min
o White: ? inspired ox ? L/min
o Yellow: ? inspired ox ? L/min
o Red: ? inspired ox ? L/min
o Green: ? inspired ox ? L/min

Answer 4

24% inspired oxygen, 2-4 L/min.
28% inspired oxygen, 4-6 L/min.
35% inspired oxygen, 8-10 L/min.
40% inspired oxygen, 10-12 L/min.
60% inspired oxygen, 12-15 L/min

Question 5

Limitations of pulse oximetry;
Cannot distinguish between ? and O;
o May be inaccurate after ? inhalation, ? poisoning or in heavy ?.
It does not reflect the oxygen carrying ? of the blood.
o E.g. in anaemia, hypovolaemia.

Answer 5

CO
smoke
co
smokers
capacity

Question 6

In ? patients, it may not be able to get a reading.
Anything that leads to venous ? can cause the probe to read the
venous rather than arterial saturations;
o E.g. ? regurgitation, or more commonly ? venous return when the probe is taped on ?.
Can be affected by nail ?.

Answer 6

hypovolaemic
pulsation
tricuspid
occluded
tightly
polish