1b Arterial Blood Gases and Acid Base Regulation

Question 1

What is meant by the pO2?

Answer 1

Partial pressure of oxygen: this variable indicates how much oxygen is dissolved in the arterial blood, and if it is particularly low it can suggest inadequate gas exchange in the lungs

Question 2

What is meant by the PCO2?

Answer 2

Partial pressure of carbon dioxide: this variable indicates how much CO2 is dissolved in the arterial blood and if it is particularly high it can suggest inadequate gas exchange in the lungs

Question 3

What is meant by the pulmonary transit time?

Answer 3

The amount of time the blood has to participate in gas exchange

Question 4

What is the pulmonary transit time?

Answer 4

0.75s

Question 5

What is the formula for pH?

Answer 5

-log10 [H+]

Question 6

What is an acid?

Answer 6

A molecule which has a loosely bound H+ ion which it can donate

Question 7

A greater H+ concentration refers to what type of pH?

Answer 7

Lower pH

Question 8

Why must the acidity of the blood be tightly regulated?

Answer 8

Marked changes will alter the 3D structure of proteins

Question 9

What is a base?

Answer 9

An anionic molecule which is capable of reversibly binding protons - reduce the amount which are free

Question 10

What are the two types of acid the body produced?

Answer 10

respiratory and metabolic acid

Question 11

What is mean by respiratory acid?

Answer 11

CO2

Question 12

What is the change in pH of the blood between offloading to tissue?

Answer 12

7.40 to 7.36

Question 13

Describe the buffering capabilities of the blood?

Answer 13

Enormous buffering capacity that can react almost immediately to imbalances

Question 14

Describe the rapid compensatory mechanism to alter pH?

Answer 14

Changes in ventilation = rapid compensatory response to change CO2 elimination and therefore alter pH

Question 15

Describe the slow compensatory mechanism to alter pH?

Answer 15

Changes in HCO3- and H= retention/ secretion in the kidneys can stimulate a slow compensatory response to increase and decrease pH

Question 16

What is acidosis?

Answer 16

Circumstances which cause the blood to become more acidic - changes which lead to an acidaemia

Question 17

What is needed to correct an acidosis?

Answer 17

Alkalosis

Question 18

What is the normal range for pH?

Answer 18

7.35-7.45

Question 19

What type of imbalance does C02 cause?

Answer 19

respiratory

Question 20

What type of imbalance does HCO3- / Base excess cause?

Answer 20

Metabolic

Question 21

What is hypoxaemia?

Answer 21

When there is low levels of oxygen

Question 22

What is the CADO framework?

Answer 22

Compensation
Aetiology
Disturbance
Oxygenation

Question 23

What is a normal pO2?

Answer 23

> 10

Question 24

What level of pO2 indicates moderate hypoxaemia?

Answer 24

6-8

Question 25

What level of pO2 indicates severe hypoxaemia?

Answer 25

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