Resp ABG

Question 1

What are measured ABG units

Answer 1

PH
P02
Pc02
Lactate

Question 2

What are derived ABG units?

Answer 2

Hc03
Base excess

Question 3

What is a normal PH

Answer 3

7.35-7.45

Question 4

What is a buffer

Answer 4

A substance that has an ability to minimise changes to PH when acid or base added

Question 5

Carbonic acid / bicarbonate buffer equation

Answer 5

C02 + h20 = h2c03 = H* + hc03

Question 6

Normal paC02 measurement

Answer 6

4.7 - 6 KPA

Question 7

Normal HC03 measurement

Answer 7

22 - 26 MMOL

Question 8

Normal pa02

Answer 8

Pa02 should be about 10 kpa less than % inspired concentration

EG
>11kpa on air (fio2 21%)

Question 9

5 step approach to ABG interpretation

Answer 9

1. How is the pt
2. Assess oxygenation
3. Determine the PH
4. Determine respiratory component
5. Determine metabolic component

Question 10

Normal base excess

Answer 10

-2 ~ +2

Question 11

Anion gap calculation

Answer 11

(Na+ + K+) - (Cl- + HC03-) =
(Sodium + potassium) - (chloride + bicarb) =

(Normal 4-12)

Question 12

Name cations

Answer 12

Sodium (Na+) and potassium (K+)

Question 13

Name anions (negatively charged)

Answer 13

Chloride (Cl-) and Bicarbonate (HC03)
And
Misc (albumin etc)

Question 14

When to check anion gap?

Answer 14

Metabolic acidosis

Question 15

Causes of low chloride - hypochloremia

Answer 15

Dehydration
Kidney disease
Respiratory acidosis
Cancer treatment
Drugs - steroids, diuretics, laxatives

Question 16

Causes of high anion gap

Answer 16

DKA
Salicylate toxicity (aspirin)
Uremia (renal failure)
Starvation ketosis
Toxic ingestion - methanol, ethylene glycol (anti freeze)

Renal / Heart failure

Question 17

Causes of respiratory acidosis

Answer 17

COPD, OSA, CNS depression
Neuromuscular (obesity, GBS, myasthenia gravis)

Question 18

Causes of respiratory alkalosis

Answer 18

Anxiety
Pain
Hypoxia

Question 19

Most common cause of metabolic alkalosis

Answer 19

Chloride loss due to gastric loss or renal loss

Question 20

Causes of lactic acidosis

Answer 20

Type A - all types of shock (ischemia)
Type B - not related to hypoxia or poor perfusion

Question 21

A-a gradient

Answer 21

Alveolar - arterial gradient
Difference between fi02 and pa02

Question 22

Etc02 and paC02 gradient

Answer 22

Awareness