Understanding an ABG

Question 1

CO2+H2O H2CO3 H+ + HCO3-

Answer 1

k

Question 2

1. How is the ?
2. Assess ?.
   a. PaO2 should be >?kPa on air, or about ?kPa less than the % inspired
   concentration.
3. Determine the pH.
   a. <7.35 is ?-aemic, >7.45 is ?-aemic.
4. Determine the ?component.
   a. If acidaemic, is the PaCO2 >6? –> ? ?
   b. If alkalaemic, is the PaCO2 <4.7? –> ? ?.
5. Determine the ?component.
   a. If acidaemic, is the Hco3• <22? –> ? ?
   b. If alkalaemic, is the PaCO2 >26? –> ? ?
6. Is there any evidence of ?

Answer 2

patient
oxygenation
10
10
acid
alkal
resp
respiratory acidosis
resp alk
metabolic
met acid
met alk
compensation

Question 3

just remember

ROME - what does it mean

Answer 3

Resp = opposite (ph + co2)
Met = equal (ph + bicarb)

Question 4

Base Excess: used to assess the ? component;

? in metabolic acidosis.
? in metabolic alkalosis

Answer 4

metabolic
negative
positive

Question 5

Lactate - should be - can go up to 2 in a ? patient

-high indicates ?

Answer 5

1
stressed
shock

Question 6

Respiratory acidosis;

Can be caused by any cause of type ? respiratory failure.

Respiratory alkalosis;

Caused by ?;
o ?.
o Pain
o Altitude.
o Increased metabolic demands: ?, ?, ?, ?.
o Drugs (NSAID OD, ?).

Answer 6

2
hyperventilation
anxiety
fever, sepsis, hyperthyroid, pregnancy
stimulants

Question 7

Metabolic acidosis;

• The ? ? is helpful to determine the cause: (Na+ + K+) - (Cl- + HCO3-). (so ? ions minus ? ions)
The normal range is ?-18 mmol/L.

• A normal anion gap in a metabolic acidosis suggests loss of ?·
o ? ? acidosis. '
o ? (gastro sx).
o Drugs (acetazolamine).
o ?/? fistula.

- A raised anion gap indicates ? of organic acids;
o ? acidosis (shock, ?).
o ? (DM / alcohol).
o Urate (? failure).
o Drugs (NSAIDs, biguanides, methanol).

Answer 7

anion gap
pos
neg
11

bicarb
renal tubular
diarrhoea
intestinal/pancreatic

production
lactic
hypoxia
ketosis
renal

Question 8

Metabolic alkalosis;

Excess ?;
o Ingestion of a base (?).

Loss of acid;
o ?,
o Hypokalaemia (excess ?).
o Burns.
o Hyper-?-ism

Answer 8

base
antacid
vomiting
diuretics
hyperaldosteronism