16 - Acid-base disorders

Question 1

Henderson-hasselbalch equation

Answer 1

H + HCO3 -> H2CO3 -> CO2 + H2O

Question 2

Tissue gas exchange

Answer 2

Cl- in put into an RBC when CO2 is reacted with hydrogen in order to maintain charge

Question 3

What happens when you shift to the right on the O2-Hb dissociation curve

Answer 3

Increased 2,3 diPG
Acidosis (H+)
Increased Temperature

Question 4

To maintain charge in kidneys what in inputed

Answer 4

Na+ with HCO3-

Question 5

Mineralocorticoid action in the kidney

Answer 5

K+/H+ go in at distal renal tubule and Na+ goes out

Question 6

Acid-base in the GI tract

Answer 6

H+ goes to stomach

Hydrogen carbonate goes to pancreas

Question 7

Acid-base balance and the liver

Answer 7

Dominant site of lactate metabolism

Only site of urea synthesis

Question 8

Acid-base balance - liver rxns

Answer 8

1: proteins catabolised to NH4+ and HCO3-
2: Average proteins produce a slight XS NH4+ (balance of dicarboxylic, dibasic, neutral a/a)
3: role of urea cycle is to combine NH4+ and CO2 to neutralise HCO3 - from protein catabolism

Question 9

Acid-base balance - severe liver failure

Answer 9

NH4 + oxo-glutarate cannot form glutamine

NH4 and CO2 cannot form urea

Metabolic alkalosis with ammonium toxicity

Question 10

Why is it metabolic alkalosis in severe liver failure?

Answer 10

2NH4 + HCO3 -> (NH2)2CO + H+

LHS is acid
RHS is base

Question 11

Compensatory mechanisms for acid-base balance

Answer 11

Resp.
Renal bicarb regen
Hepatic shift between urea synthesis and ammonia excretion

Question 12

Metabolic acidosis - what happens

Answer 12

Increased H+ formation
Acid ingestion
Reduced renal H+ excretion
Loss of bicarb

Question 13

Metabolic acidosis - blood gas affects

Answer 13

[H+] up
pCO2 down
pO2 up

Question 14

Metabolic alkalosis - what happens

Answer 14

generation of bicarb by gastric mucosa
Renal generation of HCO3- in hypokalaemia
Administration of bicarb

Question 15

Metabolic alkalosis - blood gas affects

Answer 15

[H+] down
pCO2 up
pO2 down

Question 16

Metabolic alkalosis - consequences

Answer 16

K+ goes into cells and urine
PO4 goes into cells
Resp. suppression

Question 17

Resp. acidosis - what happens

Answer 17

CO2 retention due to:
inadequate ventilation
parenchymal lung disease
inadequate perfusion

Question 18

Resp. acidosis - blood gas effects

Answer 18

[H+] up
pCO2 up
pO2 down

Question 19

Resp. alkalosis - what happens

Answer 19

Increased CO2 excretion due to excessive ventilation producing alkalosis

Question 20

Resp. alkalosis - blood gases

Answer 20

[H+ down]
pCO2 down
pO2 up

Question 21

Metabolic acidosis causes

Answer 21

increased H+ formation
Acid ingestion
Reduced renal H+ excretion
Loss of bicarbonate

Question 22

Causes of increased [H+]

Answer 22

ketoacidosis, diabetic or alcoholic
lactic acidosis
poisoning
inherited organic acidoses

Question 23

Diabetic ketoacidosis

Answer 23

Hyperglycaemia
Osmotic diuresis -> pre-renal uraemia
Hyperketonaemia
Increased FFA -> all lead to acidosis

Question 24

Lactic acidosis types

Answer 24

Type a = shock

Type b = metabolic and toxic causes

Question 25

Acidosis in an alcoholic

Answer 25

NAD+ depletion (thiamine)
Thiamine deficiency (PDH co-factor)
Enhanced glycolysis for ATP formation
Keto-acids secondary to counter-regulatory hormones
CAUSES PROFUSE VOMITING

Question 26

Does high lactate = lactic acidosis? In alkalosis

Answer 26

Increased glycolysis
Reduced O2 delivery due to shift in O2 dissociation curve
Lactate induced vasoconstriction
Impaired mitochondrial resp.

Question 27

Does high lactate = lactic acidosis? O2 debt to #2

Answer 27

Further anaerobic lactac
te production
Hyperventilation

Question 28

Renal failure effects

Answer 28

Reduced volume of nephrons
Increased bicarb loss
Reduced NH4+ excretion
NH4 to liver for urea + H+ synthesis
Only fraction of NH4+ derived from glutamine