16 - Acid-base disorders Flashcards Preview

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Flashcards in 16 - Acid-base disorders Deck (28):
1

Henderson-hasselbalch equation

H + HCO3 -> H2CO3 -> CO2 + H2O

2

Tissue gas exchange

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

3

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

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

4

To maintain charge in kidneys what in inputed

Na+ with HCO3-

5

Mineralocorticoid action in the kidney

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

6

Acid-base in the GI tract

H+ goes to stomach
Hydrogen carbonate goes to pancreas

7

Acid-base balance and the liver

Dominant site of lactate metabolism
Only site of urea synthesis

8

Acid-base balance - liver rxns

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

9

Acid-base balance - severe liver failure

NH4 + oxo-glutarate cannot form glutamine

NH4 and CO2 cannot form urea

Metabolic alkalosis with ammonium toxicity

10

Why is it metabolic alkalosis in severe liver failure?

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

LHS is acid
RHS is base

11

Compensatory mechanisms for acid-base balance

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

12

Metabolic acidosis - what happens

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

13

Metabolic acidosis - blood gas affects

[H+] up
pCO2 down
pO2 up

14

Metabolic alkalosis - what happens

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

15

Metabolic alkalosis - blood gas affects

[H+] down
pCO2 up
pO2 down

16

Metabolic alkalosis - consequences

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

17

Resp. acidosis - what happens

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

18

Resp. acidosis - blood gas effects

[H+] up
pCO2 up
pO2 down

19

Resp. alkalosis - what happens

Increased CO2 excretion due to excessive ventilation producing alkalosis

20

Resp. alkalosis - blood gases

[H+ down]
pCO2 down
pO2 up

21

Metabolic acidosis causes

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

22

Causes of increased [H+]

ketoacidosis, diabetic or alcoholic
lactic acidosis
poisoning
inherited organic acidoses

23

Diabetic ketoacidosis

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

24

Lactic acidosis types

Type a = shock
Type b = metabolic and toxic causes

25

Acidosis in an alcoholic

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

26

Does high lactate = lactic acidosis? In alkalosis

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

27

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

Further anaerobic lactac
te production
Hyperventilation

28

Renal failure effects

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