05.07 - Acid Base (Wall) - PP + Handout, No reading, Not watched Flashcards Preview

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Flashcards in 05.07 - Acid Base (Wall) - PP + Handout, No reading, Not watched Deck (99):
1

Expected HCO3, pCO2 changes for Acute Respiratory Alkalosis

HCO3 decreases 2 mEq for each 10 mm decrease in pCO2

2

Type 1 (Distal) RTA is caused by __ and causes ___

Defective H-ATPase, decreased acid secretion

3

Metabolic Acidosis is ___ Bicarb

Decreased

3

For simple acid-base disorders, pC02 and HCO3 always

change in same direction

4

Acid Base disorder caused by Hyperaldosteronism

Metabolic Alkalosis

5

2 disorders with elevated Bicarb (>30)

Metabolic Alkalosis and Chronic Respiratory Acidosis (with kidney compensation)

6

How does plasma anion gap change with respiratory disorders

Doesn't

7

Urine anion gap is an indirect estimate of

Urinary NH4+ excretion

7

__ % of Bicarb is reabsorbed in PT via __

90% via Na-H antiporter (Na is driving force)

8

Why is Citrate given in acid base

Metabolized to Bicarb

8

Normal Urine Anion Gap

Positive, 10 mEq/L

8

If PAG is normal in Metabolic acidosis

Might be kidney not making NH4+, or Losing Bicarb by Diarrhea

9

Why can you tell the difference b/t acute and chronic respiratory disorders

Takes kidneys hours to days to compensate

9

What inhibits Na channel in principal cell of cortical collecting duct?

Amiloride, Triamterene

10

Isohydric principle

All buffers change in same direction

11

Metabolic Alkalosis is ___ Bicarb

Increased

12

What must accompany NH4+ in urine

Chloride

12

What is synonymous with send a bicarb into blood

Proton pumped into urine that came from intracellular Carbonic Anhydrase

13

How does renal failure affect acid base balance

Reduced GFR - Decreased Ammonium excretion

14

What is invariably present in Simple Acid-Base disorders

Compensation

16

pH and H+ ranges

6.8-7.8; 16-160 neq/L

16

When A- from HA is excreted into urine

Normal Plasma Anion gap, increased plasma chloride

16

Anion Gap if you lose Bicarb directly in stool

None b/c there's no unmeasured anion

17

Etiology of Metabolic Alkalosis

Loss of H+ into GI or into urine

19

Respiratory Acidosis is __ CO2

Increased CO2

20

What must be present in simple acid-base disorders

Secondary physiologic compensation

20

When will you have lower or negative UAG

If you've lost bicarb by diarrhea, ammonium increases in urine, and chloride accompanies it

21

Major extracellular buffer

Bicarb

22

If Na concentration stays constant, but Chloride conc. changes, then

an acid base disorder is present

23

What acid base disorder can dietary protein intake cause

Acidosis

23

What puts bicarb back into urine

Cl/Bicarb (Pendrin) in beta-intercalated cells

24

Cl responsive in Metabolic Alkalosis means

Urine Cl

25

Patient with lower GFR develops more severe acidosis following acid load b/c

can't secrete NH4+ as well

26

Expected pH changes for Chronic Respiratory Acidosis

HCO3 increases 4 mEq for each 10 mm increase in pCO2

28

Timeframe of H+ excretion, Bicarb reabsorption, and Bicarb generation

Hours to days

29

Expected pH Changes for Acute Respiratory Acidosis

HCO3 increases 1 mEq for each 10 mm increase in pCO2

30

Type 4 (Hypoaldosteronism) RTA is caused by ___ and causes ___

Impaired proton and K secretion, decreased acid secretion

31

What drug inhibits sodium bicarb reabsorption in proximal tubule

Acetazolamide (CAi)

32

Speed and effectiveness of 2 buffering routes in respiratory acidosis

(1) Plasma: rapid but limited, 1-2 mEq/L increase in Bicarb; (2) Kidney excretes NH4, generating new bicarb, delayed 2-3 days

33

Acid Base disorder caused by Loop or Thiazides

Metabolic Alkalosis

33

How long does it take kidney to generate new bicarb ions

2-3 days

33

Bicarb transporter in beta-intercalated cells

Cl/Bicarb (Pendrin)

35

Normal HCO3-

22-26 (24mEq/L)

35

Acute Respiratory acid base disorders always have __ change in pH than chronic b/c __

Greater change, b/c kidney is slow in compensating

37

Changes in HCO3 and pCO2 in Metabolic Alkalosis

Both increase

37

Changes in HCO3 and pCO2 in Respiratory Acidosis

Both increase

38

How does CO2 in alpha-intercalated cells affect H secretion/reabsorption

CO2 binds with OH- to form bicarb that is reabsorbed instead of secreted; H+ is the secreted instead of bonding with the OH-

39

When A- from HA is reabsorbed by kidney or retained in plasma

Unmeasured Anion - Increased Plasma Anion Gap, minimal change in plasma Chloride

41

HCO3 in Respiratory Alkalosis

Slightly decreased

42

If PAG increases in metabolic acidosis, it's

Lactic Acidosis or some other renally conserved acid anion

43

How does plasma Na change with acid base disorders

Doesn't

44

Where is Bicarb primarily reabsorbed

PT and LOH

45

Cl resistance in Metabolic Alkalosis means

Urine Cl >20 mEq/L (usually >50 mEq/L)

46

Urine Anion Gap =

Na + K - Cl (in urine)

47

Primary acid we produce

CO2 from metabolism of fats and carbs

49

Timeframe of intracellular fluid buffer systems

2-4 hours

51

Which RTA results from Decreased Acid Excretion?

Type 1 (Distal) and Type 4 (Hypoaldosteronism)

52

Every proton proton pumped into the urin had to come from

Intracellular Carbonic Anhydrase

53

Most common form of chronic alkalosis where the kidney compensates

Pregnancy - Alkalemic

54

2 major buffers of urine

NH4+ and Phosphate

55

Pregnant women acid base

Slightly Alkalemic

57

Changes in HCO3 and pCO2 in Respiratory Alkalosis

Both decrease

58

Decreased Acid excretion is synonymous with

Impaired NH4+ excretion

60

Trick for converting [H+] to pH

80 - decimal digits of pH

61

How to distinguish b/t Acute and Chronic

Look at Bicarb: Small change (1-2), then acute; Larger change (4-5) then kidney has compensated and chronic

63

pKa of Bicarb

6.1

64

Normal pCO2

36-44 (40mmHg)

64

Diarrhea results in loss of

Bicarb --> Metabolic Acidosis

66

Acid Base Disorder caused by Hypokalemia

Metabolic Alkalosis

67

Final excretion of daily aci load occurs primarily in

CD

68

Where are non-Carbonic acids eliminated?

Combined with buffers and secreted by kidneys

69

Indirect estimate of urinary NH4+ excretion

Urine Anion Gap

70

Why is NH4+ trapped in urinary lumen

Lipid soluble

71

Expected pH changes for Chronic Respiratory Alkalosis

HCO3 decreases 5 mEq for each 10 mm decrease in pCO2

72

Compensation for Respiratory disorders occurs by

Alterations in Bicarb concentration

73

Normal Plasma Bicarb

24 mEq/L

74

In simple acid-base disorders, the compensatory mechanisms

Must be present, Never fully correct pH

75

Respiratory Alkalosis is __ CO2

Decreased CO2

76

Metabolic Disorders are processes that directly alter

Bicarb Concentration

77

Urine AG becomes less positve/more negative with

Increasing urinary NH4+ --> Cl must accompany NH4+

78

How to get Bicarb from Total CO2

Subtract 1-1.5

80

How does plasma Cl change with plasma HCO3

Changes equally and inversely

81

How much does Total CO2 exceed plasma bicarb?

By 1-1.5 mEq/L

82

Plasma Cl is altered in which Acid Base Disorders

All except increased Plasma AG Metabolic Acidosis

84

pH of 7.4 = what [H]

40 nEq/L

85

Action of Acetazolamide

CA inhibitor - Inhibits Na Bicarb reabsorption in PT

86

How does low pH alon drive bicarb reabsorption

More CO2 in blood freely enters tubular cell - Meaning more reactant to form H+ that goes into Na-H Antiporter

87

Changes in HCO3 and pCO2 in Metabolic Acidosis

Decrease in HCO3- and pCO2

88

[H+] =

24 x pCO2 / [HCO3]

89

HCO3 in Respiratory Acidosis

Slightly increased

90

Only caveat to Urine Chloride in Metabolic Alkalosis

If just took Loop diuretic, urine Cl can't be low b/c block reabsorption

91

Why is Isohydric principle useful

If we know what Bicarb is doing, we know what others are doing (all change in same direction)

92

Acid Base Cells in Collecting Duct

Intercalated cells

93

Where is Carbonic Acid eliminated?

Lungs

94

Which RTA results from Loss of Bicarb

Type 2 (Proximal) RTA

95

Respiratory compensation vs Metabolic Compensation

Respiratory compensations is rapid; Metabolic compensation (by kidneys) is slower over 1-2 days

97

3 Etiology Categories of Metabolic Acidosis

Decreased Renal Acid Excretion; Direct Bicarb Losses; Increased Acid Generation

98

Total CO2 concentration =

Dissolved CO2 + Bicarbonate concentration in venous sample; 25-26 mEq/L

99

Normal Chloride

105