Acid-Base Lecture Flashcards

1
Q

Normal metabolism produces ___ meq/L of non volatile (H ) acid together with volatile acid (CO2) daily.

A

1 meq/L

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2
Q

body fluid pH is tightly maintained at…

A

7.40

norm= 7.38-7.42

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3
Q

weak base

*levels regulated by kidneys and maintained for buffering

A

HCO3

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4
Q

Where is the bicarbonate buffer system located?

A

extracellular space

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5
Q

Total venous CO2 can be estimated by looking at….

A

HCO3 levels

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6
Q

Primary respiratory disorders effect….

A

pCO2

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7
Q

Primary metabolic disorders effect…

A

HCO3

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8
Q

Do compensatory changes totally correct the pH?

A

NO! …they move towards normal but do not fully compensate/correct

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9
Q

pH decreased, PCO2 increased, HCO3 increased (comp.), acute and chronic forms.

A

Respiratory acidosis

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10
Q

pH increased, PCO2 decreased, HCO3 decreased (comp.), acute and chronic forms.

A

Respiratory alkalosis

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11
Q

pH decreased, HCO3 decreased, PCO2 decreased (comp.)

A

Metabolic acidosis

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12
Q

pH increased, HCO3 increased, PCO2 increased (comp.)

A

Metabolic alkalosis

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13
Q

Compensatory mechanism includes:

*increase ventilatory drive, which will blow off more CO2 gas, causing a shift back towards normal pH

A

Metabolic acidosis

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14
Q

Compensatory mechanism: decrease ventilatory drive to hold onto CO2

A

Metabolic alkalosis

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15
Q

Primary defect is increased PCO2 as a result of decreased alveolar ventilation.

A

Respiratory acidosis

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16
Q

Trouble getting rid of CO2 gas in…

A

Respiratory acidosis

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17
Q

CO2 +H2O ⇔ H2CO3 ⇔ H + HCO3

which way will this equation shift in Respiratory acidosis?

A

Towards right

due to increase in CO2 gas

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18
Q

Conditions associated with decreased ventilation: severe COPD; asthmatic who tires; drug OD with suppression of ventilatory drive, neuromuscular diseases.
Symptoms: somnolence, confusion (CO2 narcosis), coma, resp. arrest.

A

Respiratory Acidosis

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19
Q

CO2 narcosis

A

somnolence
confusion

*seen in respiratory acidosis

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20
Q

first 24 hours of respiratory acidosis, what do HCO3 levels look like?

*when does compensation start

A

Normal in 24 hrs

*over about 3 days, HCO3 levels will increase..leading to compensation

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21
Q

Acute – the pH decreases 0.08 units for every 10mmHg increase in PCO2**

A

Respiratory acidosis

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22
Q

In ACUTE respiratory acidosis, every 10 mmHg increase in PCO2 leads to a decrease in pH of….

A

0.08 units

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23
Q

Chronic - HCO3 ↑1.1-3.5 mEq/liter per ↑10 mmHg PCO2; pH will move towards normal

A

Respiratory acidosis

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24
Q

Little Billy got into some of dad’s pain meds (oxycodone). He suffers a significant depression of mental status and respiration. You see him in the ED 3 hours after ingestion. He is somnolent with a respiratory rate of 4. A blood gas is obtained: pH- 7.16, PCO2- 70mmHg, HCO3- 24 meq/L

A

UNCOMPENSATED respiratory acidosis

*bicarb levels haven’t started to rise yet, so you know its uncompensated

(tx=ventilate and rapidly reverse effects of narcotics)

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25
Q

Ventilatory support until the underlying disorder can be corrected
*Narcotic antagonist if applicable

A

Tx for Respiratory Acidosis

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26
Q

Narcotic OD leading to decreased respirations can lead to….

A

Respiratory Acidosis

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27
Q

Increase in CO2 levels due to a decrease in respirations….

A

Respiratory acidosis

28
Q

Primary defect is decreased PCO2 as a result of increased alveolar ventilation.

A

Respiratory alkalosis

29
Q

Decreased CO2 levels due to increase in ventilation

A

Respiratory alkalosis

30
Q

CO2 +H2O ⇔ H2CO3 ⇔ H + HCO3

Which direction does this equation move in Respiratory alkalosis?

A

Left!

bc decrease of CO2 in body during Respiratory alkalosis

31
Q

Hyperventilation: anxiety, panic attacks, sepsis, CNS insult, cirrhosis, salicylates, progesterone, mechanical over ventilation, etc.
**Symptoms- lightheadedness, paresthesias, tetany.

A

Respiratory alkalosis

32
Q

Address the underlying cause; most cases of anxiety-hyperventilation syndrome are self-limited→respiratory muscle fatigue.
**When acute anxiety is a factor, re-breathing into a paper bag may be useful (short term fix only).

A

Respiratory alkalosis

33
Q

Most common acid-base disturbance?

A

Metabolic acidosis

34
Q

Primary measured defect is decreased HCO3 (combines with increased H ions to buffer) with resultant drop in pH.

A

Metabolic acidosis

35
Q

Compensatory response to Metabolic Acidosis is decreased…

A

pCO2

hyper-ventilation

36
Q

Lactic acidosis

Diabetic ketoacidosis

A

Most common causes of metabolic acidosis

37
Q

Na - (HCO3 + Cl) = 4-10

A

anion gap

most metabolic acidosis increases anion gap bc HCO3 levels go down

38
Q

Most metabolic acidosis _____ the anion gap

A

increases

bc HCO3 levels go down

39
Q

Lactic Acidosis (cardiogenic shock or arrest). Lactate (unmeasured anion) prod. due to inadequate tissue perfusion or hypoxia.

A

Metabolic acidosis

increased anion gap

40
Q

DKA-Hyperglycemia with metabolic acidosis; increased production of ß-hydroxybutyric & acetoacetic acids (ketoacids→hyperketonemia).

A

Metabolic acidosis

increased anion gap

41
Q

Toxins- Ethylene glycol, salicylates, methanol. Uremia (severe renal failure)- endogenous acids.

A

Metabolic acidosis

increased anion gap

42
Q

pH

A

increased anion gap metabolic acidosis

43
Q

Hallmark is acidosis, decreased HCO3 and hyperchloremia.

GI HCO3 losses from pancreatic or small bowel contents.

A

Normal anion gap metabolic acidosis

44
Q

massive (secretory) diarrhea with volume contraction (NaCL and K loss as well); HCO3 secretion in small/large intestine is accompanied by Cl generation/absorption (countertransport); volume contraction leads to NA and Cl retention in the kidney.

A

Normal anion gap metabolic acidosis

45
Q

Renal tubular acidosis is an example of…

A

Normal anion gap acidosis

46
Q

JR has had intermittent vomiting and severe diarrhea for 4 days. He has been unable to keep fluids down and has not urinated in 8 hours. He has a cardiomyopathy with compensated HF.
PE: P-90, BP-90/70 with postural changes. He appears lethargic and cool to touch with a prolonged capillary refill time. His arterial blood gas reveals: pH=7.30, PCO2=28mmHg, HCO3=14meq/L.
Na-136meq/L, K-3.0meq/L, Cl-110meq/L

A

Compensated metabolic acidosis

47
Q

Hallmark: High HCO3 with increased pH.

A

Metabolic alkalosis

48
Q

excessive lost of gastric contents (i.e. vomiting)

*results in loss of Na, Cl, volume and H+

A

Metabolic alkalosis

49
Q

Severe vomiting or continuous NG suction: HCl and NaCl losses from stomach initiate the alkalosis and volume contraction. Cl loss (and ↓total body stores) sustains the alkalosis because ↑renal Na reabsorption from volume contraction is accompanied by HCO3 reabsorption (most available anion with Cl depleted).

A

Metabolic alkalosis

50
Q

What happens to the anion gap during metabolic acidosis? (HCO3 is loss)

A

Increase in anion gap!

*a loss of HCO3 leads to an increase in the anion gap

51
Q

To drop pCO2 (blow off CO2) you….

A

breathe faster!

52
Q

in respiratory acidosis (increase in pCO2), there can either be no compensation (no HCO3 change) OR compensation (increased HCO3) because….

A

the kidneys take time to compensate

*compensation (increase in HCO3) takes time!

53
Q

if the pH and pCO2 are going in the same direction, it is what kind of process?

A

Metabolic

54
Q

if the pH and pCO2 are going in the opposite direction, it is what kind of process?

A

Respiratory

55
Q

ROME

A

Respiratory
Opposite

Metabolic
Equal

56
Q

When HCO is loss..what happens to the anion gap?

A

Anion gap increases

57
Q

Na - (Cl + HCO3) = 12

A

Normal anion gap

58
Q

anion gap and HCO3 concentration are ____ related

A

inversely

*anion gap increases when HCO3 concentration decreases

59
Q

GI HCO3 losses from pancreatic or small bowel contents

A

Non anion gap acidosis (NAGA)

60
Q

massive (secretory) diarrhea with volume contraction (NaCL and K loss as well); HCO3 secretion in small/large intestine is accompanied by Cl generation/absorption (countertransport); volume contraction leads to NA and Cl retention in the kidney.

A

Non anion gap acidosis (NAGA)

61
Q

seen with extracellular volume contraction and hypokalemia. Responds to saline administration.

A

Metabolic alkalosis

62
Q

Severe vomiting or continuous NG suction: HCl and NaCl losses from stomach

A

Metabolic alkalosis

63
Q

Activation of the RAA system to maintain volume results in hypokalemia (↑Na/K/H exchange in distal tubule) and additional H losses.

A

Occurs with metabolic alkalosis

64
Q
Massive diarrhea (NAGA)
Renal tubular (NAGA)
Lactic Acidosis (increased AG)
DKA (increased AG)
Toxins, uremia (increased AG)
A

Metabolic acidosis

65
Q

When HCO3 combines with H+, there is what kind of acidosis

A

anion gap

non anion gap acidosis is when HCO3 is just loss

66
Q

Entire sequence is rapidly corrected by administering 0.9% saline* (isotonic) with supplemental KCL. The process will self perpetuate until adequate amounts of Na/K/Cl and H2O are available.

A

Metabolic alkalosis tx

67
Q

For metabolic compensation..

pCO2 increases 0.5-1.0 mmHg per increase in ___ mEq/L HCO3

A

1