Acid-Base Balance Flashcards Preview

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Flashcards in Acid-Base Balance Deck (45)
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1

Buffer

combination of a weak acid or weak base and its salt
resists pH changes

2

Acidosis

pH < 7.35
describes the process that leads to an decreased blood pH

3

Acidemia

describes the state of low blood pH

4

compensation vs correction

compensation, a metabolic or respiratory change outside of the normal range to compensate for acidosis or alkalosis
correction is intervening action to return the blood pH to the proper range

5

Oxidative Metabolism

uses O2 at the mitochondrial level to metabolize nutrients and turn them into ATP & waste products

6

normal blood range pH

7.34- 7.44

7

If H+ was not regulated the acid environment would damage:

metabolic processes
alter consciousness
increase neuromuscular irritability
coma, death

8

Buffer systems (4)

bicarbonate-carbonic acid buffer
hemoglobin buffer system
proteins as buffers of H+ (usually only in cells)
phophate buffer - only for the kidneys

9

Major organs involved in acid-base maintenance

Kidney & Lungs

10

Bicarb-Carbonic Acid Buffer general characteristics

h2co3 dissociates into co2 & h20 allowing co2 to be eliminated by lungs & H+ to leave as water through the kidneys

11

correction to bicarb-carbonic acid system

changes in co2 modify the ventilation rate of the lungs

12

compensation of bicarb-carbonic acid system

hco3- concentration can be altered by the kidneys
this system also binds H+ when it appears

13

Bicarbonate- carbonic acid buffer system equation

co2 + h2o h2co3 H+ + hco3-
reaction is reversible

14

formula to calculate carbonic acid

pCO2 x 0.0307

15

tCO2 component

carbonic acid + bicarbonate (90%)

16

carbonic acid molecular formula

H2CO3

17

bicarbonate ion molecular formula

HCO3-

18

pH calculation

pKa + log salt/acid
pKa - always use 6.1 during these calculations
acid- carbonic acid
salt - bicarbonate
normal ratio is around 20/1

19

pCO2 range interpretation

respiratory associated
range 35-45 mmHg
lower than range = alkaline
higher than range = acidosis

20

tCO2 range interpretation

metabolic associated
range 23-29 mmol/L
lower than range = acidosis (loss of bicarb ion)
higher than range = alkaline (increase of bicarb ion)

21

Lung involvement

exhale co2, inhale o2
1st line of defense for acid-base disorders
quick effect on acid-base

22

Kidney involvement

reclaims hco3-
produces more hco3- if needed & takes several days to correct a hco3- deficiency
long term compensation

23

factors affecting increased levels hco3-

when hco3- is increased we excrete hco3-
retain it when compensating lung disease & when cl- loss exceeds what is needed for electrical neutrality

24

factors affecting decreased levels of hco3-

diuretics
reduced absorption when there is loss of cations
when kidney is not functioning (nephritis, infections)

25

Acid-base disorders

respiratory acidosis
respiratory alkalosis
metabolic acidosis
metabolic alkalosis

26

metabolic acidosis (non respiratory )

decreased hco3- ( bicarb ion)
increase in acids= ketoacidosis
decrease in acid excretion= renal tubular acidosis, diarrhea, loss of bicarb ion

27

respiratory acidosis

increased pCO2 ( increase in carbonic acid bc lungs cant get rid of co2)
COPD: chronic obstructive pulmonary disease, hypoventilation
CHF

28

most common causes of metabolic acidosis

ketoacidosis, shock, severe diarrhea, impaired kidney function

29

metabolic alkalosis

increased hco3- (bicarb ion)
ingestion of bicarb producing salts
disease: diuretic therapy, vomiting, nasogastric suction

30

respiratory alkalosis

decreased pCO2
more common
missing H+
hypoxia from drugs like salicylates or increased temp due to fever, hysteria, pulmonary embolism, pulmonary fibrosis
breathing into paper bag to correct - increase lvl of carbonic acid by breathing co2 rich air