Blood Gas and pH measurements Flashcards Preview

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Flashcards in Blood Gas and pH measurements Deck (105)
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1

What will diagnostic tests identify?

(and evaluate) dysfunction if patient's history and physical examination reveal evidence of respiratory dysfunction

2

one of the first test ordered to assess respiratory status because it helps evaluate gas exchange in lungs

Arterial blood gas

*measures how well the person's lung and kidneys are working and how well the body is using energy

3

Any substance that can yield hydrogen (H+) or hydronium ion (H3O+) when dissolved in water

Acid

(release of proton or H+)

4

Substance that can yield hydroxyl ions (OH-)

Base

(ACCEPT proton or H+)

5

negative logarithm of the ionziation constant of an acid

pK or pKa

6

pKa value of strong acids

<3

7

pKa value of strong bases

> 9

(^pKa ^pH)

8

It is the affinity of the acid whether or not to give out its H+

pKa

9

negative logarithm of H+ concentration

pH

(represents hydrogen concentration)
*pH= pKa + log [base]/[acid]

10

combination of a weak acid and/or weak base and its salt

buffer

*able to resist changes in pH

11

Effectiveness of buffer depends on

pK of buffering system
pH of environment in which it is placed

12

Normal pH range, acidosis and alkalosis

Normal: 7.35-7.45
Acidosis: < 7.35
Alkalosis > 7.45

13

diagnostic procedure in which blood is obtained from an artery directly by an arterial puncture or accessed by a way of indwelling arterial catheter

Arterial Blood Gas

14

Arterial blood gas is only taken for (indications):

• To obtain information about patient ventilation (pCO2), oxygenation (pO2), and acid-base balance
• To monitor gas exchange and acid-base abnormalities for patient on mechanical ventilator or not
• To evaluate response to clinical intervention and diagnostic evaluation (oxygen therapy)

15

When is arterial blood gas most useful?

when a person's breathing rate is increased or decreased
when person has very high blood sugar levels, sever infection or heart failure

16

Components of ABG

pH
pCO2
pO2
HCO3-

17

[Components of ABG]
Measures hydrogen ion concentration in the blood, it shows blood acidity or alkalinity

pH

normal value: 7.35-7.45

18

[Components of ABG]
carried by the blood for excretion by the lungs, known as respiratory parameter

pCO2

(It is the partial pressure of CO2)
normal value: 35-45 mmHg

19

[Components of ABG]
dissolved in the blood; reflects body's ability to pick up oxygen from the lungs

pO2
(partial pressure of O2)
normal value: 80-100 mmHg

20

[Components of ABG]
metabolic parameter;; reflects kidneys ability to retain and excrete bicarbonate

HCO3-

normal value: 22-28 mEq/L

21

T or F: The body constantly works to maintain a balance (homeostasis) between acids and bases

True

22

These are byproducts formed as cells use nutrients to produce energy

H+ and CO2

23

Where does Acid-base balance depend on?

regulation of free H+

*slight imbalances affect emtabolism and essential body functions

24

What conditions affect acid-base balance?

infection or trauma

25

Disorder trend for respiratory acidosis

Respiratory
Acidosis ↓pH ↑pCO2
uncompensated HCO3-

26

Disorder trend for respiratory ALKALOSIS

MATAAS NA PH
MABABANG PCO2
UNCOMPENSATED HCO3-

27

Disorder trend for METABOLIC ACIDOSIS

LOW PH
UNCOMPENSATED PCO2
LOW HCO3-

28

Disorder trend for METABOLIC ALKALOSIS

HIGH PH AND HCO3-
Uncompensated pCO2

29

T or F: The circulatory and metabolic system works together to keep the body’s acid-base balance within normal limits (compensation)

respiratory and metabolic

30

Compensation mechanism for respiratory acidosis and respiratory alkalosis

Metabolic system
r.acid: high hco3- reabsorption
r.alkal: low hco3- reabsorption