BLOOD GASES CCHM Flashcards
substance that can yield a hydrogen ion (H) or hydronium ion when dissolved in water
represents (+) charge molecules
Acids
substance that can yield hydroxyl ions (OH)
represents (-) charge molecules
Base
combination of a weak acid or weak base and its salt, is a system that resists changes in pH
Effectiveness of a buffer is determined based on:
1.
2.
Buffer
1 Ionization constant/ pKa of the
buffering system
2 pH of the environment
Function: maintain or prevent sudden
fluctuations in pH
Buffer
Major buffer system:
Plasma – bicarbonate
carbonic acid buffer system; pK of 6.1
Normal blood pH: ___, to achieve this the body uses buffers
7.35-7.45
BUFFER SYSTEMS
1 BICARBONATE-CARBONIC ACID BUFFER SYSTEM
2 PHOSPHATE BUFFER SYSTEM
3 HEMOGLOBIN-OXYHEMOGLOBIN BUFFER SYSTEM
4 PROTEIN BUFFER SYSTEM
BUFFER SYSTEMS
1 BICARBONATE-CARBONIC ACID BUFFER SYSTEM
2 PHOSPHATE BUFFER SYSTEM
3 HEMOGLOBIN-OXYHEMOGLOBIN BUFFER SYSTEM
4 PROTEIN BUFFER SYSTEM
Principal mammalian buffer system
BICARBONATE-CARBONIC ACID BUFFER SYSTEM
Acids combine with Bicarbonates in the blood
Neutral Salts (Bicarbonate Salts) –
conjugate base
Carbonic Acid (Weak Acid)
BICARBONATE-CARBONIC ACID BUFFER SYSTEM
Acids combine with Bicarbonates in the blood
Neutral Salts (Bicarbonate Salts) –
conjugate base
Carbonic Acid (Weak Acid)
Bicarbonate
Form:
Regulation:
Bicarbonate
Through Kidney renal regulation
Carbonic acid (unstable)
Form
Regulation
Changes to H2O and CO2 once it reaches the plasma.
Measurement: based on pCO2
Carbonic acid (unstable)
Form
Regulation
Changes to H2O and CO2 once it reaches the plasma.
Measurement: based on pCO2
____ unstable, changing to H2O and CO2 in fluid
H2CO3
Primary utilization is in RBCs. It is 16% of the non-bicarbonate buffer value of erythrocytes It increases the amount of ____ in ECF (more alkaline)
PHOSPHATE BUFFER SYSTEM
NaHCO3
_____ is a negatively charged molecule which makes blood pH to be more ____, but still maintaining the normal blood pH
Sodium bicarbonate (NaHCO3)
alkaline
In PHOSPHATE BUFFER SYSTEM , ____ phosphate form that acts as a buffer
2,3-diphosphoglycerate
In PHOSPHATE BUFFER SYSTEM , ____ phosphate form that acts as a buffer
2,3-diphosphoglycerate
maintains pH level (Venous and Arterial Blood)
____ is considered to be an effective buffer because it is responsible for carrying oxygen so it has the ability to off load ___ replacing it with ___
- helps in the maintenance of CO2; it facilitates its diffusion across different gradients
____ carries ____.
Each mole of Hgb binds with ____ (primarily more than 95% of Hgb binds with O2)
HEMOGLOBIN-OXYHEMOGLOBIN BUFFER SYSTEM
Hemoglobin
O2
CO2
1 gram of Hemoglobin
1.39 mL of Oxygen
1 mole of O2
Proteins can also help in maintaining the buffer due to charges present on their surfaces. Proteins are made up of ____ which has ___ and ____; consisting of (+) and (-) charge end.
Proteins can exist in 2 forms: ___, ___ > Their characteristics depend on the pH of the environment
• More (+) in _____ environment
•More (-) in ___
•Has capability to bind or release excess Hydrogen as required within blood circulation
Plasma proteins (Charges on their surface)
o pH > pI –
o pH < pI –
PROTEIN BUFFER SYSTEM
amino acids
carboxyl end
amino end
H+ protein
B Protein
acidic
basic/alkaline
(-) charge
(+) charge
second largest fraction of the anions in the plasma.
Conjugate base representative of major buffer system
Classified under electrolytes.
It includes: ___ and _____
BICARBONATE (HCO3)
ionized bicarbonate (HC03)
Bicarbonate molecules linked with amino acid:
second largest fraction of the anions in the plasma.
Conjugate base representative of major buffer system
Classified under electrolytes.
It includes: ___ and _____
BICARBONATE (HCO3)
ionized bicarbonate (HC03)
Bicarbonate molecules linked with amino acid:
measured to determine pH
ionized bicarbonate (HC03) –
measured to determine pH
ionized bicarbonate (HC03) –
carbonate and the carbamino
compounds.
Normal range is from ___
Bicarbonate molecules linked with amino acid
21 - 28 mmol/L (21 - 28 meq/L)
carbonate and the carbamino
compounds.
Normal range is from ___
Bicarbonate molecules linked with amino acid
21 - 28 mmol/L (21 - 28 meq/L)
Weak acid representative of major buffer system
readily dissociated into ___ and ___ once it reaches the blood circulation
This fraction of blood, plasma or serum includes the ___ and ___
In blood circulation, CO2 concentration is ____ than HCO3, the symbol cdCO2 (conc. of dissolved C02) is frequently used and measured from ___
Other references: the complete solubility
coefficient is ____
Normal range: ____
CARBONIC ACID (H2CO3)
H2O
CO2
undissociated carbonic acid
physically dissolved anhydrous C02
higher
pCO2 multiplied by the solubility coefficient (0.03) of CO2.
0.0307 or 0.0306
1.05 –1.45 mmol/L.
Weak acid representative of major buffer system
readily dissociated into ___ and ___ once it reaches the blood circulation
This fraction of blood, plasma or serum includes the ___ and ___
In blood circulation, CO2 concentration is ____ than HCO3, the symbol cdCO2 (conc. of dissolved C02) is frequently used and measured from ___
Other references: the complete solubility
coefficient is ____
Normal range: ____
CARBONIC ACID (H2CO3)
H2O
CO2
undissociated carbonic acid
physically dissolved anhydrous C02
higher
pCO2 multiplied by the solubility coefficient (0.03) of CO2.
0.0307 or 0.0306
1.05 –1.45 mmol/L.
pressure or tension exerted by C02 gas
dissolved in blood
It is an index of efficiency of gas exchange in the lungs and not a direct measurement of total CO2 concentration in the blood.
Function: used to determine (H2CO3) level by multiplying it with solubility coefficient
Normal range: ____
PARTIAL PRESSURE OF C02 (PCO2)
35 - 45 mmHg.
pressure or tension exerted by C02 gas
dissolved in blood
It is an index of efficiency of gas exchange in the lungs and not a direct measurement of total CO2 concentration in the blood.
Function: used to determine (H2CO3) level by multiplying it with solubility coefficient
Normal range: ____
PARTIAL PRESSURE OF C02 (PCO2)
35 - 45 mmHg.
Amount of CO2 bound within the blood
circulation depending on the sample used
The value of the CO2 combining power Is an index of the amount of CO2 that can be bound by serum, plasma, or whole blood as HCO3 at a ____ of ___ at ____ degree celsius
Normal range: ___
CARBON DIOXIDE COMBINING POWER (CO2 COMBINING POWER)
pCO2 of 40 mmHg at 25 degrees Celcius.
24 - 30 mmol/L.
Amount of CO2 bound within the blood
circulation depending on the sample used
The value of the CO2 combining power Is an index of the amount of CO2 that can be bound by serum, plasma, or whole blood as HCO3 at a ____ of ___ at ____ degree celsius
Normal range: ___
CARBON DIOXIDE COMBINING POWER (CO2 COMBINING POWER)
pCO2 of 40 mmHg at 25 degrees Celcius.
24 - 30 mmol/L.
Formerly known as ____
Sum of major buffer system or total concentration of C02 in the blood consisting of ionized HC03, C03, carbamino compound) and unionized fraction (H2C03) and physically dissolved C02.
Normal range: ____
TOTAL CARBON DIOXIDE CONCENTRATION (ctCO2)
-C02 content
21-28 mmol/L.
The negative logarithm of hydrogen ion activity with a normal average range of 7.35-7.45
pH
MAJOR FACTORS REGULATING BLOOD PH:
in order to prevent drastic fluctuation in pH, and second line which acts when major disturbances, changes or deviations from normal pH occurs.
Primary line
1) Chemical buffers (with charges)
> bicarbonate and carbonic acid buffer
system
>proteins
>Hemoglobin
>Electrolytes (Cl and HCO3)
Second line
Second line
2) Respiratory regulatory mechanism
> increased release of CO2: thru respiration or decreasing the exhalation
> Decreased release of CO2: thru
decreasing the respiratory rate
3) Renal regulatory mechanism – kidney which regulates level of bicarbonate (HCO3)
used to measure blood pH
HENDERSON-HASSELBALCH EQUATION
ph= bicarbonate/ carbonic acid
may not be encountered by MTs anymore because there are other healthcare professionals that are responsible for this procedure
as they are capable and trained to perform.
BLOOD COLLECTION FOR BLOOD GAS AND PH ANALYSIS
Keep the sample at ___technique in blood collection; at least prevent its exposure to ambient air because the concentration of ___ and ___ is different in blood and in air.
anaerobic
O2 and CO2
Keep the sample at ___technique in blood collection; at least prevent its exposure to ambient air because the concentration of ___ and ___ is different in blood and in air.
anaerobic
O2 and CO2
Preferred sample:______
____ is the more preferred
specimen for blood gas analysis
because it is of more uniform
composition than venous blood. This is due to the metabolic diversity
whole blood
Arterial blood
These specimens can also be used for blood gas analysis provided that they undergo arterialization.
Venous and Capillary (Skin punctured) Blood