LEC 11 - BLOOD GASES Flashcards
substance that can yield a hydrogen ion (H+) or hydronium ion when dissolved in water
ACIDS
raising the pH above the _______ will cause the acid to dissociate and yield an H+.
pKa
substance that can yield hydroxyl ions (OH-)
Base
lowering the pH below the pKa will cause the base to release OH−
Base
combination of a weak acid or weak base and its salt, is a
system that resists changes in pH
buffer
effectiveness of a buffer depends on the _____
pKa of the buffering system and the pH of the environment
In plasma, the bicarbonate–carbonic acid system, having a pKa of
__________, is one of the principal buffers
6.1
normla blood pH
7.35-7.45
the principal mammalian buffer system that serves as the basis in the determination of the pH level of the blood MATHEMATICALLY
bicarbonate-carbonic acid buffe system
the principal mammalian buffer system that serves as the basis in the determination of the pH level of the blood MATHEMATICALLY using what equation?
henderson-hasselbalch equation
acids combine with bicarbonate in the blood
bicarbonate-carbonic acid buffer system
in bicarbonate-carbonic acid buffer system, what is the neutral salts
bicarbonate sales - conjugate base
in bicarbonate-carbonic acid buffer system, what is the weak acid
carbonic acid
it exist in the blood circulation as it is and its primary regulation is through function of our kidneys
bicarbonate
it is unstable, readily changes to water and carbon dioxide once it reaches your plasma
carbonic acid
the measurement of carbonic acid is based on the __
partial pressure of carbon dioxide
PHOSPHATE BUFFER SYSTEM’s primary source is
RBC
PHOSPHATE BUFFER SYSTEM
what is the phosphate that forms and acts as a buffer
2.3 - diphosphoglycerate
this buffer system works by increasing the amount of NaHCO3 (sodium bicarbonate) in ECF (making it more alkaline)
phosphate buffer system
The interrelationship of the lungs and kidneys in
maintaining pH is depicted by the
Henderson-Hasselbalch
equation
hemoglobin is considered an effective buffer because __
it is carrying an oxygen
aside from carrying an oxygen as a buffer, what are the other capabilities of hemoglobin to maintain pH
it has the ability to offload oxygen and replace it with carbon dioxide
it helps the diffusion across different gradient
hemoglobin-oxyhemoglobin buffer system
Maintains pH level in ___
Venous and Arterial Blood
1 gram of Hemoglobin carries ___ mL of Oxygen and each
mole of hemoglobin binds with one mole of oxygen.
1.39
how many percent of hemoglobin binds with oxygen?
95%
it helps to maintain the buffer due to the charges present on their surface
protein buffer system
Proteins can exist in 2 forms:
H+ protein,
B Protein
Capability to bind or release excess Hydrogen as required
protein buffer system
Proteins are made up of __
amino acid
2 ends of amino acid
It has a carboxyl end and amino end.
in the mechanism of buffer system has an order in which the first line of buffer system are the ____
chemical buffers -bicarbonate, carbonic, hemoglobin
protein, chloride, electrolytes
in the mechanism of buffer system has an order in which the second line of buffer system are the ____
organ regulatory mechanism (physiological) - kidney and lungs
chemical name of bicarbonate
HC03
It is a conjugate base representative of our major buffer system
bicarbonate (HCO3)
is bicarbonate classified under electrolytes?
yes
the second largest fraction of the ANIONS in the plasma
bicarbonate
It includes the ionized bicarbonate (HCO3), carbonate and
the carbamino compounds
bicarbonate
normal range of BICARBONATE (HCO3)
22-26 mmol/L (22-26 meq/L)
Weak acid representative of major buffer system
CARBONIC ACID (H2CO3)
It is readily dissociated into water and carbon dioxide once
it reaches the blood circulation
CARBONIC ACID (H2CO3)
in blood circulation, CO2 concentration is higher than HCO3
true or false
true
The symbol _____ used is measured from pCO2 multiplied by the
solubility coefficient of CO2.
cdCO2 (concentration of dissolved C02) is
frequently)
The pressure or tension exerted by CO2 gas dissolved in
blood.
PARTIAL PRESSURE OF CO2 (pCO2)
It is an index of efficiency of gas exchange in the lungs and
not a measure of CO2 concentration in the blood.
PARTIAL PRESSURE OF CO2 (pCO2)
Used to determine carbonic acid level by multiplying it
with the solubility coefficient
PARTIAL PRESSURE OF CO2 (pCO2)
normal range of carbon dioxide combining power
24-30 mmol/l
(ctCO2) means
total carbon dioxide concentration
which refers to the total
concentration of CO2 in the blood consisting of ionized
HCO3, CO3, carbamino compound and unionized fraction
(H2CO3) and physically dissolved CO2.
TOTAL CARBON DIOXIDE CONCENTRATION (ctCO2)
It is the sum of major buffer system
TOTAL CARBON DIOXIDE CONCENTRATION (ctCO2)
normal range of TOTAL CARBON DIOXIDE CONCENTRATION (ctCO2)
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
chemical buffers
respiratory regulatory mechanism
renal regulatory mechanism
formula of henderson-hasselbalch equation
pH = (bicarbonate/pCO2)
The pCO2 of air (0.2mmHg) Is much less than that of the blood (38 mmHg) so that when blood is exposed to air, the ctCO2 and pCO2 _______
decreases
Oxygen of venous sample is significantly lower
(deoxygenated already) and have high PC02 (2-8 mmHg)
as compared with arterial
true or false
true
The pH is more acidic as well about ______units lower in venous blood sample
0.02-0.05
amount of oxygen lowers in the venous blood after release in the capillaries
60%
Arterial blood is the more preferred specimen for blood gas
analysis because it is of more uniform composition than
venous blood.
true or false
true
type of syringe for blood gas analysis
glass syringe
why do glass syringe is the preferred syringe for BGA
less porous less exposure to the air outside
preferred anticoagulant
lyophilized heparin
(powdered form)
Remember to always keep the sample in ___
TECHNIQUE
ANAEROBIC
The relationship of oxygen and carbon dioxide is ___
reversely
proportional
if capillary blood is used, it must undergo ___
arterialization
warm up the area where you’re going to
extract sample (finger or heel stick – you can dip it on water
bath with 42C and leave it there for at least 10 minutes)
o We can also use a warming pad
- Arterialization
arterialization
o patients with low blood pressure (first reading of systolic is less than 95 mmHg)
o patients with certain clinical conditions which induces vasoconstrictions like if they are undergoing oxygen therapy,
o newborns (especially first few hours after birth)
o newborns with respiratory distress syndrome
