WEEK 4 Flashcards
arterial blood
lithium heparin
ABG
can yield a hydrogen ion (H)
donor
acids
can yield hydroxyl ions
acceptor
base
weak acid
weak base, salt
bicarbonate (HCO3)
buffer
Principal mammalian buffer system
BICARBONATE-CARBONIC ACID
BUFFER SYSTEM
HCO3>H2CO3
unstable, changing to H2O and CO2 in
fluid
H2CO3, carbonic acid
Phosphate form that
acts as a buffer
2,3-diphosphoglycerate
It increases the amount of NaHCO3 in ECF
(more alkaline)
PHOSPHATE BUFFER SYSTEM
16% of the non-bicarbonate buffer value of
Erythrocytes
PHOSPHATE BUFFER SYSTEM
Maintains pH level (Venous and Arterial Blood)
HEMOGLOBIN-OXYHEMOGLOBIN
BUFFER SYSTEM
1 gram of Hemoglobin carries – of
Oxygen
1.39 mL
Proteins can exist in 2 forms: H+ protein, B
Protein
PROTEIN BUFFER SYSTEM
Capability to bind or release excess Hydrogen
as required
PROTEIN BUFFER SYSTEM
Plasma proteins (Charges on their surface)
* pH > pI – charge
-
Plasma proteins (Charges on their surface)
* pH < pI – charge
+
The second largest fraction of the anions in
the plasma. It includes the ionized
bicarbonate (HC03), carbonate and the
carbamino compounds.
BICARBONATE (HCO3)
This fraction of blood, plasma or serum
Includes the undissociated carbonic acid and
the physically dissolved anhydrous C02
CARBONIC ACID (H2CO3 )
The 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
measure of C02 concentration in the blood.
PARTIAL PRESSURE OF C02
(pC02)
Normal range is 35 - 45 mmHg
PARTIAL PRESSURE OF C02
(pC02)
an
index of the amount of CO2 that can be bound
by serum, plasma, or whole blood as HCO3 at a
pCO2 of 40 mmHg at 25 degrees Celcius.
CARBON DIOXIDE COMBINING
POWER (CO2 combining power)
consisting of ionized HC03, C03, carbamino
compound) and unionized fraction (H2C03) and
physically dissolved C02
TOTAL CARBON DIOXIDE
CONCENTRATION (ctCO2)
The negative logarithm of hydrogen ion
activity with a normal average range of
7.35-7.45
pH
Based on amperometric or polarographic
measurement of oxygen.
Clark p02 electrode
Calculation from oxygen saturation, pH and
temperature by means of the standard 02
dissociation curve.
p02
- Gasometric analysis
- Transcutaneous monitoring
p02
Based on pH measurement of a
stationary NaHCO3 solution which is in
equilibrium with the test solution and the test via
a CO2 permeable membrane
pC02 electrode
From a measured pH value interpolated in
the C02 equilibrium curve
pC02
Based on polarographic principle
PH electrode
Nomogram and Slide Rule
* Siggard -Anderson Alignment nomogram
pH
Manometric Method Using Natelson
Microgasometer
ct C02
Carbon dioxide is released front HC03 by the
addition of lactic add. The C02 and other gases
are, extracted under a partial vacuum. The
pressure difference at constant value before and
after absorption of C02 by NaOH Is the amount of
C02 present in the sample
Manometric Method Using Natelson
Microgasometer
NATELSON MICROGASOMETER
release CO2 from HCO3
10% lactic acidd
NATELSON MICROGASOMETER
for total reabsorption of CO2 gas as Na2CO3
12% NaOH
NATELSON MICROGASOMETER
for total reabsorption of O2
NaHSO3
NATELSON MICROGASOMETER
seperates the sample and other reagents prevents introduction of air and seals gasometer
mercury
NATELSON MICROGASOMETER
washes the sample and reagent into the reaction chamber
distilled water
General term applied for the any condition where
the pH of the blood and the bicarbonate
concentration of the blood are below normal.
Acidosis
General term applied for any condition with an
increase in blood pH (above normal range)
characterized by an elevation in the H+ ion
accepting buffer of the plasma (UC03) and a
reduction in the H+ ion substances (H2CO3)
Alkalosis
- Caused by bicarbonate deficiency
Metabolic Acidosis
- Compensation: Hyperventilation
Metabolic Acidosis
- (+) Hyperkalemia and hyperchloremia
Metabolic Acidosis
Production of increased amount of acid –
diabetic ketoacidosis, lactic acidosis
(alcoholism), renal failure and diarrhea
Metabolic Acidosis
- Caused by bicarbonate excess
Metabolic Alkalosis
Conditions: Vomiting with the loss of chloride from
the stomach
Metabolic Alkalosis
- Compensation: Hypoventilation
Metabolic Alkalosis
For every 10 meq/L rise in bicarbonates, the pCO2
rises by 6 mmHg
- (+) hypokalemia, hypochloremia
Metabolic Alkalosis
- Excessive CO2 accumulation
Respiratory Acidosis
- Conditions: Chronic obstructive pulmonic
disease (COPD), myasthenia gravis, CNS
disease, drug overdose (morphine,
barbiturates and opiates), pneumonia
Respiratory Acidosis
- Compensation: retention of bicarbonates
Respiratory Acidosis
- Due to excessive carbon dioxide loss
Respiratory Alkalosis
- Conditions: Anxiety, severe pain, aspirin
overdose, hepatic cirrhosis
Respiratory Alkalosis
- Compensation: decreased reabsorption
Respiratory Alkalosis
