M3: Blood Gases and Acid-Base Balance Flashcards
substances that donates hydrogen ions
(H+) when dissolved in water
Acid
Has a sour taste
Acid
substances that accepts hydrogen ions
(H+)
Base
has a bitter taste
Base
negative logarithm of hydrogen ion
concentration
pH
Strength of hydrogen ion present in a
substance
pH
a system or substance that resist
changes in pH upon adding acid or base
Buffer
Buffer contains what:
weak acid and salts of conjugate base
Most common and important buffer in the
body:
H2CO3 or carbonic acid and
HCO3- or bicarbonate
T/F: carbonic acid is a weak acid
T
T/F: bicarbonate is a salts of conjugate base
T
According to Brønsted–Lowry Theory of Acid and Bases,
Acids (H) + Bases (OH) will result to what?
Water (H2O)
In this theory, acid donates hydrogen ions to the Base
(hydroxyl ion), while the Base accepts the hydrogen ions
Brønsted–Lowry Theory of Acid and Bases
Hydrogen Ion Concentration is maintained at ___
36-44 nmol/L
Hydrogen Ion Concentration maintained at 36-44 nmol/L is equivalent to ____
normal blood pH
↑H+ = _____ (inc/dec) acidity of the substance
↑acidity of the substance
Body naturally produced hydrogen ions
approx. ____
150g H+/day
T/F: Body naturally produced hydrogen ions
approx. 150g H+/day but maintained at
36-44 nmol/L
T
What is the blood pH
7.35-7.45 (7.40)
Blood pH is _____ (in chemistry) but
_____ (physiologically)
slightly alkaline
neutral
Process that causes acidemia/alkalemia:
Acidosis
Alkalosis
<7.35 blood pH
Acidosis
> 7.45 blood pH
Alkalosis
Acidosis causes ____, which is the acidic pH of the blood
acidemia
Alkalosis causes ____, which is the basic pH of the blood
alkalemia
Control Centers of the Acid-Base Balance
→ Buffer Systems
→ Lungs:
→ Kidneys:
controls carbon dioxide
Lungs:
acidic component of the blood
carbon dioxide
↑ CO2 = _____ (acidic/basic)
↓ CO2 = _____(acidic/basic)
acidic;
basic
controls bicarbonate
Kidneys
alkaline component of the blood
bicarbonate
↑ HCO3 - = ____(acidic/basic)
↓ HCO3 = ____(acidic/basic)
basic;
acidic
What are the 4 buffer systems
- Bicarbonate-Carbonic Acid Buffer System
- Protein Buffer System
- Phosphate Buffer System
- Hemoglobin Buffer System
Most important blood buffer system
Bicarbonate-Carbonic Acid Buffer System
Utilized HCO3- (conjugate base) and H2CO3
(weak acid) to minimize pH changes
Bicarbonate-Carbonic Acid Buffer System
Bicarbonate-Carbonic Acid Buffer System:
Blood pH of ____ is equivalent to the ratio of
_____
7.40
HCO3- : H2CO3
What is the ratio of HCO3- : H2CO3 in Bicarbonate-Carbonic Acid Buffer System
(20:1)
Uses plasma proteins to minimize pH changes
Protein Buffer System
In protein Buffer System, Majority of proteins are _______
negatively charged
T/F: Negatively charged proteins are Capable of binding positively charged substance
T
determines the pH or
the acidity of the substance
hydrogen ion (H+)
T/F hydrogen ion (H+) is a cation
T
↑H+ = ___ (acidic/alkaline)
↓H+ = ____(acidic/alkaline)
acidic;
alkaline
T/F: If protein can bind hydrogen, it can maintain
pH
T
If protein can bind ___, it can maintain ___
hydrogen; pH
The primary buffer in urine
Phosphate Buffer System
Utilizes HPO4- (phosphates) and H2PO4
(phosphoric acid)
Phosphate Buffer System
Plays a role in buffering CO2 during transport to
the lungs
Hemoglobin Buffer System
Three phases of Bicarbonate-Carbonic Acid Buffer System
- Peripheral Tissue (Cells)
- Circulation (Inside the RBC)
- Lungs
PERIPHERAL TISSUE: (CELLS)
● When cells undergo _______ , they
produced _____
aerobic metabolism;
CO2
biochemical process in
the body that utilizes oxygen
Aerobic metabolism
PERIPHERAL TISSUE: (CELLS)
What are the two phases of CO2
- Small amount of CO2 will bind to the amino
group of protein forming carbamino
compounds
-Majority of CO2 diffuses into RBC (enters)
PERIPHERAL TISSUE: (CELLS)
2 phases of CO2:
→ Small amount of CO2 will bind to the ____of protein forming _____
→ Majority of CO2 ____ into ____C (enters)
→ amino group; carbamino compounds
→ diffuses; RBC
CIRCULATION (INSIDE THE RBC):
In the circulation, the CO2 will bind to the
_____ forming _____ by the
action of the enzyme ______.
intracellular H2O;
carbonic acid;
carbonic anhydrase
CIRCULATION (INSIDE THE RBC):
This enzyme will split the carbonic acid into
____ and _____
Carbonic anhydrase;
bicarbonate;
hydrogen ions
CIRCULATION (INSIDE THE RBC):
→ The hydrogen ions will _____ the pH,
therefore, _____ the ______ inside the
RBC
decrease
increasing
acidity
CIRCULATION (INSIDE THE RBC):
In order for the pH to be neutralize,
the hydrogen will be bound to
_____
Hbg (HHb)
regarded as HHb
DeoxyHbg
Why is DeoxyHbg regarded as HHb
because this is a hemoglobin that
contain hydrogen ion and not
oxygen (Hemoglobin Buffer system)
CIRCULATION (INSIDE THE RBC)
The bicarbonate will ________ of the cell
and will go to the ___.
diffuse out;
plasma
T/F: bicarbonate will not disturb
electroneutrality
F; it will disturb electroneutrality
Why bicarbonate will disturb electroneutrality
Since bicarbonate is a negatively
charged electrolyte, it will disturb
electroneutrality (there will be an
accumulation of negatively charged in
the plasma)
CIRCULATION (INSIDE THE RBC):
In order to maintain electroneutrality,
____ needs to ___ the ___ (chloride shift)
chloride;
enter;
RBC
chloride shift aka
hamburger shift
IN THE LUNGS:
The inhaled ____ will ___ from the ___ to
the ____ which will bind to _____
oxygen;
diffuse;
alveoli;
circulation;
deoxygenated hemoglobin (HHb)
IN THE LUNGS:
When the HHb binds to the oxygen it will form
_______
oxygenated hemoglobin
IN THE LUNGS:
The HHb release ___ to form _____. The ___ from the inside
of RBC will ___ the RBC.
H+;
oxygenated hemoglobin;
hydrogen;
exit
IN THE LUNGS:
The bicarbonate in the ____ (phase 2) will bind
to the ___ that is released from the binding
of ____ and ____ , forming
_____ which is then split into _____ and
____.
plasma;
hydrogen;
deoxyhemoglobin;
oxygen;
carbonic acid;
water AND carbon dioxide
IN THE LUNGS:
The ____ will ____ from the ____ and will
be eliminated through ____ or _____.
CO2;
diffuse out;
alveoli;
exhalation or ventilation
Importance of Bicarbonate-Carbonic Acid Buffer System
- _____ dissociates into ____ and ____, allowing CO2 to be eliminated by the ____and H+ as ____.
- Changes in CO2 modify the _______ (____)
- ____ concentration can be altered by the
____
- H2CO3; CO2; H2O; lungs; water
- respiratory rate (ventilation)
- HCO3- kidneys
What are the three importance of Bicarbonate-Carbonic Acid Buffer System
- H2CO3 dissociates into CO2 and H2O, allowing CO2
to be eliminated by the lungs and H+ as water. - Changes in CO2 modify the respiratory rate (ventilation)
- HCO3- concentration can be altered by the kidneys
Acid base balance by the bicarbonate-carbonic
acid buffer system is mediated by the two
organs: ____ and ____
lungs and kidneys
It expresses acid-base relationship and relates
the pH of a solution to the dissociation properties
of weak acid
HENDERSON-HASSELBACH EQUATION
What is the formula of HENDERSON-HASSELBACH EQUATION
refer to your notes hehe
dissociation/ionization constant
pKa
ability of an acid/base to dissociate in water
pKa
T/F: Carbonic acid is directly measured in the
laboratory
F; NOT directly measured
T/F: Since Carbonic acid is NOT directly measured in the
laboratory. What is then measured ?
pCO2
What is pCO2
(partial pressure of carbon dioxide
partial pressure of carbon dioxide
pCO2
Majority of CO2 in the blood are in the form of
______. Hence, by measuring _____ we
can relate it to the amount of carbonic acid
present in the ____.
____ = ____ x ____
carbonic acid;
pCO2;
blood
𝐻2𝐶𝑂3 = 𝑝𝐶𝑂2 𝑥 0. 0307 𝑚𝑚𝑜𝑙/L
What is the solubility constant of pCO2
0.0307 mmol/L
pKa at physiologic temp./37°C
6.1
Compute for the blood pH of a healthy individual
with normal lungs and kidneys has the following
blood gas values:
→ HCO3-: 24 mmol/L
→ pCO2: 40 mmHg
refer to your notes
WHAT ARE THE TWO ORGANS THAT MAINTAIN ACID BASE BALANCE
Lungs and Kidney
Regulates CO2 excretion
Lungs
acid component
CO2
Conditions assoc. with acid-base balance by the
lungs is termed “____”
“Respiratory”
CO2 is measured in the laboratory as ____
pCO2
LUNGS:
Reference value (pCO2):
35-45 mmHg
(equivalent to pH: 7.35-7.45)
Blood is acidic (acidemia) due to the problem
with the lungs
Respiratory Acidosis
Respiratory Acidosis:
___ CO2 excretion = ____ CO2 in the blood = _____ pH
↓CO2 excretion = ↑CO2 in the blood = ↓ pH
Example of Respiratory Acidosis
hypoventilation
Alkalemia due to the problem with the lungs
Respiratory Alkalosis
Respiratory Alkalosis:
___ CO2 excretion = ____ CO2 in the blood = ___ pH
↑CO2 excretion = ↓CO2 in the blood = ↑pH
Example of Respiratory Alkalosis
hyperventilation
Regulates HCO3- excretion and reabsorption
Kidneys
alkaline component of the blood
HCO3-
Conditions assoc. with acid-base balance by the
kidneys are termed “______”
Metabolic
KIDNEYS:
Reference value (HCO3-): ____
22-29 mEq/L
KIDNEYS:
<22 mEq/L = ____ (acidic/alkaline)
>29 mEq/L = ____(acidic/alkaline)
acidic
alkaline
T/F: mEq/L and mmol/L are insignificant in terms of
____ because the conversion factor is ____
T; bicarbonate; 1
→ ↑HCO3- excretion = ↓pH = ↓HCO3- in the blood
Metabolic acidosis
In Metabolic acidosis:
____ HCO3- excretion = ____ pH = ____ HCO3- in the blood
↑HCO3- excretion = ↓pH = ↓HCO3- in the blood
Acidemia (<22)
Metabolic acidosis
Metabolic acidosis is <22 (__)
Acidemia
↓HCO3- excretion = ↑pH = ↑HCO3- in the blood
Metabolic alkalosis
Alkalemia (>29)
Metabolic alkalosis
Metabolic alkalosis = >29 =
Alkalemia
T/F Bicarbonates are normally filtered by the
glomerulus.
F; NOT normally filtered
In the _____, the unfiltered bicarbonate will bind to the ____
forming _____ which will further split
to ____ and ____ by _____enzyme
proximal tubule;
hydrogen;
carbonic acid;
water and carbon dioxide ;
carbonic anhydrase
The ____ that is synthesized, will be
___ by the ____.
Inside the cell, it
will bind with the ______ forming
____ which are split into ____
and _____.
CO2;
reabsorbed;
PCT cells;
intracellular water;
carbonic acid;
hydrogen and bicarbonate.
The bicarbonate will bind to____ and they will be ____ of the cell.
intracellular sodium;
diffused out
T/F: The exit of sodium from PCT to the
bloodstream, necessitates the entry of
hydrogen
T
T/F: From the split of carbonic acid, the hydrogen
will be diffused out of the cell to the proximal tubule to look for bicarbonate so that the bicarbonate can be reabsorbed.
T
(↓ pH) = ____ pCO2
(↑ pH) = ____pCO2
(↓ pH) = ____(HCO3-)
(↑ pH) = ____(HCO3-)
↑, ↓ (opposite to the pH)
↓, ↑ (equal yung
(↓ pH) = ____ pCO2
(↑ pH) = ____pCO2
(↓ pH) = ____(HCO3-)
(↑ pH) = ____(HCO3-)
↑, ↓ (opposite yung pCO2 sa pH)
↓, ↑ (equal yung HCO3- sa pH)
ROME
R (lungs) Opposite
M (kidneys) Equal
acts against disturbances in the acid base balance:
COMPENSATION MECHANISM
Compensation in metabolic (kidneys)
Lungs
Fast action; 1-2 days but very short
term compensation
Lungs
Lungs acts fast about _____ but very ____
1-2 days;
short term compensation
In METABOLIC:
Hyperventilation = ____ pCO2
Hypoventilation = ____ pCO2
↓pCO2
↑pCO2
Compensation in Respiratory
KIDNEYS
Slow action; 2-4 days but complete compensation
Kidneys
Kidneys:
Slow action about _____ (up to ___)
but _____ compensation
2-4 days
up to 5 days
complete
Respiratory:
↑HCO3- = ________
↓HCO3- = ________
↑HCO3- = Increase Renal HCO3- reabsorption
↓HCO3- = Decreased Renal HCO3- reabsorption
Problem in the Kidneys with ↓pH
Metabolic Acidosis
Bicarbonate deficiency (↓HCO3-)
Metabolic Acidosis
Metabolic Acidosis is seen in:
- Diabetic ketoacidosis
- Lactic acidosis
- Renal tubular acidosis
- Diarrhea
- Ammonium chloride, Calcium chloride,
salicylates, ethanol
Metabolic Acidosis:
↑Acetoacetic acid
and β-hydroxybutyric acid in Diabetic ketoacidosis will ____ pH
↓
What increases in Diabetic ketoacidosis
↑Acetoacetic acid and β-hydroxybutyric acid
Metabolic Acidosis:
what increases in Lactic acidosis that causes a decrease in pH
↑lactic acid
CONDITION wherein the kidney cannot
reabsorb bicarbonate;
____ HCO3- excretion =↓pH
Renal tubular acidosis
↑
T/F: Blood is acidic because of the excretion
of alkaline component therefore urine is
alkaline
T
T/F urine is alkaline
T
Metabolic Acidosis :
Diarrhea -> _______ = ↓pH
↑HCO3- loss
Metabolic Acidosis :
Diarrhea -> _______ = ↓pH
↑HCO3- loss
acid producing substance
Ammonium chloride, Calcium chloride,
salicylates, ethanol
T/F: acid producing substance, such as Ammonium chloride, Calcium chloride, salicylates, ethanol decreases pH
T
Electrolyte Imbalance IN Metabolic Acidosis
Hyperkalemia (↑K+), hyperchloremia (↑Cl-)
What is the organ that compensates in Metabolic acidosis
Lungs
Compensation in Metabolic Acidosis
Hyperventilation
Hyperventilation ___ (inc/dec) respiratory rate
↑respiratory rate
Compensation in Metabolic Acidosis:
To normalize the pH, lungs will _____ by
eliminating ____
↓pCO2
CO2
Compensation in Metabolic Acidosis:
For every ______ = _____
For every ↓1 mEq/L HCO3- = ↓1-1.3 mmHg pCO2
The problem is in the lungs with ↓pH
Respiratory Acidosis
Excess CO2 accumulation (↑CO2)
Respiratory Acidosis
Respiratory Acidosis is seen in:
→ Chronic Obstructive Pulmonary Disease
→ Drug
→ Congestive heart failure
→ Myasthenia gravis, CNS disease, botulism,
stroke, myxedema, pneumonia
- results to hypercarbia
Chronic Obstructive Pulmonary Disease
(COPD)
(↑CO2) is a condition called
hypercarbia
What are the drugs that can cause hypoventilation
morphines, barbiturates, alcohol
Morphines and barbiturates are known
as ____
relaxants
Hypoventilation: _____ CO2 excretion = _____ CO2 = ____pH
Hypoventilation: ↓CO2 excretion = ↑CO2 = ↓pH
In Congestive heart failure, there is = ___
↓cardiac output
Compensation organ in Respiratory Acidosis
kidney
Compensation in Respiratory Acidosis
Retention of HCO3-
What happens in the Compensation of Respiratory Acidosis
The kidney will retain bicarbonate (very slow;
completed within 5 days)
In the compensation of respiratory acidosis, The kidney will retain bicarbonate. The compensation is very slow and will be completed within ___ days. But within 3 days it is ___ complete
5 days
90%
In the compensation in respiratory acidosis:
↑ ____ mmHg pCO2 = ↑ ____ mEq/L HCO3-
↑ 10 mmHg pCO2 = ↑ 1 mEq/L HCO3-
Problem in the kidney
↑pH
Metabolic Alkalosis
↑pH = ___HCO3
↑
Bicarbonate excess
Metabolic Alkalosis
Metabolic Alkalosis is seen in
Vomiting
Sodium bicarbonate excess
Sodium lactate, citrate, acetate
What happens in vomiting that causes an increased in ↑HCO3-
↑acid & Cl- loss = ↑HCO3-
What are the HCO3- producing salts
→ Sodium lactate, citrate, acetate
Metabolic Alkalosis:
Electrolyte imbalance: ____, ____
Hypokalemia,
Hypochloremia
Organ that compensates in Metabolic Alkalosis
lungs
Metabolic Alkalosis:
Compensation: ___
Hypoventilation
Metabolic Alkalosis:
hypoventilation
↓respiratory rate = ↓CO2 loss = ↑pCO2 =
↓pH
Metabolic Alkalosis:
hypoventilation:
↓respiratory rate = ____CO2 loss = ___ pCO2 = ____pH
↓respiratory rate = ↓CO2 loss = ↑pCO2 = ↓pH
Least effective compensation mechanism
Hypoventilation
Why is Hypoventilation Least effective compensation mechanism
because ↓respiratory rate results to ↓CO2
loss and ↓oxygen (hypoxemia)
Hypoxemia stimulates ____
Hyperventilation
Hyperventilation
___ CO2 loss = ____ pCO2 = ____ pH
↑CO2 loss = ↓pCO2 = ↑pH
Problem is in the lungs
↑pH
Respiratory Alkalosis
↑pH = ____ pCO2
↓
Excess CO2 loss
Respiratory Alkalosis
Respiratory Alkalosis is seen in
- Hypoxemia, hysteria, anxiety
- Drugs
- Pulmonary emboli, pulmonary fibrosis
- Progesterone
- Hepatic cirrhosis, gram-negative sepsis
results to hyperventilation
Hypoxemia, hysteria, anxiety
↑CO2 loss
hyperventilation
Example of drugs in Respiratory Alkalosis
aspirins, salicylates, nicotine
chemical stimulants; stimulates the lungs resulting to
hyperventilation
aspirins, salicylates
results to impairment of O2 exchange in the
lungs
Pulmonary emboli, pulmonary fibrosis
cause of
chronic respiratory alkalosis in pregnant
women
↑progesterone
Respiratory Alkalosis:
Electrolyte Imbalance: ___
Hypokalemia
Organ that compensates in Respiratory Alkalosis
kidneys
Respiratory Alkalosis:
Compensation (kidneys): ____
Increased HCO3- excretion
Increased HCO3- excretion in the Respiratory alkalosis reduces ___
alkalinity
Respiratory Alkalosis:
the compensation for bicarbonate: ___
↓1 mmHg pCO2 = ↓2 mEq/L HCO3-
Two or more primary acid-base disorders coexist.
Mixed Acid-Base Disorder
Result of inappropriate compensation
Mixed Acid-Base Disorder
In mixed acid-base disorder, pCO2 and HCO3- are in ____
opposite direction
Mixed Acid-Base Disorder:
○ Acidosis = ____pCO2 & ____HCO3
○ Alkalosis = ____pCO2 & ____HCO3
○ Acidosis = ↑pCO2 & ↓HCO3
○ Alkalosis = ↓pCO2 & ↑HCO3
EVALUATION OF COMPENSATION:
Acidosis or Alkalosis; pCO2 or HCO3- is normal (the other one is
abnormal)
Uncompensated
EVALUATION OF COMPENSATION:
Acidosis or Alkalosis; pCO2 and HCO3- are both abnormal
Partially Compensated
EVALUATION OF COMPENSATION:
● Normal pH
● pCO2 and HCO3- are both abnormal
Compensated / Fully-compensated
REFERENCE VALUES:
pH: __
pCO2:__
HCO3-:___
pH: 7.35-7.45
pCO2: 35-45 mmHg
HCO3-: 22-26 mEq/L
EXAMPLE #1:
pH: 7.30
pCO2: 50 mmHg
HCO3-: 25 mEq/
Respiratory Acidosis, Uncompensated
EXAMPLE #2:
pH: 7.40
pCO2: 30 mmHg
HCO3-: 10 mEq/L
Metabolic Acidosis, Compensated
EXAMPLE #2:
pH: 7.40
pCO2: 30 mmHg
HCO3-: 10 mEq/L
Metabolic Acidosis, Compensated
EXAMPLE #3:
pH: 7.10
pCO2: 40 mmHg
HCO3-: 18 mEq/L
Metabolic Acidosis, Uncompensated
EXAMPLE #4:
pH: 7.22
pCO2: 50 mmHg
HCO3-: 32 mEq/L
Respiratory Acidosis, Partially Compensated
EXAMPLE #5;
pH: 7.52
pCO2: 28 mmHg
HCO3-: 45 mEq/L
Mixed alkalosis
● aka “Oxygen Dissociation Curve”
OXYHEMOGLOBIN DISSOCIATION CURVE
OXYHEMOGLOBIN DISSOCIATION CURVE is aka
“Oxygen Dissociation Curve”
It is a graphical representation of hemoglobin
affinity to oxygen
. OXYHEMOGLOBIN DISSOCIATION CURVE
Hemoglobin transports oxygen to areas (left
and right) with low oxygen tension
OXYHEMOGLOBIN DISSOCIATION CURVE
Hemoglobin transports ___ to areas (left
and right) with _____
oxygen;
low oxygen tension
SHIFT TO THE LEFT
● ↑ O2 affinity
● ↑ pH (Alk)
● ↓ pCO2
● ↓ 2,3-BPG/DPG
● ↓ Temperature
SHIFT TO THE RIGHT
● ↓ O2 affinity
● ↓ pH (Acid)
● ↑ pCO2
● ↑ 2,3-BPG
● ↑ Temperature
2,3-BPG meaning
2,3-Bisphosphoglycerate
2,3-BPG/DPG Purpose
When bound to hemoglobin, it
decreases its affinity
↑BPG/DPG = _____ O2 affinity
↓ (vice versa)
OXYGENATION:
Normal pO2: ___
80-100 mmHg
OXYGENATION:
Hypoxemia: ____ pO2
↓pO2
Mild Hypoxemia
61-80 mmHg
Moderate Hypoxemia
41-60 mmHg
Severe Hypoxemia
≤40 mmHg
OXYGENATION:
Hypoxemia is seen in:
→ Myocardial infarction
→ intestinal pneumonia
→ severe CHF
→ normal individuals living at higher altitudes
Specimen used in blood gas analysis
Arterial Blood (through arterial puncture)
Anticoagulant used in blood gas analysis
0.05 mL heparin/mL of blood
T/F: the 0.05 mL heparin/mL of blood, is the green top tube
F; NOT THE GREEN TOP TUBE
BLOOD GAS ANALYSIS:
Syringe to be used for collection should be
____ by ___ heparin into the
___ of the syringe.
preheparinized;
flushing;
interior
BLOOD GAS ANALYSIS:
T/F: Blood should not be exposed in air during the collection only.
F; Blood should not be exposed in air DURING AND AFTER the collection
In blood gas analysis, the presence of air/air bubbles in the specimen will:
↑pO2 for 4mmHg/2 mins
↓pCO2 for 4mmHg/2 mins = false inc. in pH
T/F: In blood Gas Analysis, Blood samples should be chilled during
transport
T
Ways to chill the blood sample
ice/ice bath/ice slurry
Why Blood samples should be chilled during
transport?
Because ice will prevent:
✓ oxygen consumption by RBC
✓ glycolysis
Ice prevents what
✓ oxygen consumption by RBC
✓ glycolysis
Blood Gas Analysis:
Specimen Consideration:
On standing, pH and pO2 = ____; while pCO2 is ___
→ pH and pO2: increased
→ pCO2: decreased
According to _____ the specimen (____)
must be processed within ____ and should be
stored at ____
Clinical and Laboratory Standards
Institute (CLSI);
arterial blood;
30 mins;
room temperature
Glycolysis results to ___ (inc/dec) blood pH
decrease
results to decrease blood pH
Glycolysis
most common pre-analytic error
Excess heparin causes downward shifting of
blood pH
Excess heparin causes downward shifting of
blood pH causes false ___ (inc/dec) in pH
false ↓ in pH (acidity)
t/f: lower temperatures cause ___ oxygen
solubility in blood and a ____ shift in the
oxyhemoglobin curve resulting in ____
combining with ____
increased;
left shift;
more oxygen;
hemoglobin
What are the 4 Pre-Analytical Variables under laboratory analysis (blood gas analysis)
Temperature
Elevated Plasma Proteins
Bacterial Contamination
Improper Transport
most important factor (pre-analytical variable)
Temperature
LABORATORY ANALYSIS: (blood gas analysis)
Normal temp
37°C ± 0.1°C
T/F Analyzers used should be maintained at a
constant temperature (38°C ± 0.1°C)
F; 37°C ± 0.1°C
Why constant temp is important in analyzers
bec for every
1°C above 37°C = ↓7% pO2 : ↑3% pCO2 : ↓pH 0.015
Protein buildup in the analyzer will affect pO2
Elevated Plasma Proteins
Bacterial Contamination Will cause false ___ in ___because the ___
are consumed by ___
↓
pO2
oxygen
bacteria
Same with temperature
Improper Transport
What are the two laboratory methods under blood gas analysis
Gasometer
Electrodes
methods under gasometer
- Van Slyke
- Natelson
Natelson - uses reagents:
→ Mercury
→ Caprylic alcohol
→ Lactic acid
→ Sodium hydroxide (NaOH) & Sodium
hydrosulfate (NaHSO3)
create vacuum
Mercury
antifoam reagent; prevent
the formation of air bubbles
Caprylic alcohol
What are the 3 electrodes
pH
pO2
pCO2
pH method
potentiometry
electrodes in pH
Ag-AgCl
Calomel (Hg2Cl2)
Gas electrode
reference method/electrode for pH
Ag-AgCl
most common electrode used
for pH
Gas electrode
pO2 electrode
Clark electrode
pO2 method
polarography-amperometry
pCO2 electrode
Severinghaus electrode
pCO2 method
potentiometry
T/F: In modern analyzers pH, PO2, PCO2 cannot be
measured at the same time
F; In modern analyzers, these 3 electrodes are
already present; therefore they can all be
measured at the same time
