Exam 2 ABG's (6/17/24) Flashcards
How is Acidemia and Alkalemia defined?
Acidemia: Excess production of H+ (in relation to hydroxyl ions)
Alkalemia:Excess production of OH- (in relation to hydrogen ions)
How does CO2 and Bicarb enter and leave the body?
CO2: Lungs
Bicarb: Kidneys via proximal tubule
How is Hydrogen reabsorbed in the body?
- Distal Tubule
- Collecting Duct
Who coined the term “Acid-Base”?
Henderson and Hasselbach
Henderson-Hasselbach Equation
pH= 6.1 + log (serum bicarb/0.03 x PaCO2)
What does Amphoteric mean?
Example:
Can be both an acid and a base
Ex. Water
How do we define a strong/weak acid?
Examples:
Defined according to the degree of dissociation in water, which determines the strength
Strong Acid: Lactic Acid (pKa 3.4)
Weak Acid: Carbonic Acid (pKa 6.4)
3 Rules of acid-base balance for substances in the body:
- Electrical Neutrality (Cations = Anions)
- Dissociatoin Equilibria (The propensity to dissociate)
- Mass Conservation (Amount of the substance must remain constant)
Do strong ions dissociate completely or partially?
Completely
What are the most abundant strong ions found in the ECF?
What about some other examples?
Na+, Cl-
K+, Sulfate 2-, Mg 2+, Ca 2+
What does Strong Ion difference refer to?
The amount of total strong cations minus the total strong anions
True or False:
There are always more strong ECF anions than cations making the SID always negative?
False:
There are always more ECF cations than anions making the SID always positive.
The ability of the ECF to maintain a little more strong cations than anions is an ____ of pH.
Independent predictor
What is the first thing we should look at to determine whether or not there is an acid-base disturbance?
Look at the pH
If both PaCO2 levels and HCO3 levels increase, what kind of disorder can be identified?
Primary disorder with secondary compensation
In broad terms, If HCO3 increases but PaCO2 decreases, what kind of disorder can be identified?
Mixed acid/base disorder
Mixed alkalosis
How would we define this disturbance?
pH 7.28, PCO2 46, HCO3 18
Mixed Respiratory and Metabolic Acidosis
What are some consequences on the CV system that may occur if the pH gets down to 7.2 or 7.1?
7.2: Impaired Contractility
7.1: Decreased Responsiveness to catecholamines
What are some other consequences of acidosis on the CV system discussed in lecture?
- Decreased arterial blood pressure
- Sensitivity to re-entry dysrhythmias (V-Tach)
- Decreased threshold for v-fib
Consequences of acidosis on the nervous system:
Obtundation
Coma
Select All that Apply:
Which of the following are consequences of acidosis on the pulmonary system?
A. Hypoventilation
B. Increased Minute Volume
C. Increased ETCO2 readings
D. Hyperventilation
E. Dyspnea
F. Decreased ETCO2 readings
B. Increased Minute Volume
D. Hyperventilation
E. Dyspnea
F. Decreased ETCO2 readings
Rationale: Both D and E are directly from the powerpoint slide. B and F were discussed by Dr. Kane during lecture. “When we hyperventilate, we increase our minute volume to try and blow off more CO2 to reduce acidemia.”
Consequences of acidosis on metabolism?
- Hyperkalemia
- Insulin Resistance
- Inhibition of anaerobic glycolysis
An acute decrease in alveolar ventilation results in ___.
an increase in PaCO2
Our book states that all the many causes of Respiratory Acidosis stem from one of three main issues. What are these 3 issues?
- Central Ventilation Control
- Peripheral Ventilation Control
- V/Q Mismatch