1. Acid/Base- Exam 1 Flashcards
define an acid
Molecule containing hydrogen atom that can release hydrogen ion when placed in solution
what the difference between an strong and weak acid
Strong: Rapid dissociation with release large amount of H+ (HCl)
Weak: Slow dissociation with release small amount of H+ (H2CO3)
define a base
Ion or molecule that can accept hydrogen ions
whats the difference between a strong and weak base
Strong: Reacts strongly and rapidly with H+ and quickly removes larger quantities of H+ from solution (OH-)
Weak: Reacts slowly forming weak bonds does not remove as much H+ (HCO3-)
Most of the acids & bases in extracellular fluid involved with normal acid-base regulation are what kind of acids and bases?
weak acids and weak bases
–H2CO3 and HCO3-
Normal blood [H+] is?
40 nEq/liter
which is 0.00004 mEq/liter
what is the normal and extreme range for [H+]?
Normal variations 3 to 5 nEq/liter
Extreme range: 10 nEq/liter to 50 nEq/liter
pH= [formula]
log(1/[H+]) which equals -log[H+]
Levels at which person can live more than a few hours:
•Lower limit: ?
•Upper limit: ?
- Lower limit: 6.8
* Upper limit: 8.0
what are the 3 buffer systems
–Bicarbonate system (extracellular)
–Phosphate system (extracellular)
–Proteins (intracellular)
what do the lungs and kidneys control
Lungs: Control of carbon dioxide
Kidneys: Control of hydrogen ion and bicarb ion concentration
Hbg Buffering is special because it can do what?
act as an acid or a base
Hgb buffering titration with an acid results in what?
Net charge of +3 and 1 H+ ion
Hgb buffering titration with a base results in what?
Net charge of -3 and 1 OH- ion and 3 H20 molecules
describe what happens on the hemoglobin titration curve if 1.15 mM of H+ is added
the pH decreases by 0.16 units
Henderson-Hasselbalch pH= [general formula]
pK + log ([base]/[acid])
Henderson-Hasselbalch pH= [formula for bicarb/co2 system]
pK + log ([bicarb]/[CO2]*0.0301)
what is the plasma pK at 37C
6.1
what is the only thing that will change pK?
temperature
as temp increases, pK decreases
what is the solubility for CO2 at 37C?
0.0301
changing respiratory components, changes what on the chart?
the pCO2 isobar
changing metabolic components, changes what on the chart?
the hemoglobin buffer line
HypOventilating causes ACIDosis- describe the changes in CO2, pH, H+, Bicarb, and Hgb
CO2 INCREASE pH DECREASE H+ INCREASE Bicarb INCREASE Hgb INCREASE -Reaction moves to the LEFT
HypERventilating causes ALKALosis- describe the changes in CO2, pH, H+, Bicarb, and Hgb
CO2 DECREASE pH INCREASE H+ DECREASE Bicarb DECREASE Hgb DECREASE -Reaction moves to the RIGHT
define alkalemia
basic blood
pH >7.45
as pH increases, CO2 decreases
define alkilosis
basic ‘condition’
define acidemia
acidic blood
pH <7.35
as pH decreases, CO2 increases
define acidosis
acidic ‘condition’
describe what happens when the hgb buffer line moves up
metabolic changes- Alkilosis
Increased base= Decreased H+
describe what happens when the hgb buffer line moves down
metabolic changes- Acidosis
Decreased base= Increased H+
describe initial problem seen with metabolic acidosis
Buffer Line moves down the pCO2 isobar as [H+] increases and/or [HCO3-] decreases
–pH {DN}; [HCO3-] {DN}; pCO2 {NC}
describe compensation seen with metabolic acidosis
pCO2 isobar moves to right along Buffer Line as CO2 is blown off
–pH {UP}; [HCO3-] {DN}; pCO2 {DN}
describe the final result seen with metabolic acidosis
pH {DN}; [HCO3-] {DN}; pCO2 {DN}
describe initial problem seen with respiratory acidosis
pCO2 isobar moves left along Buffer Line as pCO2 increases
–pH {DN}; [HCO3-] {UP}; pCO2 {UP}
describe compensation seen with respiratory acidosis
Buffer Line moves up the pCO2 isobar as the kidney excretes hydrogen ions and retains bicarb
–pH {UP}; [HCO3-] {UP}; pCO2 {NC}
describe the final result seen with respiratory acidosis
pH {DN}; [HCO3-] {UP}; pCO2 {UP}
describe initial problem seen with metabolic alkalosis
Buffer Line moves up the pCO2 isobar as [H+] decreases and/or [HCO3-] increases
–pH {UP}; [HCO3-] {UP}; pCO2 {NC}
describe compensation seen with metabolic alkalosis
pCO2 isobar moves to left along Buffer Line as CO2 is retained
–pH {DN}; [HCO3-] {UP}; pCO2 {UP}
describe the final result seen with metabolic alkalosis
pH {UP}; [HCO3-] {UP}; pCO2 {UP}
describe initial problem seen with respiratory alkalosis
pCO2 isobar moves right along Buffer Line as pCO2 decreases
–pH {UP}; [HCO3-] {DN}; pCO2 {DN}
describe compensation seen with respiratory alkalosis
Buffer Line moves down the pCO2 isobar as the kidney retains hydrogen ions and removes bicarb
–pH {DN}; [HCO3-] {DN}; pCO2 {NC}
describe the final result seen with respiratory alkalosis
pH {UP}; [HCO3-] {DN}; pCO2 {DN}
After determining if the pH is acidic or basic, what do you look at next to determine if the primary cause is respiratory or metabolic?
bicarb
If pH indicates acidosis
•Metabolic (bicarbonate concentration ____)
•Respiratory (bicarbonate concentration ____)
If pH indicates acidosis
•Metabolic (bicarbonate concentration LOW)
•Respiratory (bicarbonate concentration HIGH)
If pH indicates alkalosis
•Metabolic (bicarbonate concentration ____)
•Respiratory (bicarbonate concentration ____)
If pH indicates alkalosis
•Metabolic (bicarbonate concentration HIGH)
•Respiratory (bicarbonate concentration LOW)
After determining the primary cause is METABOLIC acidosis or alkalosis, to determine if there is a secondary cause: what value do you look at?
actual pCO2 value
After determining the primary cause is RESPIRATORY acidosis or alkalosis, to determine if there is a secondary cause: what value do you look at?
actual bicarb value
If the Primary Problem is Metabolic ACIDOSIS, what formula do you use to calculate the predicted value of compensated pCO2
pCO2 = (1.5 x [HCO3-]) + 8
If the Primary Problem is Metabolic Acidosis, and you have calculated the predicted value of compensated pCO2…If OBSERVED pCO2 is more than 2 mmHg HIGHER than calculated pCO2 there is a good chance of secondary/coexisting __________
respiratory acidosis
If the Primary Problem is Metabolic Acidosis, and you have calculated the predicted value of compensated pCO2…If OBSERVED pCO2 is more than 2 mmHg LOWER than calculated pCO2 there is a good chance of secondary/coexisting __________
coexisting respiratory alkalosis
If the Primary Problem is Metabolic ALKALOSIS, what formula do you use to calculate the predicted value of compensated pCO2
pCO2 = 40 + (0.7 x ([HCO3-measured] - 24))
If the Primary Problem is Metabolic ALKALOSIS, and you have calculated the predicted value of compensated pCO2..If OBSERVED pCO2 is more than 5 mmHg HIGHER than calculated pCO2 there is a good chance of secondary/coexisting ______
respiratory acidosis.
If the Primary Problem is Metabolic ALKALOSIS, and you have calculated the predicted value of compensated pCO2..If OBSERVED pCO2 is more than 5 mmHg LOWER than calculated pCO2 there is a good chance of secondary/coexisting _______
respiratory alkalosis.
_____ is the maximum pCO2 possible when compensating for metabolic alkalosis. A pCO2 higher means there is a __________
55 mmHg
coexisting respiratory acidosis
If the Primary Problem is Respiratory ACIDOSIS, and the onset was LESS THAN 24 hrs, what equation do you use
ACUTE: 1 mEq/L increase in [HCO3-] for every 10 mmHg increase in pCO2
If the Primary Problem is Respiratory ACIDOSIS, and the onset was MORE THAN 24 hrs, what equation do you use
CHRONIC: 3.5 mEq/L increase in [HCO3-] for every 10 mmHg increase in pCO2
If the Primary Problem is Respiratory ACIDOSIS and you have calculated the predicted compensation value of bicarb… If OBSERVED [HCO3-] is MORE than the calculated [HCO3-] there is a good chance of secondary/coexisting _______
metabolic alkalosis.
If the Primary Problem is Respiratory ACIDOSIS and you have calculated the predicted compensation value of bicarb… If OBSERVED [HCO3-] is LESS than the calculated [HCO3-] there is a good chance of secondary/coexisting _______
metabolic acidosis
If the Primary Problem is Respiratory ALKALOSIS, and the onset was LESS THAN 24 hrs, what equation do you use
ACUTE: 2 mEq/L decrease in [HCO3-] for every 10 mmHg decrease in pCO2
If the Primary Problem is Respiratory ALKALOSIS, and the onset was MORE THAN 24 hrs, what equation do you use
CHRONIC: 5 mEq/L decrease in [HCO3-] for every 10 mmHg decrease in pCO2
If the Primary Problem is Respiratory ALKALOSIS and you have calculated the predicted compensation value of bicarb… If OBSERVED [HCO3-] is LESS than the calculated [HCO3-] there is a good chance of secondary/coexisting _______
metabolic acidosis
If the Primary Problem is Respiratory ALKALOSIS and you have calculated the predicted compensation value of bicarb… If OBSERVED [HCO3-] is MORE than the calculated [HCO3-] there is a good chance of secondary/coexisting _______
metabolic alkalosis
What is the formula and normal value for anion gap
AG = [Na+] – ([Cl-] + [HCO3-])
AG normal value = 9 to 16 mEq/L
AG > 30 mEq/L indicates what?
–High anion gap metabolic acidosis
AG > 20 mEq/L indicates what?
–probably high anion gap metabolic acidosis
AG >=16 and <=20 mEq/L indicates what?
–abnormal but may be due to variety things other than anion gap acidosis
Not all acidosis should be treated with bicar- BUT If the pH is below ____ bicarb should be given regardless of cause
7.10
What is the formula to calculate how much bicarb to give if there is a deficit
HCO3-deficit = .5 x Body Weight (kg) x ([HCO3-(desired)] – HCO3-(measured)])