Acid Base Flashcards
What is an acid?
substance that can donate H+
What is a base?
a substance that can accept H+
What are the 2 types of acids we produce?
carbonic = can be converted to CO2 = can be eliminated in the lungs non-carbonic = cannot be converted to CO2 = must be excreted in kidney
Carbonic acids are made from the metabolism of ____
fats and carbohydrates
Non-carbonic acuds are made from the metabolism of _____
proteins and phospholipids
When we’re in a neutral balance, if we make 100 meq of acid, we’ll use 100 meq of _______ to stay stable.
bicarbonates
Non-carbonic acids combine with _____ to be excreted by the kidney
buffers and anions
What is the clinical pH range?
7.8 and 6.8
What measures dissolved CO2 + bicarb conc in venous samples?
total CO2 conc
Why is pH outside of 7.8 to 6.8 incompatible with life?
bc every enzymes won’t work outside this range
T or F: total CO2 conc always exceeds plasma bicarb conc.
True
total CO2 is dissolved CO2 + bicrab
What is the normal bicarb conc?
24 mEq/L
What is the difference between acidemia and acidosis?
acidemia is a condition and acidosis is a process
What is the equation for the bicarb buffer sys?
CO2 + H2O H+ + HCO3-
What is the key extracellular buffer?
bicarbonate
Are humans an open or closed system? WHy is this important?
open (if we were closed out pH would be 6.1 = death)
*pH based on buffering ability of bicarb
What is the formula for determining pH?
(pH) H+ = 24 (CO2) / (HCO3)
What is the H+ when the pH = 7.4?
40 nEq/L
What is the trick to determine the H+ from the pH value?
80 - last 2 digits of pH to the right of the decimal pt
ex: pH 7.5 = H+ 30 nEq/L
What is the normal pH range?
7.35 to 7.45 (or 7.4)
What is the normla pCO2?
36-44 mmHg (40 mmHg)
Decreased bicarb is the primary dysfuction in ______
metabolic acidosis
Increased bicarb is the primary dysfuction in ______
metabolic alkalosis
Metabolic disorders directly alter the conc of _______
bicarbonate
Respiratory disorders directly alter ______
CO2
Increased CO2 is the primary dysfunction of _______
respiratory acidosis
Decreased CO2 is the primary dysfunction of _______
respiratory alkalosis
T or F: The effects of bicarbonate as buffer is immediate in onset
T
What is the buffer effect in respirators disorders?
acidosis: bicarb increases
alkalosis: bicarb decreases
T or F: Buffers completely prevent pH changes.
F: they just attenuate, do not completely prevent the pH change
What is the isohydric principle?
all buffers change in the same direction
*if you know what one buffer system did (bicarb), you know what they all did
What is the buffer pair of the bicarb system? Where in the body does it act?
H+ donor: H2CO3
H+ acceptor: HCO3-
In ECFV
What is the buffer pair in the phosphate system? Where in the body does it act?
H+ donor: H2PO4
H+ acceptor: H2PO4 2-
In urine
What is the buffer pair in the ammonia system? Where in the body does it act?
H+ donor: NH4+
H+ acceptor: NH3
In urine
What is the buffer pair in the protein system? Where in the body does it act?
H+ donor: protein
H+ acceptor: protein
In ICFV
What do the buffer systems in the kidney do?
eliminate H+ in urine
What is the role of secondary (compensatory) mechanisms?
With a disturbance in pH, we need a whole body response above and beyond the buffer system to bring the pH back toward normal
*it is a second line of defense to maintain normal pH
T or F: compensatory mechanisms are invariable present in simple acid-base disorders.
T
What does the absence/dysfunction of a compensatory mechanism imply?
the pt has a mixed disorder
The respiratory system compensates for metabolic disrders by _____
altering CO2 (via lungs)
How is a respiratory disorder compensated?
alter bicarb levels
What is the difference in response time between respiratory compensation mechanisms and metabolic compensation mechanisms
the respiratory system can compensate very rapidly by inc CO2 levels when bicarb increases and vice versa
The metabolic compensation in the kidney takes longer