Acid-Base 1

Question 1

blood gas metrics

Answer 1

• pH
• PaCO2
• PaO2
• HCO-3
• ABE
• Na+
• K+
• Cl-
• Proteins

Question 2

blood gas values???????

Answer 2

• pH: 7.4
• PaCO2: 40 mm Hg
• PaO2: 90-600 mm Hg
• HCO-3: 24 mEq/L
• ABE: -4 - +4 mEq/L
• Na+: 140 mEq/L
• K+: 4 mEq/L
• Cl-: 100 mEq/L
• Totalprotein: 65g/L

Question 3

Henderson-Hasselbalch equation use

Answer 3

– Estimates pH and base excess/deficit
– Defines magnitude of change but not the cause

Question 4

• Base excess/deficit: what does it tell us?

Answer 4

– any difference that exists from the normal value
for bicarbonate
– Reflects non volatile acid changes (metabolic)

Question 5

what is a buffer and what are examples in the body

Answer 5

• Buffer: substance that prevents extreme changes in the free concentration of H+ within a solution

– Hemoglobin (good for transporting CO2 from tissue to lung)
– NaHCO3 (most important)
– Phosphate
– Protein

Question 6

how is CO2 transported in the blood?

Answer 6

– Dissolved and H2CO3: 7%
– HCO-3: 80%
– CarbaminoHb: 13%

Question 7

cation is + or -? anion?

Answer 7

– Cation (+)
– Anion (-)

Question 8

acid vs base role wrt h+

Answer 8

• Acid: donates H+ to solutions
• Base: removes H+ from solutions

Question 9

what does a gamblegram show?

Answer 9

a graphical representation of the concentration of plasma cations (mainly Na+ and K+) and plasma anions (mainly Cl-, HCO3- and A-, also lactate).
-there are anions that are not routinely measured = unmeased anions (UA)
– Therefore, there is a deficit of anions in the gamblegram

Question 10

metabolic acidosis is caused by:

Answer 10

• Acids from tissue metabolism
  -Unmeasured anions (ketoacids, organic acids)
  -Lactic acid
• Hyperchloremia
• Combination of the two

Question 11

three independent variables in quatitative/stewarts method? what do they determine?

Answer 11

– PaCO2

– SID
* Strong ion difference

– Weak acids (Atot)
* Proteins in blood

Question 12

what is the strong ion difference? how do we calculate it, what is a normal value, and what do other values tell us?

Answer 12

• (Na++K+)-Cl- =44
• Metabolic acidosis: < 44
• Metabolic alkalosis: > 44

Question 13

what usually decreases the value of SID?

Answer 13

increase in Cl-

Question 14

what is the anion gap? what is the normal value and what do differing values mean?

Answer 14

• (Na+ + K+) – (Cl- + HCO-3)= 20
• Metabolic acidosis: > 20
• Metabolic alkalosis: < 20

Question 15

effects of proteins on anion gap and acidosis/alkalosis

Answer 15

• Affect anion gap
• Proteins act as weak acids
  – Hyperproteinemia = metabolic acidosis
  – Hypoproteinemia = metabolic alkalosis

Question 16

what substances are weak ions/buffers? what state do they exist in?

Answer 16

• Only partially dissociated
  – Proteins
  – Hemoglobin

Question 17

what is SIG vs SID? how do we calculate SIG and what does this allow us to do?

Answer 17

strong ion gap vs strong ion difference
-corrects anion gap for proteins

• Corrects Anion gap for proteins:
  – SIG = AG – (Total proteins x 0.25)
• This calculation allows to determine the unmeasured anions (UA)