intro to acid base physiology

Question 1

what is the normal pH of the body

Answer 1

7.4
(7.35 - 7.45)

Question 2

acidemia pH and alkalemia pH?

Answer 2

• acidemia: pH < 7.35
• alkalemia: pH > 7.45

Question 3

the acid-base balance is tightly regulated by two main systems:

Answer 3

• respiratory
• metabolic

Question 4

respiratory acid-base

Answer 4

• CO2 is acidic
• is pCO2 increases, pH drops

Question 5

what controls the partial pressure of CO2 in the blood

Answer 5

lung ventilation

Question 6

metabolic acid-base

Answer 6

• HCO3- is alkaline
• if HCO3- increase, pH increase

Question 7

what controls the amount of bicarbonate in the blood

Answer 7

kidney

Question 8

what is the normal PCO2 in the arterial blood and venous blood

Answer 8

40 mmHg; 46 mmHg

Question 9

what is pCO2

Answer 9

partial pressure of CO2 gas dissolved in the plasma

Question 10

how is pCO2 measured

Answer 10

• blood gas analysis
• can be venous (PvCO2) or arterial (PaCO2)

Question 11

what is ventilation

Answer 11

how much air is being moved by the lungs

Question 12

hypoventilation

Answer 12

• too much CO2 is retained (not breathed off)
• pCO2 increases
• pH drops

Question 13

hyperventilation

Answer 13

• too much CO2 is expelled
• pCO2 decreases
• pH rises

Question 14

pCO2 can change quickly or slowly?

Answer 14

quick (within seconds or minutes)

Question 15

what is the only cause of increase pCO2

Answer 15

hypoventilation

Question 16

hypoventilation problems

Answer 16

• brain problem (anesthesia, brain disease)
• diaphragm problem
• blocked airways

Question 17

hyperventilation problems

Answer 17

• fear or pain
• hypoexmia
• acidemia

Question 18

respiratory acidosis

Answer 18

pCO2 is HIGH

“hypercapnic from hypoventilation”

Question 19

respiratory alkalosis

Answer 19

pCO2 is LOW

“hypocapnic from hyperventilation”

Question 20

name the acid base abnormality for a patient with a:

• PaCO2 - 71 mmHg
• PaCO2 - 28 mmHg
• PvCO2 - 40 mmHg

Answer 20

• respiratory acidosis (hypoventilation)
• respiratory alkalosis (hyperventilation)
• normal

Question 21

what does HCO3- indicate and how can it be measured

Answer 21

• the amount of bicarbonate anion in the plasma
• measured on blood gas or serum chem analysis (called TCO2)

Question 22

HCO3- changes slowly or quickly?

Answer 22

slowly (days)

Question 22

HCO3- changes slowly or quickly?

Answer 22

slowly (days)

Question 23

what are the two mechanisms for metabolic alkalosis

Answer 23

• kidney retains too much bicarb
• chloride loss from upper GI (vomiting, pyloric obstuction)

Question 24

what are the 3 mechanisms for metabolic acidosis

Answer 24

* the kidney loses too much bicarb * the colon can lose bicarb from lower GI via diarrhea * you accumulate "poison anions" in your blood

Question 25

metabolic acidosis

Answer 25

HCO3- is LOW

Question 26

metabolic alkalosis

Answer 26

HCO3- is HIGH

Question 27

what is the normal HCO3-

Answer 27

~24 mg/dL

Question 28

name the acid base abnormality for a patient with a: * HCO3 - 26 mg/dL * TCO2 - 45 mg/dL * HCO3 - 24 mg/dL * TCO2 - 11 mg/dL

Answer 28

* metabolic alkalosis * metabolic alkalosis * normal * metabolic acidosis

Question 29

what is the HCO3- equation

Answer 29

H2O + CO2 <-> H2CO3 <-> H+ + HCO3-

Question 30

what is base excess

Answer 30

the amount of HCl or HCO3- required to return 1L of blood (at 38 deg. C with a standardized PCO2 and Hb) to a pH of 7.40

Question 31

what are the 4 main derangements of pH in the blood

Answer 31

* respiratory acidosis and alkalosis * metabolic acidosis and alkalosis

Question 32

what is the anion gap

Answer 32

measure many plasma anions (chloride) but in some diseases or intoxications, *unmeasured* anions can build up

Question 33

what is the anion gap equation

Answer 33

([Na+] + [K+]) - ([Cl-] + [HCO3-])

Question 34

an excess of unmeasured anions causes a high ____ ____, this makes the bicarbonate decrease, leading to a:

Answer 34

anion gap; metabolic acidosis

Question 35

what might be causing a high anion gap | "find the poison anion"

Answer 35

K.L.U.E (ketone, lactate, uremic toxin, ethylene glycol)

Question 36

what are the two flavors or metabolic acidosis

Answer 36

* Normal anion gap metabolic acidosis (NAGMA) (kidney problem) * High anion gap metabolic acidosis (HAGMA) (poison anion problem)

Question 37

* pH - 7.134 * pH - 7.51 * pH - 6.91 * pH - 7.4 * pH - 7.93 * pH - 7.39

Answer 37

* acidmia * alkalemia * acidemia * normal * alkalemia * normal

Question 38

compensatory acidois/alkalosis

Answer 38

if a patient has an acid-base abormality it will compensate normalaize pH