Lecture 10: Classification of Acid-Base Status

Question 1

What is the law of mass action?

Answer 1

when PCO2 changes, it causes a small change in [HCO3-] due to mass action

Question 2

what is anion gap

Answer 2

the difference b/w commonly measured plasma CATIONS (Na, K) and commonly measured Anions (Cl, HCO3)

(Na+K) - (Cl+HCO3)

Question 3

what is uncompensated (‘‘simple or primary”) disturbance

Answer 3

• defect in [HCO3-] or PCO2
• No change in other paramters

Question 4

what is a simple disturbance w/ compensation?

Answer 4

• defect in [HCO3-]
• other parameter is compensating

Question 5

what are mixed state distrubances

Answer 5

both HCO3- and PCO2 and contributing to the acid/base disturbance

Question 6

what is the immediate response to a fixed acid load (within mins)

Answer 6

H+ ions titrate bicarbonate ions in ECF and then titrate intracellular buffers (proteins, phosphate)

Question 7

what is the minutes-hours response to fixed acid load

Answer 7

• alveolar ventilation is simulated, PCO2 decreases, ratio of [HCO3-] and PCO2 is normalized

Question 8

what is the later response (hours to days) to a fixed acid load

Answer 8

kidneys regenerate titrated [HCO3], excrete TA and NH4+

Question 9

what is the body’s response to a volatile acid load?

Answer 9

within minutes: H+ ions titrate intracellular buffers (protein, hemoglobin, phosphate)

within hours to days: increase renal [HCO3] reabsorption and net acid excretion (TA, ammoniagenesis, bicarbonate reabsorption)