Acid/Base Physiology Flashcards
Ka = _________.
([H+][A-]) / [HA]
What is the Henderson-Hasselbach equation?
pH = pKa + log([A-]/[HA])
CO2 can be thought of as the conjugate acid of __________, because ________.
HCO3-; CO2 gets rapidly converted to H2CO3 by carbonic anhydrase
Give the adjusted Henderson-Hasselbach equation for arterial CO2 and bicarbonate.
pH = 6.1 + log([HCO3-]/[0.03xPaCO2])
Venous pH is only slightly higher than arterial pH because ___________.
deoxyhemoglobin is a good buffer
Acidemia is defined as _______.
blood pH
Alkalemia is defined as _________.
blood pH > 7.4
Most acidosis is caused by _________.
insufficient ventilation
For every 10 Torr increase in CO2, pH _______.
decreases by 0.08
What is Winter’s formula–the formula for compensated p(CO2) in metabolic acidosis?
p(CO2) = 1.5[HCO3-] + 8 (+/- 2)
Anion gap indicates the presence of ________.
additional acid
What are substances that can cause anion gap?
MUD PILES (methanol, uremia, DKA [and other ketoacids], propylene glycol, INH, lactate, ethylene glycol, salicylates)
Metabolic alkalosis is caused by _________.
excess bicarbonate
The body will not hypoventilate to the point of hypoxemia, so compensation for _______ is incomplete.
metabolic alkalosis
How can you differentiate acute and chronic forms of respiratory acidosis?
Chronic respiratory acidosis will have an increase in bicarb concentration.
pKa =
- log (Ka)
Intracellular buffers include _________; extracellular buffers include __________.
phosphates, hemoglobin, and proteins; phosphates, bicarbonate, albumin, and proteins
Venous pH is only slightly lower than arterial pH because of __________.
hemoglobin
The lungs adjust pH acutely by __________ and the _________ adjust pH chronically.
expelling CO2; kidneys (by retaining HCO3-)
What are some central causes of chronic respiratory acidosis?
Obesity, neuromuscular disorders like ALS, hypothyroidism, and chronic lung diseases
What are some acute causes of respiratory alkalosis? Chronic causes?
Acute = anxiety/panic, fever, mechanical ventilation, and pain. Chronic = pregnancy, salicylate toxicity, brain injury, living at high altitude.
Non-anion gap metabolic acidosis is caused by ___________.
excess loss of bicarbonate, such as from GI or renal loss
Some causes of metabolic alkalosis (in which bicarb levels are raised) are ________.
ingestion of bicarb; too much suction of gastric acid; diuretics; and hypovolemia
Normal anion gap levels are ________.
10 - 14
For chronic respiratory disturbances, a change in Pa(CO2) of 1 Torr should lead to a ___________.
a change of 0.4 mEq/L of bicarb in the same direction
