Acidosis

Question 1

What are the 3 main causes of acidosis?

Answer 1

1) Loss of HCO3- 2) Addition of acid 3) Endogenous production of acid

Question 2

What are the causes of loss of HCO3-?

Answer 2

1) Externalization of intestinal contents (vomiting, fistulas) 2) Renal wasting of HCO3- (RTA or carbonic anhydrase inhibitors)

Question 3

What are the causes of acid addition?

Answer 3

1) Fluid resus with NS 2) TPN

Question 4

What are the causes of endogenous acid production?

Answer 4

1) Ketoacidosis (DKA) 2) Lactic acidosis (sepsis) 3) RTA

Question 5

What is the relationship of pH to serum K+ levels?

Answer 5

In general, for each 0.10 decrease in the pH, serum [K+] will increase by approximately 0.5 mEq/L

Question 6

What are the causes of an elevated anion gap in the absence of an acid-base disturbance?

Answer 6

Question 7

Why is bicarb sometimes necesary in DKA?

Answer 7

In DKA, respiratory minute volume declines when pH decreases below 7.10, leading to the recommendation of initiating bicarbonate when pH falls below 7.10

Question 8

What can a person breath their PCO2 down to via spontaneous respirations alone?

Answer 8

The lowest PCO2 level achievable in spontaneous respiration is about 12 mm Hg.

Question 9

What is the realtionship between pH and serum K+ levels?

Answer 9

In general, for each 0.10 decrease in the pH, serum [K+] will increase by approximately 0.5 mEq/L

Question 10

What are the 3 causes of non-anion gap metabolic acidosis?

Answer 10

Non-AG acidosis results from

1) loss of [HCO3–]
2) failure to excrete [H+]
3) administration of [H+].

Question 11

What causes HCO3- losses resulting in acidosis?

Answer 11

Bicarbonate may be lost from the urine or GI tract and is usually accompanied by [K+] loss. However, potassium-sparing diuretics, hypoaldosteronism, urinary tract obstruction, and type IV RTA result in loss of [HCO3–] with retention of [K+]

Question 12

Giving O2 to someone who is chronically high CO2, will cause what??

Answer 12

Decrease in hypercarbic respiratory drive, which may further increase their CO2, to the point that they can no longer compensate.

A pH <7.25 portends the likely need for NIPPV.

Question 13

Rapidly decreasing the CO2 of a chronic respiratory acidosis may cause what change in serum electrolytes?

Answer 13

A metabolic alkalosis that necessitates H+ shift from intracellular stores, causing hypokalemia, and hypocalcemia (from a relative increase in anionic buffers, that reduce ionized calcium).

Abruptly lowering CO2 also reduces cerbral blood flow and tissue oxygenation (increased hemoglobin O2 binding).