Acid/Base

Question 1

Approach for Acid/Base disorders….

Answer 1

1 - determine pH from ABG
2 - Calculate anion gap
3 - If anion gap calculate osmol gap (if not skip)
4 - Calculate excess anion gap (delta gap)

Question 2

Anion Gap

Answer 2

Na - (bicarb + Cl-)

Normal 10 - 14

Must explain the gap, either its metabolic acidosis or mixed acid base problem w/ gap

Question 3

Osmol Gap

Answer 3

Measured Posm - calculated ohms

Normal < = 10

Calculated: 2*Na + glucose/18 + BUN/2.8

This will find INGESTED toxins - ethylene glycol, methanol

Question 4

Delta Gap (Excess anion gap)

Answer 4

Calculated Osm - 12 + bicarb

Should be equal to normal bicarbonate levels (24 - 26)

If low: there is also a non anion gap acidosis
If high: underlying metabolic alkalosis

Question 5

If ABG is normal but there is elevate anion gap then?

Answer 5

Mixed metabolic alkalosis and anion gap metabolic acidosis

Question 6

Mixed metabolic acidosis and respiratory alkalosis leaks to PCO2…?

Answer 6

Lower than predicted for the acidosis

Question 7

Mixed metabolic alkalosis and respiratory acidosis leads to a bicarb…?

Answer 7

Higher than predicted for the acidosis

Question 8

Mixed metabolic and respiratory alkalosis get _____ bicarb and _____ PCO2 than would be predicted.

Answer 8

Higher bicarb

Lower PCO2

Question 9

MUDPILES

Elevated anion gap metabolic acidosis

Answer 9

Methanol (Osm gap, seen in alcoholics who drink other volatiles)

Uremia (bad renal failure)

DKA, AKA (ETOH)

Paraldahyde

Iron or Isoniazid

Lactic Acid (sepsis, hypotension, CO, cyonide)

Ethylene glycol (ethanol)

Salicylates (aspirin)

Question 10

HARDUP

Normal anion gap metabolic acidosis

Answer 10

H - post hyperventalation
Acid ingestion (carbonic anhydrase inhibitor, HCl)
RTA
Diarrhea
Ureteral and ileal diversion
Pancreatic fistula

Question 11

Chloride responsive metabolic alkalosis (urine Cl < 10)

Answer 11

Vomiting
Diuretics
Diarrhea causing DEHYDRATION** (Cl wasting)
Villous adenoma

Question 12

Chloride Unresponsive metabolic alkalosis

Answer 12

Due to high ALDOSTERONE (caused increased H and K secretion in renal tubules in exchange for resorbing Na as NaHCO3)

Cushings
Barters
Bicarb ingestion

Question 13

Respiratory Acidosis

Answer 13

Airway Obstruction**
COPD, asthma, pneumothorax
Opioids
ALS

Question 14

Respiratory Alkalosis

Answer 14

Anxiety
Tachypnea
Aspirin
Cocaine