Acid-Base Disorders

Question 1

Respiratory acidosis/alkalosis

Answer 1

pH and pCO2 go opposite directions

Question 2

Metabolic acidosis/alkalosis

Answer 2

pH and bicarb go same direction

Question 3

Acute respiratory acid/base disorder

Answer 3

Uncompensated

Question 4

Chronic respiratory acid/base disorder

Answer 4

Totally compensated

Develop 2-3 days before presentation

Question 5

Anion gap

Answer 5

Na - bicarb - Cl

Normal is 10
Don’t forget glucose

Question 6

High anion gap

Answer 6

Normochloremic acidosis

Methanol
Uremia
DM
Paraldehyde
Infection
Lactic acid
Ethanol
Salicylates

Question 7

Normal anion gap

Answer 7

Hyperchloremic acidosis (compensate for lost bicarb)

Question 8

Uremic acidosis

Answer 8

Renal function severely decreased

Question 9

Lactic acidosis

Answer 9

Anaerobic metabolism: hypoxemia, heart failure, peripheral blockage, anemia
Sepsis
Liver failure
Some meds

Question 10

Ethanol high OG

Answer 10

Should equal ethanol level/4.6

Otherwise look for other alcohols

Question 11

OG

Answer 11

2(Na) + Glucose/18 + BUN/2.8

Should equal 10 or less

Question 12

Normal AG Metabolic Acidosis

Answer 12

Diarrhea
RTA or diuretics
Increase NaCl - volume expansion

Question 13

RTA Type 1

Answer 13

Distal
Decreased H excretion
Body pH decrease, urine pH increase

Increased Ca excretion -> stones
Increased K excretion -> hypokalemia

Question 14

RTA Type 2

Answer 14

Proximal
High excretion of bicarb -> low body pH
Still able to acidify urine distally
Lose Ca but no stones
Hypokalemia

Question 15

RTA Type 4

Answer 15

Chronic renal failure
Decreased aldosterone or aldosterone resistance

HYPERkalemia

Question 16

Urinary Anion Gap

Answer 16

Na + K - Cl

Question 17

Negative U AG

Answer 17

Extrarenal

Kidney still able to compensate with increased NH4+ secretion

Question 18

Positive U AG

Answer 18

RTA

Low NH4+ and high bicarb

Question 19

Step 1

Answer 19

Look at pH

Question 20

Step 2

Answer 20

Metabolic vs Respiratory
Does bicarb follow pH = metabolic
Opposite = respiratory

Question 21

Step 3

Answer 21

Compensation?
Metabolic - look to see if pH is normal
Respiratory - bicarb should change 5 for every 10 CO2

Question 22

Step 4

Answer 22

Anion gap
Na - bicarb - Cl

**Account for glucose
Add 1 for every 100 above 100

Question 23

Step 5

Answer 23

Delta-delta gap if anion gap

AG-10 / 24-bicarb

1-1.6 = pure metabolic acidosis
1.6 = concomitant metabolic alkalosis

Question 24

Step 6

Answer 24

If metabolic look at respiratory to see if additional process exists

CO2 bicarb opposite directions? additional problem

Question 25

Step 7

Answer 25

Refer back to clinical picture

Question 26

Cause of respiratory acidosis

Answer 26

``` From decreased RR: Decreased respiratory drive Drugs Coma Stroke From decreased Tidal Volume: Neuro-muscular disorders Severe kyphoscoliosis Airways obstruction COPD Obstructive sleep apnea/Obesity ```

Question 27

Cause of high AG metabolic acidosis

Answer 27

``` Methanol Uremia (End Stage Renal Disease) Diabetic ketoacidosis Paraldehyde Infection, Iron, Isoniazide Lactic acidosis Ethylene glycol (antifreeze), alcohol Salicylates, starvation ketoacidosis ```

Question 28

Normal AG metabolic acidosis

Answer 28

Diarrhea or Ileal drainage with stoma/bypasses - Due to loss of HCO3 - Except for Chloride wasting diarrhea with villous adenoma Decrease reabsorption of HCO3 by renal tubules (therefore increased loss) - Renal Tubular Acidosis - Due to diuretics ( carbonic anhydrase inhibitors [CAI]) Increase in anion intakes - Parenteral nutrition Large amount of NaCl (expansion acidosis) - Due to dilution of the bicarbonate and to decreased renal bicarbonate reabsorption as a result of volume expansion

Question 29

Cause of respiratory alkalosis

Answer 29

``` Usually acute Pain Anxiety Salicylates overdose Fever Sepsis Hypoxia from some pulmonary disorders CHF Pneumonia PE Mild asthma Mechanical ventilation ```

Question 30

Metabolic alkalosis

Answer 30

Vomiting/NG suction - Due to lose of hydrochloric acid Contraction alkalosis due to increased HCO3- reabsorption - Dehydration - Diuresis (with diuretics other than CAI) Hypokalemia - Due to resulting increased mineralocorticoid secretion Recent correction of chronic respiratory acidosis - Due to recent metabolic compensation.