Labs and Equations

Question 1

Na+ serum values

Answer 1

135-145

Question 2

K+ serum values

Answer 2

3.5-5

Question 3

Cl- serum values

Answer 3

95-105

Question 4

HCO3- (bicarb values)

Answer 4

22-28

Question 5

BUN serum values

Answer 5

7-18

Question 6

Cr serum values

Answer 6

0.6-1.2

Question 7

Normal pH

Answer 7

7.35-7.45

Question 8

Normal PaCO2

Answer 8

35-45

Question 9

Normal PaO2

Answer 9

80-100

Question 10

HCO3

Answer 10

21-27

Question 11

Normal Anion Gap

Answer 11

10-12mEq/L (+/- 2)

Question 12

Causes of metabolic acidosis with Anion Gap

Answer 12

Methanol
Uremia
DKA/ETOH
Propylene Glycol
Isoniazid
Lactate
Ethylene Glycol
Rhabdo
Salicylates

Question 13

Causes of metabolic acidosis with Non-Anion Gap

Answer 13

Ureterosigmoidostomy
Saline
Endocrine
Diarrhea
Carbonic Anhydrase
Renal Tubular Necrosis
Ammonium Chloride
Pancreatitis

Bromide
Hypoalbuminemia
Plasma Cell dysfunction

Question 14

Winter’s Equation

Answer 14

pCO2 = (1.5 x HCO3) +8 (+/-2)

Question 15

Calculated Anion Gap

Answer 15

AG = [Na+ - (Cl- + HCO3)]

Question 16

Excess AG

Answer 16

AG excess = TAG - [NAG + HCO3]

Question 17

Delta GAP

Answer 17

Delta Gap = [TAG-NAG] / [Normal HCO3 - Total HCO3]

Question 18

What does Winter’s formula tell you?

Answer 18

If the disorder is appropriately compensated? Or is there another disorder present?

Question 19

When do you calculate AG?

Answer 19

For metabolic acidosis

Question 20

What does excess AG tell you? And what are the values to give you underlying information?

Answer 20

Excess AG > 26; pt has underlying metabolic alkalosis

Excess AG<22; pt has underlying metabolic acidosis

Question 21

What does Delta Gap tell you?

Answer 21

If your pt with an elevated AG metabolic acidosis also has an underlying metabolic alkalosis.

Question 22

4 Delta Gap Rules

Answer 22

• D Gap between 1 and 2, then pure elev. AG acidosis. –> Think MUDPILERS!
• D Gap 2, simult met alk or chronic resp acidosis

Question 23

Causes of Respiratory Acidosis

Answer 23

Hypercapnea
Hypoventilation/Acute Resp Failure
CNS depressants
Airway Obstruction
ALS/Guillain-Barre/Myasthenia Gravis

Question 24

Causes of Respiratory Alkalosis

Answer 24

Hyperventilation
Ventilation-Perfusion (V/Q) mismatch
CNS Disorders
Altitute/Anxiety/Pregnancy (late)