Acid Base

Question 1

Normal Values

Answer 1

pH = 7.35-7.45

pCO2 = 35-45

pO2 = 80-100

HCO3 = 22-31

Question 2

Simple Disorders

Answer 2

Acidosis < 7.35
-Resp: high PCO2
-Met: low HCO3

Alkalosis
-Resp: low PCO2
-Met: high HCO3

Question 3

Henderson Hassel Eq

Answer 3

Question 4

Anion Gap

Answer 4

Cations - Anions
= Na - (Cl + HCO3)

Adj AG
= AG + (4-Alb)*2.5

*if AG > 12 = metabolic acidosis no matter what

Question 5

Winters Formula

Answer 5

Predicted pCO2 = (1.5*HCO3 + 8) +/- 2

Higher = Resp Acidosis

Lower = Resp Alk

Question 6

Delta Ratio

Answer 6

Calc AG - 12 / 24 - HCO3

Question 7

Osmolal Gap

Answer 7

2*Na + (Glu/18) + (BUN/2.8)

Question 8

Metabolic Acidosis

Answer 8

1. Calc AG
2. Winters
3. Delta ratio
4. Osmolal gap

Mild/Mod of 7.2-7.35
= Bicarb tabs
= Lactate, acetate, gluconate, citrate (Bicitra)

Severe of < 7.2
= IV NaBicarb or via RRT
= 0.5(IBW)*(desired HCO3 - actual HCO3)

Question 9

Sodium Bicarb AE

Answer 9

-Hypernatremia
-Volume overload
-Hypercarbia
-Alkalosis overshoot
-Para intra acidosis

Question 10

Metabolic Alkalosis: Determining Sensitivity

Answer 10

Determine sensitivity
-Urinary Cl < 25: responsive
-Urinary Cl > 25: unresponsive

Question 11

Metabolic Alkalosis: Resistant Tx

Answer 11

-CS? Decrease or change (F>H>P>M>D)
-Correct K/Mg
-Bar/Gittle? Amiloride, Triamterene, Spironolactone
-Liddle? Amilorie, Triamterene

SECAT

Question 12

Metabolic Alkalosis: Responsive Tx

Answer 12

-Mild (7.45-7.6) = normal saline
Volume = Cl - (0.2IBW*(100-Cl))/154
-IVF Intolerant (HF/cirrhosis) = Aceta 500
-Sev (> 7.6) = HCl solution

Question 13

Respiratory Acidosis + Etiologies

Answer 13

-Airway obstruction, COPD
-Hypoventilation
-Obesity, opioid
-Pneumonia
-Trauma

-Nasal cannula
-Hi flo
-CPAP
-BiPAP
-Mechanical ventilation

Question 14

Respiratory Alkalosis + Etiologies

Answer 14

-Hyperventilation (anxiety, pain)
-CNS disorders
-PE
-Tissue hypoxia
-Mechanical ventilation

-Self-limiting
-Underlying causes
-Mechanical ventilation
-Sedation/analgesia/anxio

Question 15

Metabolic Acidosis: Etiologies

Answer 15

MUDPILES = AG > 20
-Methanol
-Uremia (RF)
-Diabetic ketoacidosis
-Propylene glycol
-Intoxication, infection
-Lactic acidosis
-Ethylene glycol
-Salicylate

AS RED = AG < 12
-Excess saline
-Diarrhea
-CAIs (acetazolamide, spirono)
-Rental tubular acidosis

Question 16

Metabolic Alkalosis: Etiologies

Answer 16

Cl > 25
-Hyperaldosteronism, high mineralocorticoid
-Hypokalemia, Mg depletion
-Liddle’s

Cl < 25
-GI losses: NVD
-Exo alkali sources
-Diuretics