Acid Base Flashcards
SAMPLE COLLECTION: Plasma vs Serum
Plasma: lithium heparin preferred (no EDTA, citrate, oxalate, fluoride AC bc they raise Na/K)
Serum: K levels higher in serum (0.1-0.6), in severe thrombocythemia: use plasma K
In vitro ____, sometimes caused by a difficult blood draw, causes an ____ in the plasma/serum ____ concentration
hemolysis, increase, potassium
ADH, Vasopressin
-Produced in hypothalamus, stored in pituitary
-Causes water to be reabsorbed by collecting ducts
-Release regulated by osmolality and baroreceptors
Diabetes insipidus
kidneys do not respond to ADH (or no ADH produced)
Aldosterone, Addison’s/Conn’s
-Regulates Na, HCO3, K, Cl, H
-Released by Ang II
*Addison’s: destruction of adrenal cortex, deficit of aldosterone and cortisol
*Conn’s: hyperaldosteronism
Decrease in Anion Gap
Hypoproteinemia, multiple myeloma, increase in Ca/Mg, hemodilution
Serum Osmolality
Osmolality is usually measured on ___ since anticoagulants such as EDTA, oxalate, fluoride, etc. contribute to osmolality (some as much as 155 mOsm/kg!)
SERUM, not plasma
-Heparinized plasma, however, can be used
A high osmolal gap suggests:
either the presence of another compound (e.g., ethanol) whose identity should be sought, or elevation of endogenous constituents that may not have been measured
PH
Resp/Met/Acid/Alk
PH
-Acidosis if < 7.35
-Alkalosis if > 7.46
In acidosis:
-Respiratory if CO2 > RR
-Metabolic if HCO3 < RR
In alkalosis:
-Respiratory if CO2 < RR
-Metabolic if HCO3 > RR
Respiratory acidosis
-PCO2 high, pH low
-After compensation HCO-3 high, tCO2 high
-Urine pH low
Metabolic Alkalosis
-HCO-3 high, tCO2 high; pH high
-After compensation: pCO2 high; pH high
Respiratory alkalosis
-PCO2 low, pH high
-After compensation: HCO-3 low, tCO2 low, pH high
Ionized calcium is regulated by ___ (3)
1,25-dihydroxyvitamin D, parathyroid hormone (PTH) and calcitonin
Adjusted total calcium (mg/dL) =
Total Ca (mg/dL) + 0.8*(4-Albumin (g/dL))
= total Ca + 0.8 (4-alb)
Hypokalemia commonly present with low ___
magnesium
PARATHYROID HORMONE
Release regulated by ionized Ca++
Vit D status best monitored with ___
25-hydroxyvitamin D (> 30 ng/mL is sufficient)
Lower A1c values =
hemolytic anemia
Higher A1c values =
-post-splenectomy
-polycythemia
-iron-deficiency anemia
Definitions
Metabolic alkalosis - primary excess of bicarbonate
Metabolic acidosis - primary deficit of bicarbonate
Respiratory acidosis - primary excess of dCO2
Respiratory alkalosis - primary deficit of dCO2
SIADH
excessive production of antidiuretic hormone, resulting in serum hypo-osmolality and urine hyperosmolality
Respiratory Acidosis: Compensation Mechs
-Hemoglobin and protein buffer systems
-Hyperventilation
-Increase Na+/ H+ exchange
-Increase H2PO4, HCO-3, NH3
Metabolic Alkalosis: Compensation Mechs
-HCO-3 /H2CO3 buffer system
-Hypoventilation
-Decrease Na+/H+ exchange
-Decrease NH3, HCO-3
Respiratory Alkalosis: Compensation Mechs
-Decrease HCO-3, NH3, Na+/H+ exchange
