Acid - Base Disorders Flashcards
What is the most important extracellular buffering system?
Bicarbonate (HCO3-)
An INCREASE in CO2, will cause what change in the pH?
DECREASED pH = Acidosis
A DECREASE in CO2, will cause what change in the pH?
INCREASED pH = Alkalosis
An INCREASE in HCO3-, will cause what change in the pH?
INCREASED pH = Alkalosis
A DECREASE in HCO3-, will cause what change in the pH?
DECREASED pH = Acidosis
What portion of the pH changes does the lungs control?
CO2
What portion of the pH changes do the kidneys control?
HCO3-
Metabolic Acidosis/Alkalosis involves a change in what?
HCO3-
Respiratory Acidosis/Alkalosis involves a change in what?
CO2
Metabolic Acidosis
DECREASED HCO3-
Metabolic Alkalosis
INCREASED HCO3-
Respiratory Acidosis
INCREASED CO2
Respiratory Alkalosis
DECREASED CO2
What are the 2 types of Metabolic Acidosis?
HAGMA – high anion gap
NAGMA – normal anion gap
What are the 2 types of Metabolic Alkalosis?
Saline-responsive (hypovolemia)
Non-Saline-responsive (eu/hypervolemia)
If the kidney caused the acidosis/alkalosis, what will compensate?
Lung will compensate and vice versa
Describe what compensation should be seen with Metabolic Acidosis
LOW HCO3-
–> Means that you have HIGH CO2
–> Increase RR to blow off the CO2
=> Respiratory Alkalosis (LOW CO2)
What is the formula to calculate compensation for Metabolic Acidosis?
CO2 = 1.5[HCO3-] + 8 +/- 2
What is the formula to calculate compensation for Metabolic Alkalosis?
PCO2 increases by 0.7 for every 1 mEq/L of HCO3-
The appropriate compensation mechanisms by HCO3- for Respiratory Acidosis/Alkalosis change with every _____ change
Every 10 mmHg of CO2 change
Acute Respiratory Acidosis compensation
HCO3 increases by 1
Chronic Respiratory Acidosis compensation
HCO3 increases by 3.5
Acute Respiratory Alkalosis compensation
HCO3 decreases by 2
Chronic Respiratory Alkalosis compensation
HCO3 decreases by 5
Normal pH, level of the pH for acidosis/alkalosis
Normal = 7.4 Acidosis = 7.35 Alkalosis = 7.45
What is the normal PCO2?
40
What is the normal HCO3-?
24
What is the normal Anion Gap?
10
What is the normal Osmolar Gap?
Less than 10
What is the formula to calculate Anion Gap?
Na - (HCO3 + Cl)
What is the formula to calculate Osmolar Gap?
Measured serum osmolality - Calculated serum osmolality
If the osmolar gap is greater than 10, what does that indicate?
Additional solutes are in the blood
What is the stepwise approach to these disorders?
- Determine if acidosis/alkalosis is present
- Determine if its respiratory/metabolic
- - If metabolic acidosis, determine the Anion Gap
- - If HAGMA, determine the Osmolar Gap - Calculate appropriate compensation
What is the stepwise approach for these disorders?
- Determine if acidosis/alkalosis is present
- Determine if its respiratory/metabolic
- - If metabolic acidosis, calculate the anion gap
- - If HAGMA, calculate osmolar gap - Calculate appropriate compensation
An appropriate compensation is what type of acid base disorder?
Simple
An inappropriate compensation is what type of acid base disorder?
Mixed
Acidosis is associated with what levels of K+?
Hyperkalemia
Alkalosis is associated with what levels of K+?
Hypokalemia
What is the equation for the Anion Gap and what is its normal value?
Na - (HCO3 + Cl)
– should equal 10
If HAGMA is present, what should you screen for?
Alcohol ingestion
