Definitions and Background Approach to Acid Base DisordersType Criteria Normal values Sodium 136-140 mEq/L Chloride 96-100 mEq/L Bicarbonate 22-24 mEq/L Anion gap (AG) AG= Serum Na- (Serum Cl + Serum HCO3) Low < 8 Normal ~ 12 Elevated > 16 Delta gap (D gap) Difference between measured AG and normal AG of 12 Acidemia Overall acid base status of serum in acidic range Alkalemia Overall acid base status of serum in alkaline range Acidosis/Alkalosis Refers to actual processes (eg, metabolic, respiratory) causing acidemia or alkalemia pH < 7.40 is acidemia 7.40 is normal > 7.40 is alkalemia Arterial blood gas (ABG) pH/pCO2/PO2 7.40/40/100 Types of acid base disorders (Can be acute or chronic) Metabolic acidosis Decreased serum bicarbonate (HCO3) Anion gap metabolic acidosis (AGMA) Typically due to addition of an external acid that binds to serum bicarbonate and lowers it Non-anion gap metabolic acidosis (NAGMA) Can be due to bicarbonate wasting or acid retention Metabolic alkalosis Defect causing increased serum bicarbonate Respiratory acidosis Defect causing CO2 retention usually due to hypoventilation or impaired gas exchange in lung Respiratory alkalosis Defect causing CO2 loss usually due to hyperventilation Possible to have combination of AGMA, NAGMA, anion gap metabolic alkalosis, and either respiratory acidosis or alkalosis pH and pCO2 usually go in the same direction for above disorders (Next Lesson) Look at the pH (Step 1) Back to Approach to Acid Base Disorders No Comments Comments are closed.
No Comments