5 Acid-Base Balance Free Online FlashCards

What three mechanisms regulate arterial pH?

Chemical buffers act rapidly, the lungs regulate carbon dioxide, and the kidneys conserve or generate bicarbonate and excrete hydrogen ions. Renal compensation develops over hours to days.

How do acidosis and acidemia differ?

Acidosis and alkalosis are processes that tend to lower or raise pH; acidemia and alkalemia describe measured blood pH below $7.35$ or above $7.45$, respectively.

What are typical arterial ranges for pH, PaCO₂, and HCO₃⁻?

Typical adult arterial ranges are pH $7.35–7.45$, PaCO₂ $35–45$ mm Hg, and HCO₃⁻ $22–26$ mEq/L. Use the laboratory’s ranges and clinical context.

What is the primary change in metabolic acidosis?

Metabolic acidosis has a primary decrease in HCO₃⁻. Causes include bicarbonate loss, kidney dysfunction, lactic acidosis, and ketoacidosis.

What primary change defines respiratory acidosis?

Respiratory acidosis has a primary increase in PaCO₂, commonly from alveolar hypoventilation.

What primary change defines metabolic alkalosis?

Metabolic alkalosis has a primary increase in HCO₃⁻. Loss of gastric acid, such as through vomiting or gastric suction, is a common clue.

What primary change defines respiratory alkalosis?

Respiratory alkalosis has a primary decrease in PaCO₂, often associated with hyperventilation.

How do PaCO₂ and HCO₃⁻ relate in simple metabolic versus respiratory disorders?

In simple metabolic disorders, PaCO₂ and HCO₃⁻ move in the same direction. In simple respiratory disorders, they move in opposite directions.

What can unexpected compensation suggest?

Compensation moves pH toward normal. If compensation is outside the expected range, consider an additional primary disorder.

What is Winter’s formula used to estimate?

For metabolic acidosis, expected PaCO₂ is approximately $(1.5 × \text{HCO₃⁻}) + 8$, with a margin of $±2$ mm Hg. A value outside that range suggests an additional respiratory disorder.

How is the anion gap calculated?

Calculate the anion gap as $\text{AG} = \text{Na⁺} − (\text{Cl⁻} + \text{HCO₃⁻})$; potassium is usually omitted. A traditional reference range is about $8–12$ mEq/L.

What does a high anion gap suggest?

A high anion gap suggests unmeasured acids. Potential causes include lactate, ketoacids, kidney failure, or certain toxic ingestions.