Acide-base Balance Flashcards
What is the normal range for blood pH?
7.35 – 7.45
What are the two primary ions involved in acid-base balance?
Hydrogen ion (H⁺) and Bicarbonate (HCO₃⁻)
What is the main volatile acid in the body, and how is it eliminated?
Carbonic acid (H₂CO₃), eliminated as CO₂ via respiration.
Name two non-volatile acids and how they are eliminated.
Sulfuric acid and phosphoric acid; eliminated by the renal system.
What is the Henderson-Hasselbalch equation used for?
To calculate bicarbonate concentration ([HCO₃⁻]) from pH and pCO₂.
How does the respiratory system regulate pH?
By controlling CO₂ levels;
hypoventilation → acidosis,
hyperventilation → alkalosis.
How does the renal system regulate acid-base balance?
By excreting H⁺ and reabsorbing HCO₃⁻ in the distal tubule.
What are the direct parameters measured in an arterial blood gas (ABG) analysis?
pH, pO₂, pCO₂
What are the calculated parameters in ABG analysis?
[HCO₃⁻], total CO₂, buffer bases, base excess, oxygen saturation (HbO₂%).
What is the normal range of arterial pCO₂?
36 – 42 mmHg
What is base excess, and what does it indicate?
It represents deviations from normal buffer base levels;
positive = metabolic alkalosis,
negative = metabolic acidosis.
How does pH affect nerve and muscle excitability?
Acidosis → decreased excitability (CNS depression);
Alkalosis → increased excitability (tetany, convulsions).
What is the most important buffer system in the body?
The bicarbonate-carbonic acid buffer system (HCO₃⁻/H₂CO₃).
What happens to pH in respiratory acidosis?
pH decreases due to CO₂ retention (hypoventilation).
What is the compensation mechanism for respiratory acidosis?
The kidneys retain HCO₃⁻ to buffer excess H⁺.
What happens to pH in metabolic alkalosis?
pH increases due to excess HCO₃⁻ or H⁺ loss (vomiting, diuretics).
How does the body compensate for metabolic acidosis?
By hyperventilation to reduce CO₂ and increase pH.
What is the most commonly used arterial site for blood gas collection?
Radial artery, punctured at a 45° angle.
What condition is indicated by low pH, high pCO₂, and normal HCO₃⁻?
Respiratory acidosis.
What are the normal values for bicarbonate ([HCO₃⁻])?
22 – 26 mmol/L.
