Acid base balance

What are the five normal ABG values?

pH 7.35–7.45; PaCO₂ 35–45 mmHg; HCO₃⁻ 22–26 mEq/L; PaO₂ 90–100 mmHg; SaO₂ 95–100%.

What does pH measure?

Blood acidity or alkalinity.

What pH indicates acidosis vs. alkalosis?

Acidosis: pH

What does PaCO₂ measure?

Carbon dioxide pressure in arterial blood; normal 35–45 mmHg.

What ABG pattern indicates respiratory acidosis?

Low pH (

What causes respiratory acidosis?

Inadequate CO₂ exhalation causes CO₂ retention.

What ABG pattern indicates respiratory alkalosis?

High pH (>7.45), low PaCO₂ (<35).

What causes respiratory alkalosis?

Hyperventilation causes excessive CO₂ loss.

What pattern does the slide associate with metabolic acidosis?

Low pH and low CO₂; examples: diabetic ketoacidosis and GI bicarbonate loss.

What pattern does the slide associate with metabolic alkalosis?

High pH and high CO₂; examples: GI/renal acid loss or increased bicarbonate.

What are Dr. Harkins' three steps for interpreting ABGs?

1. Check pH. 2. Check PaCO₂. 3. Compare their directions.

What does opposite movement of pH and CO₂ suggest?

Respiratory disorder: acidosis (pH↓ CO₂↑) or alkalosis (pH↑ CO₂↓).

What does same-direction movement of pH and CO₂ suggest in the slides?

Metabolic pattern: acidosis (pH↓ CO₂↓) or alkalosis (pH↑ CO₂↑).

What is the four-pattern acid–base chart?

Resp. acidosis: ↓pH ↑CO₂; resp. alkalosis: ↑pH ↓CO₂; metabolic acidosis: ↓pH ↓CO₂; metabolic alkalosis: ↑pH ↑CO₂.

pH 7.28, CO₂ 55: What disorder?

Respiratory acidosis.

pH 7.50, CO₂ 30: What disorder?

Respiratory alkalosis.

pH 7.25, CO₂ 30: What disorder according to the slide method?

Metabolic acidosis.

pH 7.49, CO₂ 50: What disorder according to the slide method?

Metabolic alkalosis.