Table of Contents
How do you interpret a blood gas analysis?
Rules for rapid clinical interpretation of ABG
- Look at pH – < 7.40 – Acidosis; > 7.40 – Alkalosis.
- If pH indicates acidosis, then look at paCO2and HCO3-
- If paCO2is ↑, then it is primary respiratory acidosis.
- If paCO2↓ and HCO3- is also ↓→ primary metabolic acidosis.
- If HCO3-is ↓, then AG should be examined.
How do you interpret the base excess of a blood gas?
A high base excess (> +2mmol/L) indicates that there is a higher than normal amount of HCO3– in the blood, which may be due to a primary metabolic alkalosis or a compensated respiratory acidosis.
What is a normal PaO2 on blood gas?
In general, normal values at sea level include: pH: 7.35-7.45. Partial pressure of oxygen (PaO2): 75 to 100 millimeters of mercury (mmHg).
What is the difference between pO2 and SAO2?
PAO2 is the pressure exerted by O2 on the arterial wall. SAO2 is the percentage of hemoglobin binding sites that are occupied with O2. This is the main difference between PAO2 and SAO2.
How do you interpret pO2 on ABG?
The four-step ABG analysis – Examine pO2 and SaO2 to determine oxygen status. If pO2 and SaO2 values are decreased, the patient has hypoxaemia. Normal or slightly elevated pO2 and SaO2 levels indicate that the patient is well oxygenated; – Note the pH value to determine the presence of acidosis or alkalosis.
How do you determine ABG values?
- Use pH to determine Acidosis or Alkalosis. ph. < 7.35. 7.35-7.45.
- Use PaCO2 to determine respiratory effect. PaCO2. < 35.
- Assume metabolic cause when respiratory is ruled out. You’ll be right most of the time if you remember this simple table: High pH.
- Use HC03 to verify metabolic effect. Normal HCO3- is 22-26. Please note:
What are normal PO2 and PCO2 levels?
pCO2 (partial pressure of carbon dioxide) pO2 (partial pressure of oxygen)…ABG (Arterial Blood Gas)
| pH | 7.31–7.41 | |
|---|---|---|
| pCO2 | 41–51 torr | 5.5–6.8 kPa |
| pO2 | 30–40 torr | 4.0–5.3 kPa |
| CO2 | 23–30 mmol/L | |
| Base excess/deficit | ± 3 mEq/L | ± 2 mmol/L |
How do you know if its acidosis or alkalosis?
Step 1 — check the pH A pH of less than 7.35 indicates acidosis and a pH greater than 7.45 indicates alkalosis.