1. What is Total Flow?

Total Flow represents the estimated total gas flow in entrainment devices, calculated by dividing the oxygen flow rate by the fraction of inspired oxygen (FiO2). This calculation helps determine the overall gas mixture delivered to patients.

2. How Does the Calculator Work?

The calculator uses the Total Flow formula:

Where:

• \( \text{O}_2\text{ Flow} \) — Oxygen flow rate (L/min)
• \( \text{FiO}_2 \) — Fraction of inspired oxygen (decimal)

Explanation: This formula estimates the total gas flow by accounting for the dilution of oxygen with room air in entrainment devices.

3. Importance of Total Flow Calculation

Details: Calculating total flow is essential for understanding the complete gas mixture delivered to patients, ensuring proper ventilation and oxygenation, and optimizing respiratory support device settings.

4. Using the Calculator

Tips: Enter oxygen flow in L/min and FiO2 as a decimal fraction (e.g., 0.4 for 40%). All values must be valid (O2 Flow > 0, FiO2 between 0.21-1.0).

5. Frequently Asked Questions (FAQ)

Q1: What is the clinical significance of total flow?
A: Total flow helps determine if the gas delivery system can meet the patient's inspiratory flow demands, particularly important in high-flow oxygen therapy.

Q2: How accurate is this calculation?
A: This provides an approximate estimation. Actual total flow may vary depending on device characteristics and environmental factors.

Q3: When is total flow calculation most important?
A: Particularly crucial when using venturi masks, high-flow nasal cannula, and other oxygen entrainment devices where air mixing occurs.

Q4: What are typical total flow values?
A: Values typically range from 15-60 L/min depending on oxygen flow rate and FiO2 setting, with higher flows needed for higher FiO2 concentrations.

Q5: Can this formula be used for all oxygen delivery devices?
A: Primarily used for air-entrainment devices. Non-rebreather masks and closed systems may have different flow characteristics.