1. What is Dead Space Breathing?

Dead space refers to the portion of each breath that does not participate in gas exchange. It includes anatomical dead space (conducting airways) and physiological dead space (alveoli that are ventilated but not perfused).

2. How Does the Calculator Work?

The calculator uses the dead space equation:

Where:

• \( V_d \) — Dead space volume (ml)
• \( V_t \) — Tidal volume (ml)
• \( Fraction \) — Dead space fraction (decimal between 0 and 1)

Explanation: The equation calculates the absolute dead space volume by multiplying the tidal volume by the fraction of dead space.

3. Importance of Dead Space Calculation

Details: Dead space calculation is important in respiratory physiology to assess ventilation efficiency and in clinical settings to optimize mechanical ventilation.

4. Using the Calculator

Tips: Enter tidal volume in ml and dead space fraction as a decimal between 0 and 1. All values must be valid (V_t > 0, fraction between 0-1).

5. Frequently Asked Questions (FAQ)

Q1: What is normal dead space fraction?
A: Normally, dead space fraction is about 0.2-0.3 (20-30%) in healthy adults.

Q2: How does dead space affect ventilation?
A: Increased dead space reduces effective alveolar ventilation, potentially leading to CO2 retention.

Q3: What increases dead space?
A: Conditions like pulmonary embolism, emphysema, or positive pressure ventilation can increase dead space.

Q4: What's the difference between anatomical and physiological dead space?
A: Anatomical dead space is the volume of conducting airways, while physiological dead space includes non-perfused alveoli in addition to anatomical dead space.

Q5: How is dead space measured clinically?
A: The Bohr equation using expired CO2 measurements is commonly used to measure physiological dead space.