1. What is I:E Ratio?

The I:E ratio (Inspiratory to Expiratory ratio) compares the duration of inspiration to expiration during mechanical ventilation or spontaneous breathing. It's a fundamental parameter in respiratory physiology.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( I \) — Inspiratory time (seconds)
• \( E \) — Expiratory time (seconds)

Explanation: The ratio describes how much longer expiration is compared to inspiration. Normal spontaneous breathing typically has an I:E ratio of 1:2.

3. Importance of I:E Ratio

Details: The I:E ratio is critical in mechanical ventilation settings to ensure proper gas exchange and prevent complications like auto-PEEP. It affects oxygenation, ventilation, and patient comfort.

4. Using the Calculator

Tips: Enter inspiratory and expiratory times in seconds. Both values must be positive numbers. The result will show the ratio in decimal form (e.g., 0.5 for 1:2 ratio).

5. Frequently Asked Questions (FAQ)

Q1: What is a normal I:E ratio?
A: For spontaneous breathing, 1:2 is typical. In mechanical ventilation, ratios between 1:1 to 1:4 are common depending on the clinical situation.

Q2: When would you use inverse ratio ventilation?
A: Inverse ratio ventilation (I:E > 1:1) may be used in severe ARDS to improve oxygenation, though it requires careful monitoring.

Q3: How does I:E ratio affect COPD patients?
A: COPD patients often need longer expiratory times (e.g., 1:3 or 1:4) to prevent air trapping and auto-PEEP.

Q4: Can I:E ratio be expressed as 1:X?
A: Yes, the decimal result can be converted (e.g., 0.5 = 1:2). Some clinicians prefer this format for clarity.

Q5: Does I:E ratio affect hemodynamics?
A: Yes, particularly with inverse ratio ventilation which can decrease venous return and cardiac output due to increased mean airway pressure.