Mechanical Ventilation Time Calculator
Here's a comprehensive table summarizing the key aspects of mechanical ventilation timing:
| Parameter | Description | Typical Values | Notes |
|---|---|---|---|
| T-high | Time during which maximum pressure is applied | 4 to 6 seconds | Covers 80%-95% of cycle to improve oxygenation |
| T-low | Time taken to fully exhale | 0.2 to 1.5 seconds | Adjusted based on lung disease condition1 |
| Inspiratory Time (Ti) | Time for breath delivery | <1 year: 0.6–0.8s 1–5 years: 0.8–1.0s 5–12 years: 1.0–1.5s | Set depending on patient's age5 |
| Expiratory Time | Time for passive exhalation | Varies | Calculated based on total cycle time and Ti |
| I:E Ratio | Ratio of inspiratory to expiratory time | Generally 1:2 | Set indirectly by adjusting Ti and RR4 |
| Total Cycle Time | Duration of a complete breath cycle | Varies | Calculated as 60 seconds / Respiratory Rate7 |
| Respiratory Rate (RR) | Number of breaths per minute | <1 year: 25–30 1–5 years: 20–25 5–12 years: 15–20 >12 years: 12–15 | Adjusts total cycle time5 |
| PEEP | Positive End-Expiratory Pressure | Typically 5-10 cmH2O | Maintains alveolar recruitment during expiration5 |
This table provides a comprehensive overview of the timing parameters in mechanical ventilation. The T-high and T-low are particularly important in modes like Airway Pressure Release Ventilation (APRV), where T-high is set to improve oxygenation and T-low is adjusted based on the patient's lung condition13.
The Inspiratory Time (Ti) is typically set based on the patient's age, with longer times for older patients5. The I:E ratio, which represents the proportion of time spent in inspiration versus expiration, is usually set to 1:2 in healthy individuals but can be adjusted based on the patient's condition4.
The Total Cycle Time is determined by the Respiratory Rate (RR), which is also age-dependent57. PEEP is an important parameter that helps maintain alveolar recruitment during expiration5.
It's crucial to note that these parameters often need to be adjusted based on individual patient needs, underlying conditions, and response to ventilation. Continuous monitoring and readjustment are necessary to ensure optimal ventilation and oxygenation.