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High-frequency percussive ventilation: pneumotachograph validation and tidal volume analysis.
1Pulmonary Medicine Service, Landstuhl Regional Medical Center, CMR 402, Box 307, APO AE 09180, Landstuhl, Germany. patrick.allan@amedd.army.mil
Respiratory Care
|May 29, 2010
Summary
Pneumotachography accurately measures tidal volume during high-frequency percussive ventilation (HFPV). This technology reveals that typical HFPV settings may deliver lung-injurious tidal volumes, especially in acute lung injury patients.
Area of Science:
- Mechanical Ventilation
- Respiratory Physiology
- Pulmonary Engineering
Background:
- High-frequency percussive ventilation (HFPV) is an advanced mechanical ventilation technique.
- A real-time method for measuring delivered tidal volume (V(T)) during HFPV is currently lacking.
Purpose of the Study:
- To validate a pneumotachograph for accurate V(T) measurement during HFPV.
- To analyze low- and high-frequency breath characteristics using flow-sensor data.
Main Methods:
- Validated a pneumotachograph by comparing its measurements to adiabatic conditions using a glass bottle and test lung.
- Assessed sensor performance across various HFPV settings, including frequency, airway pressure, gas conditions, and endotracheal tube diameter.
Main Results:
- Pneumotachography demonstrated high accuracy and precision for both high-frequency (mean difference: -0.2 ± 1.8%) and low-frequency breaths (mean difference: 0.6 ± 2.4%).
- An exponential relationship was observed between high-frequency tidal volume and respiratory rate.
- The average low-frequency tidal volume during HFPV was 1,337 ± 700 mL.
Conclusions:
- Readily available pneumotachography is a validated tool for measuring V(T) during HFPV.
- Current HFPV settings may pose a risk of delivering injurious tidal volumes, particularly in patients with acute lung injury.
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