Bias and Precision of Continuous P_0.1 Measurement by Various Ventilators: A Simulation Study

Area of Science:

• Respiratory physiology
• Mechanical ventilation
• Medical device engineering

Background:

• Ventilators commonly measure airway occlusion pressure (occlusion P_0.1) via circuit occlusion.
• Some ventilators offer continuous P_0.1 prediction without occlusion, but their accuracy is not well-established.
• Evaluating the precision of continuous P_0.1 measurement is crucial for clinical application.

Purpose of the Study:

• To assess the accuracy of continuous P_0.1 measurement against traditional occlusion methods.
• To compare the performance of different ventilator models in P_0.1 measurement.
• To validate continuous P_0.1 accuracy using a lung simulator under various respiratory conditions.

Main Methods:

• Utilized a lung simulator (ASL5000) to generate 42 breathing patterns simulating normal and obstructed lungs.
• Employed PB980 and Dräger V500 ventilators for reference occlusion P_0.1 measurements.
• Used Hamilton-C6, Hamilton-G5, and Servo-U ventilators for continuous P_0.1 measurements.
• Analyzed data using Bland-Altman plots to determine bias and precision.

Main Results:

• Occlusion P_0.1 measurements from Dräger V500 and PB980 ventilators showed high agreement with simulator reference values (bias: 0.51, 0.54; precision: 1.06, 0.91).
• Continuous P_0.1 was underestimated by Hamilton-C6 (bias: -2.13) and Servo-U in obstructive models (bias: -0.86).
• Hamilton-G5 continuous P_0.1 was less accurate than occlusion P_0.1 (bias: 1.62, precision: 2.06).

Conclusions:

• The accuracy of continuous P_0.1 varies significantly between ventilator models.
• Clinicians should interpret continuous P_0.1 data considering individual ventilator system characteristics.
• Occlusion P_0.1 measurements may be preferable for accurate assessment of respiratory drive.