The Gliding-SLICE method: an enhanced tool for estimation of intratidal respiratory mechanics

Introduction

Focusing on lung-protective ventilation, the analysis of nonlinear dynamic respiratory mechanics appears crucial. Based on the SLICE method we developed the Gliding-SLICE method as a tool to determine respiratory system mechanics. This tool was tested in a nonlinear water-filled two-chamber lung model.

Methods

The classic SLICE method [1] determines parameters of the respiratory system for abutted volume ranges. The Gliding-SLICE method enhances this method by moving a window of analysis along the volume axis. This way, a quasi-continual course of intratidal mechanics can be determined. To test the new method we build up a physical model that consists of two connected chambers filled with water. During inspiration water is displaced from one chamber to the other resulting in a counter pressure. Using wedges of certain shapes we simulated volume-dependent nonlinear compliances.

Results

Using the Gliding-SLICE method we determined a nonlinear course of compliance in a patient (Figure 1) and in model data (Figure 2).

Figure 1

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Figure 2

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Conclusion

The Gliding-SLICE method allows one to calculate mechanical parameters of the respiratory system quasi-continually. This allows a more intuitive interpretation of data. The method is not limited to principle constrictions but can be enhanced by ventilatory maneuvers; for example, for separated view on inspiratory and expiratory respiratory mechanics.