Quantitative Evaluation Method of NPPV Mask Fitting by the Application of Strap Load Measurement Technology

Abstract

Non-invasive Positive Pressure Ventilation (NPPV), an artificial respiration therapy, is a treatment that attaches a mask to the patient’s face and delivers gas into the mask to support breathing. The NPPV mask straps are tensioned so that the supplied gas in the mask does not leak. However, leakage of the gas occurs when the mask strap tension is unbalanced or too weak, while ulcers are caused when the tension is too strong. However, there has been no technical method to know the strength and the balance of the strap tensions quantitatively in NPPV mask fitting.

In this study, we focus on the mask strap tension, and fabricated a system for measuring the mask strap loads using thin film force sensors. In order to grasp the balance of the mask strap load applied to the mask body, the center point of a distributed load (balance point) is calculated, and a real-time coordinate image is displayed on the system. Finding the distance from the ideal balance point, it is possible to fit the mask properly in consideration of the strap balance. This system is effective to measure the mask balance quantitatively, and it can be used to improve the mask fitting condition.