Model Face for VHC Facemask Seal Testing
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Solution Overview
Problem
Testing valved holding chambers (VHCs) with pressurized metered-dose inhalers is complicated by the need to achieve a seal between a facemask and a test apparatus, often resulting in small leakages that decrease medication delivery efficiency, and existing methods require removing the facemask, which does not simulate real-world conditions effectively.
Innovation Solution
The development of model faces for children and infants that simulate soft facial tissues, mounted on a testing cradle, allowing a facemask to be applied with clinically appropriate force and orientation, enabling the measurement of seal quality and medication delivery by evaluating flow rates and aerosol distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a facemask is used during VHC testing, then realism and accuracy of dead space simulation are improved, but seal leakage increases causing decreased medication delivery efficiency
Solution Approach 1:
The patent creates a model face that copies the essential features of a human face (contours, soft tissue characteristics, mouth opening position) to simulate real-world conditions during VHC testing. This allows the facemask to be tested in realistic conditions without using an actual patient face, thereby maintaining both realism and reliability.
Solution Approach 2:
The model face acts as an intermediary between the facemask and the testing apparatus. It provides a realistic interface for the facemask to seal against while allowing precise measurement and control of airflow and medication delivery, thus mediating between the conflicting requirements of realism and reliable measurement.
2Reliability
If a facemask is removed during VHC testing, then seal leakage is eliminated improving medication delivery measurement, but realism of testing conditions deteriorates
Solution Approach 1:
Instead of removing the facemask entirely, the patent uses a model face that copies the necessary sealing surfaces and anatomical features. This allows the facemask to remain in place during testing, maintaining realistic conditions while enabling reliable measurement through the controlled model face interface.
3Reliability
If a seal between facemask and test apparatus is achieved, then medication delivery efficiency is improved, but complexity of testing apparatus increases
Solution Approach 1:
The model face provides a simplified copy of human facial features that is easier to seal against than a rigid test apparatus. By copying the soft tissue characteristics and contours, it creates a more forgiving sealing surface that reduces the complexity of achieving and maintaining a reliable seal.
Solution Approach 2:
The model face allows adjustment of various parameters (mouth opening size, facial contours, soft tissue compliance) to optimize sealing conditions. This flexibility enables reliable medication delivery measurement without requiring complex rigid sealing mechanisms in the test apparatus.
Data Source
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AI summary
Systems and methods for evaluating medication delivery from valved holding chambers (VHCs) with a facemask using a model face of a child or a model face of an infant are disclosed. Generally, the model face includes a base, an elastomer cast, an air pocket, and a mouth opening. The elastomer cast is positioned on at least a portion of a top of the base. The elastomer simulates soft tissues in a face and defiens at least a nose, a chin, and a mouth sized to simulate a nose, a chin, and a mouth of a child. The air pocket is positioned between the base and the elastomer case below at least the nose, the chin, and the mouth of the elastomer cast. The mouth opening defines a passageway through the base, the air pocket, and the mouth of the elastomer cast.