FacialisDruck

The project “FacialisDruck” is intended to research a novel method for the non-invasive blood pressure measurement at the Arteria facialis (cheek). The device is conceived as a clasp that is inserted into the mouth of the patient during the measurement. The integrated pressure pillow pointedly interrupts the blood flow in the Arteria Facialis. A light-emitting diode at the outer branch of the clasp continuously sends light through the arteria and the photo diode records the light intensity at the opposite branch of the clasp. The comparison of the light signal with the pressure in the pillow allows the determination of the diastolic and systolic blood pressure.

The project objective is the research and application-oriented validation of a blood pressure method at the Arteria facialis.

The described measurement method allows an automatic blood pressure measurement at patients that are unable to use standard upper arm cuffs. These include patients with dysplastic or amputated arms, intense obese or muscular patients or accident casualties. The novel method can be used on ambulance service, because the light signal is not influenced by the vehicle movement. Automatic blood pressure measurement devices with upper arm cuffs are using the oscillations of the cuff pressure during the measurement and these oscillations are superimposed by artificial oscillation caused by the vehicle movement that will result in faulty blood pressure results. The manual auscultatory measurement with stethoscope done by a physician or paramedic is not possible because of the environmental sounds.

In pretrials measurements were compared at the cheek of healthy subjects with reference measurements at the upper arm. Both values coincide well. The differences between the two measurements could be corrected by a calibration equation. Currently it is not possible to formulate a calibration equation without reference measurement at the upper arm. The project pursues the objective to formulate a universal calibration equation without reference measurement for the described use case and patient group. The influencing variables of the calibration equation should be determined by a simulation of the pressure distribution in the cheek tissue called Finite Elements Simulation and by an experimental model. Furthermore, the programmed algorithm should determine the breathing and pulse frequency. Finally, the clasp should be optimized for usability to achieve a high user friendliness of the new principle.

The funded project enables the development of a measurement method that is currently not available on the market for the above-mentioned use cases and patient groups. This enables the diagnostic and therapeutic care of these patients.