pIRfusiX

pIRfusiX tackles an ongoing and pervasive issue for pre-hospital care and it’s link to the emergency department at receiving facilities. By relaying vital information about tissue perfusion to the staff at the facility, it gives the department time to respond and increased knowledge of the issues they face when the patient comes through the door.

Discussion with First Responders and EMT determined three key findings:
– The sensor must be unobtrusive
– Must last at least 1 hour (the golden hour in trauma)
– Must provide a metric that is useful and novel

To minimize clutter in the ambulance, we designed our solution to be wireless and modular; the gateway is capable of accepting any Bluetooth connection from commercial devices such as pulse oximeters, paving the way for a wireless sensor suite.

There are a multitude of disease/injury processes which can be monitored and indicated by a an altered StO2, which is why we chose this metric as the tell tale sign that we wanted to carefully watch and report to the attending physicians and medical staff. As this metric traditionally has no been used in this sense, we intend for pIRfusiX to provide previously unavailable information to the clinicians to help in their decision making. We achieved this through the use of near-infrared light spectroscopy and utilizing a modified beer-lambert equation to track the change in tissue oxygen perfusion.

On top of the unique use of this sensor, we also wanted to make sure that the information could get to the end-user (clinicians at the ER/ICU/Sugery), which is why we integrated multiple communication modules including satellite. This will ensure that the messages can get sent from virtually anywhere in the world. Most related sensors have very little communication standards built-in, therefore this also will give up to date information throughout the patients trip to the facility.

Careful consideration of the underlying physics of near infrared spectroscopy, input from end users and hospital staff, and laboratory consultation has allowed our solution to be tailored towards usability and functionality. The pIRfusiX system is intended to be applied once to the patient during prehospital transit and follow them throughout their cycle of care. Consultation with hospital staff highlighted that it is common for a patient’s IV-pole to follow them throughout their cycle of care. The pIRfusiX Gateway is an IV-pole mounted hardware, acting as a watchful observer through the patients journey. The wireless sensing of the pIRfusiX combined with its non-invasive readings allows the pIRfusiX system to be easily integrated into existing prehospital-care workflows, creating an effective means of monitoring tissue perfusion.

Our Sensor vs. Commercially Available Lab Equipment

A comparative analysis with a local lab demonstrated the pIRfusiX sensor’s ability to recognize traumatic tissue perfusion events.

The R&D of the device including multiple revisions of the sensor and multiple prints on the 3D printer for the enclosure came in at $1250 CAD. Now that final measurements and adjustments have been made there could be considerable savings in the manufacturing of the product. Additionally some of the components were chosen not for frugality or performance, but rather on their availability during the pandemic. This led to higher costs on some components. The most expensive and non-negotiable component is the satellite module, however each of the other components could easily have a reduction in cost.

If we look at actual cost to manufacture at our limited scale the cost of a sensor is $50.76 and the gateway is $471.55.

Also another cost we could look at is the cost to transmit one patient worth of data to the web service. By our calculations trips would cost: $122.03 for a Satellite trip and less than $0.10 for a Cellular trip.

Long term the device is not a one time use. The sensor and gateway are meant to be reusable, with the sensor having a replaceable attachment apparatus so it can be kept aseptic for multiple patients. This means that the product is an investment rather than a disposable item.

This paired with the low amount of clinician effort and usefulness of the data it provides, makes pIRfusiX an extremely feasible product to add into the pre-hospital workflow in health services everywhere.