Flow Sensor Solution for Ventilators: Patient-side and Accurate, Easy-to-Use and Safe

by donpedro

Flow sensor solutions for ventilators that include connectors and cable interfaces were launched in February 2019. They enable patient-side measurement of inhalation and exhalation flows. The different standardized variants are available to medical technology OEMs free of development and tooling costs. They are the product of the cooperation between the sensor manufacturer Sensirion AG and medical technology cable and connector specialist Nicolay GmbH.

Figure 1: Sensirion and Nicolay launched flow sensor solutions including connector and cable interfaces in February 2019

The requirements for patient-oriented ventilation which takes individual pathophysiology of the patient into account represents a challenge to the manufacturers of modern ventilators. It requires highly accurate inspiratory and expiratory gas flow measurements. Classic sensors installed inside a ventilator and distal from the patient make it difficult to achieve the required accuracy. Nicolay and Sensirion took on this challenge and launched a sensor-connector-cable solution that provides accurate, patient-side measurement while delivering a reliable flow signal to the ventilator. The solution includes different options of cables and connectors in order to reliably transport calibrated and temperature-compensated output signals of the sensor back to the ventilator. These options also ensure, among other features, compatibility with a variety of communication protocols. This sensor-connector-cable combination is now also available in Distribution.

Figure 2: The sensor-connector-cable combination enables patient-side and precise measurement of inhalation and exhalation flows

High-Quality Sensor Technology
The Sensirion Flow Meter (SFM) is available either in autoclavable and washable (AW) variants or as single-use solutions (D = disposable). The SFM3400 was developed for neonatal applications, that means for measuring very small volumes, while the SFM3300 was developed for adult ventilation. The SFM3200 is intended for expiratory applications. The performance of these gas flow sensors is based on technology developed and patented by Sensirion that combines the sensor element, signal processing and digital calibration on a single microchip. The flow rate of gases is measured using a microthermal sensor element that among other advantages, enables a wider dynamic measurement range and superior long-term stability compared to other measurement principles. All flow meters come factory calibrated which makes them straightforward to use without prior or repeated calibration.

Modern Connector and Cable Variants
All sensor variants can be connected to the ventilator using the Nicolay Flow Meter Connector. This robust mechanical interface is incredibly easy to use; it attaches easily and only in the intended manner to ensure correct use even in fast-paced situations. When connected, the interface is leak-proof to protection rating IP54, and when detached it allows for wipe disinfection. Communication with the sensor I²C bus using short cable lengths requires nothing more than a connection with simple spring contacts. A secure signal transfer over longer cables utilizes electronics integrated into the connector to convert the signals. When equipped with an RS485 or RS232 interface, the device translates the signals ready for the ventilator’s common communication protocols. There is also a range of connector options available, for example the Nicolay mini7 or mini12 interfaces. In addition to the standardized product variants, customer-specific PCB layouts can also be realized and integrated into the connector.

Buy Ready-Made – or Outsource
This readily available high-quality solution by Nicolay and Sensirion offers ventilator manufacturers an alternative to individually produced sensor connector and cable configurations. They are attractive for evaluation purposes, early stages of development or in smaller quantities, for instance when investment in in-house development and tools is time-sensitive or financially not justifiable. The range of different cabling options makes these standardized variants an attractive alternative to in-house development because sensors and cables used for patient monitoring require specialist expertise. These medical device components are often outsourced by OEMs – which leads us back to the reason why Nicolay and Sensirion partnered for this solution.

Sensirion | www.sensirion.com

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