Breathing Easy with Alicat Flow Controllers
The Standard in Flow Controllers
by Shaina Shay
The COVID-19 pandemic has resulted in unprecedented challenges for modern medicine. Procuring and manufacturing the medical supplies needed for hospital staff to support the critically ill while protecting themselves from the disease has become a priority for governments everywhere.
To meet growing demand, companies that manufacture ventilators are working hard to increase output. Due to their repeatability and accuracy, Alicat flow controllers and pressure controllers are being used in ventilator test stands to calibrate and test these new ventilators.
COVID-19 is an infectious virus that attacks healthy lung tissue which can result in mild to severe respiratory complications. While the majority of people infected have only mild symptoms, approximately 14% require hospitalization and oxygen support.1 Mechanical ventilators are used to support those who are severely impacted by the virus. Ventilators feed humidified and pressurized air into the lungs to assist in oxygen uptake. Current estimates suggest that the United States has about 200,000 ventilators, but many may already be in use.2
Alicat mass flow controllers and pressure controllers are used as calibration standards in the manufacturing process. Our controllers offer an industry leading controllable range, and feed a variety of set points to a ventilator to test accuracy and repeatability of these life support devices. This ensures ventilators are operating within the desired parameters.
Ventilators require specific flow rates and pressure conditions to ensure sufficient oxygen delivery to patients making accurate calibration of ventilators very important. The oxygen concentration in the air being delivered is set depending on FiO2 (Fraction of Inspired Oxygen), which is the lowest amount of oxygen that can help the patient reach the level of required blood oxygenation.
Because lung capacity varies by individual, a ventilator needs to be able to flow different amounts of oxygen-rich air to each patient with great accuracy. The amount of air a ventilator pumps into a patient’s lungs is dependent on many different factors which include lung function and oxygen saturation in the blood. Mechanical ventilation can be triggered by oxygen saturation levels or by a pre-determined number of breaths per minute. It is very important that the ventilator is calibrated against a reliable and stable standard so displayed flow rate and the actual flow rate being inspired is the same every time (repeatability).
Verification and Testing
To ensure each ventilator is operating within the required specifications for all settings used in the field, the calibrated ventilators must go through a testing process to ensure they are operating at a set standard. This testing process is crucial to determining the performance of the device.
Alicat mass flow meters output flow rate, pressure, and temperature to confirm that the ventilators are supplying oxygen at the desired conditions. In a wide range of available options, protocols, and measurement ranges, Alicat devices offer ease of automation to increase the efficiency of the testing process.
Alicat devices meet critical calibration standards to ensure proper operation in calibration, verification, and testing processes for ventilators. The standards these test benches must meet include specifications such as: repeatability, accuracy, and control response time.
Repeatability (also called Precision) describes the closeness of measurements between separate tests when no other factors change. Alicat’s repeatability ensures that the tidal volume of each repetitive breath measured and provided by the Alicat in testing can be trusted to be within the required specifications, and ensure proper ventilator function.
Accuracy relates the difference between the measured air flow and actual air flow in the system. Our accuracy ensures that you will get the right amount of air flow through the system ensuring your instrument always functions within tolerance.
Control response time indicates the amount of time it takes the controller to adjust to changing conditions (flow or pressure) it is given. Fast control response time is critical to both accurately simulate breathing and test a variety of flow and pressure conditions quickly. The measurements on both Alicat meters and controllers are updated every millisecond, so you know the data can be trusted.
Alicat is committed to helping meet the demands of ventilator production with products that are reliable, precise, and meet the demands of medical device testing. Our application engineering team is here to partner with you to determine the best technology for your application.
Want to learn more? Contact one of our expert applications engineers today.
1 ”Clinical management of severe acute respiratory infection (SARI) when COVID-19 disease is suspected.” World Health Organization, 2020.
2 ”Ventilators explained: Key device in fight against coronavirus.” Aljazeera Health, 29 March 2020, https://www.aljazeera.com/news/2020/03/ventilators-explained-key-device-fight-coronavirus-200329065155185.html. Accessed 3 April 2020.