Ashok Patel, Founder & CEO, Max Ventilator analyses why turbine-based ventilators have emerged as a powerful alternative to conventional compressed gas-based ventilators from the standpoint of manufacturers, medical engineers as well as patients
Ventilators as artificial breathing machines are proving to be the proverbial lifeline in the times of COVID-19. Even as both the government and the private sector have joined forces and are continuously raising the bar in terms of meeting the surging demand for this lifesaving equipment, the pandemic seems far from over. What is compounding the challenge is that there have been reports of acute shortages of medical oxygen in the country, a critical input gas component of the COVID-19 treatment.
Given that the majority of healthcare facilities in the country lack an established centralised air supply system including medical-grade oxygen, compressed air etc. critical for running an effective ventilator support system, the turbine-based ventilators emerge as a powerful alternative from the standpoint of manufacturers, medical engineers as well as patients. As per media reports, the government has mandated that the ventilator must be turbine or compressor based for COVID-19 cases which is an affirmation of the robustness, flexibility and reliability of the turbine-based technology for this critical lifesaving device during current situation.
How do turbine-based ventilators work?
Employing the concept of textbook turbine generator technology which involves the conversion of kinetic energy of primary agents such as air, water, steam, combustion gases into electrical energy, turbine ventilators use compressors to generate pressurised gas flow. By sucking the ambient air through a filter, they compress the mixture of the ambient air and the oxygen coming from oxygen source in order to generate a flow.[1]
Turbine ventilators vs. conventional compressed gas-based ventilators
When it comes to a comparison between turbine-based ventilators and the conventional compressed gas-based ventilators, there are many ways in which the former surpasses the latter. First and foremost, turbine-based ventilators do not have to be dependent on a central gas supply infrastructure. As such, since they are powered by electricity, they can use the room air to create a pressurised flow of air.
Second, studies have clearly indicated that trigger function turned out to be better with the turbine-based ventilators than the conventional compressed-gas ventilators with a shorter triggering and inspirational delay. Trigger delay is the time needed by ventilator before it responds to patient’s demand for breath.
Third, the pressurisation control of turbine ventilators has been found to be much better than the conventional compressed-gas ventilator allowing for a higher mean pressure time product (PTP). This is the amount of pressure assistance that the patient is given during his initial breathing efforts. Notably, pressure-support ventilation (PSV) is now popularly used, significantly for weaning – a process by which a patient is progressively taken off artificial machines until he can breathe successfully on his own – and for non-invasive ventilation.[2]
Fourth, turbine-based ventilators generate high flow rates enough for non-invasive ventilation. In light of the need for compensation stemming from the leaks around the fringes of the mask, the turbine-based technologies are ideal for increasingly popular non-invasive ventilators. In fact for a COVID-19 patient whose lungs are generally stiff and air passages inflated, only a high pressure high flow ventilator would fit the bill.
Fifth, since turbine-powered ventilators require low-pressure source of oxygen, they are a great fit for those health settings where there is scarcity of oxygen. At the same time, it must also be pointed out that compressed oxygen supply still remains a prerequisite even in turbine-powered ventilators.
Sixth, some of the latest turbine-driven transport ventilators have been reported to have been greater successes than gas compressed-ventilators.[3] In fact, pneumatic performance of turbine-based ventilators has been assessed to be no less than, and even better than conventional compressed-air driven ICU ventilators.[4]
Seventh, as regards initial costs and energy consumption, turbine-based ventilators again outshine the conventional gas-compressed ventilators. And eighth, turbine ventilators don’t require bulky and noisy special high pressure medical-grade air compressors. They are relatively lightweight and can be easily handled, quickly shifted and readily installed.
From the standpoint of COVID-19 wherein the need for the conversion of an existing hospital into a COVID-19 hospital or setting up of COVID-19 ICU wards within a hospital often arises, turbine-based ventilators can be the perfect solution. In such exigencies where time is at a premium, they clearly overshadow their compressor-based counterparts because the latter would definitely require a centralised air infrastructure, a difficult, time-taking and even unwieldy proposition.
Versatility the biggest virtue
One of the most notable features of turbine-based ventilators is that they are versatile and can be built and adapted for most modes prevailing in High Performance Critical Care Ventilators. Not only can they be built for both invasive and non-invasive modes, they can be adapted for right from basic modes for mechanical ventilation to spontaneous modes, supportive modes, auto modes and special therapeutic modes. Most appropriate for providing non-invasive modes of ventilation, turbine-based ventilators are suitable for therapeutic Modes such as Bi- Level, CPAP and High Flow Oxygen Therapy modes, all of which can be effectively administered and worked with these ventilators. Although gas-driven pneumatic ventilators have distinct clinical advantages over turbine ventilators, the sheer versatility and portability of the latter makes them a great attraction for hospitals.
The scarcity of oxygen: turbine ventilators more of a necessity than a choice
The widespread reports of shortage and rising prices of oxygen during recent COVID-19 months again underline the need to develop turbine-driven ventilators. Since most oxygen plants are located built near big cities and towns with supplies to far-flung and remote areas being a cumbersome task, it is easier to adopt turbine-based ventilators which require less oxygen as well as low-pressure oxygen.
Therefore, even as the health authorities continue to battle COVID-19 with ventilators serving as frontline weaponry, it is important to know that the turbine-based ventilators are an all-purpose, versatile and easy-to-deploy option.
References:
[1] https://derangedphysiology.com/main/cicm-primary-exam/required-reading/respiratory-system/Chapter%20503/methods-generating-gas-flow
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873304/
[3] https://www.hamilton-medical.com/dam/jcr:0d4a7c9d-e5e1-4d23-a580-c1bda737a17a/Pneumatic-performance-turbine-driven-ventilators-white-paper-en-2014-04.pdf
[4] https://www.hamilton-medical.com/dam/jcr:0d4a7c9d-e5e1-4d23-a580-c1bda737a17a/Pneumatic-performance-turbine-driven-ventilators-white-paper-en-2014-04.pdf