COVID-19: Must-have features in ventilators for patients with severe symptoms

There are two types of ventilators that are used for the treatment of COVID-19 patients - non-invasive ventilators and mechanical ventilators.

The non-invasive ventilators have a mask which is applied over the nose and the mouth. This mask is attached to the oxygen supply which is then delivered to the patient.

Mechanical ventilators work in the following manner:

• A tube is inserted in the nose and mouth of the patient to provide both food and air to their body. 
• A nasogastric tube is inserted through the nose of the patient which goes till the stomach. It is used to deliver food to the body.
• Another tube called the endotracheal tube (ET tube) is inserted through the mouth to the windpipe (trachea). The other end of this ET tube is attached to the ventilator.
• The ventilator blows air into the airway with the help of the ET tube, from where the oxygen is transported to the lungs.
• Once the oxygen is supplied to the lungs, the ET tube collects the carbon dioxide from the lungs and then the ET tube oxygen again and so on.

As of 2 April 2020, more than 2,030 cases of COVID-19 infections had been reported in India. Doctors are using oxygen hoods for patients who are having breathing difficulties. These hoods have a valve which allows pressurised oxygen to enter the hood. It also reduces the risk of transmission of the virus in the form of droplets from the breath.

India has approximately 48,000 ventilators and all of them are currently in use. Currently, the ventilators that are made by two Indian companies cost around Rs1.5 lakh each as the components of the ventilators are imported from other countries. One of these ventilator companies, AgVa Healthcare, is planning on making 20,000 more ventilators within a month. 

To meet the increasing need for ventilators, engineers from the Massachusetts Institute of Technology, US, and the Indian Institutes of Technology (IITs) are working together to make low-cost ventilators.

The engineers at Nocca Robotics, a Maharashtra-based firm known for its invention of water-less robotic cleaning of solar panels and other surfaces, is working on building mechanical ventilators that would cost only Rs50,000 or one-third of their current cost. The group of seven engineers has already built three prototypes of a portable machine within five days of beginning work. Their plan is to make 30,000 ventilators by the middle of May.

They are also working on making ventilators that can run on oxygen cylinders, as the small towns and villages of India do not have oxygen pipelines.

The Ministry of Health and Family Welfare has laid down some essential technical features which are required in the ventilators that are being used for COVID-19 patients. These are:

• Make sure that the machines are turbine or compressor-based as the installation sites such as small villages might not have central oxygen lines.
• The same ventilation machine should have the ability to provide invasive, non-invasive and continuous positive airway pressure (CPAP) ventilation. 
• The machines should have a mechanical display of lungs and the tidal volume should be around 200-600 ML. Tidal volume is the amount of air a person inhales during a normal breath. 
• The ventilator should be able to monitor the plateau pressure, positive end-expiratory pressure (PEEP), pressure support (PS), oxygen concentration and lung mechanics or inverse ratio. 
• The ventilator should have pressure and volume control. The ventilator should be able to work in PSV mode where the patient initiates the breath and the ventilator supports the further process. 
• The ventilator should have the ability to work continuously for four to five days.