Video Editor: Mohd ibrahim

We know that a majority – nearly 80% of COVID-19 infections are asymptomatic or mild and may not require hospitalisation. But in almost five percent of all patients, the disease can turn critical.

Now when some critically ill patients suffer extreme lung damage and struggle to breathe, they need to be admitted in an intensive care unit, and a subset of them need to be put on a ventilator.

Recently, reports about ‘fake ventilators’ and other machines being passed off as ventilators have been coming in. But critical care specialists believe these could cause more harm than good.

Here is what we need to know about ventilators and why they are needed during COVID-19. Dr Sumit Ray, critical care specialist in Delhi answers some pertinent questions, and Dr Arun V, Lead Consultant, Critical Care & Anaesthesiology, Aster CMI Hospital, Bangalore, shows how innovative techniques are being used to make up for the shortage of these machines.

WHAT DOES A VENTILATOR DO?

Dr Sumit Ray: A ventilator in its most-simplest definition is a machine which delivers air and oxygen into the lungs of the patients.

But the delivery of breath into a patient’s lung is a complex process. It needs to take into consideration not just the volume of gas or air which has to go into the lungs, but with what pressure it goes in, and which patterns or flow it follows.

That is why we need technologically advanced ventilators which help us control these parameters very tightly and significantly. This takes years of training and learning to be able to use a ventilator properly in the right context in a particular patient in a particular condition.

WHAT ARE THE TWO TYPES?

Dr Sumit Ray: There are two broad kinds of interfaces that a ventilator can give breath from: one is invasive where the breath is delivered into the lung of a patient through a tube which is pushed into the windpipe or trachea. This is called intubation.

The other interface is where a tightly fitted mask is placed on the face of the patient and breath is delivered through the nose.

Now, most of the modern invasive ventilators can perform both roles. But a large subset of non-invasive ventilators cannot be used as invasive.

WHY DO SOME COVID-19 PATIENTS NEED VENTILATORS?

Dr Sumit Ray: In a COVID patient who needs a ventilator, there is significant lung damage - as is true of other viral pneumonia as well. It is common to all patients who have ARDS, which is a complex disease process where large parts of the lung are damaged and many parts are not; it is a very heterogenous damage of the lungs. When we ventilate these patients, we have to control and fine-tune the flow of the gas into the lungs by varying the pressures, the volumes and the patterns of the gases to do the best we can to maintain the gases and the oxygen and the carbon dioxide levels.

To understand that, it takes a lot of time and learning. While delivering the breath, we should not be damaging the lung itself, which is an absolutely possible thing which happens if we do it wrongly.

At this present moment, we need both invasive and non-invasive ventilators. Non-invasive are used in COVID patients with mild ARDS, but if the illness becomes severe, then we require invasive ventilation. So, both types are necessary to build and to increase the supply of.

WHAT OTHER MACHINES ARE BEING PASSED OFF AS VENTILATORS? WHY IS THAT WORRYING?

Dr Sumit Ray: In this crisis, there are reports of people using very basic ‘ambu bags’ with a mechanical system to pump the gases into the lungs; and calling it a ventilator. That does not work.

These machines, which are being passed off as ventilators can do more harm. It would be very difficult to ventilate these COVID patients with severe lung damage without causing further damage to the lungs with ambu bags.

The reason is that the Ambu bag is basically a plastic bag through which you push in gases to give some breaths. It is used as a short-term temporary measure while we are doing CPR on a patient. It is pumped with our hand.

These new machines that are claiming to be ventilators are basically mechanical devices which squeeze the Ambu bag in place of your hand, and this squeezing just pushes some gas into the lungs. That is not going to work in COVID, it is actually going to harm the patients. And that is why it is necessary to have really good quality ventilators when we are ventilating COVID patients.

And people think that if there is nothing then why not this?

But it doesn’t work like that. We can cause more damage to the lungs.

HOSPITALS ARE NOW RESPONDING TO VENTILATOR SHORTAGE USING INNOVATIVE TECHNIQUES

As COVID-19 cases increase, the demand for ventilators will increase too. To meet the problem of shortage, hospitals, such as Aster hospital in Bengaluru, are using devices called 'splitters'.

Dr Arun V explains: Devices known as 'splitters’ help us use one ventilator on two patients. We can set the pressure and volume of the air separately for both. Earlier, 50-50 split was the only option. But now we can regulate and customize based on the needs of both the patients with the controls available.

It is important to understand, here, that using a single ventilator for two patients is usually our last option. But in such times of distress, this helps us meet the demand of ventilators. It will take 4-5 months before we actually receive high-end ventilators. Splitters cost only a few hundred rupees and can be locally made. Ventilators will take time and will cost 12-15 lakhs. We can make these splitters using 3D printing too.