Low breathing rate increases chances of virus depositing in lungs: IIT Madras

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Indian Institute of Technology Madras (IIT-M) researchers have found that the process of virus-laden droplets being transported into deep lung increases with decreasing breathing frequency.

The research team modelled the breathing frequency and found that low breathing frequency increases the time of residence of the virus and therefore it increases chances of deposition and consequently the infection. Also, the multiscale lung structure has a significant effect on a person’s susceptibility to Covid-19.

The research was led by Mahesh Panchagnula, Department of Applied Mechanics, IIT Madras, with research scholars, Arnab Kumar Mallik and Soumalya Mukherjee. The findings of this study were published in Physics of Fluids, says a press release.

“Covid-19 has opened a gap in our understanding of deep pulmonological systemic diseases. Our study unravels the mystery behind how particles are transported and deposited in the deep lung. The study demonstrates the physical process by which aerosol particles are transported into the deep generations of the lung,” said Panchagnula.

His team worked to gain a deeper understanding of how the rate of flow of droplet laden with virus determines the deposition of the virus in the lungs. In their research, the team reported that holding the breath and having low breathing rate can increase chances of virus deposition in the lungs. The study was conducted to pave the way for developing better therapies and drugs for respiratory infections. Previous work from the group has also highlighted the significant variability in aerosol uptake from individual to individual, suggesting a reason why some people are more susceptible to airborne diseases than others, the release said.

Droplet dynamics

Airborne infections such as Coronavirus spread through sneezing and coughing as it instantly releases a lot of tiny droplets. The IIT Madras Research team imitated the droplet dynamics in the lung by studying the movement of droplets in the small capillaries which were of a diameter similar to bronchioles. They took water mixed with fluorescent particles and generated aerosols from this liquid using a nebuliser. These fluorescent aerosols were used to track the movement and deposition of particles in the capillaries.

The researchers studied the movement of fluorescent aerosol particles in capillaries of size ranging 0.3-2 millimetres which covers the range of bronchiole diameters. They found the deposition is inversely proportional to the aspect ratio of capillaries, suggesting that droplets are likely to deposit in longer bronchioles, the release said.