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Smart breath sensor for assessing nasal blockage

As we all know, human breathing is dependent on inhaling and exhaling air through the nose. Slight changes in the nasal cavity can cause blockages to normal airflow, which is a symptom in many nasal infections. Measuring the magnitude of nasal blockage is of value in diagnosing and treating the condition.

In a routine clinical practice, ENT physician measure nasal blockages by direct observation. Otherwise, conventional techniques available till now are expensive and difficult to carry around. Some are not suitable for “unilateral” assessment, which is necessary when only one side of the nose – either the right or the left nostril – is affected.

In a collaborative study, scientists at the Indian Institute of Science and an ENT surgeon from M.S. Ramaiah Medical College, Bengaluru have devised a novel sensor to assess blockage of the nose. Reduced nasal airflow caused by blockage is a commonly encountered symptom in the ENT clinics and is known to affect all age groups.

The innovative new sensor employs PolyVinyliDene Fluoride(PVDF), a lightweight, flexible polymer that produces a small voltage when stretched or pulled. The polymer is also non-reactive and biocompatible, making it suitable for use as a diagnostic tool in the body.

The setup is simple: a PVDF sensing element is suspended from each side of a headset, which is linked to a computer (see image) through a suitable electronic circuits. The PVDF sensing elements are positioned beneath each nostril, and the patient was asked to breathe normally for 2 minutes. The sensor relays the record of airflow to the computer for storage and analysis.

When the nasal passage is normal, the flow rate would be constant; in the presence of irregularities like a deviated septum or nasal polyps, the airflow would be turbulent. This method allows for air flow through each nostril to be measured. Moreover, each PVDF measurement took just about five minutes. The sensor is also able to assess the severity of obstruction, by comparing the airflow in patients with healthy individuals.

This novel PVDF nasal sensor has effectively overcome the disadvantages of its contemporaries by its simple design making it more economical, portable and a reliable means of assessing nasal obstruction with minimal discomfort to the patient. This makes it suitable for regular use by clinicians for screening patients to quantify nasal obstruction, in the routine clinical setup. The authors have suggested larger multicentre studies to fully assess the effectiveness of this promising new innovation.

This work received funding from the Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore, India.

Author information:

Dr Roopa Manjunatha and Prof K Rajanna are at the Department of Instrumentation and Applied Physics, IISc.

Prof Roy Mahapatra is at the Department of Aerospace Engineering, IISc.

Dr Surya Prakash is at the Department of Ear, Nose and Throat, M S Ramaiah Medical College and Hospital.

Contact: (K. Rajanna). Tel: + 91-80-22933188

The paper appeared in The American Journal of Otolaryngology.