Respiratory Rate Counter - The RRate app

Respiratory rate (RR) is a fundamental measurement for disease diagnosis, prognosis, and treatment in children. Unfortunately, many studies have demonstrated that clinically obtained measures can be inaccurate in a variety of health care setting. We have developed and validated a mobile phone application for the efficient and accurate measurement of respiratory rate. Download the app for iOS or Android.

A large button to click on each inhale.
The touch screen is tapped each time the child inhales.
An animated baby for confirming the breathing rate.
Once enough consistent taps have been made an animation of a baby breathing is displayed.

Detecting Fast Breathing

One of the keys to detecting pneumonia in children, is the measurement of Respiratory Rate, specifically determining if a child has fast breathing. The World Health Organization's (WHO) Integrated Management of Childhood Illness guidelines identify fast breathing as 50 breaths per minute or more in children aged 2 months to 12 months and 40 breaths per minute or more in children aged 12 months up to 5 years.

The WHO promotes measuring RR by counting the number of breaths in a minute. There are many limitations to this method. It is time consuming and requires full attention. If any disruption to the counting occurs, the minute must be restarted. The RRate application is meant to solve this problem by providing a mobile application that can accurately calculate the respiratory rate in less than 10 seconds.

Detecting Consistent Taps

The RRate app displays the RR value as soon as enough consistently timed taps have been performed. Two parameters control this consistency check, as shown on the settings page of the application (version 2.4+).

The first parameter, z, is the number of taps used in the RR calculation. If z = 4, then the RR is calculated based on the median of the 3 time intervals between the most recent 4 taps. This means you must tap at least 4 times, and if the 4 taps are not consistent enough, then you keep tapping and each time you tap the consistency is checked again using the timing of the most recent 4 taps.

The second parameter, C, is the consistency threshold necessary for the time intervals between the most recent z taps. The consistency zone is defined as the median of these intervals plus and minus C% of this median. For example, if the median time interval = 2.0 seconds and C = 10%, the time intervals must all be in the range of 1.8 - 2.2 seconds. If they are in this range the application shows a breathing baby with animation and sound/vibration for confirmation of the RR. If one or more of the time intervals is not in this range, the user must keep tapping.

Settings allowed are the number of taps from 3-6 and the consistency from 10-14%
The number of taps and consistency threshold can be set on the settings page.

Publications

W Karlen, H Gan, M Chiu, D Dunsmuir, G Zhou, GA Dumont,  & JM Ansermino (2014). Improving the Accuracy and Efficiency of Respiratory Rate Measurements in Children Using Mobile Devices. PLoS ONE, 9(6), e99266. doi.org/10.1371/journal.pone.0099266

http://www.stahq.org/files/5113/9171/8086/44_Abstract_Dunsmuir.pdf

 

Data used in optimization study that will be published in PLoS ONE

Below you can download supplemental material, including recorded data used for the writing of the PLoS ONE article. The article describes the research for the design and optimization of the RRate app and the respiratory rate calculation using tapping intervals.

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Electrical and Computer Engineering

Electrical & Computer Engineering in Medicine (ECEM)
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e-mail part@cw.bc.ca

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