This content is for the Kenek Edge pulse oximeter.
Using Kenek Quick Grapher
Kenek Quick Grapher is a Java Script tool that runs locally on your browser, either on your mobile device or on your laptop/PC. Due to the difficulties of sharing files on smartphones, particularly Apple/iOS devices, it is advisable to send the data from your smartphone to your laptop/PC and then follow these instructions.
Please see the detailed instructions to record and send information to Kenek Quick Grapher.
Generating Overnight Data
The Kenek Edge pulse oximeter can record measurements of SpO2 (blood oxygen saturation) and pulse rate. For more details read this article on how to record measures, change the period of recording, and to export data or this article for tips on extended or overnight recording .
How To Graph Your Overnight CSV Data
The Kenek Edge pulse oximeter records and exports comma separated values data files (CSV) that can be read by a human or imported easily. Here we provide step-by-step instructions on how to use the Kenek Quick Grapher.
Kenek Quick Grapher is a Web-based graphing tool available for Kenek Edge users. It quickly graphs and summarizes data produced by Kenek Edge. To use Kenek Quick Grapher, please go to http://kenekedge.com/grapher/ or follow the link provided in your exported data email.
1. On the Kenek Edge app for iPhone, record and export some data on the Oximeter screen (see the section above)
- Mail the CSV file attached to the export to yourself
2. On your PC or laptop, open your email client and save the file to your desktop
3. Open a browser on your PC/laptop and go to the URL below - it should say Kenek Quick Grapher at the top
4. On the browser page that appears, click the Browse button - select the CSV file you saved to your Desktop
5. The Kenek Quick Grapher will then show you graphs of your data as well as statistical summaries
Understanding the Graphs and Charts
A variety of charts, graphs and statistics are generated by Kenek Quick Grapher. A typical graph is shown below - each component of the graph is numbered in red:
- Print button - prints the entire report on your printer
- Detail level - increase number to smooth data (10 is default)
- Show SQI - optional graphing (in grey) of signal quality index
- Graphs of SpO2 and heart rate - shown for selected data; axis on the left is both % SpO2 and bpm; axis on bottom is time; optional SQI
- Data selector - move the knobs on left and right to select data shown in 4.
- SpO2 distribution charts - cumulative density function on the left; probability density function on the right
- Heartrate distribution charts - cumulative density function on the left; probability density function on the right
- Recording time - statistics of the recording time for this data
- Max/min/mean - maximum, minimum and typical values for SpO2 and heart rate
- SpO2 Events - amount of time, number of events (changes), and mean time per event at each level of SpO2
- Expanded graphs - SpO2 and heart rate shown in detail; optional SQI
- (not shown at bottom) Metadata - details of the app version, date of export, email address, Apple device
About CDF and PDF Graphs
Cumulative Density Function (CDF) and Probability Density Function (PDF) graphs can be a challenging to understand if you are not a mathematician or statistician. However they offer some useful insights that anyone can benefit from.
You can learn a lot more about PDFs and CDFs by checking out Wikipedia or the Khan Academy. But you will find that the descriptions get very mathematical, very fast. This article simplifies the meanings to make these graphs accessible for non-mathematicians.
Unlike the other graphs, CDFs and PDFs are not about time - they show all the data together, representing the whole collection of measurements in a recording. Their shape is useful way to make comparisons between data sets and help focus on features related to the entire distribution of data, instead of specific events in time.
In brief, the probability density function graph (PDF for short) is the one on the right that shows how often (or how probable) a given value appears in your data. In the example above, the blue column for SpO2 = 97% is the tallest compared to the rest of the columns. That means it is the most common value in the dataset and that SpO2 level most often appeared during the recording.
In the blue SpO2 values, there is one peak, around which the rest of the data is scattered. In the green heart rate values, there are two fairly clear peaks - this says that there were two distinct values around which the person measured most of the time - a lower rate of around 57 and a higher rate of 64. Most of the measures though were scattered fairly evenly between the maximum and minimum.
The cumulative distribution or density function (CDF) graph is on the left - blue on top for SpO2 and green below for heart rate. It indicates how much of the data falls below a given measurement. Reading from left to right on the bottom of the CDF for the heart rate, there was no data (zero) below the value of 52 - so that is the minimum. As the graph goes to the right, it linearly (in a straight line) increases until it reaches all data (one) at around 69 - that is the maximum value in the data set. All of the data falls between 52 and 69. The shape of the graph shows how the data is distributed between the maximum and minimum - either bunched at one side or the other (see the PDFs) or scattered evenly between the limits.
In the example, the shape of the SpO2 CDF is quite different from the heart rate CDF - it rises slowly at first and then very quickly to the halfway point and then slows down again as it finally reaches one. This suggests that the data is bunched in the middle (as seen in the SpO2 PDF). The heart rate CDF is fairly flat and rises evenly from zero to one - suggesting that it is distributed between the maximum and minimum. The two peaks seen in the heart rate PDF cause slight bumps in the linear increase of the CDF but are not very easy to see - so they are not very significant peaks.
This is why CDFs and PDFs - while closely related - offer unique views of the data.
Please let us know how to improve the Kenek Edge Grapher - firstname.lastname@example.org