Quality
Quality values are between 0 and 4 (0:very low, 1:low, 2:fair, 3:good, 4:very good)
1.1 Summary of Quality Index (Q-Index)
The Q-Index has been established to confirm the quality of a given vital parameter (Pulse Rate, SpO2, Respiration Rate) taken by the bracelet, prior to transmission as a measured parameter to the Corsano App & Web Portal.
The Q-Index may vary due to the paDent, including :
- wearing incorrectly the bracelet (ie too loose)
- not wearing the bracelet (outside charging period)
- wearing it whilst going swimming or showering
- wearing it over damaged skin (or taNooed)
- variaDons in skin color
- using cream on the skin
- varying levels paDent movement / moDon
1.2 Explanation of how the Q-Index is calculated
In summary, the Q-Index’s are calculated individually for each Pulse Rate, SpO2, Respiration Rate, whereby the :
- PPG signal is filtered
- Peaks and Valleys are detected
- Determination of good and bad PPG pulses, based on Dme and amplitude parameters -- PWD (Pulse Wave Duration) -- PWA (Pulse Wave Amplitude) -- RT (Rise Time) As such the Q-Index is a function of: -- Ratio of “good” pulses in the last window of measurement -- Standard deviation of the previously calculated values (Pulse Rate, SpO2, Respiration Rate)
The Q-Index has an established range of 0 to 4 to evaluate the quality of the signal to the associated measurement.
| Q-Index | Description | Conditions | Impact |
|---|---|---|---|
| 0 | Very bad quality or no measurement possible | Good PPG pulses in the measurement period < 20% OR Standard deviation in the measurement periodis > 20% | Not transmitted by the Bracelet Firmware |
| 1 | Bad quality | Good PPG pulses in the measurement period > 20% AND Standard deviation in the measurement period > 20% | Transmitted, no Alarms. Informative, not for clinical decision |
| 2 | Fair quality | Good PPG pulses in the measurement period > 20% OR Standard deviation in the measurement period is 10% to 20% | Transmitted |
| 3 | Good quality | Good PPG pulses in the measurement period > 20% OR Standard deviation in the measurement period is 5% to 10% | Transmitted |
| 4 | Very good quality | Good PPG pulses in the measurement period > 20% OR Standard deviation in the measurement period is < 5% | Transmitted |
1.3 Quality and alerts
Quality levels 0 and 1 are intended for informational purposes only and should not be used to trigger medical alerts. Alerts should only be triggered for values with a quality level of 2, 3, or 4.