I am looking for as accurately as possible method of counting the number of human breaths per minute (repiration rate) in the LabChart software.
Option which are proposed by LabChart software (cylic measurment → Preset → Respiration - Respiratory belt with SD = 0.9) fails to find all of the breaths (there are no marks for about 30% peaks of breaths).
It seems to me that much more precise are such option like:
- General - Spikey shape with SD = 2.5 SD
- Sine shape with SD = 2.0 SD
Are there any guidelines for the size of standard deviations which should I use? Can I use Spikey shape or Sine shape method?
I would be very grateful for any help!
Dariusz,
Typically we use General Sine shape. As far as I know, there are no guidelines for setting the SD. For us, there can be sigificant within and between animal variability in the amplitude of the respiratory signal, so we manually adjust the SD so as to pick up all breaths without picking up noise. We also go into "Customize" on the Cylic Measurments window, and set the Detection Parameters to "Two-sided Height" - this seems to work best for us (doesn't matter if you set the trigger to "Maximum" or Minimum" if your respiratory signal is mostly sinusoidal.
I recommend you try this first - if it doesn't work just play around with the settings until you pick up all breaths without picking up stuff that isn't breaths.
Hope that helps,
Kevin
Hi, if you are working off-line on pre-recorded data, a simple way is to activate the piece of data of interest and choose spectrum view. Breathing data is usually clean enough to show one clear maximum in the spectrum, corresponding to true breathing frequency. No hassle with SD's. Of course, when you need the rate online, cyclic measurement is better.
Cheers,
-Esa
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