Ponemah Whole Body Plethysmography (WBP) Data Analysis/Review using URP or URPM module
This article is to help develop your process on analysis WBP data with Ponemah. Also, the following user manual has more information on the use of this analysis module: Ponemah Analysis Module Manual
Recommend setting the graph page up with a black background and the flow trace to a contrasting color within the P3 setup (see image below).
Standard Attributes (Std Attrib)
Please see the following article about the setting the attribute analysis: Ponemah URP Analysis Module Attribute Overview for Whole Body Plethysmography
The following values within the attributes settings with essentially disable the rejection of cycles:
- Setting the baseline shift attribute to a value several times larger than the respiration signal, it will be effectively disabled.
- Setting the Max Variation attribute to 100%
- Setting the Volume Match attribute to 50% or less
Advance Attribute1 (Adv Attrib1)
See the Advance Attribute1 fields appropriately. The maximum BPM (breaths per minute) should be set appropriately for the specie/animal model being used. A low pass filter can be applied and should be set conservatively.
Advance Attribute2 (Adv Attrib2)
See the Advance Attribute2 fields appropriately to the channel that is collecting the data. If no channel is being acquired to measure the temperature, humidity, or barometric pressure, the user should enter an appropriate value for each.
Temperature values should be entered in Kelvins, NOT Celsius!
Turn on Marks to see how Ponemah is placing the various validation marks
Recommend turning on just the Start of Inspiration and Start of Expiration validation marks (Marks Tab in the attribute settings).
Visual Inspection of Data
Scroll through the data using the primary graph page (see section above, Graph Setup). Unlike other analysis modules within Ponemah, the URP or URPM module does not use bad data marks (BDM). Data is automatically rejected based on the 3 criterias listed in the Caution box above.
- Inspiration is displayed as a POSITIVE peak.
- Expiration is displayed as a Negative peak.
Cycles being reported are cycles that have the start of inspiration (positive peak) and start of expiration (negative peak) appropriately placed.
In the figure below, all these cycles are being reported.
The following screenshot shows examples of cycles (#1575) that are marked but do not have both validation marks (also not that the start of inspiration is not appropriately placed) and thus is not being reported. Cycles #1573, #1574, & #1576 ARE being reported.
Inverted Flow Signal
If the flow signal is inverted, the start of inspiration and the start of expiration will be placed in the exact opposite location. When reviewing the signal, look for areas where there is apnea occurring. These long pauses should occuring after the start of expiration, but prior to the start of inspiration; long pauses occuring between the blue and white validation marks.
The following is an example of an inverted flow signal.
If Blood Pressure was acquired during the WBP collection, you can verify if the flow signal is inverted by using the blood pressure signal.
Systolic blood pressure
- Systolic Pressure decreases (↓) during inspiration
- Systolic Pressure Increases (↑) during expiration - the highest systolic value will occur 1/3 to 1/2 way through the expiration time.
Invert Flow Signal in the Attribute Settings
This can be easily fixed, by selecting the inverted flow signal checkbox in the Attribute Settings of the URP/URPM analysis module.
Common Reasons for having an Inverted Flow Signal
- Transducer was not placed in the correct orientation.
If you are using a Buxco transducer with a Buxco Chamber, your signal will NOT be inverted as the system has been designed to prevent this mistake.
- Transducer orientation is correct, but the bias flow has been set to pull mode.
- The tubing is hooked up incorrectly (i.e. inflow and outflow tubing are connected to the wrong port)
You can ensure your signal is displayed within Ponemah correctly, by injecting air into the system via a syringe and ensuring that pushing air into the chamber (representing inhalation) causes a positive deflection, while pushing air back out by pulling air out with a syringe (representing exhalation) causes a negative deflection.
Other Tools to Consider
The following tools within Ponemah can be used to further remove artifacts from being reported or for visual inspections.
- Video Tutorial - Ponemah v5.x Data Cleaning
- Data Insights searches can be created to find anomalies or specific events (e.g. apnea, low respiratory rates, high respiratory rates)
Please sign in to leave a comment.