You may notice that, on average, some channels on your BP-2000 Blood Pressure Analysis System gives higher or lower blood pressure values than other channels.
Systematic channel-to-channel variations in the measured BP values are caused by differences in the cuff elastic itself, and how it is installed. Everything else – including the software, electronics, and the pressurization system – are identical for all channels.
Thus, the following issues may adversely affect the measured BP values:
How the cuff elastic is installed. If the cuff elastic is installed differently on different channels, then some channels may show incorrectly high or low blood pressure. For example, if a channel is giving higher BP values, it is probably because the elastic is stretched more tightly on that cuff.
Old cuff elastic. Old cuff elastic tends to lose its elasticity. This can result in incorrectly low BP values. Generally cuff elastic more than nine months old should be discarded and replaced. (Also, we recommend keeping cuff elastic in a sealed package and in a dark place.)
Cuff elastic obtained from unreliable sources. If you get your cuff elastic from a store, it may not have consistent thickness. We have some that some brands of balloons sold in toy stores may have a wide variation in thickness from package to package, or even within a package. To avoid this problem, you should obtain cuff elastic only from Visitech Systems.
Note that even if you follow all these recommendations, there may be still be small channel-to-channel variations, as it is impossible to install the cuff elastic completely consistently. To help with this, we recommend systematically rotating the animals through all channels. For example, if mouse 101 is in channel 1 on Monday, it should be in channel 2 on Tuesday, channel 3 on Wednesday, etc. This takes additional planning, but the result is that the channel-to-channel variations tend to average out, giving better results.
To help you resolve these issues, the following documents are available on our website, or possibly on the Help menu of your BP-2000 Analysis Software:
How to Install BP-2000 Cuff Elastic
BP-2000 Protocol Recommendations