On a site note: the monitor did show both signals (HR waves and RR sinewave), but it just didn't show the RR value, which means that the signal was measured, right?
Edit: The guy who tried switching the LA/LL switch said the respiration wave flatlined after switching to LA.
The fact that the monitor showed the RR waveform means it was seeing it and should have been showing the rate you are correct in that. This makes me think again that it is because the HR and RR were the same but perhaps some investigation into how HP/Agilent/Philips do their resp measurement is worth a look. Are there tech/user manuals available on-line?
As to the second point, this is to be expected. If you switch from Lead II (RA to LL) to lead I (RA to LA) then you need to tell the monitor to look at the different lead as well. Unlike ECG monitoring where multiple leads are checked simultaneously resp monitoring looks at only a single lead at any one time.
