Journal of Applied Physiology, Vol 56, Issue 4 1126-1134, Copyright © 1984 by American Physiological Society
Computer processing of phrenic neurograms
H. J. Bryant and P. H. Abbrecht
Manual processing of large numbers of electrophysiological waveforms is a
tedious process prone to subjective errors in judgment. To eliminate these
problems, we developed computer algorithms and techniques to analyze cat
phrenic neurograms produced in response to step changes in end-tidal PCO2.
The computer analyzed the neurogram in terms of a model waveform, which
consisted of 1) base-line activity made up primarily of noise, 2) an
initial sharp increase from base line, 3) a slower ramplike increase in
activity, 4) a peak value, and 5) a rapid decrease in activity back to base
line. Parameters describing these model elements as well as inspiratory and
expiratory times were calculated by the computer. Computer-produced
parameters were compared with manually calculated parameters from chart
recordings for over 200 individual neurograms. Repeated manual processing
of the neurogram had a variability of +/- 10% in the parameter estimates.
The computer-produced parameters fell within this range more than 89% of
the time. Although the techniques described are directed specifically
toward phrenic neurogram analysis, the methods are general enough to be
useful in computer processing of other types of physiological waveforms.
