REAL-TIME, TIME-SHARING COMPUTERS 
IN THE ANIMAL LABORATORY 
W. S. Topham* 
The classical approach to analyzing physiological 
data obtained from animal experiments has been to re- 
cord the analog waveforms on an oscillographic recorder. 
This direct observation coupled with tedious man- 
ual measurement have given insight into physiological 
phenomena. The use of digital computers has allowed 
the reduction of data to be performed more efficiently 
as well as providing a convenient storage medium from 
which the data easily can be retrieved and analyzed at a 
future date. Early in the establishment of the Utah 
Biomedical Test Laboratory in Salt Lake City, and 
after a study of data acquisition was conducted, a 
sixteen-bit general purpose computer was chosen to 
serve as the heart of the data acquisition system. The 
advantages of using the computer (i.e., automatic data 
collection and reduction; immediate display of calcu- 
lated values; storage of calculated data for easy re- 
trieval, future analysis and automatic report genera- 
tion) were used as guides in developing the data system. 
Several users time-share the computer in real-time 
and the main control of high priority foreground is 
through remote terminals. A program is loaded into 
memory and a message is displayed indicating the op- 
tions and operation of the program. The desired option 
is selected. This concept makes many programs availa- 
ble for on-line analysis to users in the operating rooms, 
intensive care area, and catheterization laboratory. 
Some of the "user" programs which have been written 
and are currently under final test provide for analysis 
of indicator dilution curves, measurement of oxygen 
saturation, evaluation of any physiological pressure and 
analysis of any physiological flow. A data review pro- 
gram allows a user to review at any time any data that 
has been collected on a given animal. An automatic 
monitor is being written which will sample up to eight 
channels of data from any animal every fifteen minutes. 
This program is controlled by a remote terminal located 
in the monitor mezzanine where there is visual and 
audio contact with all operating rooms and the animal 
intensive care area. If the computer detects an alarm 
condition, an indicator alerts the terminal operator, 
and the necessary corrective action can be taken. 
INTRODUCTION 
Physiological data have been analyzed classi- 
cally by the the use of analog recording devices. 
* Director of Biophysical Services, Utah Biomedical Test Labora- 
tory, Salt Lake City, Utah. 
From the use of a smoked drum to the present 
sophisticated multi-channel pressurized ink sys- 
tems and optical systems, the analog physiologi- 
cal waveform has provided assistance in the un- 
derstanding of the complex functioning of the 
living organism. These methods are important 
and some v^ill continue to be used, but they have 
limitations. While they provide observations of 
trends, variation in maximums and minimums, 
vi^aveform variation and timing relationships, it 
is difficult to obtain areas under curves, extract 
mean values, and obtain mathematical relation- 
ships of the variables. Part of this problem has 
been solved by the use of the analog computer 
or special electronic preprocessing devices 
which generally use the heart of the analog 
computer, the operational amplifier. 
Calculations have been done using the analog 
computer in the real-time mode, ^-^ but the re- 
sults must still be stored using an oscillographic 
recorder. To compare the data obtained at var- 
ious times during the experiment, a rather tedi- 
ous search through rolls of oscillographic data 
need be undertaken, and to arrange the data 
with statistical significance requires laborious 
hand digitization. These techniques cause sig- 
nificant delays in obtaining the desired infor- 
mation. However, if the analog signals are 
directed into an A-D converter of a digital com- 
puter, the calculated values are obtained, 
stored, and are easily retrievable. With the com- 
puter operating on-line, the calculated values 
are immediately available to the researcher; 
and during the experimental run, the results 
are displayed. This provides a feedback which 
keeps the researcher continuously informed 
with analyzed data while the experiment is in 
progress and often assists in guiding the direc- 
tion of the experiment so that more significant 
data may be obtained. 
The digital computer can be used to automati- 
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