Infusion system delivers incremental volumes from a reservoir with a piston pump at a rate that varies in time and follows the envelope of a preprogrammed curve

Adachi, R. R.

Howard, W. H.

Young, D. R.

English

NASA Technical Reports Server

1972	 B72-10126 
NASA TECH BRIEF 
Ames Research Center
	 -4r 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Programmed Physiological Infusion System 
The problem: 
A device was needed to infuse a substance into 
an animal's body at a preprogrammed rate. Such 
tailored inputs are necessary for reproducing or 
simulating natural time-varying inputs, the pulsating 
nature of many animal processes, and random dy-
namic inputs. Analysis of the frequency, phase, and 
amplitude characteristics of the responding system 
provides insights as to the ways in which body sys-
tems are capable of responding to dynamic chemical 
inputs. 
The solution: 
A rate-programmed infusion system capable of 
delivering incremental volumes from a reservoir with 
a piston pump at a rate that varies in time and 
follows the envelope of a preprogrammed curve. 
How it's done: 
The system consists of a printed paper tape, a 
photoelectric tape reader, a signal conditioner, and 
a solenoid-operated piston pump. The programmed 
curve is represented as marks printed on a contin-
uous-loop paper tape prepared by a computer and 
a suitable program; a pulse-modulated signal is pro-
duced when the tape is run at constant speed through 
a photoelectric reader. As the marks are sensed by 
the tape reader, the resulting pulsed signals are used 
to activate the pump and thereby force a small 
volume of solution into the vein of the animal under 
examination. The marks on the paper tape are sep-
arated by distances which are determined by the 
shape of the desired programmed curve; at any given 
interval of time, the sum of the incremental volumes
infused is represented by the area under the pro-
grammed curve up to that time. A signal conditioner 
operating on the output of the photoelectric tape 
reader has been found useful to provide additional 
latitude in system performance and for selection of 
the total volume and concentration of the infusion 
solution; for example, the signal conditioner gen-
erates one to ten pulses (depending on its setting) 
for each mark appearing on the paper tape. 
By means of this system, the volume of infusions 
can be made to be sinvidal in time. To obtain the 
tape for this curve, the computer is programmed to 
find the total area under the curve for one cycle; 
the trapezoidal method is used to integrate the func-
tion 1 + cosX between 180° and 540°. Since the 
total number of marks on the tape is determined by 
the volume of solution and its concentration, a deci-
sion must be made regarding these factors. For con-
venience, the total area is divided by 100 and the 
centers of the 100 equal areas are located along the 
abscissa. Then, a representation of the relative posi-
tions of the centers is printed out at the computer 
terminal, using a dash to mark the centers and a line 
feed to provide relative distances; the result is a 
series of printed dashes of varying distances in modu-
lation with the original curve. 
The printout is removed from the terminal, trimmed 
to about a 5-cm width, and the ends are fastened 
to form a continuous loop. The loop is loaded onto 
a photoelectric tape reader with a capstan drive and 
moved under a metal mask with a slit that lines up 
with the path of the dashes. The speed of the tape 
is controlled by the variable-speed motor that drives 
the capstan. As the tape is run at constant speed, 
(continued overleaf) 
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the photocell senses the appearance of a dash in the 
slit and actuates the signal conditioner. Depending 
on its setting, the signal conditioner will generate 
one to ten pulses of appropriate voltage, current, and 
duration to operate the piston pump. 
Note: 
Requests for further information may be di-
rected to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: TSP72- 10126
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to: 
Patent Counsel 
Mail Code 200-1A 
Ames Research Center 
Moffett Field, California 94035 
Source: Wayne H. Howard, Donald R. Young, and
Richard R. Adachi 
Ames Research Center 
(ARC-10447) 
B72.10126	 Category 05


Programmed physiological infusion system

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