Two flexible pipes, attached to face mask, are connected to spirometers in mobile cart. Inhaled air volume is measured as it is drawn from one spirometer, and exhaled air volume is measured as it is breathed into second spirometer. Sensor is used to monitor heartbeat rate

Bynum, B. G.

Currie, J. R.

English

NASA Technical Reports Server

May 1975	 875-10077 
•	 NASA TECH BRIEF 
Marshall Space Flight Center 
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. 
Mobile Automatic Metabolic Analyzer 
He: 
Ra 
•	 I Cassette 
Recorder I Intake	 - 
Sample 1 I 
The problem: 
One of the goals in the design and fitting of 
prosthetics is to minimize the amount of energy that 
must be expended to use them. Energy consumption 
is normally measured while the device is being worn 
by a patient walking on a treadmill. In the case of 
above-the-knee amputees, however, treadmill exercise 
does not allow the forward motion necessary to 
operate the prosthetic. 
Gas Analyzer 
Measures: 
% CO2 
% N2 
% 02 
% H2O 
-	 Exhaust 
III}
Sample
The solution: 
By adapting technology developed for NASA's 
Apollo program, a mobile automatic metabolic 
analyzer (MAMA) has been developed to measure and 
analyze breathed gases. The analyzer is housed in a 
mobile cart that overcomes the treadmill problem by 
automatically moving alongside a walking patient. 
Air Intake 
[inhalation S pi rometer L	 J	 I 
Conditioning i 
Electronics I 
Exhalation Spirometer 
Exhaust 
rt
L=_Jj 
.
Heartbeat-Rate
Sensor 
Analysis System for MAMA
(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights. 
Face 
Mask
https://ntrs.nasa.gov/search.jsp?R=19750000077 2020-03-19T20:04:07+00:00Z
S How it's done: 
The patient wears a face mask attached to two 
flexible pipes that are connected to spirometers in the 
cart. Inhaled air volume is measured as it is drawn 
from one spirometer, and exhaled air volume is 
measured as it is breathed into the second spirometer. 
A sensor, worn on the ear and connected to the cart, is 
used to monitor the patient's heartbeat rate. The 
medical equipment in the analyzer is shown in the 
illustration. 
The heartbeat rate and the volumes of inhaled and 
exhaled air are each recorded on a tape as a function 
of time. Inhaled air is analyzed once prior to an 
experiment, and exhaled air is analyzed after each 
breath. These results are also stored on the tape.
(These data are later fed into a computer to determine 
the metabolic rate.) The analyzer also includes a 
handswitch on an extension cord, for use by the 
physician to mark events of interest on the tape, and 
to stop the cart. 
The cart is powered by three battery-operated 
electric motors. It may be operated manually or 
automatically. In the automatic mode, the system 
optically senses a guidance tape laid out on the floor. 
The transistorized, automatic, speed and acceleration 
controls include safety features to accommodate 
possible patient problems. Some specifications of the 
mobile automatic metabolic analyzer are shown in the 
following table. 
Acceleration 1 to 3 ft/s2	 (0.3 to 0.9 m/0 
Speed (Level Ground) 0 to 5.5 mi/h ±1% (0 to 2.5 m/s) 
Speed (10% Slope) 0 to 4 mi/h ±3% (0 to 1.8 m/s) 
Braking (Normal Stop) 4 ft/s 2 (0.9 m/0 
Braking (Emergency Stop) 5 ft/s2 0.5 m/0 
Turning Radius 3.8 ft (1.16 m) 
Operating Time 3 to 5 h
Specifications for Mobile Automatic Metabolic Analyzer 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Marshall Space Flight Center 
Code ATO1 
Marshall Space Flight Center, Alabama 35812 
Reference: B75-10077 
Patent status: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
Patent Counsel 
Marshall Space Flight Center 
Code CCO1 
Marshall Space Flight Center, Alabama 35812 
Source: B. G. Bynum and J. R. Currie 
• Marshall Space Flight Center 
(MFS-23143)
. 
. 
B75-10077	 Category: 05 (Life Sciences) 


Mobile automatic metabolic analyzer

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