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Evaluation of transit-time and electromagnetic flow measurement in a chronically instrumented nonhuman primate modelThe Physiology Research Branch at Brooks AFB conducts both human and nonhuman primate experiments to determine the effects of microgravity and hypergravity on the cardiovascular system and to identify the particular mechanisms that invoke these responses. Primary investigative efforts in our nonhuman primate model require the determination of total peripheral resistance, systemic arterial compliance, and pressure-volume loop characteristics. These calculations require beat-to-beat measurement of aortic flow. This study evaluated accuracy, linearity, biocompatability, and anatomical features of commercially available electromagnetic (EMF) and transit-time flow measurement techniques. Five rhesus monkeys were instrumented with either EMF (3 subjects) or transit-time (2 subjects) flow sensors encircling the proximal ascending aorta. Cardiac outputs computed from these transducers taken over ranges of 0.5 to 2.0 L/min were compared to values obtained using thermodilution. In vivo experiments demonstrated that the EMF probe produced an average error of 15% (r = .896) and 8.6% average linearity per reading, and the transit-time flow probe produced an average error of 6% (r = .955) and 5.3% average linearity per reading. Postoperative performance and biocompatability of the probes were maintained throughout the study. The transit-time sensors provided the advantages of greater accuracy, smaller size, and lighter weight than the EMF probes. In conclusion, the characteristic features and performance of the transit-time sensors were superior to those of the EMF sensors in this study.
Document ID
20040173101
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Koenig, S. C.
(Armstrong Laboratory Brooks AFB, Texas 78235-5117, United States)
Reister, C. A.
Schaub, J.
Swope, R. D.
Ewert, D.
Fanton, J. W.
Convertino, V. A.
Date Acquired
August 22, 2013
Publication Date
November 1, 1996
Publication Information
Publication: Journal of investigative surgery : the official journal of the Academy of Surgical Research
Volume: 9
Issue: 6
ISSN: 0894-1939
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Cardiopulmonary
NASA Program Space Physiology and Countermeasures
NASA Discipline Number 14-10

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