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Reliability of the DAMEC Portable Pulmonary Function System (PPFS) (EORS_PPFS_II)
Principal Investigator
Research Area:
Exercise physiology
Network physiology
Technology development
Species Studied
Scientific Name: Homo sapiens Species: Human

The National Aeronautics and Space Administration (NASA) Human Research Program’s Integrated Research Plan specifies that acquisition of data regarding the changes in maximum exercise oxygen consumption (VO2max) during and following space flight is a high priority to support future space exploration endeavors. In order to support such measurements, a metabolic gas analysis system capable of being used in a spacecraft is required. One such device, known as the Pulmonary Function System, was developed for International Space Station (ISS) use and was validated in the Exercise Physiology Laboratory at NASA-Johnson Space Center (JSC). The PFS is currently being used to support studies of resting metabolism and cardiac function on board the ISS, but is not portable and is confined to a relatively immobile rack location. The exercise equipment on board the ISS changed locations since earlier expeditions, and the cycle ergometer used for exercise testing was moved to a different module than the PFS. Thus, the need for a portable metabolic gas analysis device for ISS use arose. The Portable Pulmonary Function System (PPFS) was developed by a contractor to the European Space Agency (ESA) to fill this need. The PPFS is a sized-optimized variant of the PFS which is capable of being used in any location on board the ISS that has available power and data connections.

A NASA sponsored validation study of the PPFS was conducted in 2009 (EORS_PPFS), prior to its delivery to the ISS. The general findings of that study were that the PPFS yielded metabolic gas analysis values fairly comparable to a well-validated clinical system, and where statistically significant differences did occur, they were not large enough to be of clinical relevance. However, the reproducibility of the PPFS remained untested. In addition, the validation findings suggested that expired carbon dioxide (FECO2) when measured with the PPFS may differ from that measured by the clinical reference system. Because the validation study design precluded simultaneous measurements of either expired oxygen (FEO2) or FECO2 from both devices, this finding was speculative.

The purpose of the current study was to examine the reliability and intra-subject repeatability of PPFS obtained metabolic gas analysis and cardiovascular data during exercise tests which contained both steady-state submaximal stages and maximal exertion levels. In addition, a portion of the current study was designed to obtain PPFS and reference system values of FEO2 and FECO2 in a manner which would allow direct comparison of the data.

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Cardiac output
Oxygen consumption

Data Information
Data Availability
Archive is complete. Data sets are not publicly available but can be requested.
Data Sets+ Request data

Cardiac output - Qc
Expired ventilation - VE
Fractions of expired oxygen and carbon dioxide - FEO2
Heart rate - HR
Oxygen uptake - VO2
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
ECP 02/01/2005 12/31/2010 In Progress

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Jessica Keune
Institutional Support
National Aeronautics and Space Administration (NASA)