Simultaneous Determination of Blood Pressure by Oscillometry and Photoplethysmography Compared to the Standard Inert Gas Rebreathing Technique

Simultaneous Determination of Blood Pressure by Oscillometry and Photoplethysmography Compared to the Standard Inert Gas Rebreathing Technique

Main objective of the experiment is threefold: 1) to technically test a device for central blood pressure estimation for its applicability in a spaceflight-related environment and on the International Space Station. 2) Furthermore the objective is to compare central blood pressure estimates based on arterial pressure readings of different peripheral arteries. For central blood pressure estimation mathematical transfer functions as described by Karamanoglu and colleagues (11) will be used. 3) Finally the experiments' objective is to simultaneously apply phonocardiography together with ECG and carotid plethysmography to determine cardiac systolic time intervals in parabolic flight during gravity transitions.

Secondary objective of the experiment is to simultaneously measure key variables of the central circulation during gravity transitions to expand the understanding of cardiovascular regulation in weightlessness. Furthermore spirometric measurements shall be performed during a parabolic flight day to observe changes in end-expiratory CO2. Arterial CO2 content is central for cardiovascular regulation.

Our main hypothesis is that there is no difference between different methods of central arteria pressure determination.

Concerning our secondary objective, this experiment is designed as an observational study. Thus no clear hypothesis was generated but the measured cardiovascular and respiratory variables will be analysed regarding differences correlated to gravity.

Inclusion Criteria:

• Healthy volunteers (men or women)
• Aged from 18 to 65
• Affiliated to a Social Security system and, for non-French resident, holding a European Health Insurance Card (EHIC)
• Who accepted to take part in the study
• Who have given their written stated consent
• Who has passed a medical examination similar to a standard aviation medical examination for private pilot aptitude (JAR FCL3 Class 2 medical examination). There will be no additional test performed for subject selection.

Subjects will be staff member of the team or of other teams participating in the parabolic flight campaign

Exclusion Criteria:

• Person who took part in a previous biomedical research protocol, of which exclusion period is not terminated
• Treated or non-treated arterial hypertension
• Pregnant women