Beat-to-beat agreement of noninvasive tonometric and intra-radial arterial blood pressure during microgravity and hypergravity generated by parabolic flights

Abstract

Background: Accurate measurement of beat-to-beat arterial blood pressure is essential for understanding the cardiovascular adaptation to weightlessness; however, the intra-arterial standard of beat-to-beat blood pressure measurement has never been used during space flight because of its invasive nature.

Objectives: The aim of the present study was to compare noninvasive radial artery tonometry blood pressure measurement with intra-radial pressure measurement during microgravity and hypergravity generated by parabolic flights.

Methods: Two study participants, equipped with an intra-radial pressure line on the left arm and a Colin CBM-7000 (Colin Corp., Komaki City, Japan) beat-to-beat pressure measurement apparatus on the right arm, were studied in a supine position, during parabolic flights on board of the Airbus A300 OG of the Centre National d'Etudes Spatiales. The mean and standard deviations of the beat-to-beat difference between tonometric and intra-radial blood pressure were calculated for systolic and diastolic arterial pressure in the three gravity conditions (1g, 0 g and 1.8 g) experienced during parabolic flight.

Results: The Colin CBM-7000 met the specifications required by the Association for the Advancement of Medical Instrumentation in the 0 g environment. Gravity, however, significantly affected the difference between tonometric and intra-arterial blood pressure, possibly owing to the effect of gravity on the apparent weight of the device and the corresponding calibration factor.

Conclusion: We conclude that the Colin CBM-7000 can be used with confidence during space flight.