Sex differences in the effects of the combined exposure to cephalad fluid shift and mild hypercapnia on cerebral autoregulation

JRCT ID: jRCT1030230757

Registered date:29/03/2024

Basic Information

• Recruitment status: Recruiting
• Health condition(s) or Problem(s) studied: Attenuated cerebral autoregulation due to microgravity
• Date of first enrollment: 29/03/2024
• Target sample size: 50
• Study type: Interventional
• Intervention(s): -10 degree head down tilt and 3% carbon dioxide inhalation

Outcome(s)

Primary Outcome

cerebral blood flow velocity in the middle cerebral artery
Index of dynamic cerebral autoregulation : gain, phase, coherence

• Secondary Outcome: heart rate, blood pressure, respiratory rate, end-tidal carbon dioxide concentration, percutaneous saturation of arterial oxygen

Key inclusion & exclusion criteria

• Age minimum: >= 18age old
• Age maximum: <= 35age old
• Gender: Both

Include criteria

1)Persons who are within the age range of 18 to 35 at the time of consent.
2)Persons who have voluntarily consented to participate in this study, after being fully informed and understanding the study.
3)Persons who were determined to be healthy after a medical history and physical examination.
4)Women with menstrual cycles within the normal range (25 to 38 days).
5)Persons who can have a stable brain blood flow velocity waveform displayed by transcranial Doppler sonography in the supine position at rest.

Exclude criteria

1)Persons who have refused to participate in this study.
2Ppersons deemed ineligible by the principal investigator, such as those taller than 180 cm due to the specifications of the adjustable tilt electric bed.
3)Persons with or a history of cardiovascular diseases (including hypertension and arrhythmia), neurological disorders, respiratory diseases, autonomic nervous system dysfunction, severe systemic diseases, or anemia that has not been improved by treatment (as identified through medical history and physical examination).
4)Persons with a history of hypersensitivity to ultrasound transmission gel or other skin reactions (confirmed by medical interview)
5)Women taking oral contraceptives or other hormonal agents, those with irregular menstrual cycles (outside the normal range of 25 to 38 days), and pregnant women
6)Women whose menstrual cycles make it difficult to schedule experiments during the follicular phase

Related Information

• Primary Sponsor: Iwasaki Kenichi
• Source(s) of Monetary Support: Japan Society for the Promotion of Science