Changes in retinal vessel width (veins and arteries) under different gravity conditions
Conditions
Interventions
Group 1: Two runs on the SAHC with head in the direction of the axis of rotation (head inwards), 9 different steps with +Gz:
-0.2 / 0.4 / 0.6 / 0.8 / 1.0 / 1.2 / 1.4 / 1.6 / 1.8 +Gz at eye level, prov
digital vessel analyser measurement (Fig. 5), transcranial Doppler
2nd run: head inwards
intraocular pressure measurement, ultrasound of the carotid/jugular vein, medical monitoring (ECG, blood pressure, Sp02)
Group 2: Two runs on the SAHC with head against the axis of rotation (head outw
digital vascular analyser measurement (Fig. 5), transcranial Doppler, thoracic impedance, medical monitoring (ECG, blood pressure, Sp02)
2nd run: head outwards
intraocular pressure measurement, ultrasound of the carotid/jugular vein, medical monitoring (ECG, blood pressure, Sp02)
Group 3: Recording of the vascular control variables during head-facing acceler
Sponsors
Deutsches Zentrum für Luft- und Raumfahrt - Institut für Luft- und Raumfahrtmedizin
Eligibility
Sex/Gender
All
Age
18 Years to 50 Years
Inclusion criteria
Inclusion criteria: ? Male and female healthy subjects aged between 18 and 50 years and a height of 170-200 cm ? BMI < 30 ? Subjects who are willing and able to participate in the entire study ? Successful completion of the inclusion examination or presentation of a valid SAHC medical ? Present, signed declaration of consent before the start of the first study- related examination
Exclusion criteria
Exclusion criteria: ? All other chronic (infectious) diseases (e.g. anemia, renal insufficiency, chronic obstructive pulmonary disease, asthma, diabetes, rheumatism, HIV, hepatitis, varicosis, hypertension > 140 mmHg systolic or > 90 mmHg diastolic**, etc.)*, ** ? Acute (or chronic) disc damage (protrusion / prolapse) with neurological symptoms and/or pain symptoms ? Neurological/psychiatric diseases (e.g. stroke, epilepsy, depression) ? Cardiac diseases requiring treatment (e.g. myocardial infarction, coronary heart disease, stents in place (time of implantation -6 dpt ? Laser eye surgery ? Acute injuries to the musculoskeletal system ? Abusive substance use (alcohol, other drugs) ? Current or past tendency to bleed or coagulation disorder coagulation disorder ? Exclusion criteria resulting from the medical inclusion examination exclusion criteria (e.g. indications of an existing heart heart disease in the ergometry or in the case of previously unknown narrow-angle glaucoma) ? Known allergic reactions to atropine derivatives * except for chronic, stable thyroid diseases (e.g. hypothyroidism) with normal TSH, which are supplemented with L-thyroxine ** Brunström, M., et al. "2023 ESH Guidelines for the management of arterial hypertension The Task Force for the management of arterial hypertension of the European Society of Hypertension. Endorsed by the International Society of Hypertension (ISH) and the European Renal Association (ERA)." J Hypertension 41 (2023). ***Baumgartner, Helmut, et al. "2017 ESC/EACTS Guidelines for the management of valvular heart disease." European heart journal 38.36 (2017): 2739-2786.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The primary endpoint of the study is the measurement of venous retinal vessel width under +Gz and -Gz conditions on a human centrifuge using a Digital Vessel Analyzer. Based on previous parabolic flight experiments, we expect deviations of more than 13 µm from the normal values of 148 µm +/- 10 µm. | — |
Secondary
| Measure | Time frame |
|---|---|
| - Measurement of the arterial retinal vessel width (DVA) and intraocular pressure using a tonometer. - Measurement of the venous volume load using ultrasound examination of the jugular vein. - Measurement of serological inflammatory parameters associated with retinal venous regulation. - Cerebral blood flow velocity (CBFV) of the right middle cerebral artery (MCA) by transcranial ultrasound. - Assessment of macrocirculation and fluid shifts using thoracic impedance, finger blood pressure sensor and ECG systems. | — |
Countries
Germany
Contacts
Public ContactTimo Frett
DLR Institut für Luft- und Raumfahrtmedizin, DLR Institut für Luft- und Raumfahrtmedizin, Abteilung Muskel- und Knochenstoffwechsel
Outcome results
None listed