An interventional study of Head up tilt (HUT) and Lower body negative pressure (LBNP) in Orthostatic Hypotension, Ischemia and Hypoxia, sponsored by Military Institute of Aviation Medicine. Completed at 1 site in Poland. Open to participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-09.
Sponsored by Military Institute of Aviation Medicine · Not applicable, Interventional, and Basic science
The pilot study aims to evaluate a prototype system that enables military pilots to train under conditions of orthostatic hypotension and ischemic hypoxia. Both of these phenomena are experienced by aircraft crews of mainly highly maneuverable aircraft, and their syndromes include loss of color vision, loss of peripheral vision, blackout and finally G-induced loss of consciousness (G-LOC). A motorized tilt table to generate orthostatic (ORTHO) stress combined with an automatically controlled lower body negative pressure (LBNP) chamber to extort pooling of blood in the lower extremities has been developed in order to obtain new knowledge on counteracting the above-mentioned effects and minimizing the risk of their occurrence. This will help optimize the selection procedures of candidates with the best physiological predispositions to work as military pilots. The system is equipped with modules for monitoring biomedical parameters of a subject, including cerebral oxygenation, which ensures their safety and provides a source of data for performing advanced analyses. The ORTHO-LBNP system has been subjected to comprehensive laboratory tests and after a successful testing is ready for a pilot study involving pilots and/or cadets of the Polish Air Force Academy (PAFA). It is anticipated that new indicators will be proposed to enable an objective assessment of the predispositions to pursue a military pilot career. The prototype system can be easily adaptable to the needs of clinical and sports medicine as well as rehabilitation.
The pilot study consists of two research scenarios, in which two different sequences of the interventions taking the form of the pre-programmed tilt and LBNP profiles are to be investigated.
The pilot study will be carried out in an isolated room in the presence of a physician (physiologist), a paramedic and an ORTHO-LBNP system operator. The paramedic will prepare the subject for the study by placing on his/her body electrodes and measuring sensors that will be removed after completion of the study. The subject will be asked to close his/her eyes during the tests and to place his/her hands on the rest. In order to cause the least disturbance, no conversation will be held with the subject. Only if disturbing symptoms will occur, will the subject immediately report this to the personnel. The physician will systematically be observing the subject's cardiogram, his/her HR, continuous non-invasive arterial pressure (CNAP) wave, and systolic and diastolic blood pressure (SBP and DBP, respectively) in comparison with the changing tilt of the table and negative pressure in the chamber. Any time, at the request of the subject or on the instruction of the physician, the operator will interrupt the tests. The tilt table then will return to the Trendelenburg position if interruption occur during HUT and/or LBNP stimuli, or horizontal position if interruption occur during HDT stimulus. At the same time atmospheric pressure will be resumed in the chamber.
159 studies on the registry are indexed under Hypotension, Orthostatic; 35 are open to participants now.
This study's enrollment of 46 is above the median of 28 across 113 interventional studies indexed under Hypotension, Orthostatic.
Browse Hypotension, Orthostatic studies →Military Institute of Aviation Medicine is the lead sponsor of 3 studies on the registry; none are open to participants now.
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Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
1. 300-s check before the stimuli 2. LBNP is applied stepwise with 11.1 mmHg/15 s decrement to -100 mmHg, and then this value is sustained for 120 s 3. 180-second phase of rest between stimuli 4. 75°-HUT (5°/s) for 120 s after a 15-s reversing of the gravity vector (-30°) 5. 180-second phase of rest between stimuli 6. 75°-HUT (5°/s) accompanied by an exposure to an LBNP of -60 mmHg increased linearly by -4 mmHg/s, and then this value is sustained for 120 s during HUT 7. 120-s check after the stimuli
Other: Head up tilt (HUT) · Other: Lower body negative pressure (LBNP) · Other: Head down tilt (HDT) · Device: Tilt table · Device: LBNP chamber
1. 120-s check before the stimuli 2. 75°-HUT (45°/s) for 60 s after a 3-s reversing of the gravity vector (-30°) 3. 180-second phase of rest between stimuli 4. LBNP decreases linearly by -20 mmHg/s to -100 mmHg, and then this value is sustained for 60 s. 5. 180 second phase of rest between stimuli 6. push-pull, i.e., 3 x 75°-HUT (45°/s) preceded by -30°-HDT (45°/s) and accompanied by an exposure to an LBNP of -60 mmHg decreased linearly by -20 mmHg/s, and then this value is sustained for 30 s during HUT 7. 120-s check after the stimuli
Other: Head up tilt (HUT) · Other: Lower body negative pressure (LBNP) · Other: Head down tilt (HDT) · Device: Tilt table · Device: LBNP chamber
Model of -Gz: HUT up to 75 degrees (maximum)
Model of -Gz: LBNP down to -100 mmHg (maximum)
Model of +Gz: HDT down to -30 degrees (maximum)
Range of tilt angles: -45° to +80°, rate of tilt changes: up to 45°/s
Range of generated underpressure: 0 to -100 mmHg, rate of underpressure changes: up to 20 mmHg/s
HR
Heart rate in beats per minute
Time frame: 24 minutes (scenario I)
IBI
Inter-beat interval in seconds
Time frame: 24 minutes (scenario I)
SBP
Systolic blood pressure in millimeters of mercury
Time frame: 24 minutes (scenario I)
DBP
Diastolic blood pressure in millimeters of mercury
Time frame: 24 minutes (scenario I)
MAP
Mean arterial pressure in millimeters of mercury
Time frame: 24 minutes (scenario I)
SV
Stroke volume in milliliters
Time frame: 24 minutes (scenario I)
CO
Cardiac output in liters per minute
Time frame: 24 minutes (scenario I)
LVET
Left ventricular ejection time in milliseconds
Time frame: 24 minutes (scenario I)
RPP
Rate pressure product in millimeters of mercury
Time frame: 24 minutes (scenario I)
TPR
Total peripheral resistance in medical units
Time frame: 24 minutes (scenario I)
Z0_T
Base transthoracic impedance in ohms
Time frame: 16 minutes (scenario II)
dZ/dt_T
First derivative of transthoracic impedance in ohms per second
Time frame: 16 minutes (scenario II)
Z0_H
Base transcephalic impedance in ohms
Time frame: 16 minutes (scenario II)
dZ/dt_H
First derivative of transcephalic impedance in ohms per second
Time frame: 16 minutes (scenario II)
ΔC_HbO2
Changes in oxygenated hemoglobin in micromolars
Time frame: 16 minutes (scenario II)
ΔC_Hb
Changes in deoxygenated hemoglobin in micromolars
Time frame: 16 minutes (scenario II)
ΔC_tot
Changes in total hemoglobin in micromolars
Time frame: 16 minutes (scenario II)
PDFs hosted by the registry, ClinicalTrials.gov.
Ran from Jan 2017 to primary completion in Feb 2018, 13 months.
Of 34 interventional studies with no phase under Hypotension, Orthostatic, half reached primary completion within 54 months of starting (the median), counting those still running; a quarter within 32 and three quarters within 70. This study's 13 months is below that.
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This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Military Institute of Aviation Medicine