Effect of Hyperoxia and Hypergravity on Lung Ventilation and Perfusion

Influence of Hyperoxia and Hypergravity on Pulmonary Ventilation and Perfusion

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT01993394

Enrollment

Registered

2013-11-25

Start date

2011-10-31

Completion date

2012-07-31

Last updated

2013-11-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Atelectasis

Keywords

human centrifuge, oxygen, imaging, stroke volume, lung

Brief summary

The primary aim of this project is to get further knowledge on the effects of + Gz accelerations and hyperoxia on lung ventilation in humans. The secondary aim is to study lung perfusion and cardiovascular function in these conditions.

Detailed description

Experiments were conducted in a human centrifuge. The protocol aimed at mimicking a routine peacetime flight in combat aircraft, and included 10-min exposure to +1.4 - +3.5 Gz. Subjects were exposed three times to this sequence, breathing air, 44.5% O2 or 100% O2. Ten volunteers wearing anti-G trousers participated in the study. The Ethics Committee Ile-de-France III and the French National Agency for Drug Safety (ANSM) approved the protocol (number 2009-A01092-55). Three different imaging techniques, electrical impedance tomography (EIT), pulmonary ultrasound and chest SPECT/CT were used and compared. EIT enabled ventilation monitoring in the human centrifuge, whereas pulmonary ultrasound and SPECT/CT gave functional and topographical information before and after exposure to +Gz accelerations. EIT analysis focused on regional ventilation, SPECT on global lung ventilation and perfusion, CT on the presence of atelectasis, and pulmonary ultrasound analysis looked for comet tails in 64 chest areas. Arterial blood pressure was recorded continuously by finger photoplethysmography. Cardiac output and stroke volume were computed from these recordings, using three different algorithms. Echocardiography was used as reference non-invasive technique for stroke volume determination and performed before and after exposure to +Gz accelerations.

Interventions

OTHERhypergravity

1hr sitting rest followed by 10 min of hypergravity (2 centrifuge runs)

OTHERgas mixture

breathing air, 44.5%O2 or 100%O2

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

BASIC_SCIENCE

Masking

SINGLE (Outcomes Assessor)

Eligibility

Sex/Gender

MALE

Age

25 Years to 45 Years

Healthy volunteers

Yes

Inclusion criteria

* normal lung function checked by pulmonary function tests Part 1

Exclusion criteria

* past medical history of heart or lung disease * current medical treatment for heart or lung disease * smoking * bad tolerance to +Gz accelerations (G-induced loss of consciousness, motion sickness) Part 2

Design outcomes

Primary

Measure	Time frame	Description
change in regional ventilation distribution	baseline, 2hrs 30min	per lobe and per quadrant at 5th intercostal space level

Secondary

Measure	Time frame	Description
change in regional pulmonary perfusion	baseline, 2hrs 30min	per lobe and per quadrant at 5th intercostal space level
cardiac output (L/min)	2hrs	echocardiography (sub-aortic diameter), photoplethysmography (Liljestrand, systolic area and Windkessel algorithms)

Other

Measure	Time frame	Description
tidal volume	2hrs 30min	global (mL, area under the flow versus time curve) and regional (% change per quadrant at 5th intercostal space level)

Countries

France

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026