Clinical Trial: Effect of Hyperoxia and Hypergravity on Lung Ventilation and Perfusion

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Influence of Hyperoxia and Hypergravity on Pulmonary Ventilation and Perfusion

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 Summary:

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.


Sponsor: Direction Centrale du Service de Santé des Armées

Current Primary Outcome: change in regional ventilation distribution [ Time Frame: baseline, 2hrs 30min ]

"per lobe and per quadrant at 5th intercostal space level"


Original Primary Outcome: Same as current

Current Secondary Outcome:

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


Original Secondary Outcome: Same as current

Information By: Direction Centrale du Service de Santé des Armées

Dates:
Date Received: November 14, 2013
Date Started: October 2011
Date Completion:
Last Updated: November 20, 2013
Last Verified: November 2013