Effect of Hyperoxia and Hypergravity on Lung Ventilation and Perfusion

Influence of Hyperoxia and Hypergravity on Pulmonary Ventilation and Perfusion

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.

Study Overview

• Status: Completed
• Conditions: Atelectasis
• Intervention / Treatment: Other: hypergravity; Other: gas mixture

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.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Brétigny-sur-Orge, France, 91 223
    • Armed Forces Biomedical Research Institute
  • Paris, France, 75005
    • Department of Nuclear Medicine, Val-de-Grâce hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 25 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

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 exclusion criteria:

• past medical history of heart or lung disease
• current medical treatment for heart or lung disease
• smoking
• The use of medication for hypertension
• asymmetric values of left/right humeral arterial blood pressure
• significant echocardiographic abnormalities or bad echogenicity
• bad tolerance to +Gz accelerations (G-induced loss of consciousness, motion sickness)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: Single

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: ventilation; hypergravity gas mixture	Other: hypergravity; 1hr sitting rest followed by 10 min of hypergravity (2 centrifuge runs); Other: gas mixture; breathing air, 44.5%O2 or 100%O2

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

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

Other Outcome Measures

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

Collaborators and Investigators

• Sponsor: Direction Centrale du Service de Santé des Armées
• Collaborators: Uppsala University Hospital; Val de Grâce Hospital
• Investigators: Study Chair: Daniel Garin, MD, PhD, Armed Forces Biomedical Research Institute

Study record dates

Study Major Dates

• Study Start: October 1, 2011
• Primary Completion (Actual): July 1, 2012
• Study Completion (Actual): July 1, 2012

Study Registration Dates

• First Submitted: November 14, 2013
• First Submitted That Met QC Criteria: November 20, 2013
• First Posted (Estimate): November 25, 2013

Study Record Updates

• Last Update Posted (Estimate): November 25, 2013
• Last Update Submitted That Met QC Criteria: November 20, 2013
• Last Verified: November 1, 2013

More Information

Terms related to this study

• Keywords: human centrifuge, oxygen, imaging, stroke volume, lung
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Signs and Symptoms, Respiratory; Pulmonary Atelectasis; Hyperoxia
• Other Study ID Numbers: 10co706