Acceleration Atelectasis G-induced airway collapse
Conditions
Interventions
Equipment: 
+Gz will be simulated using a human centrifuge. In this centrifuge an participant sits in a gondola at the end of a long arm. G forces generated when the gondola starts to spin. The speed of Gz increa
During the runs the participants will wear MK10 Skeletal Anti-G Suit (Survitec Group Limited, Ellesmere Port, United Kingdom). The Anti-G Suit delivers pressure to the abdomen, thighs and legs in dire
Central and peripheral lung function, including small airway function, will be measured using the TremoFlo ® c-100 18 (THORASYS Thoracic Medical Systems Inc, Montreal, Canada), using airwave oscillome
Procedure: 
The intervention will take place on three separate test days for each participant. Each test condition will be performed on a separate day, not on consecutive days. Days or weeks can separate the test
Sponsors
Koninklijke Luchtmacht, Centrum voor Mens en Luchtvaart
Eligibility
Age
18 Years to 64 Years
Inclusion criteria
Inclusion criteria: - Participants must be part of military personnel (either active military or reservist). - Aged between 18 and 55 years old.
Exclusion criteria
Exclusion criteria: - Presence of any chronical respiratory illness. - Current or recent (past 2 weeks) respiratory illness, e.g. a cold. - Unfit assessment following flight medical examination.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The primary outcome measure of this study will be the change in airway compliance (xrs) before compared to directly after +5Gz exposure, and 30 minutes after exposure, when breathing ambient air (21% oxygen) and oxygen enriched air (60% oxygen) with and without the breathing component of the AGSM. Measuring airway compliance before +Gz exposure will serve as baseline measurement. The specific outcome measure provided by the tremoFlo IOS, that fits this primary parameter best is: Reactance Area (AX), a derived parameter representing the total energy loss due to airway distensibility or compliance, as reflected by the echo or rebound of oscillatory air waves. | — |
Secondary
| Measure | Time frame |
|---|---|
| Secondary outcome measures will provide a comprehensive assessment of changes in respiratory function in response to +Gz exposure, facilitating a detailed analysis of both central and peripheral airway mechanics under varying conditions of oxygen concentration. These include: • Total airway resistance measured at a low-frequency oscillation of 5 Hz (R5), which reflects resistance across both central and peripheral airways. • Central airway resistance, determined at higher frequencies of 19 Hz and 20 Hz (R19, R20), which isolates the resistance primarily in the larger, more central airways. • Peripheral airway resistance, calculated by subtracting central airway resistance from total airway resistance (R5-R19, R5-R20), representing the resistance in smaller, more distal airways. • Reactance at 5 Hz (X5), which captures the elastic properties of the airways and lungs, indicating how easily airways return to their resting state following inhalation. • Tidal volume (VT), the volume of air inhaled and exhaled with each breath during normal breathing, providing an indicator of lung ventilation efficiency. Other study parameters (if applicable) Through asking by a researcher the additionally data is collected on the following factors: • Subjective ratings of perceived breathing difficulty during and after +Gz exposure expressed in the following categories: no difficulty, mild, moderate and severe. • Incidence of acceleration atelectasis symptoms (e.g., couching and chest pain). • Visual symptoms (either tunnel vision or grey-out) during +Gz exposure. | — |
Countries
Netherlands
Contacts
Public ContactSJWM Cornelissen
Koninklijke Luchtmacht, Centrum voor Mens en Luchtvaart
Outcome results
None listed