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Trial registered on ANZCTR

Registration number

ACTRN12613000850774

Ethics application status

Approved

Date submitted

11/07/2013

Date registered

1/08/2013

Date last updated

5/08/2013

Type of registration

Retrospectively registered

Titles & IDs

Public title

Comparison of normobaric hypoxia and hypoxic hypoxia protocol on human performance and physiology

Scientific title

In young male population, is there difference in physiology, performance and hypoxia symptoms between normobaric hypoxia and hypobaric hypoxia?

Secondary ID [1]

Nil

Universal Trial Number (UTN)

U1111-1145-5064

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

symptoms and physiological changes under hypoxia in healthy young male

Condition category

Condition code

Respiratory

Other respiratory disorders / diseases

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

normobaric hypoxia: subjects in sitting position, exposed to hypoxia by inhaling 7% oxygen through face mask at sea level
hypoxia duration < 5 min (depend on invidual tolerance and SpO2)
Each participant undergo the two sessions on one occasion only. Each sessions are separated by at least 48 hours.

Intervention code [1]

Other interventions

Comparator / control treatment

hypobaric hypoxia: subjects sitting in altitude chamber, exposed to hypoxia by ascending to simulated 25,000 feet environment; total duration of hypoxia exposure in altitude chamber varies in each individual but around 3-5 min (depend on invidivual tolerance and SpO2). All participants undergo this intervention on one occasion only.

Control group

Active

Outcomes

Primary outcome [1]

PaO2 drop below 60% (evaluated by pulse oximeter with sensor attached to subjects' middle finger)

Timepoint [1]

between 3-4 minutes of hypoxia exposure

Primary outcome [2]

unable to hold on to hypoxia exposure (subjective feeling of participants, also judged by inside observer [aerospace physiologist])

Timepoint [2]

3-4 minutes of hypoxia exposure

Primary outcome [3]

heart rate drop > 20 bpm (monitored by polysomograph, with three EKG sensors over chest region)

Timepoint [3]

3-4 minutes after hypoxia exposure

Secondary outcome [1]

severe hypoxia symptoms (observed by aviation physiologist, combined with subjective check list with 17 hypoxia symptom items filled out by participants)

Timepoint [1]

3-4 minutes after hypoxia exposure

Eligibility

Key inclusion criteria

healthy volunteer
able to detect middle cerebral artery blood flow by doppler at temporal region.

Minimum age

20 Years

Maximum age

40 Years

Sex

Males

Can healthy volunteers participate?

Yes

Key exclusion criteria

1. pulmonary disease (asthma, COPD, pneumothorax, pulmonary tuberculosis)
2. claustrophobia
3. heart disease
4. severe anemia

Study design

Purpose of the study

Educational / counselling / training

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Healthy volunteers were recruited from staff and trainees taking aviation physiology course in Aviation Physiology Research Laboratory of Kaoshiung Armed Forces Hospital Gangshan Branch. Inclusion criteria include: male between 20 to 40 years old and successful sonographic detection of blood flow signals in the middle cerebral artery using transcranial Doppler sonography. No female subjects were enrolled in order to minimize gender-related variability.

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Each subject was asked to complete the NH and HH sessions in a randomized order. A list of random numbers was determined using a computer program (Research Randomizer). Numbers were placed in sealed opaque envelopes before the beginning of the study so that randomization was concealed from the recruiter.

Masking / blinding

Blinded (masking used)

Who is / are masked / blinded?

The people assessing the outcomes
The people analysing the results/data

Intervention assignment

Crossover

Other design features

within group study

Phase

Not Applicable

Type of endpoint/s

Safety

Statistical methods / analysis

Data were presented as mean+/-standard deviation. Statistical analysis wereperformed using generalized linear model (GzLM) and generalized equation estimation (GEE). Coreelation analysis was performed with Pearson analysis.
Data analysis was performed using the Statistical Package for the Social Sciences (SPSS; version 19.0, SPSS,USA). Results were considered significant when p<0.05.The sample size was calculated using G*power. With an a of 0.05, power of 0.80, and effect size of 0.5, required number of valid samples was at least 16.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

1/08/2012

Actual

3/08/2012

Date of last participant enrolment

Anticipated

31/10/2012

Actual

25/10/2012

Date of last data collection

Anticipated

Actual

Sample size

Target

Accrual to date

Final

Recruitment outside Australia

Country [1]

Taiwan, Province Of China

State/province [1]

Funding & Sponsors

Funding source category [1]

University

Name [1]

National Defense Medical Center

Address [1]

161 Minchuan East Road, Sec. 6, Taipei 11490, Taiwan, R.O.C.

Country [1]

Taiwan, Province Of China

Primary sponsor type

University

Name

National Defense Medical Center

Address

161 Minchuan East Road, Sec. 6, Taipei 11490, Taiwan, R.O.C.

Country

Taiwan, Province Of China

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Institutional Review Board, Tri-Service General Hospital

Ethics committee address [1]

No.325,Sec.2,Chenggong Rd.,Neihu District,Taipei City 114,Taiwan(R.O.C)

Ethics committee country [1]

Taiwan, Province Of China

Date submitted for ethics approval [1]

21/06/2013

Approval date [1]

30/07/2012

Ethics approval number [1]

2-101-05-080

Summary

Brief summary

When unexpected situations such as oxygen system failure or loss of cabin pressure occur, a pilot may suffer hypoxia. Without early recognition of hypoxia symptoms and prompt corrective measures, in-flight hypoxia could affect cognition and judgment, even jeopardize flight safety. Hypoxia symptoms are determined by inherent tolerance, among other factors.It is believed that “hypoxia signature”, aconstellation of hypoxia symptoms, is unique for each individual. To familiarize with hypoxia symptoms, all military pilots in Taiwan have to undergo hypoxia awareness training by exposing themselves to simulated hypoxia environment in altitude chamber. This hypobaric hypoxia (HH) training protocol has the potential danger of decompression sickness and barotrauma. Alternatively, normobaric hypoxia (NH) training has been developed involving breath low concentration of oxygen at sea level. NH is safer, more economical andtime saving. However, there’s no conclusion as to whether NH protocol can faithfully imitate altitude hypoxia, as represented by HH protocol currently implemented in many countries as the mainstay of hypoxia awareness training. The purpose of this study is to compare the physiological responses, performances and hypoxia symptoms between HH and NH hypoxia awareness training protocol.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Hsin Chu

Address

Institute of Aerospace and Undersea Medicine, School of Medicine, National Defense Medical Center.

No. 161, Section 6, Min-Chuan East Road. Taipei, 114 Taiwan, R.O.C.

Country

Taiwan, Province Of China

Phone

+886-2-87923100

Fax

+886-2-87923176

hrchu@ndmctsgh.edu.tw

Contact person for public queries

Name

Hsin Chu

Address

Institute of Aerospace and Undersea Medicine, School of Medicine, National Defense Medical Center.

No. 161, Section 6, Min-Chuan East Road. Taipei, 114 Taiwan, R.O.C.

Country

Taiwan, Province Of China

Phone

+886-2-87923100

Fax

hrchu@ndmctsgh.edu.tw

Contact person for scientific queries

Name

Hsin Chu

Address

Institute of Aerospace and Undersea Medicine, School of Medicine, National Defense Medical Center.

No. 161, Section 6, Min-Chuan East Road. Taipei, 114 Taiwan, R.O.C.

Country

Taiwan, Province Of China

Phone

+886-2-87923100

Fax

hrchu@ndmctsgh.edu.tw

No information has been provided regarding IPD availability

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.

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