NCT01782625

Brief Summary

The investigators will simulate the conditions of a working, helmeted diver by using exercising, "head out" immersed subjects to test the following hypotheses:

  1. 1.An algorithm can be developed which predicts cognitive performance in immersed exercising divers, based on the exhaled carbon dioxide (PETCO2) and the diver's inspired partial pressures of oxygen and nitrogen (PIO2 and PIN2).
  2. 2.PETCO2 using mass spectrometry is an accurate estimate of arterial carbon dioxide (PaCO2) at rest and during immersed exercise and can be used as a PaCO2 surrogate at levels exceeding 50 mmHg and depths up to 158 fsw (gas density 6.4 g/l, similar to 165 fsw density of 6.8 g/l).

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
58

participants targeted

Target at P25-P50 for not_applicable

Timeline
Completed

Started Jan 2013

Typical duration for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

January 1, 2013

Completed
1 month until next milestone

First Submitted

Initial submission to the registry

January 31, 2013

Completed
4 days until next milestone

First Posted

Study publicly available on registry

February 4, 2013

Completed
3 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 1, 2016

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

February 1, 2016

Completed
Last Updated

May 25, 2016

Status Verified

May 1, 2016

Enrollment Period

3.1 years

First QC Date

January 31, 2013

Last Update Submit

May 24, 2016

Conditions

HypercapniaExerciseNitrogen NarcosisDivingImmersion

Keywords

divingcognitive impairmentnitrogen narcosisnarcosisend tidal carbon dioxidearterial carbon dioxideimmersion

Outcome Measures

Primary Outcomes (1)

  • Is cognitive ability different while resting versus compared to cognitive ability while diving, breathing different gas mixtures and while exercising?

    Subjects will undergo computerized cognitive testing before, during and after a simulated dive in the Duke Hyperbaric Chamber. Different exercise conditions (rest or exercise) and different breathing gas mixtures (added carbon dioxide or not)will be assessed and compared to the pre-dive conditions.

    pre-dive to dive to post-dive (approximately 2 hours)

Secondary Outcomes (1)

  • How does exhaled (end tidal) carbon dioxide compare with arterial carbon dioxide?

    pre-dive to dive to post dive (approximately 2 hours)

Study Arms (4)

dive to 122 feet, no exercise

EXPERIMENTAL

Subjects will undergo a simulated dive to a maximum depth of 122 feet of seawater with no exercise at depth

Other: NO exercise at depth

dive to 158 feet, no exercise

EXPERIMENTAL

Subjects will undergo a simulated dive to a maximum depth of 154 feet of seawater with no exercise at depth

Other: NO exercise at depth

dive to 122 feet, exercise

EXPERIMENTAL

Subjects will undergo a simulated dive to a maximum depth of 122 feet of seawater with exercise at depth

Other: exercise at depth

dive to 158 feet, exercise

EXPERIMENTAL

Subjects will undergo a simulated dive to a maximum depth of 154 feet of seawater with exercise at depth.

Other: exercise at depth

Interventions

NO exercise at depthOTHER

Subjects will NOT exercise while at depth

dive to 122 feet, no exercisedive to 158 feet, no exercise
exercise at depthOTHER

Subjects will exercise while at depth

dive to 122 feet, exercisedive to 158 feet, exercise

Eligibility Criteria

Age18 Years - 50 Years
Sexmale
Healthy VolunteersYes
Age GroupsAdult (18-64)

You may qualify if:

  • healthy,
  • male,
  • age greater than 18,
  • age less than 50

You may not qualify if:

  • smoker,
  • asthma,
  • cardiac disease,
  • inability to pedal a bicycle ergometer,
  • inability to perform vigorous exercise

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Duke Center for Hyperbaric Medicine and Environmental Physiology

Durham, North Carolina, 27710, United States

Location

MeSH Terms

Conditions

HypercapniaMotor ActivityInert Gas NarcosisCognitive DysfunctionStupor

Condition Hierarchy (Ancestors)

Signs and Symptoms, RespiratorySigns and SymptomsPathological Conditions, Signs and SymptomsBehaviorOccupational DiseasesGas PoisoningPoisoningChemically-Induced DisordersCognition DisordersNeurocognitive DisordersMental DisordersUnconsciousnessConsciousness DisordersNeurobehavioral ManifestationsNeurologic ManifestationsNervous System Diseases

Study Officials

  • John J Freiberger, MD

    Duke University

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
BASIC SCIENCE
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

January 31, 2013

First Posted

February 4, 2013

Study Start

January 1, 2013

Primary Completion

February 1, 2016

Study Completion

February 1, 2016

Last Updated

May 25, 2016

Record last verified: 2016-05

Locations

US(1)