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Hypercapnia: Cognitive Effects and Monitoring

Primary Purpose

Hypercapnia, Exercise, Nitrogen Narcosis

Status
Completed
Phase
Not Applicable
Locations
United States
Study Type
Interventional
Intervention
NO exercise at depth
exercise at depth
Sponsored by
Duke University
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional basic science trial for Hypercapnia focused on measuring diving, cognitive impairment, nitrogen narcosis, narcosis, end tidal carbon dioxide, arterial carbon dioxide, immersion

Eligibility Criteria

18 Years - 50 Years (Adult)MaleAccepts Healthy Volunteers

Inclusion Criteria:

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

Exclusion Criteria:

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

Sites / Locations

  • Duke Center for Hyperbaric Medicine and Environmental Physiology

Arms of the Study

Arm 1

Arm 2

Arm 3

Arm 4

Arm Type

Experimental

Experimental

Experimental

Experimental

Arm Label

dive to 122 feet, no exercise

dive to 158 feet, no exercise

dive to 122 feet, exercise

dive to 158 feet, exercise

Arm Description

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

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

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

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

Outcomes

Primary Outcome Measures

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.

Secondary Outcome Measures

How does exhaled (end tidal) carbon dioxide compare with arterial carbon dioxide?
Exhaled (end tidal) carbon dioxide will be compared to arterial carbon dioxide at the various experimental conditions of the study (at the surface versus during the dive, during exercise versus during rest, breathing gas with added carbon dioxide versus breathing gas without added carbon dioxide)

Full Information

First Posted
January 31, 2013
Last Updated
May 24, 2016
Sponsor
Duke University
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1. Study Identification

Unique Protocol Identification Number
NCT01782625
Brief Title
Hypercapnia: Cognitive Effects and Monitoring
Official Title
Hypercapnia: Cognitive Effects and Monitoring
Study Type
Interventional

2. Study Status

Record Verification Date
May 2016
Overall Recruitment Status
Completed
Study Start Date
January 2013 (undefined)
Primary Completion Date
February 2016 (Actual)
Study Completion Date
February 2016 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Sponsor
Name of the Sponsor
Duke University

4. Oversight

Data Monitoring Committee
No

5. Study Description

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: 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). 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).

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Hypercapnia, Exercise, Nitrogen Narcosis, Diving, Immersion
Keywords
diving, cognitive impairment, nitrogen narcosis, narcosis, end tidal carbon dioxide, arterial carbon dioxide, immersion

7. Study Design

Primary Purpose
Basic Science
Study Phase
Not Applicable
Interventional Study Model
Parallel Assignment
Masking
None (Open Label)
Allocation
Randomized
Enrollment
58 (Actual)

8. Arms, Groups, and Interventions

Arm Title
dive to 122 feet, no exercise
Arm Type
Experimental
Arm Description
Subjects will undergo a simulated dive to a maximum depth of 122 feet of seawater with no exercise at depth
Arm Title
dive to 158 feet, no exercise
Arm Type
Experimental
Arm Description
Subjects will undergo a simulated dive to a maximum depth of 154 feet of seawater with no exercise at depth
Arm Title
dive to 122 feet, exercise
Arm Type
Experimental
Arm Description
Subjects will undergo a simulated dive to a maximum depth of 122 feet of seawater with exercise at depth
Arm Title
dive to 158 feet, exercise
Arm Type
Experimental
Arm Description
Subjects will undergo a simulated dive to a maximum depth of 154 feet of seawater with exercise at depth.
Intervention Type
Other
Intervention Name(s)
NO exercise at depth
Intervention Description
Subjects will NOT exercise while at depth
Intervention Type
Other
Intervention Name(s)
exercise at depth
Intervention Description
Subjects will exercise while at depth
Primary Outcome Measure Information:
Title
Is cognitive ability different while resting versus compared to cognitive ability while diving, breathing different gas mixtures and while exercising?
Description
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.
Time Frame
pre-dive to dive to post-dive (approximately 2 hours)
Secondary Outcome Measure Information:
Title
How does exhaled (end tidal) carbon dioxide compare with arterial carbon dioxide?
Description
Exhaled (end tidal) carbon dioxide will be compared to arterial carbon dioxide at the various experimental conditions of the study (at the surface versus during the dive, during exercise versus during rest, breathing gas with added carbon dioxide versus breathing gas without added carbon dioxide)
Time Frame
pre-dive to dive to post dive (approximately 2 hours)

10. Eligibility

Sex
Male
Minimum Age & Unit of Time
18 Years
Maximum Age & Unit of Time
50 Years
Accepts Healthy Volunteers
Accepts Healthy Volunteers
Eligibility Criteria
Inclusion Criteria: healthy, male, age greater than 18, age less than 50 Exclusion Criteria: smoker, asthma, cardiac disease, inability to pedal a bicycle ergometer, inability to perform vigorous exercise
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
John J Freiberger, MD
Organizational Affiliation
Duke University
Official's Role
Principal Investigator
Facility Information:
Facility Name
Duke Center for Hyperbaric Medicine and Environmental Physiology
City
Durham
State/Province
North Carolina
ZIP/Postal Code
27710
Country
United States

12. IPD Sharing Statement

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Hypercapnia: Cognitive Effects and Monitoring

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