Hypercapnia: Cognitive Effects and Monitoring

May 24, 2016 updated by: Duke University

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

  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. 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).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

58

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • North Carolina
      • Durham, North Carolina, United States, 27710
        • Duke Center for Hyperbaric Medicine and Environmental Physiology

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 50 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Male

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: BASIC_SCIENCE
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: NONE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
EXPERIMENTAL: dive to 122 feet, no exercise
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
Subjects will NOT exercise while at depth
EXPERIMENTAL: dive to 158 feet, no exercise
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
Subjects will NOT exercise while at depth
EXPERIMENTAL: dive to 122 feet, exercise
Subjects will undergo a simulated dive to a maximum depth of 122 feet of seawater with exercise at depth
Other: exercise at depth
Subjects will exercise while at depth
EXPERIMENTAL: dive to 158 feet, exercise
Subjects will undergo a simulated dive to a maximum depth of 154 feet of seawater with exercise at depth.
Other: exercise at depth
Subjects will exercise while at depth

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Is cognitive ability different while resting versus compared to cognitive ability while diving, breathing different gas mixtures and while exercising?
Time Frame: pre-dive to dive to post-dive (approximately 2 hours)
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 Outcome Measures

Outcome Measure
Measure Description
Time Frame
How does exhaled (end tidal) carbon dioxide compare with arterial carbon dioxide?
Time Frame: pre-dive to dive to post dive (approximately 2 hours)
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)
pre-dive to dive to post dive (approximately 2 hours)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Duke University

Investigators

  • Principal Investigator: John J Freiberger, MD, Duke University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

January 1, 2013

Primary Completion (ACTUAL)

February 1, 2016

Study Completion (ACTUAL)

February 1, 2016

Study Registration Dates

First Submitted

January 31, 2013

First Submitted That Met QC Criteria

February 1, 2013

First Posted (ESTIMATE)

February 4, 2013

Study Record Updates

Last Update Posted (ESTIMATE)

May 25, 2016

Last Update Submitted That Met QC Criteria

May 24, 2016

Last Verified

May 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Pro00036937
  • SPS 181258 (REGISTRY: Sponsored Programs)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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