Hypercapnia: Cognitive Effects and Monitoring

This study is currently recruiting participants. (see Contacts and Locations)
Verified April 2014 by Duke University
Sponsor:
Information provided by (Responsible Party):
Duke University
ClinicalTrials.gov Identifier:
NCT01782625
First received: January 31, 2013
Last updated: April 8, 2014
Last verified: April 2014
  Purpose

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).

Condition Intervention
Hypercapnia
Exercise
Nitrogen Narcosis
Diving
Immersion
Other: NO exercise at depth
Other: exercise at depth

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Hypercapnia: Cognitive Effects and Monitoring

Resource links provided by NLM:


Further study details as provided by Duke University:

Primary Outcome Measures:
  • 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) ] [ Designated as safety issue: No ]
    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? [ Time Frame: pre-dive to dive to post dive (approximately 2 hours) ] [ Designated as safety issue: No ]
    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)


Estimated Enrollment: 50
Study Start Date: January 2013
Estimated Primary Completion Date: March 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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

  Eligibility

Ages Eligible for Study:   18 Years to 50 Years
Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01782625

Locations
United States, North Carolina
Duke Center for Hyperbaric Medicine and Environmental Physiology Recruiting
Durham, North Carolina, United States, 27710
Contact: Mike Natoli, MS    919-684-6726    michael.natoli@dm.duke.edu   
Contact: John Freiberger, MD    919-684-6726    john.freiberger@duke.edu   
Principal Investigator: John J Freiberger, MD, MPH         
Sub-Investigator: Bruce Derrick, MD         
Sponsors and Collaborators
Duke University
Investigators
Principal Investigator: John J Freiberger, MD Duke University
  More Information

No publications provided

Responsible Party: Duke University
ClinicalTrials.gov Identifier: NCT01782625     History of Changes
Other Study ID Numbers: Pro00036937, SPS 181258
Study First Received: January 31, 2013
Last Updated: April 8, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Duke University:
diving
cognitive impairment
nitrogen narcosis
narcosis
end tidal carbon dioxide
arterial carbon dioxide
immersion

Additional relevant MeSH terms:
Hypercapnia
Inert Gas Narcosis
Stupor
Signs and Symptoms, Respiratory
Signs and Symptoms
Occupational Diseases
Gas Poisoning
Poisoning
Substance-Related Disorders
Unconsciousness
Consciousness Disorders
Neurobehavioral Manifestations
Neurologic Manifestations
Nervous System Diseases

ClinicalTrials.gov processed this record on July 24, 2014