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Effectiveness of Heat Donation Through the Head or Torso on Mild Hypothermic Rewarming

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT01603511
First Posted: May 23, 2012
Last Update Posted: April 8, 2013
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by (Responsible Party):
Dr.Gordon Giesbrecht, University of Manitoba
  Purpose
The study will compare the rewarming effectiveness of heat donation through the head or the torso during rewarming of mildly hypothermic subjects. Warming will be accomplished through either forced-air warming or using a charcoal heater; both units are commonly used for warming. The investigators hypothesize that head warming will be as, or more, effective compared to

Condition Intervention
Rewarming by Shivering Heat Production Only Rewarming by External Heat to the Torso Rewarming by External Heat to the Head Device: Rewarming modality

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Effectiveness of Heat Donation Through the Head or Torso on Mild Hypothermic Rewarming

Resource links provided by NLM:


Further study details as provided by Dr.Gordon Giesbrecht, University of Manitoba:

Primary Outcome Measures:
  • Rate of body core rewarming [ Time Frame: 60 minutes ]
    Esophageal temperature will be used to determine the rate of core temperature rewarming during 60 minutes of rewarming via either shivering only, or external heat donated to the torso or the head.


Enrollment: 7
Study Start Date: June 2012
Study Completion Date: December 2012
Primary Completion Date: December 2012 (Final data collection date for primary outcome measure)
Intervention Details:
    Device: Rewarming modality
    A commercial charcoal heater will be applied to the torso or the head in two of the trials. The control trial involves shivering only.
    Other Names:
    • Charcoal heater
    • STK Heatpac
Detailed Description:

Dr. Gordon Giesbrecht is studying/comparing the effectiveness of heat donation through the head or the torso in rewarming a mildly hypothermic individual. A rigid forced-air warming cover for the head or the torso will be used to rewarm the hypothermic individuals.

Subjects will be asked to participate in three experimental trials, separated by at least 48 hours. Each trial will last about 4 hours (1 hour for setup, 1 hour for cooling, and 2 hours for rewarming and removal of instrumentation).

On each of the three trials, subjects will undergo immersion to the level of the sternal notch in a tank of 8˚C water for up to 60 minutes. They will then exit the water, be dried off and lie in a hooded sleeping bag with the head inside the hood where one of the three warming procedures will be administered for 60 minutes or until core temperature returns to normal values ( ̴ 36.5-37˚C).

A. Spontaneous rewarming (Shivering Only) - In this control condition, no external heat will be provided and you will rewarm spontaneously with the heat produced from shivering.

B. Head Warming (Head): Either of these rewarming methods will be used:

  • Forced-Air Warming to the Head (FAW-H) - A modified rigid forced-air warming cover will be placed over your head. Warm air ( ̴43˚C) will blow into the cover through an inlet on top of the cover and will escape from the bottom of the cover. You will be breathing warm air (̴ 43˚C).
  • Charcoal Heater to the Head (CH-H) - A charcoal heater will be placed on right side of your face/head with ducts wrapping around the dorsum of the head, anteriorly over the forehead, nose, chin and the neck, not covering the eyes or the mouth. You will be breathing ambient air (̴ 22˚C).

C. Torso Warming - Either of these rewarming methods will be used:

  • Forced-Air Warming to the Torso (FAW-T) - A specially designed portable rigid forced-air cover (PORIFAC) will be placed over your torso and the upper thighs. Warm air (̴ 43˚C) will blow into the cover through an inlet above the abdomen and will escape from the bottom of the cover. Participant will be breathing ambient air (̴ 22˚C).
  • Charcoal Heater to the Torso (CH-T) - The charcoal heater will be placed on your anterior chest with a towel in between. The flexible ducts will be applied to the areas of high heat transfer i.e. over the shoulders, neck, and then anteriorly under the axillae to cross over the lower anterior chest. You will be breathing ambient air at room temperature (~22˚C).

After 60 minutes of warming, subjects will be placed in a warm water bath (40-42˚C) until they are comfortable and core temperature returns to normal values (̴ 36.5-37˚C).

Outcome measures include rate of core cooling, afterdrop amount, rate of rewarming, skin heat flux, oxygen consumption and shivering intensity.

  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • 18-45 yrs old, males or females, healthy

Exclusion Criteria:

  • cardiopulmonary disease
  • any symptoms caused by cold exposure
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01603511


Locations
Canada, Manitoba
University of Manitoba
Winnipeg, Manitoba, Canada, R3T 2N2
Sponsors and Collaborators
University of Manitoba
Investigators
Principal Investigator: Gordon G Giesbrecht, Ph.D. University of Manitoba
  More Information

Responsible Party: Dr.Gordon Giesbrecht, Professor, University of Manitoba
ClinicalTrials.gov Identifier: NCT01603511     History of Changes
Other Study ID Numbers: B2012:024
NSERC PIN ( Other Grant/Funding Number: NSERC PIN )
First Submitted: May 18, 2012
First Posted: May 23, 2012
Last Update Posted: April 8, 2013
Last Verified: April 2013

Keywords provided by Dr.Gordon Giesbrecht, University of Manitoba:
rewarming
core cooling
afterdrop
pre-hospital treatment
hypothermia

Additional relevant MeSH terms:
Hypothermia
Body Temperature Changes
Signs and Symptoms
Charcoal
Antidotes
Protective Agents
Physiological Effects of Drugs