Head and Torso Rewarming Using a Human Model for Severe Hypothermia

NCT ID: NCT02685176

Last Updated: 2019-03-01

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 8 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2016-09-30
• Study Completion Date: 2018-09-30

Brief Summary

This Clinical trial is being conducted to study the effectiveness of heat donation through head or torso in hypothermic rewarming efficacy using a human model for severe hypothermia. The purpose of the study is to compare the core rewarming effectiveness of the same amount of heat donation through the head or torso in treatment of hypothermia using a human model for severe hypothermia. The information obtained from this study will give a better understanding of heat-transfer mechanisms. This might help in the ongoing research in hypothermia treatment.

Detailed Description

Procedure:

Eight healthy, non-pregnant participants between 18 and 45 years old will be cooled in 8°C water, for 60 minutes or to a core temperature of 35ºC on three occasions and then warmed by each of three warming conditions.

The study will include following specific procedures:

Anthropometric data which includes age, weight, height, and measurements of skinfold thickness at four sites- biceps, triceps, subscapularis, and suprailiac will be collected. Participant's heart rate and electrocardiogram will be monitored continuously throughout the experiment.

Conditions: The three treatment methods are as follows. A. Spontaneous rewarming (Shivering inhibition) In this control condition, Demerol will be infused through the arm or hand vein.

The first 1.5 mg/kg will be slowly injected in five equal doses (of 0.3 mg/kg) at 2 minute intervals during the last 10 minutes of cold water immersion. After removal from the water, further aliquots of 0.3 mg/kg (at minimum of 2-minute intervals) will be given only as necessary to inhibit any shivering that may develop, to a maximum cumulative dose of 3.2 mg/kg body weight.

After towel drying the subject will lie on a mattress under an insulated cover without any extra heating modality. Spontaneous rewarming will be the first condition for every subject, the results will be used to determine the dosage schedule for demerol in the active warming conditions below.

B. Head warming:

Charcoal Heater applied to the Head (CH-H) - A charcoal heater (HEATPAC Personal Heater, Emergco Tech. Solutions, Vancouver) consists of a combustion chamber, a canister containing the charcoal fuel, and a branched heating duct that produces 250 W of heat. The canister is placed inside the combustion chamber and the charcoal fuel is ignited. Heated air is blown through the impermeable heating ducts by a fan within the charcoal heater above the combustion chamber. The combustion chamber will be placed on right side of the 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. The participant will be breathing ambient air (̴ 22˚C).

C. Torso warming:

Charcoal Heater to the Torso (CH-T) - The same charcoal heater as above will be used. The combustion chamber will be placed on the subject's 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. Participant will be breathing ambient air at room temperature (~22˚C).

Rewarming procedures will be administered either for a period of 60 minutes or until core temperature returns to normal values ( ̴ 36.5-37˚C). Following that, participants will be placed in a warm water bath (40-42˚C) until they wish to exit or core temperature reaches 37°C.

Research Design:

Each of the three experimental trials will be separated by at least 48 hours. On each of the three trials, participants will be immersed up to the level of the sternal notch in 8˚C for up to 60 minutes or until the core temperature falls to 35˚C. Demerol will be administered by a licensed physician during the final 10 minutes of immersion to suppress shivering. Participants will then exit the water, be dried off and rewarmed with either head or torso warming techniques. After removal from the water, an extra dosage of demerol might be given to suppress shivering only if its necessary. The rewarming will be administered for 120 minutes or until the core temperature returns to normal values (̴36.5-37˚C). The order of warming methods will follow a modified balanced design with control being first and the two active warming conditions being balanced.

Conditions

Hypothermia

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

No Heat

No active heating will be provided post cooling

Group Type: EXPERIMENTAL

No heat

Intervention Type: OTHER

No active heating provided post cooling

Head

Charcoal Heater (STK Heatpac, Emergco Tech Solutions, Vancouver) will be applied to the head following cooling

Group Type: EXPERIMENTAL

Charcoal Heater (STK Heatpac, Emergco Tech Solutions, B.C.)

Intervention Type: DEVICE

A heater (STK Heatpac) will be used in the active warming arms of the study.

Torso

Charcoal Heater (STK Heatpac, Emergco Tech Solutions, Vancouver) will be applied to the torso following cooling

Group Type: EXPERIMENTAL

Charcoal Heater (STK Heatpac, Emergco Tech Solutions, B.C.)

Intervention Type: DEVICE

A heater (STK Heatpac) will be used in the active warming arms of the study.

Interventions

Charcoal Heater (STK Heatpac, Emergco Tech Solutions, B.C.)

A heater (STK Heatpac) will be used in the active warming arms of the study.

Intervention Type: DEVICE

No heat

No active heating provided post cooling

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Healthy adults, who answer "No" to all the questions on a Physical Activity Readiness Questionnaire (PAR-Q). Participants will also be interviewed to determine if they have any cardio-respiratory diseases, Raynaud's Syndrome, or any other conditions that can be aggravated by cold exposure.

Exclusion Criteria

• A positive answer to any PAR-Q question, or any cardio-respiratory diseases, Renal dysfunction, Raynaud's Syndrome, past recreational drug use or any other conditions that can be aggravated by cold exposure.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Manitoba

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Gordon G Giesbrecht, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Manitoba

Locations

University of Manitoba

Winnipeg, Manitoba, Canada

Countries

Canada

Other Identifiers

B2015:101

Identifier Type: -

Identifier Source: org_study_id