Cooling Strategies for Hyperthermia in the Elderly

Overseen By Taysom Wallace, MS

Age: 65+

Sex: Any

Trial Phase: Academic

Sponsor: University of Texas Southwestern Medical Center

Disqualifiers: Heart disease, Cancer, Diabetes, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 8

50 Participants Needed

Trial Summary

What is the purpose of this trial?

The purpose of this study is to assess how well cooling modalities work in reducing cardiovascular stress of the elderly to heat wave conditions

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but it excludes people with chronic conditions that require regular medication.

What data supports the effectiveness of the treatment Cooling Strategies for Hyperthermia in the Elderly?

Research shows that wearing a water-soaked t-shirt without a fan can effectively reduce heat strain in older individuals in hot conditions. Additionally, active cooling methods, like evaporative cooling, are associated with lower mortality in severe heat illness cases. ^{1 2 3 4 5}

Is it safe for elderly people to use cooling methods like fans and water-soaked clothing during heat exposure?

Research suggests that using a water-soaked t-shirt without a fan is a safe and effective way to manage heat in older adults, as it reduces sweat loss and heat strain. However, combining a fan with a water-soaked t-shirt may increase sweat loss without reducing heat strain. ^{1 3 6 7 8}

How does the treatment for hyperthermia in the elderly using cooling strategies differ from other treatments?

This treatment is unique because it combines methods like using a fan, skin cooling, and water spray to manage heat in older adults, focusing on evaporative cooling, which is effective when air conditioning is not available. Unlike other methods like cold-water immersion, this approach is more accessible and practical for use in everyday settings. ^{1 3 4 7 9}

Eligibility Criteria

This trial is for people aged 65 or older who are generally healthy, without significant medical issues based on a thorough check-up. It's not open to those with certain heart problems, a BMI of 31 or higher, chronic conditions needing ongoing treatment, known heart disease, current smokers or those who quit within the last three years.

Inclusion Criteria

I am 65 years old or older.

Free of any significant underlying medical problems based upon a detailed medical history and physical exam

Exclusion Criteria

My heart screening showed possible signs of blocked blood flow or a new heart condition.

Current smokers, as well as individuals who regularly smoked within the past 3 years

My BMI is 31 or higher.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment - Hot and Humid

Participants are exposed to a hot and humid climate chamber for 3 hours with different cooling modalities applied across four visits.

4 visits

4 visits (in-person)

Treatment - Very Hot and Dry

Participants are exposed to a very hot and dry climate chamber for 3 hours with different cooling modalities applied across four visits.

4 visits

4 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment, including evaluation of cardiovascular and thermal responses.

2-4 weeks

Treatment Details

Interventions

• Control
• Fan
• Skin Cooling, Fan, or Combination of Skin Cooling and Fan
• Water Spray
• Water Spray and Fan

Trial Overview The study is looking at how different cooling methods like fans and water sprays can help reduce heat-related cardiovascular stress in elderly individuals during heat waves. Some participants will use just a fan, others just a spray, some both together, and there'll be a control group with no intervention.

Participant Groups

Group I: Very hot and dry Experimental Treatment 4 Interventions

Subjects will be exposed to 3 hours in a climate chamber set to approximately 47 deg C and 15% relative humidity, which reflects a very hot and dry heat wave condition similar to the 2018 Los Angeles heat wave. Four visits will be required to complete this arm, with each visit a different cooling modality applied.

Group II: Hot and humid Experimental Treatment 4 Interventions

Subjects will be exposed to 3 hours in a climate chamber set to approximately 41 deg C and 40% relative humidity, which reflects hot and humid heat wave similar to the 1995 Chicago heat wave. Four visits will be required to complete this arm, with each visit a different cooling modality applied.

Who Is Running the Clinical Trial?

University of Texas Southwestern Medical Center

Lead Sponsor

Trials

1,102

Recruited

1,077,000+

Findings from Research

Wearing a water-soaked t-shirt significantly reduces core temperature and thermal strain in older individuals exposed to hot and humid conditions, compared to wearing a dry t-shirt.

Using an electric fan with the water-soaked t-shirt increases sweat losses without providing additional benefits for heat management, making the combination less effective than just the wet t-shirt alone.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Keeping older individuals cool in hot and moderately humid conditions: wetted clothing with and without an electric fan. Cramer, MN., Huang, M., Moralez, G., et al.[2021]

In a study of heat stroke patients in Japan, active cooling combined with rehydration significantly reduced in-hospital mortality rates in severe cases (21.5% mortality) compared to rehydration-only therapy (35.5% mortality).

For patients with mild-to-moderate heat illness, active cooling did not show a significant benefit over rehydration alone, suggesting that cooling is particularly important for those with severe symptoms.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Association between active cooling and lower mortality among patients with heat stroke and heat exhaustion. Kanda, J., Nakahara, S., Nakamura, S., et al.[2023]

In two cases of drug-induced hyperthermia, ice water submersion demonstrated rapid cooling rates, with core temperatures dropping significantly: from 41.4°C to 38°C in 18 minutes and from 44.4°C to 38.8°C in 20 minutes.

These results suggest that ice water submersion may be more effective than mist and fan techniques for quickly reducing body temperature in hyperthermic patients, highlighting the need for further clinical data to determine the best cooling methods.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Ice water submersion for rapid cooling in severe drug-induced hyperthermia. Laskowski, LK., Landry, A., Vassallo, SU., et al.[2018]

Rapid cooling is crucial for managing heat-stroke, as prolonged hyperpyrexia can lead to poor patient outcomes.

Evaporative cooling has been identified as the most efficient method for cooling, supported by both military and civilian experiences, and should be prioritized in treatment protocols.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Heat-stroke: a review of rapid cooling techniques. Harker, J., Gibson, P.[2019]

Rapid cooling is crucial for treating heat stroke, as the prognosis depends on the severity and duration of hyperthermia; immediate cooling methods should be initiated as soon as a patient collapses.

Effective cooling techniques include immersion in ice water (1-5 degrees C) or evaporative cooling, which should be tailored to the patient's age and medical history, ensuring both efficacy and safety.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Heat stroke : a review of cooling methods. Hadad, E., Rav-Acha, M., Heled, Y., et al.[2018]

In a study involving 18 participants (9 young adults and 9 aged adults) exposed to extreme heat and humidity, using an electric fan increased physiological strain in older adults, leading to higher heart rates and core temperatures compared to when no fan was used.

Conversely, young adults experienced a slight reduction in heart rate and only minor changes in core and skin temperatures with fan use, suggesting that fans may not provide the same cooling benefits for older individuals in extreme conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Age Modulates Physiological Responses during Fan Use under Extreme Heat and Humidity. Gagnon, D., Romero, SA., Cramer, MN., et al.[2020]

In a study with 9 human volunteers, face fanning during heat exposure effectively lowered brain temperature by maintaining a tympanic temperature that was 0.57 degrees Celsius cooler than esophageal temperature, suggesting a protective effect on the brain.

The results indicate that external head cooling methods, like face fanning, can enhance brain cooling and improve comfort during heat stress, potentially offering a strategy for protecting the brain during therapeutic hyperthermia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Enhanced brain protection during passive hyperthermia in humans. Brinnel, H., Nagasaka, T., Cabanac, M.[2022]

Infants, children, and adolescents are particularly vulnerable to heat-related illnesses, and the risk increases with prolonged elevated core temperatures, making rapid cooling essential to prevent serious health consequences.

Effective cooling methods include conduction (like ice-water immersion) and convection (using moisture and moving air), with recommendations provided for best practices in treating heat illness, especially for at-risk groups such as obese children or those with special needs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pediatric heat-related illness: recommendations for prevention and management Dunn, RJ., Kim, TY.[2019]

The tarp-assisted cooling with oscillation (TACO) method is the only alternative cooling strategy that provides an effective core body temperature cooling rate (0.14-0.17°C/min) for treating exertional heat stroke (EHS) when cold-water immersion (CWI) is not feasible.

Other methods like hand cooling, cold-water showers, and ice-sheet cooling have significantly lower cooling rates (0.03-0.08°C/min) and should not be used if better options are available, emphasizing the importance of using CWI whenever possible.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Do Alternative Cooling Methods Have Effective Cooling Rates for Hyperthermia Compared With Previously Established CWI Cooling Rates? Parker, KC., Shelton, RR., Lopez, RM.[2021]

References

1. United States pubmed.ncbi.nlm.nih.gov

Keeping older individuals cool in hot and moderately humid conditions: wetted clothing with and without an electric fan. [2021]

2. United States pubmed.ncbi.nlm.nih.gov

Association between active cooling and lower mortality among patients with heat stroke and heat exhaustion. [2023]

3. England pubmed.ncbi.nlm.nih.gov

Ice water submersion for rapid cooling in severe drug-induced hyperthermia. [2018]

4. Netherlands pubmed.ncbi.nlm.nih.gov

Heat-stroke: a review of rapid cooling techniques. [2019]

5. New Zealand pubmed.ncbi.nlm.nih.gov

Heat stroke : a review of cooling methods. [2018]

6. United States pubmed.ncbi.nlm.nih.gov

Age Modulates Physiological Responses during Fan Use under Extreme Heat and Humidity. [2020]

7. Germany pubmed.ncbi.nlm.nih.gov

Enhanced brain protection during passive hyperthermia in humans. [2022]

8. United States pubmed.ncbi.nlm.nih.gov

Pediatric heat-related illness: recommendations for prevention and management [2019]

9. United States pubmed.ncbi.nlm.nih.gov

Do Alternative Cooling Methods Have Effective Cooling Rates for Hyperthermia Compared With Previously Established CWI Cooling Rates? [2021]