Clinical trial NCT05484739: Heat Waves and the Elderly - Cooling Modalities
Official title: Heat Waves in the Elderly: Reducing Thermal and Cardiovascular Consequences
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Aging
Hyperthermia
Keywords: aging
heat wave
cardiovascular
low-energy cooling
Lead sponsor: University of Texas Southwestern Medical Center
Sponsor class: OTHER
First posted: 2022-08-02
Enrollment: 50
Sex: ALL
Minimum age (years): 65
Standard ages: OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: The investigators will conduct a randomized crossover design study. Older individuals will be exposed to one of two heat wave conditions (Very hot and dry or hot and humid). For each heat wave condition the individual will receive one of the following cooling strategies, with each cooling strategy applied on a different day: A) a control trial, B) skin wetting only trial, C) fan only trial, and D) a combination of skin wetting with a fan trial. Thus, to complete the trial for a selected heat wave condition (e.g., either very hot and dry or hot and humid) four experimental visits will be required - one visit for each cooling strategy.
Primary purpose: PREVENTION

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

Detailed description: Heat waves are lethal and cause a disproportionate number of deaths in the elderly relative to any other age group. Such deaths are primarily cardiovascular, not hyperthermia itself, in origin. The central hypothesis of this work is that cardiovascular stress during heat wave conditions in the elderly can be reduced by applying low-energy cooling modalities. Comprehensive cardiovascular and thermal responses in the elderly will be evaluated during exposure to two prolonged heat wave conditions: hot and humid (replicating the 1995 Chicago heat wave), very hot and dry (replicating the 2018 Los Angeles heat wave). With each of these heat wave conditions individuals will be exposed to the following cooling modalities: no cooling (control), water spray, fan use, and fan use plus water spray.

Eligibility criteria: Inclusion Criteria:

* 65 years of age or older
* Free of any significant underlying medical problems based upon a detailed medical history and physical exam

Exclusion Criteria:

* Known heart disease
* Other chronic medical conditions requiring regular medical therapy including cancer, diabetes, uncontrolled hypertension, and uncontrolled hypercholesterolemia etc;
* Abnormality detected on routine screening suggestive of provokable ischemia or previously undetected cardiac disease or resting left bundle branch block on screening electrocardiogram.
* Current smokers, as well as individuals who regularly smoked within the past 3 years
* Subject with a body mass index ≥31 kg/m2
* Pregnant individuals

Primary outcomes:
measure: Change in core body temperature
timeFrame: Body core temperature will be obtained within 60 min before the heat wave exposure after the 3 hour heat wave exposure.
measure: Change in left ventricular function
timeFrame: Within 60 minutes before each simulated heat wave exposure, around minute 90 of the heat wave exposure, and at the end of the 3 hour heat wave exposure
Secondary outcomes:
measure: Heart rate
timeFrame: Prior to and throughout each simulated heat wave exposure; approximately 420 minutes
measure: Cardiac output
timeFrame: Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
measure: Arterial blood pressure
timeFrame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes
measure: Whole body sweat rate
timeFrame: Within 60 minutes before each simulated heat wave exposure and within 30 minutes after each heat wave exposure.
measure: Markers of renal function and injury - Cystatin C
timeFrame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
measure: Markers of renal function and injury - Creatinine Clearance
timeFrame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
measure: Markers of renal function and injury - Insulin-like growth factor-binding protein 7
timeFrame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
measure: Markers of renal function and injury - Tissue inhibitor of metalloproteinases 2
timeFrame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
measure: Cerebral perfusion
timeFrame: Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
measure: High sensitive cardiac troponin
timeFrame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
measure: Skin temperature
timeFrame: Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
measure: Forced vital capacity (FVC)
timeFrame: Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
Other outcomes:
Locations:
city: Dallas
country: United States
facility: Texas Health Presbyterian Hospital Dallas
state: Texas
Study officials:
References: