Heat Waves in the Elderly: Reducing Thermal and Cardiovascular Consequences
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 100
- 试验地点
- 2
- 主要终点
- Change in core body temperature
研究概览
简要总结
The purpose of this study is to assess how well cooling modalities work in reducing cardiovascular stress of the elderly to heat wave conditions
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 65 Years 至 —（Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •65 years of age or older
- •Free of any significant underlying medical problems based upon a detailed medical history and physical exam
排除标准
- •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
研究组 & 干预措施
Hot and humid
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.
干预措施: Fan (Other)
Hot and humid
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.
干预措施: Water Spray and Fan (Other)
Hot and humid
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.
干预措施: Control (Other)
Very hot and dry
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.
干预措施: Fan (Other)
Very hot and dry
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.
干预措施: Water Spray and Fan (Other)
Very hot and dry
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.
干预措施: Control (Other)
Very hot and dry
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.
干预措施: Water Spray (Other)
Hot and humid
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.
干预措施: Water Spray (Other)
结局指标
主要结局
Change in core body temperature
时间窗: Body core temperature will be obtained within 60 min before the heat wave exposure after the 3 hour heat wave exposure.
Change in core body temperature will be measured either from a temperature sensor pill or from a rectal thermometer
Change in left ventricular function
时间窗: 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
Measures of left ventricular function, such as ventricular wall motion and ventricular filling, will be obtained from echocardiography images.
次要结局
- Cardiac output(Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours))
- Markers of renal function and injury - Tissue inhibitor of metalloproteinases 2(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)
- High sensitive cardiac troponin(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)
- Heart rate(Prior to and throughout each simulated heat wave exposure; approximately 420 minutes)
- Arterial blood pressure(Prior to and throughout each simulated heat wave exposure; an average of 480 minutes)
- Whole body sweat rate(Within 60 minutes before each simulated heat wave exposure and within 30 minutes after each heat wave exposure.)
- Markers of renal function and injury - Creatinine Clearance(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)
- Cerebral perfusion(Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours))
- Markers of renal function and injury - Cystatin C(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)
- Markers of renal function and injury - Insulin-like growth factor-binding protein 7(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)
- Skin temperature(Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours))
- Forced vital capacity (FVC)(Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours))
研究者
Craig Crandall
Professor of Internal Medicine
University of Texas Southwestern Medical Center