Skin Rewarming After Exercise Cold Stress and Tolerance to Simulated Blood Loss
试验速览
- 阶段
- 不适用
- 状态
- 进行中（未招募）
- 发起方
- 入组人数
- 10
- 试验地点
- 2
- 主要终点
- Arterial blood pressure
研究概览
简要总结
Assess the effect of skin rewarming during lower body negative pressure upon arterial blood pressure and tolerance to simulated blood loss after exercise in the cold.
详细描述
Individuals who have experienced a hemorrhagic insult are often wrapped in a warm blanket. In individuals who have exercise in a cold environment, it is unknown how this skin warming influence tolerance to simulated blood loss and whether there is an optimal temperature to warm the skin up to in order to lower blood pressure (permissive hypotension).
After an initial study visit to examine exercise capacity (Visit 1), participants will complete four trials (Visits 2 through 5) After exercise in a cold environment, participants will have cold skin temperatures (~82°F; Visit 2). Researchers will examine how increasing skin temperature to normal (~90°F; Visit 3), warm (93°F; Visit 4) and hot (95°F; Visit 5) influences arterial blood pressure and tolerance to simulated blood loss compared to when the skin remains cold.
This project will test the hypothesis that skin rewarming to ~95°F lowers arterial blood pressure without impairing tolerance to simulated blood loss (lower body negative pressure; LBNP) relative to when the skin is kept cold (82°F).
Primary data include core and skin temperatures, arterial blood pressure and LBNP tolerance time. Secondary variables include skin blood flow and heart rate. After completing visit 1 first, all participants will complete visits 2 through 5 in a randomized order and participants are blinded. The order will be counterbalanced between participants.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
盲法说明
Participants are blinded to the skin temperature control.
入排标准
- 年龄范围
- 18 Years 至 40 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •18 and 40 years old
- •free of known disease and illness
- •Speak English
- •Systolic blood pressure <140mmHg
- •Diastolic blood pressure <90 mmHg
排除标准
- •Currently pregnant or breast feeding
- •Individuals with diagnosed with cardiac, respiratory, neurological and/or metabolic illness or disease.
- •Currently taking prescribed or over the counter medications known to influence the cardiovascular, pulmonary, renal and/or central nervous system.
- •Current use of tobacco or nicotine products
- •Any physical limitations that impede completion of the tests, such as exercise tests will also be an exclusion criteria.
- •Body mass< 80 pounds body weight
- •Appendectomy
结局指标
主要结局
Arterial blood pressure
时间窗: Before and during lower body negative pressure (LBNP) procedure
During simulated blood loss is the reduction in arterial blood pressure greater with progressive skin heating
Tolerance to simulated blood loss
时间窗: Lower body negative pressure test duration in all trials.
Tolerance to LBNP will be quantified using the cumulative stress index (CSI) calculated by summing the time at each level of LBNP multiplied by that level (i.e., 20 mmHg \* 3 min + 30 mmHg \* 3 min + 40 mmHg \* 3 min, etc.) until test termination.
次要结局
- Core temperature(Throughout exercise cold exposure and continuously during LBNP)
- Cutaneous Vascular Conductance(Before and during lower body negative pressure (LBNP) procedure)
研究者
James Pearson
Associate Professor
University of Colorado, Colorado Springs