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感冒发烧,强行物理降温,是否合适?

心脏外科医师 · 最后编辑于 2011-06-17 · IP 江苏江苏
3.8 万 浏览
这个帖子发布于 14 年零 23 天前,其中的信息可能已发生改变或有所发展。
感冒发烧是临床常见病多发病。鼓励病人多休息、多喝水,必要时使用退烧药和抗生素,这些是常规处理。
在遇到高烧不退的病人时,我们有时会采取酒精擦浴等物理降温措施。可是,发热是人体的一种积极的防御反应,强行进行散热,真的合理吗?
在民间,老百姓流传的方法是,在感冒时给自己捂上厚厚的被子睡上一觉,曰“发汗”。并且都认为有效果。
显然,这样的做法与我们物理降温的方法背道而驰。那么,经验和书本,究竟哪个才是真理?
带着这样一个问题,笔者查阅了一篇发表于1994年的文献(见文末)。翻译得不好,不足之处,还请大家指正。
文中的研究表明:
1、 人体的体温调节中枢并非我们想象的那么简单。在体温中枢的调控中存在一个范围。若输入信号超出了这个范围,便引起出汗,低于这个范围便引起寒战。
2、冷热的信号不仅仅来自于人体深部,还来自末端的皮肤及组织,两种信号在体温调节中枢进行整合,各自占有一个固定的比例。然而,对末端皮肤、组织温度的管理,却总是被我们忽略。
3、两种信号相互补充、此消彼长。如果末端皮肤、组织的温度较高,人体深部对于高温的需求便可相应地降低。相反的,如果人为地降低末端皮肤、组织的温度,人体深部的温度将被迫升得更高,从而防止两种信号的总和过度下降,进而避免寒战的发生。
综上所述,强行进行散热是粗暴和鲁莽的,并不符合人体体温调节的生理特点!如果直接进行物理降温,不但导致人体深部的温度向着进一步升高的趋势发展,还容易导致寒战的发生。
从一些资料中得知,有些临床医生选择在颈部、腋窝、腹股沟等大的动静脉处进行物理降温,从而直接地迅速地降低人体深部的温度。其效果远远优于对大面积皮肤进行的擦浴。
借鉴这样的成功经验,笔者认为:在颈部、腋窝、腹股沟等大的动静脉处进行物理降温,同时,对胸部、腹部、四肢的皮肤进行局部加热(如增加衣物、红外线照射等)才是正确的温度管理方案。因为,这样的方法一方面有效降低了人体深部的温度,另一方面提高了末梢皮肤、组织的温度,从而抑制了体温调节中枢对于升高深部温度的需求。

虽然体温调节中枢的生理机制还不完全清楚,并且缺乏足够的临床调查,但是对人体深部温度和末梢温度进行区别管理是一个崭新的思路,需要引起临床医生的重视!




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硬脊膜外麻醉可产生腿部变热的错觉,并因此降低寒战发生的阈值。

Epidural Anesthesia Increase Apparent Leg Temperature And Decrease The Shivering Threshold
Background:

背景:
Lower core temperatures than usual are required to trigger shivering during epidural and spinal anesthesia, but the etiology of this impairment remains unknown.
在硬脊膜外麻醉和蛛网膜下麻醉下,人体往往需要一个更低的核心温度才能激发寒战的产生。然而这种现象的病因学机制仍然未知。
In this investigation, we propose and test a specific mechanism by which a peripheral action of regional anesthesia might alter centrally mediated thermoregulatory responses.
在本研究中,我们提出并验证了一种特殊的机制。区域麻醉所带来的副作用通过该机制干扰了体温调节中枢的判断。
Conduction anesthesia blocks all thermal sensations; however, cold signals are disproportionately affected because at typical leg temperatures mostly cold receptors fire tonically.
麻醉剂可以阻滞所有的冷热感觉。然而事实上,冷信号却不相称受到了更大的削弱。因为在正常情况下,腿部的冷敏神经元(较温敏神经元)更占主导地位。
It thus seems likely that epidural and spinal anesthesia increase the leg temperature perceived by the thermoregulatory system.
这似乎可以被看作,是硬脊膜外麻醉和蛛网膜下麻醉通过迷惑体温调节中枢,产生了“腿部变热”的错觉。
Because skin temperature reportedly contributes 5-20% to thermoregulatory control, increased apparent (as distinguished from actual) leg temperature would produce a complimentary decrease in the core temperature triggering thermoregulatory shivering.
据报道,皮肤的温度对人体体温的调控有着5-20%的影响。因此,“腿部变热”的错觉(区别于腿部的实际温度)使得人体需要用一个更低的核心体温才能激发寒战的产生。
Accordingly, we tested the hypothesis that abnormal tolerance for hypothermia during epidural anesthesia coincides with an increase in apparent leg temperature.
据此,我们验证了一个假说,即:硬脊膜外麻醉下,人体对低体温的反常耐受,与硬脊膜外麻醉所致的“腿部变热”的错觉相关。
We defined apparent temperature as the leg-skin temperature required to induce a reduction in the shivering threshold comparable to that produced by epidural anesthesia.
在非麻醉条件下,想要诱导一个与硬脊膜外麻醉所带来的(效果)相似的寒战阈值的下降,就需要腿部皮肤的温度(提高至某个值)。我们便将(硬脊膜外麻醉所带来的)错觉中的温度定义为这个温度值。
Method:

方法:
Six women were studied on 4 randomly ordered days: (1) leg-skin temperature near 32 degrees C; (2) leg-skin temperature near 36 degrees C; (3) leg-skin temperature near 38 degrees C; and (4) epidural anesthesia without leg-warming (leg-skin temperature approximately 34 degrees C).
有六名女性在随机选择的四天时间里接受了实验:(1)腿部温度保持在32℃;(2)腿部温度保持在36℃;(3)腿部温度保持在38℃;(4)无腿部加温下的硬膜外麻醉(腿部皮肤实际温度约为34℃)。
At each designated leg temperature, core hypothermia sufficient to evoke shivering was induced by central venous infusion of cold fluid. Upper-body skin temperature was kept constant throughout.
在每组实验中,我们通过低温液体的中心静脉灌注来降低核心体温,进而激发寒战产生。当然,上身皮肤的温度是保持恒定的。
In each volunteer, linear regression was used to calculate the correlation between the shivering thresholds on the 3 non-epidural days and concurrent leg temperatures.
在每个志愿者身上,用线性回归的方法计算了非麻醉条件下的三天里,寒战阈值以及当时皮肤温度之间的关系。
The slope of these regression equations thus indicated the extent to which leg-warming increased thermoregulatory tolerance for core hypothermia, and was expressed as a percentage leg-skin and leg-tissue contribution to total thermal afferent input.
该回归方程的斜率揭示了腿部加温可以在多大程度上提高体温调节中枢对低体温的耐受,以及腿部皮肤和组织温度在整个人体冷热信号传入中所占的比例。
The skin and tissue temperatures that would have been required to produce the observed shivering threshold during epidural anesthesia, the apparent temperatures, were then interpolated from the regression.
硬膜外麻醉下测出的寒战阈值在方程上所对应的腿部皮肤及组织的温度,即错觉中的温度,便可以通过这个回归方程求出。
正文中的部分片段:
Part 1
Induction of regional anesthesia usually is accompanied by a sensation of increased warmth in the affected body parts; patients, for example, often comment that their legs feel warmer after induction of epidural or spinal anesthesia.
在受到麻醉的身体部位,常常有一种温度上升的感觉伴随着区域麻醉的进行。例如,患者们常常会在接受硬脊膜外麻醉或蛛网膜下麻醉后提及,他们觉得腿部更热了。
Some of this warming sensation certainly is a response to an actual increase in leg temperature, resulting from a core-to-peripheral redistribution of body heat.
这种热的感觉,其部分原因确实是腿部温度的实际上升。它源自于一种“核心—外周”的机体热量重新分布。
However, the ≈1℃actual increase in leg-skin temperature may not fully explain the reported sensation of warmth.
然而,这种只有约1℃的腿部温度实际上升,不能充分地解释患者所述的这种热的感觉。
Furthermore, the sensation of relative warmth persists when surgical levels of anesthesia are established—and thus well after actual leg temperature can be directly sensed.
此外,从外科水平的麻醉建立开始,到腿部的实际温度能够被直接感受到为止,这种(与麻醉)相关的热感一直持续着。
Part 2
To determine the fractional contribution of leg-skin to thermoregulatory control of shivering, we assumed the following relation:
为了确定腿部皮肤在体温调节中枢对寒战的的控制中所付出的比例,我们假设了如下的公式。
TMBT =βTSkin +(1-β)TCore
Where the TMBT = the shivering threshold in terms of mean body temperature and the β= the cutaneous contribution to the threshold.
其中TMBT为激发寒战所需的温度,而β则是皮肤温度所占的比例。
Part 3
Both skin and core temperatures contribute to thermoregulation.
皮肤和核心温度都作用于体温调节中枢。
Most warm receptors are quiescent at typical skin temperatures.
在常规皮肤温度下,大多数温敏感受器处于静息状态。
Consequently, at typical ambient temperatures, predominantly cold signals converge on the central thermoregulatory system.
因此,在常规外周温度下,占主导地位的冷敏信号充斥着体温调节中枢。
Although regional anesthesia blocks all thermal information from the lower portion of the body, tonic cold signals would be the major traffic disrupted.
虽然区域麻醉阻滞了来自身体下部的所有的温度信号,但是原本活跃的冷敏信号将受到更加严重的干扰。

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Epidural_Anesthesia_Increases_Apparent_Leg.5.pdf (873 KB)
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