Hypothermia
From WikiLectures
Hypothermia occurs when the body temperature drops below 35°C due to excessive heat loss.
Causes of hypothermia[edit | edit source]
- Environmental influence - 'hypothermia (+ high humidity, wind, physical exhaustion, drunkenness, injuries, ...)
- Reduced metabolism - severe hypothyroidism, hypoglycemia, hypopituitarism, ketoacidosis, malnutrition
- Intoxication (alcohol, barbiturates, sedatives)
- Brain damage, trauma, sepsis
- Increased heat loss through the skin - burns
Consequences of hypothermia[edit | edit source]
- The first signs arise from the effect of abnormal temperature on the CNS - ataxia, amnesia, speech disorders, behavior (paradoxical undressing), hallucinations, ...
- Below 33 °C, muscle tremors stop, metabolism decreases (at 28°C by 50%)
- Hematocrit and viscosity of the blood increase
- Impaired renal function - cold diuresis followed by oliguria
- Rise in pH (spontaneous return when the temperature rises)
- Impaired detoxification and conjugation function of the liver, hyperglycemia
- Often pancreatitis and gastric bleeding
Effect on the heart
- Progressive decline of heart rate and MSV!
- Blood pressure first rises, then falls - poorly palpable pulse
- Despite hyperkalemia, myocardial excitability increases - frequent atrial fibrillation
- When the temperature drops below 28 - 30 °C risk of ventricular fibrillation! (terminal stage!)
- Changes on ECG (Osborn wave)
The body can cope with hypothermia (up to 20 °C) surprisingly well. This is because there is a reduction in metabolism and requirements for O2. Therefore, prolonged resuscitation is recommended and justified in critical hypothermic states. In case of death due to hypothermia, the postmortem signs are - purple skin, swelling in the face, gastric erosion, multi-organ infarctions as a result of hypothermic shock.
Use of hypothermia in medicine[edit | edit source]
- Controlled surgical hypothermia (heart, brain surgery), local anesthesia
- Cold treatment (hypoxic conditions, physiotherapy, sports, swelling, inflammation, hardening, cryotherapy, cryosauna, ...)
Links[edit | edit source]
Related Articles[edit | edit source]
- Hyperthermia
- Cryosurgery
- Cryotherapy
- Thermoregulation
- Effects of extreme temperatures on living organisms
External links[edit | edit source]
- [1]
- [2]
- Hypothermia (TECHmED)
- Osborn wave (TECHmED)
- About hypothermia and their treatment, article on the Objective Source of E-Learning server, 2012
- Homeostasis, IHW March 2006
- Lecture by Ladislav Sieger - polar scientist, non-physician, practical information
References[edit | edit source]
BLATTEIS, Clark. Physiology and Pathophysiology of Temperature Regulation. - edition. World Scientific, 1998. 294 pp. ISBN 9789810231729.
