Thermoregulation Study Guide PDF

**Temperature** **Thermoregulation → The process of maintaining the core body** **temperature at a nearly constant value.** **Normothermia -- normal body temperature ranges between 36.2 C to 37.6 C (97.1 to 99.6 F)** **Hyperpyrexia -- extremely high body temperature above 41.5 C (106.7 F)** **P...

**Temperature** **Thermoregulation → The process of maintaining the core body** **temperature at a nearly constant value.** **Normothermia -- normal body temperature ranges between 36.2 C to 37.6 C (97.1 to 99.6 F)** **Hyperpyrexia -- extremely high body temperature above 41.5 C (106.7 F)** **Populations at GREATEST risk for thermoregulation problems are: infants, babies, elders, poor persons, and persons living in very hot or cold climates.** **Definitions:** - Fever - Pyrexia - Malignant Hyperthermia - Hyperthermia **Interventions for hyperthermia:** **Remove excess clothing** **Provide external cool packs** **Provide a cooling blanket** **Hydration (oral or IV)** **Give antipyretic drug therapy** - Hypothermia **Interventions for hypothermia:** **Remove person from cold** **Provide external warming measures** **Provide internal warming measures** - Non-shivering thermogenesis Increased temperature will cause the **[blood vessels to dilate]** (skin flushed), sweat glands are activated Decreased temperature will cause the **[blood vessels to constrict]**, trapping heat in the deeper tissues. Sweat glands are nonactive. Skeletal muscles contract → shivering **Body temperature regulation** (Potter, page 501) Four methods of heat loss: 1\. Radiation is the transfer of heat from the surface of one object to the surface of another without direct contact between the two 2\. Conduction is the transfer of heat from one object to another with direct contact. Solids, liquids, and gases conduct heat through contact. 3\. Convection is the transfer of heat away by air movement 4\. Evaporation is the transfer of heat energy when a liquid is changed to a gas. (5). Diaphoresis is visible perspiration primarily occurring on the forehead and upper thorax, although it occurs in other places on the body. Five methods of temperature measurement 1. 2. 3. 4. 5. Three invasive core temperature sites 1. 2. 3. **Medications for pyrexia/fever:** Acetaminophen Ibuprofen Aspirin **Heat-Related Emergencies** Definitions: - Heat cramps -- severe cramps in large muscle groups fatigued by heavy work. - Heat exhaustion -- prolonged exposure to heat over hours or days when engaged in strenuous activity in hot, humid weather conditions. Presents with fatigue, nausea and vomiting, exreme thirst. Hypotension, tachycardia, elevated body temp, dilated pupils, mild confusion, ashen color, profuse sweating - Heat Stroke -- **The most serious form of heat stress → medical emergency. Results from failure of hypothalamic thermoregulatory processes:** Increased sweating, vasodilation, and increased respiratory rate deplete fluids and electrolytes Sweat glands eventually stop working Assessment findings Core temp rises within 10 to 15 minutes higher than 105.8 F (41 C) Altered mental status → confusion → coma Hypotension Tachycardia Tachypnea Weakness Hot, dry skin, no sweating present Circulatory collapse Can lead to cerebral edema and hemorrhage. Death is directly related to amount of time patients body temperature remains high. Interventions: Stabilize ABCs Rapidly lower core temperature Monitor for dysrhythmias Administer 100% oxygen, ventilate with BVM or intubate with mechanical ventilation Continuous ECG and pulse ox Monitor labs Correct electrolyte and coagulation abnormalities ***Most effective treatment is cold water immersion*** Interprofessional Care (page 393) Medications: Intravenous fluids: 0.9% NaCl (normal saline) Lactated Ringers (LR) Electrolyte replacement: Potassium, Sodium, **Cold-Related Emergencies** Definitions: - Frostbite -- localized. Tissue freezing leads to ice crystals in tissues and cells. Cold stress causes peripheral **[vasoconstriction]** that can lead to decreased blood flow and vascular stasis. As cell temperature decreases, ice crystals form in intracellular spaces. Organelles are damaged and cell membranes are destroyed causing edema. Most cases involve hands and feet (90%) → Cheeks, nose, ears, penis also commonly affected Superficial frostbite -- involves the skin and subcutaneous tissue. Effects the ears, nose, fingers and toes. Skin will appear waxy pale yellow to blue to mottled and will feel crunchy. Never squeeze, massage or scrub the injured tissue The skin will swell while it thaws and blisters form within a few hours Immerse affected area in circulating water that is temp controlled at 99. To 102 F. Deep frostbite -- involves muscle, bone and tendon. The skin will appear white, hard and insensitive to touch. Mottling gradually leads to gangrene (loss of blood circulation to the area and the skin tissue will die) - Hypothermia -- systemic. Core temp lower than 95 F or 35 C. older adults are at risk due to decreased body fat, energy reserves, basal metabolic rate, shivering response, and chronic medical problems (secondary hypothermia) - Mild is 93 to 95 F (33.9 to 35 C): Shivering, lethargy, confusion, rational to irrational behavior, minor heart rate changes - Moderate is 86 to 93 F (30 to 33.9 C) Rigidity, bradycardia, bradypnea, BP only obtainable by doppler, metabolic and respiratory acidosis, hypovolemia, shivering decreases or disappears at core temperatures of 86 F (30 C). Cold blood is thick and will act as a thrombus which will increase risk for stroke, MI, PE, renal failure Cold myocardium → dysrhythmias Decreased renal blood flow → decreased GFR and decreased water absorption → dehydration âĨĴ Increased hematocrit → decreased intravascular volume Decreased blood flow → hypoxia, anaerobic metabolism, lactic acid accumulation, and metabolic acidosis - Severe is less than 86 F (30 C). life threatening → person looks dead. Vital signs are difficult to detect, reflexes are absent such as pupils are fixed and dilated. May have: bradycardia, ventricular fibrillation, pulseless electrical activity (PEA). Every effect is made to warm patient to at **[least 86 F (30 C) before they are announced dead, the cause will be refractory ventricular fibrillation.]** Interprofessional Care: manage and maintain ABCs rewarm patient -- passive or active external measures for **mild** hypothermia. Active internal rewarming measures for **moderate or severe** hypothermia. Correct dehydration and acidosis Treat dysrhythmias Monitor core temperature during rewarming → risks of rewarming: after drop -- further drop in core temperature when cold peripheral blood returns to central circulation. Shock -- hypotension and dysrhythmias. Extracorporeal membrane oxygenation (ECMO) Medications: Intravenous fluids: 0.9% NaCl (normal saline) Lactated Ringers (LR) Electrolyte replacement: Potassium, Sodium,