Page-by-Page Notes: Alterations in Thermoregulation

Page 1

ALTERATIONS IN THERMOREGULATION

  • Topic introduced: Alterations in thermoregulation. This set of slides covers the body's temperature regulation, its disorders, and contrasts among different states of heat production, loss, and fever.

Page 2

What is Thermoregulation?

  • Definition: Thermoregulation is the body's ability to maintain a stable internal temperature within an optimal range despite external temperature changes.

  • Control center: The hypothalamus regulates thermoregulation by sensing temperature changes and initiating physiological adjustments.

  • Normothermia: 36.5∘C≤T≤38∘C36.5^{\circ}\mathrm{C} \le T \le 38^{\circ}\mathrm{C} or 97.7∘F≤T≤100.4∘F97.7^{\circ}\mathrm{F} \le T \le 100.4^{\circ}\mathrm{F}

Page 3

Who is at risk for altered thermoregulation?

Infants, elderly, young children, laborers, homeless, athletes, hyper/hypothyroidism, intraoperative, drugs/alcohol, impaired cognition, malnurished

  • Question posed: Who is at risk for altered thermoregulation?

  • Note: The transcript does not provide specific risk groups or factors on this page.

Page 4

Mechanisms of Heat Production/ Conservation

  • Body Hair → goosebumps→ piloerection

  • Increased BMR, Increased T3, T4, Increased epinephrine, norepinephrine (SNS)

  • Vasoconstriction

  • Shivering

  • Brown fat metabolism (this is how babies keep warm because they have an impaired nervous system which causes them to not shiver.

  • move around, add clother, drink something warm, use a heater

  • Content details are not provided in the transcript. (Typically would include shivering, non-shivering thermogenesis, metabolic rate increases, vasoconstriction, etc., but these are not enumerated here.)

Page 5

Mechanisms of Heat Loss/ Dispersion

  • Vasodilation

  • Diaphoresis

  • Profuse sweating

  • Decrease in BMR, Decreased T3, T4, epi, norepi

  • Go somewhere cool, drink something cold, get a fan, find a shady area

  • Content details are not provided in the transcript. (Common mechanisms would include vasodilation, sweating, radiation, convection, evaporation, etc., but none are specified in this slide text.)

Page 6

Hypothermia

  • Section heading: Hypothermia.

  • No additional detail provided on this page beyond the topic heading.

Page 7

What is Hypothermia?

  • Definition: Hypothermia occurs when the body loses heat faster than it can produce it.

  • Common causes: Prolonged exposure to cold environments, inadequate clothing, and wet conditions.

  • Symptoms: Shivering, confusion, slowed heart rate; can progress to unconsciousness and death.

Page 8

Hypothermia Stages/Assessment

  • Mild: 32∘C≤T≤35∘C32^{\circ}\mathrm{C} \le T \le 35^{\circ}\mathrm{C} (equivalently, 89.6∘F≤T≤95∘F89.6^{\circ}\mathrm{F} \le T \le 95^{\circ}\mathrm{F})

    • Shivering

    • Vasoconstriction

    • Disorientation

    • Increased HR

    • Cyanosis

    • hyperventalation

  • Moderate: 28∘C≤T≤32∘C28^{\circ}\mathrm{C} \le T \le 32^{\circ}\mathrm{C} (equivalently, 82.4∘F≤T≤89.6∘F82.4^{\circ}\mathrm{F} \le T \le 89.6^{\circ}\mathrm{F})

    • NO shivering (Because the body is loosing energy it is not able to shiver)

    • shallow breathing, Respiratory acidosis

    • Hypotensive

    • Decreased LOC

    • Decreased HR (think of the body slowing down)

    • Cardiac arrythmias, Slow VT

    • Muscle rigidity

    • Hyper reactive reflexes

  • Severe/Deep: T < 28^{\circ}\mathrm{C}} (equivalently, T < 82.4^{\circ}\mathrm{F})

    • Lactic acidosis

    • Tissue hypoperfusion (the body starts going into shock

    • Cardiac arrythmias

    • Decreased reflexes

    • Unconscious

    • Unresponsive

    • Pupils fixed and dilated

    • Organ failure

    • Edema/ erythema

    • Risk of PERMANANENT brain damage

    • Decreased palpable pulses

    • Decreased cardiac output

  • Profound: T < 28^{\circ}\mathrm{C}} quivalently, T < 82.4^{\circ}\mathrm{F})

    • Death s/s

    • Cardia arrest

    • Resp arrest

    • ECMO (Extracorporeal Membrane Oxygenation)

    • No reflexes

    • Cardiopulmonary bypass

    • SEVERE brain damage

Notes:

  • The thresholds provide a graded severity from mild to profound hypothermia.

  • The Fahrenheit values are the approximate conversions of the Celsius ranges.

Page 9

Hypothermia Treatments

  • Warm them up!!

  • Warming blankets

  • Warm IV fluids

  • Increase the room temperature

  • Heat lamps

  • Cover

  • Take off any wet clothes

Page 10

Frostbite

  • Pathophysiology: Cold exposure leads to vasoconstriction, reducing blood flow to extremities, resulting in progressive dermal ischemia and, if severe, tissue necrosis.

  • Stages: Described as 3 stages, though the specific stages are not enumerated in this transcript.

    • Frostnip

    • Superficial

    • Deep (Necrosis)

  • Treatments:

    • Pain management

    • Debridement of the necrotic tissue

    • Amputation

    • Warm them up (lukewarm) “slowly”

Page 11

Therapeutic Hypothermia / Targeted Temperature Management (TTM)

  • Definition: Medically induced reduction of core body temperature to protect neurological function.

  • Indications:

    • Trauma brain injury

    • Cardiac arrest → MI

    • “Some” strokes

    • CABG

    • HIE- birth inury

  • Process:

    • Ice packs

    • Fans

    • COOL IV fluids

    • Cooling blankets

    • 1-1.5 C per hour

    • Warm up: warm iv fluids, blankets, heated fans

    • slow 6hr-12hr

    • Continuos monnitoring

      • Epi drip

      • V/S

      • electrolyte imbalances

      • coagulopathy- think blood

      • DONT LET THEM SHIVER

  • LESS THAN 24 HOURS

  • Rationale: Reduces metabolic demand, preventing further ischemic tissue damage.

  • Target temperature range: 32∘C≤T≤36∘C32^{\circ}\mathrm{C} \le T \le 36^{\circ}\mathrm{C} ( 89.6∘F≤T≤96.8∘F89.6^{\circ}\mathrm{F} \le T \le 96.8^{\circ}\mathrm{F} ) for 12−24 hours12-24\text{ hours}.

Page 12

Therapeutic Hypothermia / Targeted Temperature Management (TTM)

  • Indications: Not specified in the transcript.

  • Process: Not specified in the transcript.

Page 13

Pyrexia

  • Title: Pyrexia (Fever).

Page 14

What is Pyrexia?

  • Definition: Fever is a temporary increase in body temperature, usually due to infection or inflammation, as well as autoimmune disorders and cancer.

  • Role: Fever is a protective response that enhances the immune system's ability to fight pathogens.

  • Mechanism: The hypothalamus raises the set point for body temperature, initiating heat-producing mechanisms such as shivering.

Page 15

Stages of Pyrexia/ Assessment

  • Prodromal stage

    • HA

    • Fatigue

    • Myalgia

    • Malaise

    • n/v

  • Chill stage

    • Piloerection

    • shivering

    • dizziness

    • “rigors”

    • “chills”

    • pallor

    • “vasoconstriction

  • Plateau stage

    • Sweating

    • flush,warm

    • erythemia

    • vasodilation

    • muscle aches

    • fatigue

    • Increased heart rate

    • Decreased mental state (mental impairment)

    • Decreased appetite and thirsty

  • Defervescence stage

    • Sweating

    • Warm/flushed

    • Vasodilation

    • Fatigue

    • Weakness

Page 16

Pyrexia Treatments

  • Acetometnophin, ibuprofen

  • cool compresses

  • ice packs

  • “chill”→blanket for comfort

  • Iv fluids

  • increase oral fluid intake

Page 17

Hyperthermia

  • Section heading: Hyperthermia.

Page 18

What is Hyperthermia?

  • Definition: Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate.

  • Causes: Excessive heat exposure, vigorous exercise, and certain medical conditions.

  • Symptoms: Range from heat cramps to heat exhaustion and heat stroke; heat stroke can be fatal.

Page 19

Hyperthermia Stages/ Assessment

  • Mild (Heat Stress): Temperature within normal limits (WNL) or mildly elevated.

    • Sweat

    • Muscle cramps

    • Increased heart rate

    • flushed skin

    • weakness,fatigue

    • Increased RR

  • Moderate (Heat Exhaustion): T > 38.3^{\circ}\mathrm{C}} ( > 101^{\circ}\mathrm{F})

    • Profuse diaphoresis

    • Ams- light delirium

    • Vasodilation

    • N/V

    • dehydration

    • Oliguria, decreased urine output

    • Syncope

  • Severe (Heat Stroke): T > 40^{\circ}\mathrm{C}} ( > 104^{\circ}\mathrm{F})

    • DRY, HOT SKIN

    • ams- worsening

    • hypotension,bradycardia

    • cardiac arrest

    • multi organ failure

Notes:

  • The slide aligns with a staged approach to hyperthermia similar to hypothermia but with elevated temperature categories.

Page 20

Hyperthermia Treatments

  • Cool IV fluids

  • shade from sun

  • oral fluids

  • cooling blankets

  • fans

  • cold compresses, ice pack →carefully

  • decrease environment temp

Page 21

Malignant Hyperthermia

  • Cause: Genetic mutation of the RYR1 gene.

  • Pathophysiology: Leads to hypercalcemia, uncontrolled heat production, and body temperature rising to >40∘C40^{\circ}\mathrm{C}.

    • S/S

    • muscle rigidity- jaw

    • increased hr

    • hypercapnia

    • increased temp

    • acidosis

  • Nature: Life-threatening hypermetabolic crisis.

  • Triggers: Can be triggered by certain medical treatments. (general anethesia, succynlcholine

Page 22

Key Differences Between Hyperthermia and Pyrexia

  • Hyperthermia vs Pyrexia:

    • Cause: External heat or metabolic disorder vs Infection or inflammation.

    • Mechanism: Failed heat dissipation vs Hypothalamic set point increase.

    • Sweating: Absent in heatstroke (hyperthermia) (profuse in moderate) vs Present in fever (pyrexia).

    • Treatment: External cooling and internal vs Antipyretics & hydration.

    • Body increases epinephrine in the body to conserve heat

Page 23

Compare/Contrast

  • Condition categories listed: Hypothermia, Therapeutic Hypothermia, Hyperthermia, Pyrexia.

  • For each, consider: Temperature range, Key Causes, Key Treatments.

  • The slide appears to offer a matrix for side-by-side comparison across these conditions.

Page 24

Stay Cool

  • Concluding slide title: Stay Cool.

Summary of Key Concepts

  • Thermoregulation is a homeostatic process controlled by the hypothalamus, maintaining temperature within a normal range (normothermia).

  • Hypothermia results from heat loss exceeding production; staged by core temperature with clear C and F ranges; treatment details are sparse in this transcript.

  • Frostbite involves cold-induced vasoconstriction leading to ischemia and possible necrosis; three stages are mentioned but not specified here.

  • Therapeutic hypothermia/TTM deliberately lowers core temperature (32-36°C) to protect neurological tissue; duration typically 12-24 hours.

  • Pyrexia is fever, a regulated rise in set point due to infection/inflammation, with stages including prodrome, chill, plateau, and defervescence; mechanisms involve hypothalamic set point elevation and heat production (shivering).

  • Hyperthermia occurs when heat gain exceeds dissipation without a change in set point; severity ranges from heat stress to heat stroke, with temperature thresholds: >38.3°C (101°F) for moderate, >40°C (104°F) for severe.

  • Malignant hyperthermia is a rare, life-threatening condition caused by a genetic mutation in RYR1, leading to unchecked heat production and hyperthermia (>40°C), potentially triggered by medical treatments.

  • Distinctions between hyperthermia and pyrexia emphasize external heat/metabolic factors and the lack of hypothalamic set-point elevation in hyperthermia, versus fever where the set point is raised; sweating patterns differ accordingly.

  • Across conditions, treatments center on cooling when appropriate, with fever often treated differently (antipyretics, hydration) than hyperthermia.