Environmental Emergencies - Hypothermia and Hyperthermia

Environmental Emergencies

Introduction to Environmental Emergencies

• Definition of Environment: All surrounding external factors influencing the functioning of living organisms.

• Impact on Health: Environmental factors can induce stress leading to medical emergencies.

Temperature Extremes

• Effects on Body:

  • Slowed liquid movement aka. clot causing a thrombus and can cause ischemia.

  • Changes in metabolism

  • Protein (enzymes) failure (gas exchange can’t occur)

  • Muscle physiology alterations

  • Coagulation issues,

  • ATP Pump dysfunctions: bradycardia occurs when temp is reduced significantly

  • Impact on neurotransmitters.

Anti-Diuretic Hormone (ADH)

• Function: Released by the pituitary gland when blood concentration increases to reabsorb water and sodium, effectively 'thinning' the blood.

• High Concentrations: Induces vasoconstriction.

• Influence: Alcohol, caffeine, and stress inhibit ADH production/release.

Mechanisms of Temperature Regulation

• Heat Gain & Loss:

  • from. within the body and the contact with the external environment

  • Influenced by thermal gradients, wind, and humidity.

Thermoregulatory Mechanisms

• Hypothalamus: Main control center for thermoregulation.

  Functions:

  • Thermogenic: Heat generation mechanisms.

  • Thermolytic: Heat loss mechanisms.

Thermoregulation Processes

• Heat Dissipation Mechanisms: Sweating, vasodilation.

• Heat Conservation Mechanisms: Shivering, vasoconstriction. shunting blood from the extremities and keeps it focused in the core

• Body Temperature Variation: Normal range and effects of extremes.

Responses to Cold Stress

• Thermogenesis: Increases muscle tone and thyroid hormone levels; shunting of blood to core.

• Thermolysis: Heat release through radiation, conduction, convection, and evaporation.

  • conduction: direct contact with a cooler surface

  • convection: heat loss to cooler air currents

  • radiation: radiates heat in the form of infrared rays

  • evaporation: water evaporates from skin

  • respiration: combines convection, radiation and evaporation.

Cold Weather Adjustments

• Mechanisms of Cold Exposure:

  • Peripheral thermoreceptors (skin) and central thermoreceptors (deep tissues).

  • Body adjusts heat production and retention mechanisms in response to cold stressors.

Hypothermia

• Definition: Abnormally low body temperature.

  • Symptoms start at core body temperature (CBT) of 35°C.

• Causes:

  • Inadequate thermogenesis and excessive cold stress.

  • Commonly affects more vulnerable populations such as the elderly.

Pathophysiology

• Symptoms increase severity with temperature drop:

  • Loss of fine motor skills, irrational behavior, mobility issues, etc.

Risk Factors for Hypothermia

• Older adults, medications affecting thermoregulation, lifestyle factors, and extreme environmental exposure increase susceptibility.

Clinical Presentation of Hypothermia

• Common terms: “umbles” (stumbles, mumbles, fumbles, grumbles).

• Degrees of Hypothermia:

  • Mild: Core temp 32°-35°C.

  • Severe: Core temp < 32°C.

Management of Hypothermia

• Immediate Response:

  • Remove wet clothing, protect warmth, horizontal positioning.

  • Avoid rough movements; monitor temperature and cardiac rhythm.

• Rewarming Techniques:

  • Mild cases: blankets, heat packs, IV Fluids

  • Severe cases: hospital-based intervention required.

Risks Associated with Rewarming

• Rewarming Shock: Potential for complications such as sudden core temperature drops due to trapped cold blood returning to the heart.

Frostbite

• Definition: Freezing of body tissues leading to cell destruction and loss of vascular integrity.

• Symptoms: Altered sensation, discoloration, hard texture, and potential for gangrene.

  • Management: Gentle handling, do not thaw prematurely, cover thawed areas with a sterile dressing.

transport and CPR initiation:

• H- hypothermia

• O- overdose

• P- pediatrics

• E- eletrical activity on ECG

Transport:

• gentle transportation

  • due to myocardial irritability

• patient level or head slightly down

• consider availability of cardiac bypass rewarming

Hyperthermia

• Definition: Elevated core body temperature with symptoms of thermolysis failure.

• Signs: Diaphoresis, flushed skin, confusion, altered consciousness.

• Risk Factors: Age, poor health, medications contributing to decreased thermoregulation.

Heat-Related Disorders

1. Heat Cramps: Caused by overexertion and dehydration. Painful but not severe.

2. Heat Exhaustion: Symptoms include dehydration, weakness, headache. Requires immediate cooling and hydration.

3. Heat Stroke: A medical emergency with core temp >40°C and significant changes in mental state. Requires aggressive cooling and monitoring.