CBT385-EMT11: Environmental Emergencies 2011

1. CBT385-EMT11: Environmental Emergencies 2011

2. Introduction • Heat & cold illnesses triggered when body unable to maintain constant temperature • In addition to heat & cold-related illnesses, this course addresses: • Diving emergencies • Stings & bites • Gas poisoning

3. Objectives • Identify the ways the body produces and loses heat. • Identify examples of conduction, convection, radiation and evaporation. • Identify factors that affect heat production and heat loss. • Identify signs and symptoms of heat-related emergencies. • Identify signs and symptoms of cold-related emergencies. • Identify emergency care for heat- and cold-related emergencies and drowning. • Identify the two primary components of anaphylaxis and emergency care for the condition.

4. Terms • core temperature — The operating temperature of an organism. Also, the temperature of the body’s internal structures. • diuretic — A drug such as Lasix (furosemide) and HCTZ (hyrdrochlorothiazide) used in treating congestive heart failure and other ailments. They can cause dehydration making a person more susceptible to heat stress. • evaporation — The conversion of a liquid to a gas.

5. Terms, continued • LOC — Abbreviation for level of consciousness. • metabolism — The human body produces heat by converting food to energy. All bodily functions such as digestion, muscle contractions and breathing require energy. Heat is a by-product of these processes. The body's temperature-control mechanism, located in the hypothalamus region below the brainstem, maintains a core temperature of about 98°F (37°C). There is a balance between production and loss. • tachypnea — A rapid respiratory rate.

6. New Terms • conduction — Conduction is a transfer process by which heat moves between two touching objects from the warmer object to the colder object. It is the motion of molecules bumping into one another, like billiard balls that spreads heat. • convection — Convection is the transfer of heat due to movement of a gas or liquid in response to a temperature or pressure differential. It occurs when a moving gas (e.g., air) or liquid carries heat from a warmer body to a cooler body. It can also work in reverse, carrying heat from a warmer environment to a cooler one. Rising warm air from the earth's surface is an example of convection. • electrocution — Termination of life (stopped heart) by any type of electric shock. • radiation — Radiation occurs when a warm body releases energy without direct contact with another body. Not only can heat energy travel by bumping molecules (as in conduction), it can also travel through electromagnetic waves. .

7. HEAT PRODUCTION AND LOSS

8. Heat Production • Four ways body can produce heat: • Metabolism • Shivering • Exercise • External heat sources

9. Metabolism Metabolism Conversion of food to energy Activity of bodily functions (such as circulation, respiration and muscle tone) Some substances broken down to create energy while other substances are synthesized into tissue building material

10. Shivering Rapid contraction & expansion of muscle tissues Shivering can produce 40 times more heat than baseline metabolism

11. Exercise Produce heat through exercise Happens as long as there is activity, fuel (for instance, glucose or fat), oxygen and water

12. External Heat Sources External heat sources come from environment Sun Fire Chemical sources

13. Factors That Affect Heat Production Many factors affect how well body can produce heat: Core temperature Medical conditions Body fluid status (dehydration) Drugs and chemicals

14. Factors That Affect Heat Production Core Temperature Colder body – less able it to produce adequate heat through metabolism Hypothermia greatly reduces body’s ability to produce heat Cooling slows chemistry of body Medical Conditions Cardiac disease decreases ability to compensate for heat stress Endocrine diseases such as thyroid, adrenal & insulin deficiencies may contribute to hypothermia Strokes can cause immobility with reduced muscular activity Temperature control centers of brain may be damaged

15. Factors That Affect Heat Production Body Fluid Status Metabolism is not as efficient when the body is dehydrated Dehydration is a common problem in hot environments. Drugs and Chemicals Beta-blockers decrease cardiac output & peripheral vascular control mechanisms Effect works to lower body temperature Drugs such as cocaine and amphetamines may contribute to hyperthermia (heatstroke) Mimic stimulation of sympathetic nervous system

16. Heat Loss Four heat loss mechanisms are: Conduction Convection Radiation Evaporation Under normal conditions, heat loss mechanisms are balanced with heat production mechanisms

17. Conduction Transfer process – heat moves between two touching objects From warmer object to colder object Motion of molecules bumping into one another spreads heat Molecules bump around like billiard balls on a billiards table Major source of heat loss in case of cold-water immersion Water conducts heat 25 times more quickly than air

18. Convection As air warms, rises & cooler air replaces it Cool air then is warmed Example – blow on your food to cool it Transfer of heat between body & air or water that surrounds it Occurs when a gas or liquid carries heat away Body’s heat energy is lost more rapidly in moving air or water Example – rising warm air from earth’s surface

19. Radiation Warm body releases energy without direct contact Heat energy travels by bumping molecules (as in conduction) Also travel through electromagnetic waves Sun is best known example of heat transfer through radiation

20. Evaporation Conversion of a liquid to a gas Heat pan of water, energy applied to water will cause to evaporate Requires a lot of heat Takes a lot of energy to break water molecules apart & convert liquid to gas Human body takes advantage of evaporation’s heat loss powers by sweating

21. HEAT ILLNESS

22. Heat Cramps Heat cramps or muscle cramps result from uneven distribution of body fluids & salts Muscle cramps from this condition can be mild to severe, involving the extremities or the abdomen Cramps can be accompanied by: Dizziness Weakness Nausea

23. Heat Exhaustion Named for feeling of exhaustion people experience Result of excessive heat & dehydration Reduce circulating blood volume & increase peripheral pooling due to vasodilation Cooling mechanisms of radiation & evaporation become inefficient due to loss of fluids : Clinical findings associated with heat exhaustion include: Dizziness, weakness and nausea Rapid, weak pulse Cool, clammy skin Profuse sweating Altered LOC

24. Heatstroke Life-threatening emergency – occurs when body's heat-regulating ability fails Happens when body is subjected to more heat than it can deal with & four heat loss mechanisms overwhelmed Clinical findings of heatstroke include: Altered LOC (confusion, disorientation, or unconsciousness) Rapid, bounding pulse Rapid, deep respirations Hot, dry, flushed skin* Dilated pupils Seizures * Can be damp if rapid onset

25. Emergency Care for Heat-Related Emergencies Reduce core temperature: Remove or loosen clothing Provide a cool environment Apply cool packs Request paramedics when ALS indicators are present provide oxygen and/or ventilatory assistance Position patient appropriately Monitor vital signs Patient responsive & not nauseated, consider giving water

26. Cooling Strategies Provide a Cool Environment As soon as time allows, move patient to back of air-conditioned aid car with the air conditioner running on maximum Fan patient aggressively if staffing allows Keep skin wet by applying cool water with a sponge or wet towel

27. Cooling Strategies Remove Clothing Loosen or remove clothing to promote efficient convention Consider applying water with a sponge or wet towels on patient’s skin If you apply water to skin to encourage evaporation, use room temperature water Do not induce shivering

28. Cooling Strategies Apply Cold Packs Neck, groin & armpits Hospitals generally have tools necessary to properly lower core temperature Do not delay transport Notify hospital early to allow ED staff time to prepare

29. COLD EXPOSURE

30. Hypothermia Cooling of core temperature below 98.6°F Caused by loss of body heat or decreased heat production Exposure to a cool environment Immobile elderly person lying on a floor Drowning victim & who has been submerged Hypothermia can occur rapidly in wet environments

31. Hypothermia Early recognition increases chances of survival

32. Frostbite Superficial Injury - Clinical Findings Blanching of skin Loss of feeling & sensation in injured area Tingling sensation if re-warmed Deep Injury - Clinical Findings White, waxy skin Swelling and/or blisters Skin can appear flushed with areas of purple & blanching or mottled & cyanotic

33. Emergency Care for Cold-Related Emergencies Prehospital emergency care for a hypothermic patient is as follows: Remove patient from cold environment Protect from heat loss Provide high-flow oxygen

34. Emergency Care for Hypothermia Remove from Cold/Protect from Heat Loss Move patient to aid car warmed to 80°F Keep patient flat Remove wet clothing May need to protect from heat loss by insulating patient with blankets Provide High Flow Oxygen Provide high flow oxygen via pocket facemask or BVM for a non-breathing patient Recommend use of pocket facemask when ventilating a non-breathing hypothermic patient Helps warm patient more effectively Oxygen administered through BVM is ambient air temperature & low humidity Causes increased heat loss (through evaporation) when compared to warm, moist oxygen/air via pocket facemask Can use a BVM if necessary

35. Hypothermic Cardiac Arrest Hypothermic patient in cardiac arrest or with profound bradycardia, following guidelines apply: If no pulse detected after 1 minute, begin CPR & apply AED If breathing, assume there is cerebral perfusion, therefore NO CPR If AED analysis yields a “shock indicated” follow cardiac arrest protocol If pulse is present withhold CPR regardless of rate or BP

36. Emergency care for Frostbite Protect affected area from further injury Remove constricting or wet clothing & jewelry Cover with dry bulky dressing Splint affected extremity, prevent use of extremity

37. Transport Times Over Two Hours Do not re-warm frozen tissue unless transport time will exceed 2 hours & you are certain the thawed tissue will not refreeze Obtain medical direction prior to initiating re-warming Re-warming should be done with 100 – 105°F water Do not use dry heat—it heats unevenly and can burn frozen tissue Stop re-warming when tissue turns red-purple & becomes pliable

38. WATER-RELATED

39. Drowning and Near Drowning Drowning – death caused by hypoxia following submersion in water Near drowning – submersion in water that does not result in death Without oxygen, hypotension, bradycardia & cardiac arrest ensue Several things you should determine: Length of submersion Temperature of water Depth of water

40. Length of Submersion Include length of submersion in report to hospital staff May have to estimate based on bystander testimony & other indicators Submersion is short duration (2 minutes or less), a short period of CPR likely will result in successful resuscitation Significant number of near-drowning patients who look fine initially develop pulmonary edema several hours later Non-cardiac related condition is called acute respiratory distress syndrome (ARDS).

41. Water Temperature Important factor in how long someone can survive without oxygen Cold water drowning victims (less than 70°F) can survive for up to 1 hour without oxygen Record for a successful resuscitation – 3-year-old child immersed for 66 minutes in 33°F water Children often survive longer because they cool faster than adults Some studies indicate that temperatures need to be below 50°F for any significant chances of survival to occur after long immersion

42. Water Temperature Submersion times greater than 10 minutes make successful resuscitation unlikely in most warm water drowning situations Survival from long submersion times more likely when brain cools fast enough to receive protection from hypoxia People who cool before they drown (e.g., hanging onto ice or overturned boat) may have a better neurological outcome

43. Depth of Water Spinal injuries seen in many water-related accidents Diving into shallow water common mechanism for head & spinal injury & subsequent drowning Potential for a spinal injury, stabilize cervical spine while in the water, if possible Other conditions associated with drowning: Skeletal & soft tissue injuries Drug or alcohol intoxication Underlying medical conditions

44. Emergency Care for Drowning/Near Drowning Management requires prompt basic life support & following measures: Safely remove victim from the water Stabilize c-spine and place patient on a backboard* Follow resuscitation protocols for cardiac or pulmonary arrest Administer oxygen and/or ventilatory assistance Place in a supine position to avoid cerebral edema Prepare suction and expect vomiting Warm up the aid unit Monitor vital signs *If spine injury is suspected or patient is unresponsive. If possible, initiate stabilization during removal from water

45. Air Embolism Most SCUBA dives occur without incident, use of compressed air or other gases in an underwater environment can be hazardous In addition to drowning, common diving-related hazards include air embolism and decompression illness bubbles into bloodstream

46. Air Embolism Air embolism – presence of gas bubbles in bloodstream that obstruct circulation Occurs during ascent when pressure in lungs forces air

47. AIR EMBOLISM Signs: Apnea (no breathing) Frothy fluid from nose or mouth Loss of consciousness Partial weakness or paralysis Seizures Irregular pulse Death Symptoms: Dizziness Confusion Chest pain Diminished sensation in parts of the body Visual blurring

48. Decompression Sickness Nitrogen in blood forms bubbles due to rapid ascent Bubbles collect in tissues & interfere with blood flow Significant history for all diving emergencies includes: Number of dives in past 24 hours Depth of dive Length of time underwater Problems encountered while diving Significant medical history (including meds)

49. Decompression Sickness Dive usually at depth of at least 33 feet Less likely at depths <33 feet Still can happen Longer & deeper the dive, more nitrogen dissolves in blood Dehydration, exertion & air travel within 12 hours after diving all increase the probability of DCI Symptoms of DCI vary widely depending on where bubbles collect Joint pain, abdominal pain, neurological symptoms & difficulty urinating are common Diver who complains of feeling ill after diving should be evaluated for DCI Symptoms can appear within a few minutes of surfacing or it may take hours

50. ALLERGIC REACTION