environmental illness Flashcards
temperature is regulated by
hypothalamus
body can tolerate hypothermic change of about
en bas de 5ºC
body can tolerate hyperthermic change of about
en haut de 3ºC
Body functions within narrow temperature range of about _°C on either side of 37C
3
mechanism of heat loss
convection
conduction
evaporation
radiation
what is convection
Air currents blowing across the body remove heat from body. (eg: windchill)
40% loss through head and neck
what is conduction
Direct heat exchange from one body surface to another. The second body can be air, solid, or a liquid
Whatever is in contact with the patient can remove heat if colder.
Can generally lose heat twice as fast through the _ than to the _
ground than the air
A person loses much more heat in the _ than _ of same temp
water than air
(ie: keep victim dry ; remove wet clothing)
what is evaporation
Changing from liquid to gas requires calories. A liquid that evaporates from the skin surface removes calories in the process.
During exercise evaporation accounts for as much as % of total heat loss in a hot/humid environment (% if hot/dry).
75, 90
what is radiation
Energy in the form of heat radiates in waves (Infra-red) through the air or other medium.
❑Patient heat is absorbed by cooler environment or nearby objects. (ie: warm air from lungs)
_ air ambient temp, _ heat loss via conduction, radiation, convection
increase, decrease
_ ambient temp, _ heat loss gradually by conduction, convection (worst in windy or wet environment)
decrease, increase
Wet Bulb & Black Globe temperature taken for minute at specific site
1
wet bulb + black globe green, yellow, red, black flag
<18 ºc green flag low risk
18-23ºc yellow flag, moderate risk
23-28ºC red flag, high risk
>28ºC black flag, extreme risk
heat stress prevention
Education
❑ On-site medical coverage with authority to
withdraw individuals
❑ Pre-season exam with appropriate info
❑ Optimal Hydration
Common for athletes to lose between _ lbs of sweat playing a game
5-8
Losses as little as % of body weight can impair performance / ↑ fatigue (eg: lbs in a 200 lb player)
2, 4lbs
how most research show that sport drinks out perform water for athlete rehydration.
- encourages voluntary drinking when
❑ athletes hot and thirsty (flavour)
❑- stimulates rapid fluid absorption
❑ (mix of carbs <7%, electrolytes)
❑- helps prevent dehydration
dehydration factor
- When athletes do not replenishlost fluids… leads to dehydration
❑Mild dehydration is often unavoidable (< 2% body weight loss BWL )
❑Difficult to maintain peak hydration, as little as 2% BML can begin to hinder performance thermo- regulatory function
❑Optimum hydration is the replacement of fluids and electrolytes in accordance with individual needs.
❑Fluid intake = Fluid losses
❑Fluid intake beyond fluid needs for many hours can also be quite harmful.
recognition of dehydration
❑Thirst
❑Dry mouth
❑Headache
❑Head/Neck heat sensation ❑Apathy
❑Chills
❑Excessive fatigue ❑Irritability
❑Weakness
❑Vomiting
❑Decrease performance ❑General malaise ❑Dizziness
❑Cramps
Maintaining normal hydration (as per baseline body weight) is critical If athlete’s BWL is > % within a given day, should _
Maintaining normal hydration (as per baseline body weight) is critical If athlete’s BWL is > 1-2% within a given day, should return to normal hydration status before being allowed to practice.
Fluid deficits should be replaced within _hrs after exercise
is complete
1-2
_ with + _ optimal before & during exercise (athletes usually only replace 1⁄2 of fluid lost when drinking plain water)
sport drink, carbs + electrolyte
T/F.A nauseated / vomiting athlete should seek medical attention (IV fluid)
T
T/F. If dehydration minor and athlete symptom free ….may return
T
Do not allow hydration losses to go above % body weight
2
When high rate of fluid intake necessary:
When high rate of fluid intake necessary: carb composition <7%
Factors that may increase the risk associated with exercise in the heat include:
INTRINSIC:
History of exertional heat illness ❑Inadequate heat acclimatization ❑ Lower level of fitness
❑High % body fat
❑Dehydration or over-hydration ❑Presence of a fever
❑Presence GI illness
❑Salt deficiency
❑Skin condition (sunburn, skin rash etc)
❑ Medications(anti-histamines,diuretics,ephedra) ❑Motivation to push oneself (warrior) ❑Reluctance to report problems: macho/macha ❑ Pre-pubescence
Factors that may increase the risk associated with exercise in the heat include:
EXTRINSIC:
Intense/prolonged exercise with minimal breaks ❑ High temperature/humidity/sun exposure
❑ Previous days exposure to heat / humidity
❑ Inappropriate work/rest ratios based on intensity, ❑ WBGT
❑ Clothing
❑ Equipment
❑ Fitness
❑ Medical conditions.
❑ Lack of education/awareness heat illness among coaches, athletes, medical staff
❑ No EAP to identify/ tx exertional heat stress
❑ No access to shade during exercise or rest breaks
❑ Duration and number of rest breaks is limited
❑ Minimal access to fluids before /after practice and rest breaks is limited
❑ Delay in recognition of early warning signs
Exertional heat stroke is a severe illness characterized by
Exertional heat stroke is a severe illness characterized by CNS abnormalities and potentially tissue damage.
Exertional heat stroke result from
elevated body temperatures induced by strenuous physical exercise and increased environmental heat stress.
critical factors of Exertional heat stroke
- CNS dysfunction-
❑ altered consciousness
❑ coma
❑ convulsions,
❑ disorientation,
❑ irritable behaviour, ❑ ↓ mental acuity
❑ emotional instability, ❑ confusion,
❑ hysteria
❑ apathy
BP, HR and RESP of Exertional heat stroke
increase HR, decrease BP, increase rest
_ temps are not valid in athletes exercising in hot environments
❑Axillary, oral, tympanic temps are not valid in athletes exercising in hot environments.
Rectal temperature technique:
❑Athlete side-lying,
❑Safe position /unable to roll on back.
❑Shake mercury down disinfected glass thermometer
❑Prep small bulb thermometer (sheath) with Muco/ KY
❑Gloved hands spread gluteal fold, locate anus
❑Gently insert thermometer into rectum without resistance Insert within approximately 1” depending size of athlete.
❑If using a wired thermistor, should insert between 1-2” ❑Take core temperature for 2-3 minutes a glass thermometer.
Electronic models will beep when measurement is taken.
when are you consider hyperthermic
Rectal temperature >40C (104F) post activity
treatment of Exertional heat stroke
Aggressive whole body cooling ideally via cold water immersion within minutes post incident approximately 2- 14 C (35-58 F)
❑ Temperature drop should be monitored, once dropped -transport
❑ “Cool First , Transport Second”
❑ Cease cooling when core reaches approx: 38.4 - 39C
(101-102F)
initial response of Exertional heat stroke
Tank can be filled with ice and cold water before an event (or have tub half-filled with water and three to four coolers of ice next to tub; this prevents having to keep tub cold throughout the day. Ice should cover the surface of the water at all times. If the athlete collapses near an athletic training room, a whirlpool tub or cold shower may be used
when do you take vital sign with Exertional heat stroke
Determine vital signs. Just before immersing the heat-stroke patient, take vital signs.
Assess core body temperature with a rectal thermistor (thermistor implies flexible thermometer that stays in during cooling and allows for continuous monitoring of temperature during immersion therapy).
temperature of water during ice water immersion
<15
position of athlete in ice water immersion
otal body coverage. Cover as much of the body as possible with ice water while cooling.
* If full body coverage is not possible due to the container’s size, cover the torso as much as possible.
* Keep the athlete’s head and neck above water, an assistant may hold the victim under the axillae – armpits – with a towel or sheet wrapped across the chest and under the arms.
what need to be done with water during ice immersion bath to optimize cooling
- Vigorously circulate water. During cooling, water should be continuously circulated or stirred to enhance the water- to-skin temperature gradient, which optimizes cooling.
Continue cooling until the patient’s rectal temperature lowers to at least
38.4
If rectal temperature cannot be measured and cold water immersion is indicated, cool for
10-15 minutes and then transport to a medical facility.
An approximate estimate of cooling via cold water immersion is:
1°C for every five minutes and
* 1°F every 3 minutes (if the water is aggressively stirred).
* This means, the cooling rate will be slower initially, and increase the longer the person is in the tub. For example, if someone is in the tub for 15 minutes they would cool approximately 3°C or 5°F during that time.
cool , transport
first, second
T/F.During transportation, maintain the rectal thermistor, which allows body temperature to be monitored continuously.
T
If cold water immersion is not available or feasible, then cool via the best available means. A good highly portable alternative is a
cooler filled with ice, water, and 12 towels. Place six ice/wet towels all over body and leave on for 2-3 minutes, then place those back in cooler and put the six others on the patient. Continue this rotation every 2-3 minutes. Another alternative when a tub is not available is cold water dousing from a locker room shower or from a hose.
Alternate Cooling Strategies:
TACO Tarp Assisted Cooling with Oscillation ❑ Ice bags-neck, axillary, groin, cold towels
(40% heat loss at head/neck)
❑ Cold water/mist spray, fans
❑ Monitor ABC, Core Temperature, CNS Status, prep for transport (organ damage?)
RTP guideline of Exertional heat stroke
MD clearance
❑ Avoid all exercise until completely asymptomatic / labs normal
❑ Severity of illness dictates length of recovery time
❑ Avoid exercise at least 1 week after release from medical
care
❑ Gradual return to supervised conditioning and acclimatization
HEAT EXHAUSTION
Factors:
Moderate illness with inability to sustain adequate cardiac output, resulting from strenuous physical exercise and environmental heat stress.
recognition, critical factors of heat exhaustion
Athlete has obvious difficulty continuing intense exercise in the heat
2. Lack of severe hyperthermia usually <40C (104F)
Would expect to find: 37.7-39.4C (100-103F) 3. Lack of severe CNS dysfunction
(mild symptoms quickly resolve)
Any symptoms would resolve quickly
with treatment/rest
other factor of heat exhaustion
- Physical fatigue
- dehydration / electrolyte depletion
- coordination problems, syncope, dizziness
- profuse sweating, pallor
- headache, nausea, vomiting, diarrhea
- stomach/intestinal cramps,
persistent muscle cramps - rapid recovery with treatment
treatment of heat exhaustion
Remove athlete from play and move to shaded /air conditioning
❑ Remove excess clothing / equipment
❑ Cool athlete until rectal temperature approx.
38.3C (101F )
❑ Place athlete supine with legs elevated above
heart level
❑ If not nauseated/vomiting, without CNS symptoms…rehydrate
❑ Monitor: HR, BP, Resp, Rectal temp, CNS status
❑ Transport to ER if not rapidly improving with treatment
RTP with heat exhaustion
❑ Symptom free and fully rehydrated
❑ MD clearance if severe
❑ Rule out underlying conditions/illnesses
❑ Avoid intense practice in heat until at least
next day
❑ Correct underlying problems before return to full intensity
HEAT CRAMPS
Factors:
Causes not well understood, may be number of causes
❑ Often present in athletes who perform strenuous exercise in the heat
❑ Can also happen in absence of warm/hot conditions (eg: hockey players)
❑ Tend to occur later in an activity in conjunction with muscle fatigue and after fluid/electrolyte imbalance at critical level.
❑ Often accompany heat exhaustion in up to 60% of the cases
❑ Can be avoided: adequate conditioning , acclimatization, rehydration, electrolyte replacement, good diet
critical factors of heat exhaustion
Intense pain (not a muscle strain)
Persistent muscle contractions in working muscles during and after prolonged exercise, often in the heat
other factors of heat cramp
Salty sweaters
2. High sweat rate
3. Lack of heat acclimatization 4. Insufficient sodium intake
(during meals and practice) 5. Dehydration, thirsty
6. Irregular meals
7. Increased fatigue
8. Previous history of cramping
treatment of heat cramp
Re-establish normal hydration status Replenish some sodium losses (electrolyte drink)
❑ Extra sodium for those with cramping history (1/4 tsp table salt in 1 liter sports drink taken early in exercise session)
❑ Light stretching, relaxation ❑ Massage of involved muscle
RTP heat cramp
Assess whether athlete can perform
Review:
❑ diet,
❑rehydration practices, ❑electrolyte consumption ❑fitness level, ❑acclimatization level, ❑dietary supplements
EXERTIONAL HYPONATREMIA
FACTORS:
When an athlete consumes more fluids (especially water) than necessary, and/or sodium lost in sweat is not adequately replaced.
Sodium in the bloodstream can become diluted and cause cerebral and/or pulmonary edema.
Hyponatremia (low blood sodium levels) tends to occur during warm / hot weather activities.
The risks can be reduced if fluid consumption during activity does not exceed fluid losses and sodium is adequately replaced.
Exertional hyponatremia critical factor
- Low blood sodium levels (< 130 mmol/Liter) Severity of condition increases as sodium level ↓
- Likelihood of excessive fluid consumption before, during, after activity (weight gain during activity!)
- Low sodium intake
- Likelihood of sodium deficits before, during, after exercise
- If condition continues…CNS changes: altered LOC, confusion, coma, convulsions, altered cognitive fcn, respiratory changes fro cerebral and/or pulmonary edema
other criteria of hyponatrenia
- ↑ Headache
* 2. Nausea, vomiting (repetitive)
* 3. Swelling of extremities
* 4. Irregular diet
* 5. During prolonged activities(usually >4hrs) * 6. Copious urine with low specific gravity
following exercise
* 7. Lethargy, apathy
* 8. Agitation
* 9. Absence of severe hyperthermia <40C
( 104F )
treatment of hyponatremia
- If unable to assess blood sodium levels onsite, avoid rehydrating, transport to ER
- Athlete may need sodium, certain diuretics, or IV solutions, and monitoring
RTP hyponatremia
MD clearance
* In mild cases, resume in a few days * Educate regarding individual specific
hydration protocols
what is cold emergencies
Changes in core temperature and reduced circulation are the primary associated complications with cold injuries.
* When the body is cold, blood vessels near the skin constrict, deepening warm blood in the center of the body. When constriction of blood vessels is not enough to keep the body warm, the body starts to shiver. Shivering produces heat through muscle actions.
T/F. The clinical conditions of cold injuries are not as dramatic as with heat trauma, neither in rapidity of onset nor as immediately visible diagnostic clues.
T
what is frostbite
In frostbite, there is actual freezing of the water in the body tissue as a result of exposure to freezing or below freezing temperatures.
* Intra-cellular and extra-cellular fluids can freeze resulting in the formation of ice crystals. As the ice crystals form, they expand and cause damage to local tissues.
* Blood clots may also form, further impairing circulation in the area
what is superficial frostbite
Athlete feels slight pain or burning sensation in affected extremity
which later develops into numbness.
* Skin appears grayish or yellow.
* When digital pressure is applied to the area, the tissue below will feel soft
and malleable like normal tissue.
what are deep frostbite
If athlete does not recognize or react to the numbing sensation, the freezing of the tissue continues until area becomes more waxy looking.
* When nerve endings become frozen, numbness and pain stop.
* The frozen parts are hard and not pliable when affected tissue is compressed.
* The longer exposed to the cold, the more severe the injury will become. Severity only known once body part has thawed and body attempts to repair the damage.
assessment of superficial frostbite
- Environmental conditions below freezing
- Complaint of numbness of a digit, hand,
foot, facial area - Observed discoloration of skin in the area
- “Gentle”palpation to determine if tissue
pliable or hard when compressed - Complaint of pain with manipulation of frostbitten area
assessment deep frostbite
- environmental conditions ↓ freezing
- pain and numbness have stopped while frozen
- more waxy looking tissue
- gentle palpation painless , hard tissue with compression 5. no complain of pain while still frozen
management of deep frostbite
Remove patient from cold environment Suspect also systemic hypothermia
Appropriate shelter, supportive care, early transport
Patient can drink something warm (no alcohol) if good LOC No re-warming in the field, needs controlled setting:
1. Needs rapid immersion with consistent water temp 38-42C (102-108F)
2. Re-warming process extremely painful – need IV analgesics
3. If re-warming has been started, and for some
reason extremity allowed to re-freeze, gangrene
may occur and may need partial/full amputation
If re-warming as been initiated, affected body
parts should be elevated gently to reduce swelling while maintaining re-warming process. Individual
digits should be seperated, blisters should not be burst.
management of superficial frostbite
Place affected area against a warm body surface re-warm at normal body temperatures
HYPOTHERMIA Condition:
Condition in which core body temperature is measured below 35C (95F) when using a rectal thermometer.
* Can occur in environments with temperatures well above freezing.
* If unrecognized or improperly treated can be fatal, in some cases within 2 hours.
what happen when body core temperature fall below 35ºC
As the body’s core temperature falls below 35C ( 95F), the HR, ventilatory drive, BP, and cerebral and peripheral blood flow all begin to decrease.
The reduced peripheral blood flow shunts warm blood to the core at the expense of the shell. This higher core blood volume causes cold diuresis (↑ urine secretion by kidneys) and ultimately hypovolemia.
* Skeletal muscles begin to shiver subtly, more violently and gradually ceases as muscles become stiff and core temp. drops below 32C ( 90F).
* Progressive cellular hypoxia,↑ lactic acid, metabolic acidosis, vitals drop off, arrhythmias, death…
Hypothermia Severity
Determined by core temperature:
Mild: core temperature > 32C (90F) Profound: core temperature < 32C (90F)
HYPOTHERMIA
Categories:
- Immersion
- Submersion
- Field
- Urban
what is hypothermia immersion
Victim in a cold environment without preparation eg: fallen through the ice in a river
what is hypothermia submersion
Combination of hypothermia and hypoxia Survival outcomes determinants:
1. Age (younger do better)
2. Submersion time
(< time the better, poor outcome > 66 min.)
3. Water temperature
(colder the water the better <21C (70F) 4. Struggle (less struggle the better)
5. Cleanliness of water (cleaner the better)
6. Quality of the CPR / resuscitative efforts
7. Associated injuries or illness
what is hypothermia field
overexposure to cold temperatures eg: outdoor wilderness sports
what is hypothermia urban
Cold exposure to people with illness/conditions/ young /old
assessment hypotjermia
Environmental conditions
* Need LOW RANGE rectal thermometer * Presence of muscular shivering
* LOC status
caractheristic of mild hypothermia
Core temp >32C (90F)
* Altered LOC
* Confusion
* Slurred speech
* Altered gait * Clumsiness * Shivering
characteristic of profound hypothermia
Core temp <32C (90F)
* Not complaining of cold
* Marked decrease in LOC
* Near unconsciousness/coma
* Shivering absent
* Pupils: react slowly,
* Pupils: may be dilated / fixed
* Palpable pulses absent/diminished * BP may be low / indeterminate
* Ventilations slowed to 1-2 /minute * A-fib /V-fib
management of hypothermia
Prevent further heat loss
* Gentle handling (may cause V-fib)
* Rapid transport / 911
* Re-warming in some circumstances (severe blizzard/disaster)
* Patient placed in a bathtub of warm water 40C (104F) with extremities left out, body’s core will warm first (prevent after-drop).
Warm shelter, Remove wet clothing (cut)
* “Buritto Technique”-blanket cover including the head,
re-warm with body heat while awaiting 911
* If conscious/alert drink warm/sweet fluids
* NO hot packs or massaging or re-warming of the extremities before the core
* CPR once commenced must be continued until patient arrives at hospital and is re-warmed.
* Patient must be warm before death can be determined
