Chapter 6: Environmental Considerations Flashcards
Define Hyperthermia
Elevated body temp.
5 ways heat can be gained or lost
1) metabolic heat production
2) conductive heat exchange
3) convective heat exchange
4) radiant heat exchange
5) evaporative heat loss
Define Metabolic Heat Production
Heat produced by normal metabolic function.
. Increase in activity increases metabolic function and therefor amount of heat produced
Define conductive heat exchange
A heat loss or gain as a result of physical contact with other objects
Define convective heat exchange
heat loss or gain when a mass of either air or water moves around an individual.
Define convective heat exchange
heat loss or gain when a mass of either air or water moves around an individual.
. Removes heat from the body’s surface
Define radiant heat exchange
dilation of superficial blood vessels allowing heat to dissipate through the skin.
. can gain heat through radiant exchange from the sun
Define evaporative heat loss
Sweat evaporates taking heat w/ it.
. sweating doesn’t cause heat loss, it must evaporate off the skin.
How does humidity affect evaporative heat loss?
Increased air humidity causes a decrease in sweat evaporation.
. heat loss is severely impaired when relative humidity is 65% and virtually stops at 75%
Factors affecting sweat rates
height and weight acclimatization fitness levels hydration status environmental conditions clothing intensity & duration of activity heredity
S&S of mild dehydration
thirst / dry mouth headache dixxiness irritability lethargy excessive fatigue cramps
an adult doing minimal activity needs ___L of water/day
2.5 L
Average sweat loss during an hour of exercise is ____L
1.5 L
Gradual acclimatization to avoid heat stress should occur over ____ days
7-10 Days
. days 1-6 80% acclimatization w/ 2hr practices in the mornings and evenings
. sessions broken down into 20min work, 20 min rest
Individuals susceptible to heat stress
young & elderly over weight ppl w/ poor fitness levels ppl w/ history of heat illness ppl w/ fever ppl w/ sickle cell trait
what does WBGT stand for and what does it do
Wet Bulb Globe Temperature
what does WBGT stand for and what does it do
Wet Bulb Globe Temperature
. Objective means of determining heat index
what is the WBGT calculation
WBGT = 0.1 X DBT + 0.7 X WBT + GT X 0.2
. DBT = Dry bulb temp (mercury thermometer)
. GT = Globe temp (measures sun’s radiation)
What is the WBGT calculation if there is no GT reading?
WBGT = 0.3 x DBT +0.7 X WBT
What is heat rash?
red raised rash that prickles/tingles during sweating
usually occurs when skin is continually wet
What is heat syncope / heat collapse
rapid physical fatigue during over exposure to heat
. caused by peripheral vasodilation of superficial vessels and pooling of blood in the extremities
Signs of heat syncope and Tx
. dizziness, fainting and nausea
. lay pt in a cool environment, elevate legs and replace fluids
What are Exertional Heat Cramps
. Painful muscle spasms (calf and abdomen)
. loss of water and electrolytes causing an imbalance
Tx of Exertional Heat Cramps
. Sports drinks
. mild, prolonged stretching w/ ice massage
What is Exertional Heat Exhaustion
. Results from dehydration, heat stress, & exercise
. unable to sustain cardiac output
. rectal temp of less than 104
. no CNS dysfunction
S&S of Exertional heat exhaustion
. no CNS impairment . pale skin . profuse sweating . stomach cramps . vomiting . diarrhea . headache . persistant MUS cramps . dizziness . loss of coordination
Tx of Exertional heat exhaustion
. Immediately remove from play and put in shade
. remove excessive clothing
. lay down and elevate legs
. cool until internal temp of 101
. rehydrate w/ sports drinks (if not nauseous or vomiting)
. transport to ER if there is no rapid improvement
what is Exertional Heatstroke
. CNS abnormalities
. potential tissue damage from increase body temp
. can occur suddenly w/out warning
. rectal temp is 104 and up
S&S of Exertional Heatstroke
. sudden collapse w/ CNS dysfunction . altered consciousness, seizures, confusion, emotional instability, irrational behaviour and/or decreased mental acuity . flushed, hot, and dry skin . shallow, fast breathing . rapid, strong pulse . Nausea &/or vomiting . diarrhea . headache . dizziness . weakness . low BP . dehydration
Tx of exertional heatstroke
. lower body temp ASAP
. remove clothing, cold water immersion or sponge, fans, ice packs
. activate EAP
. pt should avoid exercise for 1 week, and gradually RTP after being fully cleared by Dr.
What is Malignant Hyperthermia
. rare genetic muscle disorder
. causes hypersensitivity to anesthesia & extreme exercise in hot environments
. muscle temp increases to the point of tissue breakdown
.products of breakdown may damage kidneys and cause acute renal failure
. pt complains of muscle P after exercise, rectal temp remains elevated 10-15 min post exercise
. need biopsy for Dx
What is Acute Exertional Rhabdomyolysis
. sudden destruction of skeletal muscle w/ leakage of myoglobin and muscle enzymes into blood.
. gradual onset of muscle weakness, swelling, P, darkened urine & renal dysfunction
. associated w/ ppl w/ sickle cell trait
What is Exertional Hyponatremia
. Low sodium levels . caused by ingesting too many fluids S&S: . worsening headache, nausea/vomiting, swelling of hands and feet, lethargy, apathy, agitation . very low amounts can compromise CNS
what is the average body temp
98.6 F or 37 C
at what body temp does shivering stop
85-90 F
29.4-32.2 C
death is imminent at what core body temp
77-85 F
25-29 F
What is frost nip
. affects ears, nose, cheeks, chin, fingers & toes
. occurs with high wind or severe cold
. skin is firm, w/ cold painless areas
. skin may peel or blister in 24-72hrs
Tx of frost nip
. firm sustained pressure
. blowing hot air on spot
. placing fingers in armpits
. NO RUBBING
What are the 3 types of frostbite
1) chilblains
2) superficial frostbite
3) deep frostbite
Chilblans
. prolonged exposure to cold (many hrs)
. skin redness, swelling, tingling and P in fingers and toes
. problems w/ peripheral circulation
Superficial Frostbite
. involves only the skin & subcutaneous tissue
. skin is pale, hard, cold & waxy
. rewarm by immersing area in warm water
Deep Frostbite
. tissues are frozen
. immediate hospitalization
. tissue is first cold, hard, pale/white & numb
. after rewarming is blotchy, swollen and extremely painful
. rewarm w/ hot drinks, heating pads and hot water
bottles
. tissue may become gangrenous
