Environmental Conditions

Question 1

What is the best way to monitor dehydration?

Answer 1

Measuring BODY WEIGHT CHANGE before, during and after activity

Question 2

What are the four mechanisms of heat transfer between skin and environment? Give examples

Answer 2

• Conduction – between two surfaces (ice pack on swollen knee)
• Convection – flow of liquid or air (cooling fan, submersion in cool bath)
• Radiation – electroradiation (sunlight)
• Evaporation – heat release with energy change between forms (sweat to vapor) = most common and efficient method

Question 3

List the environmental risk factors associated with heat intolerance

Answer 3

• High TEMPERATURE (high outside temp above body temp), High HUMIDITY (largest factor determining WBGT score) → when both are high, diminishes evaporative heat loss = increased risk of EHI
• Other factors = WIND SPEED and SOLAR RADIATION
• Wet bulb globe temperature = combines 4 variables into a single number to determine EHI risk

Question 4

List the non-environmental risk factors associated with heat intolerance

Answer 4

• AGE (kids; middle and older age), WOMEN (during luteal phase of cycle = higher body core temp, delayed onset of sweating), HIGH BMI (>30, increased body fat and low surface area:body mass), POOR ACCLIMATIZATION (body will respond over 2-week period = altered Frank Starling Reflex [inc SV, dec HR], inc sweat rate, dec body temp, dec skin temp), AEROBIC CAPACITY (untrained, lower capacity), HYDRATION STATUS, MEDICATIONS (pg.49), PREVIOUS HEAT RELATED ILLNESS, CLOTHING (rubber or plastic suits, excessive clothing), SPORT SPECIFICITY (American football)

Question 5

What is the most critical aspect of managing EHI to avoid serious/adverse outcomes?

Answer 5

• LIMIT the DEGREE and DURATION of elevated core temp (assess temp via rectal thermometer)
• COLD WATER IMMERSION = fastest whole body cooling rate and lowers morbidity and mortality rate

Question 6

What underlying medical condition should you be aware of with exercise associated muscle cramps?

Answer 6

Sickle Cell trait: cramping is preceded by subtle muscle twitching versus EMACs which come on quickly

Question 7

What is the primary goal of cooling someone suffering for Exertional Heat Stroke?

Answer 7

LOWER body core temperate to <38.9 deg C/102 deg F WITHIN 30 MIN of collapse

Question 8

Differentiate the temperatures associated with each heat related injury.

Answer 8

• Heat Syncope = <39 deg C/102.2 deg F (not commonly assessed)
• Heat Exhaustion = <40.5 deg C/105 deg F
• Exertional Heat Stroke = >40.5 deg C/105 deg F

Question 9

What are the primary differences in characteristics between heat related injuries?

Answer 9

• Heat Syncope/Orthostatic Dizziness = DIZZINESS, tunnel vision, paleness, dec pulse rate
• Heat Exhaustion = heavy SWEATING, dehydration, fatigue, HA, dizziness, confusion, vomiting, lightheaded, low BP, impaired coordination
• Exertional Heat Stroke = first sign is CNS DYSFUNCTION (collapse, confusion, seizures, altered LOC), hot skin, lack of sweat, may collapse

Question 10

Cover acute management strategies for each heat related illness

Answer 10

• Heat Syncope = remove from play→ shaded area, legs elevated, cool skin, rehydrate and monitor vitals
• Heat Exhaustion = same as above but include ice towels/fans/cold water immersion, MONITOR temp every 10 min
• Exertional Heat Stroke = IMMEDIATE cold water immersion up to neck, get temp DOWN to 38.6/101.5 and then transport

Question 11

What causes Exercise Induced Muscle cramps and how are they managed?

Answer 11

• Exercise Induced Muscle Cramps are due to overexertion, or fatigue (usually mild, and last <5 min).
• Managed by: rest, rehydration and electrolyte replacement (ingest beverage with CHO and sodium).

*Can acutely passively stretch involved muscles (GTO = inhibition of muscle contraction)

Question 12

What are the return to play recommendations for Heat syncope? Heat Exhaustion? Heat stroke?

Answer 12

• Heat Syncope = can resume once dizziness subsides (typically the following practice)
• Heat Exhaustion = when symptoms resolve and vitals normalize (same day return not recommended; MILD 1-2 days; SEVERE 2-4 weeks)
• Heat Stroke = asymptomatic with normal bloodwork prior to initiating RTP protocol (usually determined by length of time temp was elevated), typically SHOULD REST 7-21 days

Question 13

What are the key prevention strategies for heat-related illness?

Answer 13

• ACCLIMATIZATION (takes 7-14 days)
• Monitoring HYDRATION STATUS and BODY WEIGHT (establish baseline body weight – morning, over several non-training days)
• Establish GOOD HYDRATION practices -> drinking as needed, drink 5-7 mm/kg body weight within 4 hours before exercises, drink water+CHO sol’n for events >1 hour, ~1.5 L for every kg bodyweight lost = when aggressive rehydration required

Question 14

How does the body respond, physiologically, to cold exposure?

Answer 14

• Cold causes skin temp to decrease with resulting VASOCONSTRICTION and DECREASED PERIPHERAL BLOOD FLOW (to reduce heat loss). Intermittent bouts of vasodilation (every 5-10 min) will occur to protect against freezing = brings cold blood back to core with resulting dec in core temp
• SHIVERING occurs (involuntary contractions of skeletal muscle) to produce heat (6x greater than resting metabolism; vigorous exercise = up to 10x) once skin and core temp hits specific threshold.

Question 15

What are the environmental risk factors for cold related injury?

Answer 15

• COLD, WET, WIND combination; cold temp and stronger winds = shorter time to frostbite onset; wet = water transfers a greater amount of heat → greater heat loss at higher ambient temps when wet
• APPAREL WORN (warm clothing, wind barriers and shelters) before and after competition

Question 16

What is the ACSM recommendation regarding wind-chill and ambient temperatures to assess frostbite risk?

Answer 16

• When skin is WET and EXPOSED TO WIND = ambient temp used should be 10 deg C LOWER than actual reading (10 deg C should be 0 deg C)

Question 17

What are the non-environmental risk factors for cold related injury?

Answer 17

• AGE (kids and >60 yrs produce less heat)
• GENDER (heat loss greater in women with > surface:mass)
• BODY FAT (higher % = insulation, protective)
• PRE-EXISTING MEDICAL CONDITION (hypoglycemia, endocrine conditions)
• MEDICATIONS (beta blockers, benzodiazepines = may delay response to cold by effecting nervous and vascular systems)
• PREVIOUS cold-related injury
• ACUTE INJURY (protect from cold while managing acute needs of injured)
• OVERTRAINING, FATIGUE, UNDER-NOURISHED

Question 18

What is hypothermia? Differentiate between each types.

Answer 18

• Hypothermia is when the body LOSES heat to the environment at a greater rate than it is able to preserve or generate heat.
• MILD Hypothermia body core temp 32-35 C/90-95 F.
• MODERATE Hypothermia body core temp is 28-32 C/82.5-90 F
• SEVERE Hypothermia <28 C/82.5 F

Question 19

What are the primary signs and symptoms for each type of hypothermia?

Answer 19

• MILD Hypothermia S+S = often vague → shivering, irritability, apathy, pale and cool extremities, increased urination (from blood shunting to core)
• MODERATE Hypothermia S+S = shivering stops, bradycardia and hypotension, stupor
• SEVERE Hypothermia S+S = coma-like appearance (hypopnea, bradycardia, hypotension, areflexia), risk for dysrhythmia (acid-base imbalance)

Question 20

Discuss acute management strategies for all forms of hypothermia

Answer 20

• MILD Hypothermia Tx = move indoors, remove wet clothing, wrap in blankets
• MODERATE and SEVERE Hypothermia Tx = remove wet clothing, active external rewarming (warm blanket, heating pad, warm bath, forced warm air)

Question 21

What is Afterdrop?

Answer 21

• AFTERDROP occurs when rewarming peripheral extremities results in peripheral cold blood returning to the core and causing core temp to drop.
• This is why frostnip or frostbitten extremities SHOULD NOT be re-warmed until core temp reaches 35C/95F; extremities should be warmed one at a time.
• ALSO, rewarming shock (cardiac dysrhythmia and vascular collapse) can develop.
• Afterdrop = reason why athletes should be transported to sheltered area horizontally (to avoid using peripheral musculature) with mod to severe hypothermia

Question 22

What is Chilblains? Which athletes are you most likely to see this?

Answer 22

• Chilblains is a PRE-FREEZING injury and a response to repeated cold (seen as red papules usually on hands and feet – can progress to ulcers).
• Typically from exposure b/t 0-5 hours at 0-10 deg C (32-50 F).
• More common in athletes who have multiple games on same day (soccer, softball, lacrosse) = prolonged cold exposure

Question 23

Differentiate between different types of frostbite injury classifications

Answer 23

• FROSTNIP = superficial non-freezing injury of skin, may have N+T, skin may be pale or red, sx resolve with skin covering
• SUPERFICIAL frostbite (1st and 2nd degree)= skin temp drops below 10 deg C, skin is red stiff edema and blistering, N+T or burning
• DEEP Frosbite (3rd and 4th degree) = tissue hard and doesn’t rebound, tissue black and blue appearance, hemhorragic blisters, sometimes have mild sx but with rewarming can identify deep tissue involvement

*severity of frostbite can vary within extremity (see table 5 for stages of frostbite)

Question 24

What is the biggest risk factor for frostbite?

Answer 24

• AIR TEMPERATURE → must be less than 0 deg C (32 F)

Question 25

What are the positive predictive findings of frostbite injuries?

Answer 25

• Normal skin color, normal skin sensation, clear fluid in blisters

Question 26

What are the negative predictive findings of frostbite injuries?

Answer 26

• Non-blanching cyanosis, cloudy fluid blisters, firm/hard skin

Question 27

What are the different types of treatment for frostbite injury – both acute and subacute?

Answer 27

• ACUTE → Remove from cold environment, remove wet clothing, replace with warm clothing, ensure if re-warming to account for afterdrop (rewarm when core temp is stabilized at 35 deg C), re-warm ONLY when no risk of re-freezing (can lead to more substantial tissue damage), if need to pre-hospital warm = avoid fires and stoves (due to dec sensation) and avoid rubbing (can damage tissue).
• SUBACUTE → warm bath/whirlpool at 37-39 deg (98.6 to 102.2 F) [greater than 39 C doesn’t increase rate of thawing], rewarming takes ~20-30 min (skin will become red or purple and soft, pliable), air dry or gently blot to dry (to avoid tissue damage), manage blisters (NSAIDs and topical aloe vera), monitor blisters for infection

Question 28

What does the athlete need to be cautious of after episode of frostbite?

Answer 28

• After frostbite injury the athlete needs to be cautious of cold exposure – especially in the first 6-12 months (may be contraindicated depending on extent of injury)

Question 29

What are some of the chronic complications associated with frostbite injury?

Answer 29

• Cold hypersensitivity, digit numbness, decreased touch sensitivity, chronic pain (may require amitriptyline or gabapentin), arthritis, localized osteoporosis and subchondral bone loss (due to vascular insult), in children = possible physes injury with growth deformity. Proposed mechanism for these changes = thermophysiologic response with increased tendency to vasospasm

Question 30

What are some ways you can help to prevent cold injuries?

Answer 30

• KEY IS PREPARATION: Appropriate CLOTHING [(most important) – base layer thin wicking material; middle layer insulation synthetic fleece or wool; outer layer light and wind/water resistant]; wet SOCKS changed frequently; properly fitting SHOES (tight = dec circulation); EDUCATION to prepare for environment; AVOID – coffee, tobacco, drugs and alcohol; HYDRATE and increase CHO intake (fuel for thermogenesis)

Question 31

What are the physiological responses to environmental hypoxia?

Answer 31

• @ 500-2000 meters above sea level = dec air density, dec partial pressure of inspired oxygen (air is thinner).
• Physiological changes = inc HR, CO and BP, dec in max oxygen consumption, peripheral edema (common), diuresis (early stage of acclimatization)

Question 32

What are the 3 distinct acute high altitude conditions? What are the signs and symptoms and treatments for each?

Answer 32

• Acute MOUNTAIN Sickness (S+S = HA, nausea, vomit, dizzy, fatigue; TX = descent, Diamox/acetazolamide, supplemental 02)
• High altitude PULMONARY edema = (S+S = dyspnea, coughing, wheezing, chest tightness, central cyanosis; TX = descent, supplemental 02, asthma medication [salmeterol/Serevent], Ca channel blocker [nifedipine], portable hyperbaric chamber)
• High altitude CEREBRAL edema = (S+S = similar to other conditions PLUS changes in mental status, and ataxia; TX = descent, a corticosteroid, acetazolamide, supplemental 02, portable hyperbaric chamber)

Question 33

List the ways you can prevent altitude sickness

Answer 33

• SLOW ASCENSION to altitudes >2500 meters (increase at rate of 600-1200 m/24 hours)
• Acetazolamide/Diamox prior to trip may help

Question 34

Why is Sickle Cell Trait important at high altitude?

Answer 34

• Sickle cell trait (not the disease; a carrier) are at increased risk of symptoms at altitude = due to low oxygen tension causing erythrocytes to become viscous, stiff, sickle-shaped and stick to structures in microvascular system (spleen) → high altitude combined with high-intensity exertion and dehydration = increased risk
• S+S of sickling = LE weakness (no appearance of cramping, no LOC); need to examine for splenomegaly = RISK OF SPLENIC INFARCT
• TX = DESCEND, treat at hospital (aggressive fluid and electrolyte management, cardiac monitoring, lab studies) - EDUCATE athlete and med staff = maintain euhydrated status, monitor closely while exercising at altitude

Question 35

What are the different mechanisms of lightning injuries?

Answer 35

• CLOUD TO GROUND (direct) strike (most dangerous and least likely)
• CONTACT (electrical surge passes through wiring)
• SIDEFLASH (person in underground shelter)
• STEP VOLTAGE (surge travels to victim via the ground)
• BAROTRAUMA (rupture of tympanic membrane from sonic blast)

Question 36

How do you prevent lightning injuries?

Answer 36

• Early MONITORING of weather with specific plan in place.
  “30-30” RULE = recommended for safety→ everyone should be in safe structure (fully enclosed building with wiring and plumbing) when thunder is heard within 30 seconds of seeing lightning, AND can’t return until 30 min since last thunder heard/lightning seen.
• See figure 5 for NATA 5 step emergency action plan.

Question 37

How do you manage lightning injuries?

Answer 37

• Determine if environment is SAFE.
• TRANSPORT victim to safe/protected area.
• ASSESS patient – determine if CPR, AED needed (activate EMS if needed).
• PRIMARY role of SCS = educate coaches, parents, athletes about lightning safety and inform them of established protocols