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Evaluation of Heat Illness. Physiology of Temperature Regulation HypothalamusHypothalamus –Center for thermal regulation –integrates input from thermal.

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Presentation on theme: "Evaluation of Heat Illness. Physiology of Temperature Regulation HypothalamusHypothalamus –Center for thermal regulation –integrates input from thermal."— Presentation transcript:

1 Evaluation of Heat Illness

2 Physiology of Temperature Regulation HypothalamusHypothalamus –Center for thermal regulation –integrates input from thermal receptors –Sends autonomic impulses to increase vasodilation / vasoconstriction to periphery and cause sweating / shivering

3 Body Temperature Determined by balance between heat production (BMR, muscular activity) and heat lossDetermined by balance between heat production (BMR, muscular activity) and heat loss Environmental conditions can make 98.6° difficult to maintainEnvironmental conditions can make 98.6° difficult to maintain

4 Mechanisms to Promote Heat Loss ConductionConduction ConvectionConvection EvaporationEvaporation RadiationRadiation S = M +/- R +/- K +/- Cv - E

5 Assumptions Convection, and radiation are very effective when external temp is lower than 87°Convection, and radiation are very effective when external temp is lower than 87° If external temp is higher than body temp, heat transfer is reversedIf external temp is higher than body temp, heat transfer is reversed Evaporation becomes primary methodEvaporation becomes primary method The more humidity, the less effective evaporation becomes. (Big decrease when >60%).The more humidity, the less effective evaporation becomes. (Big decrease when >60%).

6 Sweat Rates Up to 2 liters per hourUp to 2 liters per hour 2% body weight impairs performance2% body weight impairs performance Thirst not a good indicator of hydration statusThirst not a good indicator of hydration status 1L of sweat = 1.25L ingested beverage1L of sweat = 1.25L ingested beverage < 50% of fluid lost is typically replaced< 50% of fluid lost is typically replaced

7 Electrolyte Losses Na+, Cl-, K+, Mg+Na+, Cl-, K+, Mg+ Na – main one – muscle crampsNa – main one – muscle cramps Typical American diet replaces most electrolytesTypical American diet replaces most electrolytes

8 Heat Exposure Syndromes TraditionalTraditional –Heat Cramps –Heat Exhaustion –Heat Stroke New ClassificationsNew Classifications –Heat Syncope –Exertional Hyponatremia

9 Heat Cramps Water loss vs Electrolyte loss?Water loss vs Electrolyte loss? Athletes most at risk have a HxAthletes most at risk have a Hx Extremities & abdominalsExtremities & abdominals

10 Rx for Heat Cramps Fluid replacement w/ NaFluid replacement w/ Na Gentle Stretching and MassageGentle Stretching and Massage Lie Down to increase blood flow to the legsLie Down to increase blood flow to the legs IceIce

11 Heat Syncope AKA Orthostatic DizzinessAKA Orthostatic Dizziness Caused by peripheral vasodilation, postural pooling of blood, decreased venous return and QCaused by peripheral vasodilation, postural pooling of blood, decreased venous return and Q 1 st 5 days before acclimatized1 st 5 days before acclimatized

12 Heat Syncope Recognition Brief episode of dizziness associated with tunnel vision, pale or sweaty skin, decreased pulseBrief episode of dizziness associated with tunnel vision, pale or sweaty skin, decreased pulse Normal Temp (97-104°)Normal Temp (97-104°)

13 Heat Exhaustion AKA Heat ProstrationAKA Heat Prostration Caused by inadequate CV responseCaused by inadequate CV response –brain vs skin vs muscles –Dehydration decreases blood volume Unified View Unarchived General Archived B&W - Film B&W - Printing Camera Equipment Canon EOS Digital Cameras Digital Darkroom Film & Processing Large Format Leica Lighting Medium Format Minolta Nature Nikon People Photography Travel Photography All/Other Forums Forums... Site Feedback Recommendations Stolen Equipment Directory Who's online now? Related Sites Your portfolio Critique photos Top Photos Tutorial Point and Shoot Tips Books Workshops Film recommendation Using Filters Tilt-Shift Lenses Portraits Gardens Architecture Interiors Macro Studio Nudes Underwater Sports and Action Concerts Astrophotography Star Trails Infrared and UV Pinhole Street Photography Nature Ruins Recommended Labs Evaluating Photos Storing Framing Digital Editing Darkroom Tutorial Digital Imaging Projectors for the web using photo.net Cleaning Repair Insurance History Optics Beginners... Other resources... Taking Pictures... Post-Exposure... Publishing... Care... Background... Interviews 35mm Medium Format Large Format Digital Scanners APS Scanners Color Printers Tripods Camera Bags Pinhole cameras Video By camera type By situation For a long trip SLR System Tutorial 35mm SLR Insurance Reviews... What Camera?... Where to buy? Classifieds Background... 35mm Digital Medium Format Panorama Large Format APS All Classifieds Place an Ad Seller Ratings Samantha Footsteps NYC Vignettes Great Road Trips Too Moo Moments of Clarity California New Mexico Las Vegas Cape Cod Grand Canyon Las Vegas New Mexico New England Foliage Boston Canyonlands NP Manitoba Costa Rica Cayman Islands Italy Sweden Barcelona London Paris Berlin and Prague Israel Scotland South Africa Uganda China Japan New Zealand Bangkok India Vietnam International Airlines Travel Tips Long Drives Motorhomes SCUBA diving Book Reviews Why I wrote these Links Stories... North America... C. America/Carib... Europe... Africa... Asia... Everything Else... Community Community Gallery Gallery Learn Learn Equipment Equipment ezShop ezShop Classifieds Classifieds Travel Travel Sign in | SearchSearch Available as a 1000x1500 pixel JPEG. Tug of war. Seattle, Washington.a 1000x1500 pixel JPEG copyright 1996 philg@mit.edu philg@mit.edu Unified View Unarchived General Archived B&W - Film B&W - Printing Camera Equipment Canon EOS Digital Cameras Digital Darkroom Film & Processing Large Format Leica Lighting Medium Format Minolta Nature Nikon People Photography Travel Photography All/Other Forums Forums... Site Feedback Recommendations Stolen Equipment Directory Who's online now? Related Sites Your portfolio Critique photos Top Photos Tutorial Point and Shoot Tips Books Workshops Film recommendation Using Filters Tilt-Shift Lenses Portraits Gardens Architecture Interiors Macro Studio Nudes Underwater Sports and Action Concerts Astrophotography Star Trails Infrared and UV Pinhole Street Photography Nature Ruins Recommended Labs Evaluating Photos Storing Framing Digital Editing Darkroom Tutorial Digital Imaging Projectors for the web using photo.net Cleaning Repair Insurance History Optics Beginners... Other resources... Taking Pictures... Post-Exposure... Publishing... Care... Background... Interviews 35mm Medium Format Large Format Digital Scanners APS Scanners Color Printers Tripods Camera Bags Pinhole cameras Video By camera type By situation For a long trip SLR System Tutorial 35mm SLR Insurance Reviews... What Camera?... Where to buy? Classifieds Background... 35mm Digital Medium Format Panorama Large Format APS All Classifieds Place an Ad Seller Ratings Samantha Footsteps NYC Vignettes Great Road Trips Too Moo Moments of Clarity California New Mexico Las Vegas Cape Cod Grand Canyon Las Vegas New Mexico New England Foliage Boston Canyonlands NP Manitoba Costa Rica Cayman Islands Italy Sweden Barcelona London Paris Berlin and Prague Israel Scotland South Africa Uganda China Japan New Zealand Bangkok India Vietnam International Airlines Travel Tips Long Drives Motorhomes SCUBA diving Book Reviews Why I wrote these Links Stories... North America... C. America/Carib... Europe... Africa... Asia... Everything Else... Community Community Gallery Gallery Learn Learn Equipment Equipment ezShop ezShop Classifieds Classifieds Travel Travel Sign in | SearchSearch Available as a 1000x1500 pixel JPEG. Tug of war. Seattle, Washington.a 1000x1500 pixel JPEG copyright 1996 philg@mit.edu philg@mit.edu

14 Heat Syncope Rx ShadeShade Monitor VitalsMonitor Vitals Elevate LegsElevate Legs RehydrateRehydrate

15 Signs and Symptoms of Heat Exhaustion Hypovolemic ShockHypovolemic Shock Sx vary in severity and numberSx vary in severity and number Weakness, fatigue, dizziness, headache, loss of appetite, nausea, pallor, profuse sweating, vomiting, urge to defecate, syncope, thirsty, irritableWeakness, fatigue, dizziness, headache, loss of appetite, nausea, pallor, profuse sweating, vomiting, urge to defecate, syncope, thirsty, irritable Can be difficult to distinguish from Heat Stroke w/ out rectal tempCan be difficult to distinguish from Heat Stroke w/ out rectal temp Body Core Temp ranges from 97-104°Body Core Temp ranges from 97-104° Assess cognitive skills to rule more serious conditionsAssess cognitive skills to rule more serious conditions

16 Rx for Heat Exhaustion Rest in CoolRest in Cool Fluid ReplacementFluid Replacement –Ingesting –IV Electrolyte ReplacementElectrolyte Replacement Supine PostureSupine Posture Remove excessive clothingRemove excessive clothing Cold Buckets / FansCold Buckets / Fans

17 Heat Stroke Bodys cooling mechanisms have failed leading to hyperpyrexia (body temp > 104°)Bodys cooling mechanisms have failed leading to hyperpyrexia (body temp > 104°) Anhidrosis – body stops sweatingAnhidrosis – body stops sweating Causes damage to CNS and internal organsCauses damage to CNS and internal organs May develop suddenly or progress from heat exhaustionMay develop suddenly or progress from heat exhaustion Medical EmergencyMedical Emergency

18 Signs and Symptoms of Heat Stroke Hot, dry skinHot, dry skin Decreasing BPDecreasing BP Rapid, full pulse becomes rapid, weakRapid, full pulse becomes rapid, weak Vomiting, diarrhea, seizures, comaVomiting, diarrhea, seizures, coma Poor cognitive functionPoor cognitive function Multiple organ failure Multiple organ failure

19 Conditions Resulting from Heat Stroke Lactic AcidosisLactic Acidosis Hyperkalemia (excessive K+)Hyperkalemia (excessive K+) Renal FailureRenal Failure Disseminated Intervascular CoagulatonDisseminated Intervascular Coagulaton

20 Rx for Heat Stroke Cooling immediately – immerse in cold bath (35-59 degrees) to reduce body temp to < 100°Cooling immediately – immerse in cold bath (35-59 degrees) to reduce body temp to < 100° –Remove from pool when body temp reaches 101° Use wet towels /ice bags and fanning in transport to hospitalUse wet towels /ice bags and fanning in transport to hospital Treat for shockTreat for shock

21 Exertional Hyponatremia Rare?Rare? Low serum-Na level (< 130mmol/L)Low serum-Na level (< 130mmol/L) Ingest too much water vs ingest too little Na?Ingest too much water vs ingest too little Na? Sx – disorientation, headache, vomiting, lethargy, swelling of extremities, pulmonary and cerebral edema, seizuresSx – disorientation, headache, vomiting, lethargy, swelling of extremities, pulmonary and cerebral edema, seizures Results in death if not treated by rehydrating w/ fluids w/ NaResults in death if not treated by rehydrating w/ fluids w/ Na

22 Reducing Risk of Heat Illness Pre-participation Physical / ScreeningPre-participation Physical / Screening Early Recognition of SxEarly Recognition of Sx ConditioningConditioning AcclimatizationAcclimatization –4–7 days vs 10-14 days vs months? –After 6 weeks able to produce 2.5x normal amount of sweat –Diminishes by day 6 of inactivity

23 Reducing Risk (cont) Educate players and coachesEducate players and coaches Diet – extra Na+Diet – extra Na+ Rest and DigestRest and Digest Monitor urine color and amountMonitor urine color and amount Weigh in and outWeigh in and out Clothing / Equipment modificationsClothing / Equipment modifications

24 Reducing Risk (cont) Stay well hydrated (NATA Position Statement: Fluid Replacement )Stay well hydrated (NATA Position Statement: Fluid Replacement ) –Pre: 17-20oz, 2-3 hours before and 7-10oz. – 20 min before –During: 7-10oz every 20 min –Replace lost fluid

25 Reducing Risk (cont) –Beverage Temp 50-59° –Beverage Choice WaterWater 6-8% CHO solution if longer than 45 mins6-8% CHO solution if longer than 45 mins No Caffeine, alcoholNo Caffeine, alcohol.3-.7g/L Salt (esp 1 st 3-5 days).3-.7g/L Salt (esp 1 st 3-5 days)

26 Reducing Risk (cont) FansFans ShadeShade Cold bucketsCold buckets Cold TubCold Tub ThermometerThermometer BP CuffBP Cuff TelephoneTelephone

27 Predisposing Medical Conditions for Heat Illness Sickle Cell Trait – carry less O2Sickle Cell Trait – carry less O2 Cystic Fibrosis Trait – increases salt loss in sweatCystic Fibrosis Trait – increases salt loss in sweat Arteriosclerotic Vascular Disease – thicker arterial walls decrease blood flowArteriosclerotic Vascular Disease – thicker arterial walls decrease blood flow Scleroderma – skin disorder that increases sweatingScleroderma – skin disorder that increases sweating

28 Predisposing Medical Conditions for Heat Illness (cont) Drug / Supplement Use – EphedraDrug / Supplement Use – Ephedra –Diuretics –Antidepressants decrease sweating –Beta blockers reduce skin blood flow –Antihistamines constrict blood vessels.

29 Recommendations

30 National Weather Service Recommendations Cease activity when Heat index is over 105°Cease activity when Heat index is over 105° Heat index only includes temperature and humidityHeat index only includes temperature and humidity

31 Instruments to Evaluate Hot/Humid Environments WBGT Sling/Digital Pyschomoter WBGT=.1(DBT)+.7(WBT)+.2(GT) Temperature & Humidity Temperature, humidity, radiant heat, and air movement WBGT =.7(WBT) +.3(DBT )

32 Event and Practice Guidelines Arnheim & Prentice, 1993 –Watch the Obese 80-90 degrees & < 70% humidity80-90 degrees & < 70% humidity –Take a 10 min rest every hour, change t-shirts when wet, watch all athletes 80-90 degrees and > 70% or 90-100 degrees and 70% or 90-100 degrees and < 70% –Suspend practice > 100 degrees or > 90 degrees & humidity over 70%> 100 degrees or > 90 degrees & humidity over 70% WBGT > 90 No training, skull sessions

33 NATA Position Statement Activity Modification Guidelines Using WBGT

34 Event and Practice Guidelines (NATA Position Statement: Exertional Heat, 2002) Wet Bulb Globe TemperatureWet Bulb Globe Temperature –WBGT > 82, reschedule, if possible Even in the South? Wed never practice!

35 Disclaimer Certified athletic trainers work in a variety of professional and geographic settings….. obviously the ATC in Florida will adapt the recommendations to his or her environment, while the ATC in Maine will make different adjustments. - CasaCertified athletic trainers work in a variety of professional and geographic settings….. obviously the ATC in Florida will adapt the recommendations to his or her environment, while the ATC in Maine will make different adjustments. - Casa Athletic trainers should recognize that temperature ranges might vary widely based upon geographic regions. Athletic trainers may practice in regions, such as the southeastern United States, where the WBGT is routinely in the high or extreme or hazardous level of risk throughout a significant part of the year. In these regions, while it may not be practical to reschedule or delay events, the athletic trainer must recognize that the level of risk is high and take appropriate steps to reduce risk. – NATAAthletic trainers should recognize that temperature ranges might vary widely based upon geographic regions. Athletic trainers may practice in regions, such as the southeastern United States, where the WBGT is routinely in the high or extreme or hazardous level of risk throughout a significant part of the year. In these regions, while it may not be practical to reschedule or delay events, the athletic trainer must recognize that the level of risk is high and take appropriate steps to reduce risk. – NATA

36 NATA Position Statement Activity Modification Guidelines using Temp and Humidity Add 5 degrees to temp on bright sunny days bwtn 10 and 4Add 5 degrees to temp on bright sunny days bwtn 10 and 4 Lt of triangles - Full gearLt of triangles - Full gear Rt of circles - walk-thruRt of circles - walk-thru Btwn squares and circles - break every 15-20 min & shorts onlyBtwn squares and circles - break every 15-20 min & shorts only Bwtn triangles and squares - break every 20-30 min & helmet and shoulder padsBwtn triangles and squares - break every 20-30 min & helmet and shoulder pads

37 Risk of Heat Exhaustion in Hot/Humid Environments

38 Take a look at the Inter- Association Task Force Heat Illness Consensus Statement

39

40 Inter-Association Task Force on Exertional Heat Illnesses Consensus Statement (June 2004) These guidelines were established to increase safety and performance for individuals engaged in physical activity, especially in warm and hot environments. The risks associated with exercise in the heat are well documented, but policies and procedures often do not reflect current state-of-the-art knowledge. Many cases of exertional heat illness are preventable and can be successfully treated if onsite personnel identify the condition and implement appropriate care in a timely manner. Strategies to optimize proper care of dehydration, exertional heat stroke (EHS), heat exhaustion, heat cramps and exertional hyponatremia are presented here. This consensus statement was developed by medical / scientific experts experienced in the prevention, recognition and treatment of exertional heat illnesses.

41 Return to Play Criteria for Dehydration A nauseated or vomiting athlete should seek medical attention to replace fluids via an intravenous line.A nauseated or vomiting athlete should seek medical attention to replace fluids via an intravenous line. Return-to-Play ConsiderationsReturn-to-Play Considerations –If the degree of dehydration is minor and the athlete is symptom free, continued participation is acceptable. The athlete must maintain hydration status and should receive periodic checks from onsite medical personnel.

42 Return-to-Play Considerations After Heat Stroke Physiological changes may occur after an episode of EHS. Heat tolerance may be compromised. The following guidelines are recommended for return- to-play after EHS: Physician clearance: Avoid exercise until completely asymptomatic & lab tests are normal.Physician clearance: Avoid exercise until completely asymptomatic & lab tests are normal. Severity of the incident should dictate the length of recovery time.Severity of the incident should dictate the length of recovery time. Avoid exercise for the minimum of 1 week after release from medical care. Avoid exercise for the minimum of 1 week after release from medical care. Gradual return to physical activity. Gradual return to physical activity.

43 Return-to-Play Considerations After Heat Stroke (cont) Type and length of exercise should be determined by the athlete's physician and might follow this pattern: 1. Easy-to-moderate exercise in a climate controlled environment for several days, followed by strenuous exercise in a climate-controlled environment for several days. 2. Easy-to-moderate exercise in heat for several days, followed by strenuous exercise in heat for several days. 3. (If applicable) Easy-to-moderate exercise in heat with equipment for several days, followed by strenuous exercise in heat with equipment for several days.

44 Return to Play Criteria for Heat Exhaustion No Sx and fully hydrated.No Sx and fully hydrated. Recommend physician clearance or, at minimum, a discussion w/ supervising physician before return.Recommend physician clearance or, at minimum, a discussion w/ supervising physician before return. Rule out underlying condition or illness that predisposed athlete for continued problems.Rule out underlying condition or illness that predisposed athlete for continued problems.

45 Return to Play Criteria for Heat Exhaustion (cont) Avoid intense practice in heat until at least the next day to ensure recovery from fatigue & dehydration. (In severe cases, intense practice in heat should be delayed for > 1 day.)Avoid intense practice in heat until at least the next day to ensure recovery from fatigue & dehydration. (In severe cases, intense practice in heat should be delayed for > 1 day.) If underlying cause was lack of acclimatization and/or fitness level, correct this problem before athlete returns to full- intensity training in heat (especially in sports with equipment).If underlying cause was lack of acclimatization and/or fitness level, correct this problem before athlete returns to full- intensity training in heat (especially in sports with equipment).

46 Return to Play Guidelines for Heat Cramps Perform at the level needed for successful participation?Perform at the level needed for successful participation? ReviewReview –Diet –Rehydration practices –Electrolyte consumption –Fitness status –Level of acclimatization –Use of dietary supplements

47 Return to Play Criteria for Exertional Hyponatriema Physician clearancePhysician clearance Mild cases, activity can resume a few days after completing an educational session on establishing an individual-specific hydration protocolMild cases, activity can resume a few days after completing an educational session on establishing an individual-specific hydration protocol –ensures proper amount and type of beverages and meals are consumed before, during and after physical activity (see Table 2).

48

49 References Arnheim D.D. & Prentice W.E. (1993). Principles of Athletic Training. (8 th ed.) St. Louis: Mosby-Year Book.Arnheim D.D. & Prentice W.E. (1993). Principles of Athletic Training. (8 th ed.) St. Louis: Mosby-Year Book. American Academy of Orthopaedic Surgeons. (1999). Athletic Training and Sports Medicine. (3 rd ed.)American Academy of Orthopaedic Surgeons. (1999). Athletic Training and Sports Medicine. (3 rd ed.) Binkley HM, Beckett, Casa DJ, Kleiner DM, Plummer PE. (2002). National Athletic Trainers Association Position Statement: exertional heat illness. Journal of Athletic Training, 37(3):329- 343.Binkley HM, Beckett, Casa DJ, Kleiner DM, Plummer PE. (2002). National Athletic Trainers Association Position Statement: exertional heat illness. Journal of Athletic Training, 37(3):329- 343. Casa DJ, Armstrong LE, Hillman SK, Montain SJ, Reiff RV, Rich BS, Roberts WO, Stone JA. (2000). National Athletic Trainers Association Position Statement: fluid replacement for athletes. Journal of Athletic Training, 35(2):212-224.Casa DJ, Armstrong LE, Hillman SK, Montain SJ, Reiff RV, Rich BS, Roberts WO, Stone JA. (2000). National Athletic Trainers Association Position Statement: fluid replacement for athletes. Journal of Athletic Training, 35(2):212-224. Inter-Association Task Force on Exertional Heat Illness Consensus Statement (2004). www.nata.orgInter-Association Task Force on Exertional Heat Illness Consensus Statement (2004). www.nata.orgwww.nata.org


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