Roundtable on Preseason Heat Safety in Secondary School Athletics: Prehospital Care of Patients With Exertional Heat Stroke

Preventing Exertional Heat Stroke in Football: Time for a Paradigm Shift

CONTEXT

Among American sports, football has the highest incidence of exertional heat stroke (EHS), despite decades of prevention strategies. Based on recent reports, 100% of high school and college EHS football fatalities occur during conditioning sessions. Linemen are the at-risk population, constituting 97% of football EHS deaths. Linemen heat up faster and cool down slower than other players.

EVIDENCE ACQUISITION

Case series were identified from organized, supervised football at the youth, high school, and collegiate levels and compiled in the National Registry of Catastrophic Sports Injuries. Sources for event occurrence were media reports and newspaper clippings, autopsy reports, certificates of death, school-sponsored investigations, and published medical literature. Articles were identified through PubMed with search terms "football," "exertional heat stroke," and "prevention."

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

Football EHS is tied to (1) high-intensity drills and conditioning that is not specific to individual player positions, (2) physical exertion as punishment; (3) failure to modify physical activity for high heat and humidity, (4) failure to recognize early signs and symptoms of EHS, and (5) death when cooling is delayed.

CONCLUSION

To prevent football EHS, (1) all training and conditioning should be position specific; (2) physical activity should be modified per the heat load; (3) understand that some players have a "do-or-die" mentality that supersedes their personal safety; (4) never use physical exertion as punishment; (5) eliminate conditioning tests, serial sprints, and any reckless drills that are inappropriate for linemen; and (6) consider air-conditioned venues for linemen during hot practices. To prevent EHS, train linemen based on game demands.

STRENGTH-OF-RECOMMENDATION TAXONOMY

n/a.

Body Bag Cooling with Two Different Water Temperatures for the Treatment of Hyperthermia

INTRODUCTION: Exertional heatstroke (EHS) is a life-threatening condition that requires quick recognition and cooling for survival. Experts recommend using cooling modalities that reduce rectal temperature (TREC) faster than 0.16°C/min though rates above 0.08°C/min are considered "acceptable." Hyperthermic individuals treated in body bags filled with ice water (∼3°C) have excellent cooling rates (0.28 ± 0.09°C/min). However, clinicians may not have access to large amounts of ice or ice water when treating EHS victims. The purpose of this study was to determine if using a body bag filled with water near the upper limits of expert recommendations for EHS treatment would produce acceptable (>0.08°C/min) or "ideal (>0.16°C/min)" TREC cooling rates or different nadir values.METHODS: A total of 12 individuals (9 men, 3 women; age: 21 ± 2 yr; mass: 74.6 ± 10.2 kg; height: 179.5 ± 9.6 cm) exercised in the heat until TREC was 39.5°C. They lay supine while 211.4 ± 19.5 L of 10°C (Ten) or 15°C (Fifteen) water was poured into a body bag. Subjects cooled until TREC was 38°C. They exited the body bag and rested in the heat for 10 min.RESULTS: Subjects exercised in similar conditions and for similar durations (Ten = 46.3 ± 8.6 min, Fifteen = 46.2 ± 7.8 min). TREC cooling rates were faster in Ten than Fifteen (Ten = 0.18 ± 0.07°C/min, Fifteen = 0.14 ± 0.09°C/min). TREC nadir was slightly higher in Fifteen (37.3 ± 0.2°C) than Ten (37.1 ± 0.3°C).DISCUSSION: Body bag cooling rates met expert definitions of acceptable (Fifteen) and ideal (Ten) for EHS treatment. This information is valuable for clinicians who do not have access to or the resources for ice water cooling to treat EHS.Miller KC, Amaria NY. Body bag cooling with two different water temperatures for the treatment of hyperthermia. Aerosp Med Hum Perform. 2024; 95(4):194-199.

The initial visibility of updated recommendations on preseason heat safety in high school athletics among United States athletic trainers

Updated recommendations on preseason heat safety in high school (HS) athletics ("2021 Consensus Statements") were published in April 2021. This cross-sectional survey study explored the initial roll-out of the 2021 Consensus Statements, including their visibility among United States HS athletic trainers (ATs) and perceived levels of confidence in implementing them. Recruitment occurred first, from a random selection of ATs from the Board of Certification, Inc., and second, an open invitation via social media. An online cross-sectional questionnaire had participating ATs note whether they had seen the 2021 Consensus Statements. If yes, ATs reported their perceived level of confidence in implementing them (5-point-ordinal scale from "not at all confident" to "very confident); if no, ATs disclosed (open-ended) why they had not yet seen them. Descriptive statistics were calculated for quantitative variables; template analysis identified codes related to visibility of and confidence in implementing 2021 Consensus Statements. Nearly half (45.7%) of 116 responding HS ATs reported having seen at least one 2021 Consensus Statements; 23.3% had reviewed all three. Common reasons among the 63 that had not seen them included: not aware they were published (n = 22), have yet to read them (n = 19), and believed they could not access the journal (n = 10). Of the 53 ATs having seen at least one of the 2021 Consensus Statements, 67.9% (n = 36) were very/fairly confident in implementing them at their HS. Reasons for confidence included their schools ensuring up-to-date EHI prevention and management practices (n = 18) and athletics constituent support (n = 8). This exploratory study observed proportions of surveyed HS ATs that had not seen the 2021 Consensus Statements and were not confident in implementing them. Findings highlight the need to continue improving messaging about access to best-practice recommendations. Further, continued efforts inclusive of active and passive dissemination strategies across all athletics constituents are needed to aid proper implementation.

Exertional Heat Illness: Adoption of Policies and Influencing Contextual Factors as Reported by Athletic Administrators

BACKGROUND

Little is known about the adoption by athletic administrators (AAs) of exertional heat illness (EHI) policies, and the corresponding facilitators and barriers of such policies within high school athletics. This study describes the adoption of comprehensive EHI policies by high school AAs and explores factors influencing EHI policy adoption.

HYPOTHESIS

We hypothesized that <50% of AAs would report adoption of an EHI policy, and that the most common facilitator would be access to an athletic trainer (AT), whereas the most common barrier would be financial limitations.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 466 AAs (82.4% male; age, 48 ± 9 years) completed a validated online survey to assess EHI prevention and treatment policy adoption (11 components), as well as facilitators and barriers to policy implementation. Access to athletic training services was ascertained by matching the participants' zip codes with the Athletic Training Locations and Services Project. Policy adoption, facilitators, and barriers data are presented as summary statistics (proportions, interquartile range (IQR)). A Welch t test evaluated the association between access to athletic training services and EHI policy adoption.

RESULTS

Of the AAs surveyed, 77.9% (n = 363) reported adopting a written EHI policy. The median of EHI policy components adopted was 5 (IQR = 1,7), with only 5.6% (n = 26) of AAs reporting adoption of all policy components. AAs who had access to an AT (P = 0.04) were more likely to adopt a greater number of EHI-related policies, compared with those without access to an AT. An AT employed at the school was the most frequently reported facilitator (36.9%).

CONCLUSION

Most AAs reported having written EHI policy components, and access to an AT resulted in a more comprehensive policy.

CLINICAL RELEVANCE

Employment of an AT within high school athletics may serve as a vital component in facilitating the adoption of comprehensive EHI policies.

Rectal Temperature Cooling Using 2 Cold-Water Immersion Preparation Strategies

CONTEXT

Cold-water immersion (CWI) is essential to treat patients with exertional heatstroke (EHS). Experts recommend that patients with EHS be immersed in water between 1.7°C and 15°C within 30 minutes of collapse. Some clinicians fill cooling tubs several hours before exercise, keep the tub in hot conditions, and then add ice in the event of an EHS emergency. No data exist on whether adding ice to water at the time of treatment is as effective as keeping water in the recommended range.

OBJECTIVES

To (1) compare the cooling rates of individuals immersed in a water bath kept at 10°C (CON) or 17°C water with 75.7 L (20 gal) of ice added to it immediately upon immersion (ICE) and (2) examine perceptual responses before, during, and after cooling.

DESIGN

Crossover study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twelve individuals (7 men, 5 women; age = 22 ± 2 years, height = 176.0 ± 12.8 cm, mass = 74.5 ± 10.6 kg).

INTERVENTIONS

Participants exercised in the heat until rectal temperature was 39.5°C. They then immersed themselves in CON (initial water volume = 681 ± 7.6 L, 10.0°C ± 0.03°C) or ICE (initial water volume = 605.7 ± 7.6 L water at 17.0°C ± 0.03°C with 75.7 L ice) until rectal temperature was 38°C. Thermal sensation and environmental symptoms questionnaire (ESQ) responses were recorded before, during, and after exercise and cooling.

MAIN OUTCOME MEASURE(S)

Rectal temperature cooling rates, thermal sensation, ESQ responses.

RESULTS

Participants exercised for similar durations (CON = 39.6 ± 18.2 minutes, ICE = 38.8 ± 14.3 minutes, Z11 = 0.94, P = .38) and had similar thermal sensation and ESQ scores immediately postexercise each day (P values > .05). They cooled quickly and at similar rates in both conditions (CON = 0.20°C ± 0.06°C/min, ICE = 0.21°C ± 0.12°C/min, t12 = 0.72, P = .49). Perception data were similar between conditions during and after cooling (P < .05).

CONCLUSIONS

Clinicians can cool patients with EHS quickly by adding ice to water that has warmed to above expert recommendations. Adding ice to a water bath at the time of EHS emergencies could save time, energy, and resources instead of always maintaining water bath temperatures within expert-recommended ranges.

Proper Recognition and Management of Exertional Heat Stroke in a High School Cross-Country Runner: A Validation Clinical Case Report

A 14-year-old female high school cross- country runner (height = 154 cm, mass = 48.1 kg) with no history of exertional heat stroke (EHS) collapsed at the end of a race. An athletic trainer assessed the patient, who presented with difficulty breathing and then other signs of EHS (eg, confusion and agitation). The patient was taken to the medical area and draped with a towel, and a rectal temperature (Tre) of 106.9°F (41.6°C) was obtained. The emergency action plan was activated, and emergency medical services was called. The patient was submerged in a cold-water immersion tub until emergency medical services arrived (∼15 minutes; Tre = 100.1°F; cooling rate: 0.41°F.min-1[0.25°C.min-1]). At the hospital, the patient received intravenous fluids, and urine and blood tests were normal. She was not admitted and returned to running without sequelae. Following best practices, secondary school athletic trainers can prevent deaths from EHS by properly recognizing the condition and providing rapid cooling before transport.

Development and evaluation of a predictive nomogram for survival in heat stroke patients: a retrospective cohort study

BACKGROUND

This study aimed to establish an effective nomogram to predict the survival of heat stroke (HS) based on risk factors.

METHODS

This was a retrospective, observational multicenter cohort study. We analyzed patients diagnosed with HS, who were treated between May 1 and September 30, 2018 at 15 tertiary hospitals from 11 cities in Northern China.

RESULTS

Among the 175 patients, 32 patients (18.29%) died before hospital discharge. After the univariate analysis, mechanical ventilation, initial mean arterial pressure <70 mmHg, maximum heart rate, lab results on day 1 (white blood cell count, alanine aminotransferase, creatinine), and Glasgow admission prediction score were included in multivariate analysis. Multivariate Cox regression showed that invasive ventilation, initial mean arterial pressure <70 mmHg (1 mmHg=0.133 kPa), and Glasgow admission prediction score were independent risk factors for HS. The nomogram was established for predicting 7-d and 14-d survival in the training cohort. The nomogram exhibited a concordance index (C-index) of 0.880 (95% confidence interval [95% CI] 0.831-0.930) by bootstrapping validation (B=1,000). Furthermore, the nomogram performed better when predicting 14-d survival, compared to 7-d survival. The prognostic index cut-off value was set at 2.085, according to the operating characteristic curve for overall survival prediction. The model showed good calibration ability in the internal and external validation datasets.

CONCLUSION

A novel nomogram, integrated with prognostic factors, was proposed; it was highly predictive of the survival in HS patients.

Roundtable on Preseason Heat Safety in Secondary School Athletics: Heat Acclimatization

OBJECTIVE

To provide best-practice recommendations for developing and implementing heat-acclimatization strategies in secondary school athletics.

DATA SOURCES

An extensive literature review on topics related to heat acclimatization and heat acclimation was conducted by a group of content experts. Using the Delphi method, action-oriented recommendations were developed.

CONCLUSIONS

A period of heat acclimatization consisting of ≥14 consecutive days should be implemented at the start of fall preseason training or practices for all secondary school athletes to mitigate the risk of exertional heat illness. The heat-acclimatization guidelines should outline specific actions for secondary school athletics personnel to use, including the duration of training, the number of training sessions permitted per day, and adequate rest periods in a cool environment. Further, these guidelines should include sport-specific and athlete-specific recommendations, such as phasing in protective equipment and reintroducing heat acclimatization after periods of inactivity. Heat-acclimatization guidelines should be clearly detailed in the secondary school's policy and procedures manual and disseminated to all stakeholders. Heat-acclimatization guidelines, when used in conjunction with current best practices surrounding the prevention, management, and care of secondary school student-athletes with exertional heat stroke, will optimize their health and safety.

Common body temperature sites provide invalid measures of body core temperature in hyperthermic humans wearing American football uniforms

Valid body core temperature measurements are essential for diagnosing and monitoring athletes with exertional heat stroke (EHS). Experts question the validity of body temperature sites that vary by >±0.27°C from the gold standard, rectal temperature (TREC). No research has established the validity of body temperature sites when American football uniforms (PADS) are worn during simulated EHS scenarios. Thirteen men (age, 22 ± 2 y; mass, 77.5 ± 8.8 kg; height, 181.3 ± 5.7 cm) donned PADS and entered an environmental chamber (38.7 ± 0.8°C, 38.9 ± 2.4% relative humidity). We compared TREC to a forehead liquid crystal temperature monitor (TFHD), axillary (TAXL), oral (TORL), and aural temperatures (TEAR) 34 times over four consecutive periods: 10-minutes of rest; exercise until participants TREC was between 39.7°C and 39.8°C; cold-water immersion (CWI, 10.0 ± 0.1°C) until all temperature sites indicated ≤38°C; and a 15-minute post-immersion recovery period. Body temperatures varied between sites during all periods (F36,432 ≥ 2.5, P ≤ 0.001). TAXL and TORL statistically differed from TREC and exceeded the 0.27°C bias threshold at all 34 measurement times (100%). TFHD differed from TREC eight times during rest; eight times during exercise; 0 times during CWI; and twice during recovery (18/34, 53%). TFHD exceeded the bias threshold 28 times (82%). TEAR differed from TREC five times during rest; 0 times during exercise; five times during CWI; and once during recovery (11/34, 32%). TEAR exceeded the 0.27°C bias threshold 15 times during testing (44%). TAXL, TFHD, TEAR, and TORL should not be used to diagnose or monitor American football players with EHS. Abbreviations ANOVA: analysis of variance; CWI: cold water immersion; EHS: exertional heatstroke; PADS: full American football uniform consisting of a helmet; shoulder, knee, thigh, hip and tailbone pads; a jersey top; undergarments; and half-length pants; TAXL: axillary temperature; TEAR: aural temperature; TFHD: liquid crystal temperature monitor; TORL: oral temperature; TREC: rectal temperature.