Pseudothrombocytosis Associated with Heatstroke.

BACKGROUND: In several situations, spurious results are observed in the use of hematology analyzers including pseudothrombocytosis caused by part of the cytoplasm of abnormal cells which was reported in leukemic blasts, monoblasts, or lymphoblasts. METHODS AND RESULTS: Here, we report a rare case of pseudothrombocytosis caused by mature leukocyte fragments associated with heatstroke. It was identified by the peripheral blood smear and obvious difference between the PLT-F (fluorescence) and I (impedance) channel. CONCLUSIONS: Observation of peripheral blood smears and determination on the PLT-F channel can identify this interference caused by leukocyte fragments in heatstroke.

Recommended water immersion duration for the field treatment of exertional heat stroke when rectal temperature is unavailable.

INTRODUCTION: The recommended treatment for exertional heat stroke is immediate, whole-body immersion in < 10 °C water until rectal temperature (Tre) reaches ≤ 38.6 °C. However, real-time Tre assessment is not always feasible or available in field settings or emergency situations. We defined and validated immersion durations for water temperatures of 2-26 °C for treating exertional heat stroke. METHODS: We compiled data for 54 men and 18 women from 7 previous laboratory studies and derived immersion durations for reaching 38.6 °C Tre. The resulting immersion durations were validated against the durations of cold-water immersion used to treat 162 (98 men; 64 women) exertional heat stroke cases at the Falmouth Road Race between 1984 and 2011. RESULTS: Age, height, weight, body surface area, body fat, fat mass, lean body mass, and peak oxygen uptake were weakly associated with the cooling time to a safe Tre of 38.6 °C during immersions to 2-26 °C water (R2 range: 0.00-0.16). Using a specificity criterion of 0.9, receiver operating characteristics curve analysis showed that exertional heat stroke patients must be immersed for 11-12 min when water temperature is ≤ 9 °C, and for 18-19 min when water temperature is 10-26 °C (Cohen's Kappa: 0.32-0.75, p < 0.001; diagnostic odds ratio: 8.63-103.27). CONCLUSION: The reported immersion durations are effective for > 90% of exertional heat stroke patients with pre-immersion Tre of 39.5-42.8 °C. When available, real-time Tre monitoring is the standard of care to accurately diagnose and treat exertional heat stroke, avoiding adverse health outcomes associated with under- or over-cooling, and for implementing cool-first transport second exertional heat stroke policies.

Every Picture Tells A Story: Managing Exertional Heatstroke with Rotating Ice Water Towels.

ABSTRACT: A 23-year-old woman completing her first marathon collapsed near the finish line at 4 hours 6 min with a rectal temperature of 41.8°C. She was in good health before the race with no recent illness, had completed a full training program, and was taking no medications or supplements. On the initial exam, she was unconscious with a response to painful stimulus, spontaneous breathing, rapid pulse, eyes closed, fully dilated pupils, poor muscle tone, and pale skin that was warm to touch. The medical team initiated whole-body cooling using rapidly rotating ice water towels and ice packs placed in the neck, axilla, and groin. She developed echolalia during active cooling. About 20 minutes into the cooling procedure, she "woke up," was able to answer questions coherently, and her pupils were normal size and reactive. She was discharged home with instructions to follow-up in 2 d for evaluation and blood chemistry testing.

Heat-related illness.

ABSTRACT: This article concisely overviews heat-related illnesses, emphasizing their significant impact on public health. It explores the pathophysiology of conditions ranging from mild heat cramps to life-threatening heat stroke, highlighting key heat transfer mechanisms and the importance of environmental factors. Differential diagnosis considerations, prevention strategies, and nursing implications are discussed, underscoring the need for prompt recognition and intervention in managing these conditions.

Body mass index, but not sex, influences exertional heat stroke risk in young healthy men and women.

Exertional heat stroke (EHS) remains a persistent threat for individuals working or playing in the heat, including athletes and military and emergency service personnel. However, influence of biological sex and/or body mass index (BMI) on the risk of EHS remain poorly understood. The purpose of this study was to retrospectively assess the influence of sex and BMI on risk of EHS in the active-duty US Army. We analyzed data from 2016 to 2021, using a matched case-control approach, where each individual with a diagnosis of EHS was matched to five controls based on calendar time, unit ID, and job category, to capture control individuals who were matched to EHS events by location, time, and activity. We used a multivariate logistic regression model mutually adjusted for sex, BMI, and age to compare 745 (n = 61 F) individuals (26 ± 7 yr) with a diagnosed EHS to 4,290 (n = 384 F) case controls (25 ± 5 yr). Group average BMI were similar: 26.6 ± 3.1 (EHS) and 26.5 ± 3.6 kg/m2 (CON). BMI was significantly (P < 0.0001) associated with higher risk of EHS with a 3% increase in risk of EHS for every unit increase in BMI. Notably, sex was not associated with any difference in risk for EHS (P = 0.54). These data suggest that young healthy people with higher BMI have significantly higher risk of EHS, but, contrary to what some have proposed, this risk was not higher in young women.

Glasgow Coma Scale as an Indicator of Patient Prognosis: A Retrospective Study of 257 Patients with Heatstroke from 3 Medical Centers in Guangdong, China.

BACKGROUND Coma has been considered as a valuable symptom of heatstroke. This study aimed to evaluate the role of the Glasgow Coma Scale (GCS) as an indicator of prognosis of patients with heatstroke. MATERIAL AND METHODS From Jan 1st, 2013 to Dec 31st, 2020, the clinical courses of 257 heatstroke patients from 3 medical centers in Guangdong, China, were observed. Diagnosis of heatstroke was made according to Expert Consensus in China. GCSs were calculated on the 1st, 3rd, and 5th days after admission to intensive care units (ICUs). GCS £8, as a coma criterion, was employed to predict the outcomes. RESULTS Seventy-five patients (29.18%) were comatose at admission. Twenty-seven (10.50%) patients, including 24 (24/75, 32.00%) coma patients and 3 (3/182,1.65%) non-coma patients died during ICU stay (P<0.0001). Patients with GCS ≤8 had a 2-fold higher risk of death as compared with those with GCS >8. The area under curves (AUCs) of GCSs on the 1st, 3rd, and 5th days to predict mortality were 0.81 (0.70-0.91), 0.91 (0.84-0.98), and 0.91 (0.82-0.99), respectively. Each additional 1 year of age, 1/min of respiratory rate (RR), and 1% of hematocrit (HCT) increased the risk of death of coma patients by 3%, 6%, and 4%, respectively (all P≤0.05). Patients with improving GCSs had lower mortality rates than non-improving patients (5.71% vs 55.00%, P<0.0001) within 5 days after admission. CONCLUSIONS GCS ≤8 at admission predicted worse outcomes in heatstroke patients, which possibly enhanced the risks of death for other factors, including age, RR, and HCT.

Improvement in the diagnosis and practices of emergency healthcare providers for heat emergencies after HEAT (heat emergency awareness & treatment) an educational intervention: a multicenter quasi-experimental study.

BACKGROUND: The incidence of heat emergencies, including heat stroke and heat exhaustion, have increased recently due to climate change. This has affected global health and has become an issue of consideration for human health and well-being. Due to overlapping clinical manifestations with other diseases, and most of these emergencies occurring in an elderly patient, patients with a comorbid condition, or patients on poly medicine, diagnosing and managing them in the emergency department can be challenging. This study assessed whether an educational training on heat emergencies, defined as heat intervention in our study, could improve the diagnosis and management practices of ED healthcare providers in the ED setting. METHODS: A quasi-experimental study was conducted in the EDs of four hospitals in Karachi, Pakistan. Eight thousand two hundred three (8203) patients were enrolled at the ED triage based on symptoms of heat emergencies. The pre-intervention data were collected from May to July 2017, while the post-intervention data were collected from May to July 2018. The HEAT intervention, consisting of educational activities targeted toward ED healthcare providers, was implemented in April 2018. The outcomes assessed were improved recognition-measured by increased frequency of diagnosing heat emergencies and improved management-measured by increased temperature monitoring, external cooling measures, and intravenous fluids in the post-intervention period compared to pre-intervention. RESULTS: Four thousand one hundred eighty-two patients were enrolled in the pre-intervention period and 4022 in the post-intervention period, with at least one symptom falling under the criteria for diagnosis of a heat emergency. The diagnosis rate improved from 3% (n = 125/4181) to 7.5% (n = 7.5/4022) (p-value < 0.001), temperature monitoring improved from 0.9% (n = 41/4181) to 13% (n = 496/4022) (p-value < 0.001) and external cooling measure (water sponging) improved from 1.3% (n = 89/4181) to 3.4% (n = 210/4022) (p-value < 0.001) after the administration of the HEAT intervention. CONCLUSION: The HEAT intervention in our study improved ED healthcare providers' approach towards diagnosis and management practices of patients presenting with health emergencies (heat stroke or heat exhaustion) in the ED setting. The findings support the case of training ED healthcare providers to address emerging health issues due to rising temperatures/ climate change using standardized treatment algorithms.

ACSM Expert Consensus Statement on Exertional Heat Illness: Recognition, Management, and Return to Activity.

ABSTRACT: Exertional heat stroke is a true medical emergency with potential for organ injury and death. This consensus statement emphasizes that optimal exertional heat illness management is promoted by a synchronized chain of survival that promotes rapid recognition and management, as well as communication between care teams. Health care providers should be confident in the definitions, etiologies, and nuances of exertional heat exhaustion, exertional heat injury, and exertional heat stroke. Identifying the athlete with suspected exertional heat stroke early in the course, stopping activity (body heat generation), and providing rapid total body cooling are essential for survival, and like any critical life-threatening situation (cardiac arrest, brain stroke, sepsis), time is tissue. Recovery from exertional heat stroke is variable and outcomes are likely related to the duration of severe hyperthermia. Most exertional heat illnesses can be prevented with the recognition and modification of well-described risk factors ideally addressed through leadership, policy, and on-site health care.

Exertional heat stroke: an evidence based approach to clinical assessment and management.

NEW FINDINGS: What is the topic of this review? The treatment of exertional heat stress, from initial field care through the return-to-activity decision. What advances does it highlight? Clinical assessment during field care using AVPU and vital signs to gauge recovery, approaches to field cooling and end of active cooling, and shared clinical decision making for return to activity recommendations. ABSTRACT: Exertional heat stroke (EHS) is a potentially fatal condition characterized by central nervous system (CNS) dysfunction and body temperature often but not always >40°C that occurs in the context of physical work in warm or hot environments. In this paper, we review the continuum of care, from initial recognition and field care to transport and hospital care, and finally return-to-duty considerations. Morbidity and mortality can be greatly reduced if not eliminated with prompt recognition and aggressive cooling. If medical personnel are not present at point of collapse during or immediately following exercise, EHS should be the presumptive diagnosis until a formal diagnosis can be determined by qualified medical staff. EHS is a rare medical situation where initial treatment (cooling) takes precedence over transport to a medical facility, where advanced medical care may be required for severe EHS casualties. Recovery from EHS and return to activity is usually straightforward and unremarkable provided the casualty is rapidly cooled at time of collapse and adequate time is allowed for body healing. However, evidence-based data to guide return to activity following EHS are limited. Current research suggests that most individuals recover completely within a few weeks though some individuals may suffer prolonged sequalae and additional evaluation may be warranted, including heat tolerance testing (HTT). Several aspects of the care of the EHS casualty are based on best practices derived from personal experience and continued research is necessary to optimize evaluation and management.

Prehospital management of exertional heat stroke at sports competitions for Paralympic athletes.

OBJECTIVES: To adapt key components of exertional heat stroke (EHS) prehospital management proposed by the Intenational Olympic Committee Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020 so that it is applicable for the Paralympic athletes. METHODS: An expert working group representing members with research, clinical and lived sports experience from a Para sports perspective reviewed and revised the IOC consensus document of current best practice regarding the prehospital management of EHS. RESULTS: Similar to Olympic competitions, Paralympic competitions are also scheduled under high environmental heat stress; thus, policies and procedures for EHS prehospital management should also be established and followed. For Olympic athletes, the basic principles of EHS prehospital care are: early recognition, early diagnosis, rapid, on-site cooling and advanced clinical care. Although these principles also apply for Paralympic athletes, slight differences related to athlete physiology (eg, autonomic dysfunction) and mechanisms for hands-on management (eg, transferring the collapsed athlete or techniques for whole-body cooling) may require adaptation for care of the Paralympic athlete. CONCLUSIONS: Prehospital management of EHS in the Paralympic setting employs the same procedures as for Olympic athletes with some important alterations.

Gait instability and estimated core temperature predict exertional heat stroke.

OBJECTIVE: Exertional heat stroke (EHS), characterised by a high core body temperature (Tcr) and central nervous system (CNS) dysfunction, is a concern for athletes, workers and military personnel who must train and perform in hot environments. The objective of this study was to determine whether algorithms that estimate Tcr from heart rate and gait instability from a trunk-worn sensor system can forward predict EHS onset. METHODS: Heart rate and three-axis accelerometry data were collected from chest-worn sensors from 1806 US military personnel participating in timed 4/5-mile runs, and loaded marches of 7 and 12 miles; in total, 3422 high EHS-risk training datasets were available for analysis. Six soldiers were diagnosed with heat stroke and all had rectal temperatures of >41°C when first measured and were exhibiting CNS dysfunction. Estimated core temperature (ECTemp) was computed from sequential measures of heart rate. Gait instability was computed from three-axis accelerometry using features of pattern dispersion and autocorrelation. RESULTS: The six soldiers who experienced heat stroke were among the hottest compared with the other soldiers in the respective training events with ECTemps ranging from 39.2°C to 40.8°C. Combining ECTemp and gait instability measures successfully identified all six EHS casualties at least 3.5 min in advance of collapse while falsely identifying 6.1% (209 total false positives) examples where exertional heat illness symptoms were neither observed nor reported. No false-negative cases were noted. CONCLUSION: The combination of two algorithms that estimate Tcr and ataxic gate appears promising for real-time alerting of impending EHS.

An Advanced Internet of Things System for Heatstroke Prevention with a Noninvasive Dual-Heat-Flux Thermometer.

Heatstroke is a concern during sudden heat waves. We designed and prototyped an Internet of Things system for heatstroke prevention, which integrates physiological information, including deep body temperature (DBT), based on the dual-heat-flux method. A dual-heat-flux thermometer developed to monitor DBT in real-time was also evaluated. Real-time readings from the thermometer are stored on a cloud platform and processed by a decision rule, which can alert the user to heatstroke. Although the validation of the system is ongoing, its feasibility is demonstrated in a preliminary experiment.

Context-aware heatstroke relief station placement and route optimization for large outdoor events.

BACKGROUND: Heatstroke is becoming an increasingly serious threat to outdoor activities, especially, at the time of large events organized during summer, including the Olympic Games or various types of happenings in amusement parks like Disneyland or other popular venues. The risk of heatstroke is naturally affected by a high temperature, but it is also dependent on various other contextual factors such as the presence of shaded areas along traveling routes or the distribution of relief stations. The purpose of the study is to develop a method to reduce the heatstroke risk of pedestrians for large outdoor events by optimizing relief station placement, volume scheduling and route. RESULTS: Our experiments conducted on the planned site of the Tokyo Olympics and simulated during the two weeks of the Olympics schedule indicate that planning routes and setting relief stations with our proposed optimization model could effectively reduce heatstroke risk. Besides, the results show that supply volume scheduling optimization can further reduce the risk of heatstroke. The route with the shortest length may not be the route with the least risk, relief station and physical environment need to be considered and the proposed method can balance these factors. CONCLUSIONS: This study proposed a novel emergency service problem that can be applied in large outdoor event scenarios with multiple walking flows. To solve the problem, an effective method is developed and evaluates the heatstroke risk in outdoor space by utilizing context-aware indicators which are determined by large and heterogeneous data including facilities, road networks and street view images. We propose a Mixed Integer Nonlinear Programming model for optimizing routes of pedestrians, determining the location of relief stations and the supply volume in each relief station. The proposed method can help organizers better prepare for the event and pedestrians participate in the event more safely.

Prehospital management of exertional heat stroke at sports competitions: International Olympic Committee Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020.

OBJECTIVES: This document aimed to summarise the key components of exertional heat stroke (EHS) prehospital management. METHODS: Members of the International Olympic Committee Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020 summarised the current best practice regarding the EHS prehospital management. RESULTS: Sports competitions that are scheduled under high environmental heat stress or those that include events with high metabolic demands should implement and adopt policy and procedures for EHS prehospital management. The basic principles of EHS prehospital care are: early recognition, early diagnosis, rapid, on-site cooling and advanced clinical care. In order to achieve these principles, medical organisers must establish an area called the heat deck within or adjacent to the main medical tent that is optimised for EHS diagnosis, treatment and monitoring. Once admitted to the heat deck, the rectal temperature of the athlete with suspected EHS is assessed to confirm an elevated core body temperature. After EHS is diagnosed, the athlete must be cooled on-site until the rectal temperature is below 39°C. While cooling the athlete, medical providers are recommended to conduct a blood analysis to rule out exercise-associated hyponatraemia or hypoglycaemia, provided that this can be safely performed without interrupting cooling. The athlete is transported to advanced care for a full medical evaluation only after the treatment has been provided on-site. CONCLUSIONS: A coordination of care among all medical stakeholders at the sports venue, during transport, and at the hospital is warranted to ensure effective management is provided to the EHS athlete.

ACSM Expert Consensus Statement on Exertional Heat Illness: Recognition, Management, and Return to Activity.

ABSTRACT: Exertional heat stroke (EHS) is a true medical emergency with potential for organ injury and death. This consensus statement emphasizes that optimal exertional heat illness management is promoted by a synchronized chain of survival that promotes rapid recognition and management, as well as communication between care teams. Health care providers should be confident in the definitions, etiologies, and nuances of exertional heat exhaustion, exertional heat injury, and EHS. Identifying the athlete with suspected EHS early in the course, stopping activity (body heat generation), and providing rapid total body cooling are essential for survival, and like any critical life-threatening situation (cardiac arrest, brain stroke, sepsis), time is tissue. Recovery from EHS is variable, and outcomes are likely related to the duration of severe hyperthermia. Most exertional heat illnesses can be prevented with the recognition and modification of well-described risk factors ideally addressed through leadership, policy, and on-site health care.

Exertional heat stroke in an amateur runner - Challenges in diagnostics and the role of unhealthy competition.

Exertional heat stroke (EHS) is a potentially life-threatening condition with a variety of symptoms and abnormal laboratory findings. Nevertheless, data evaluating the course of making an EHS diagnosis in real-life practice, as well as the role of predisposing psychological components are limited. Thus, the aim of our study was to present a multi-faceted differentiation process and show the role of unhealthy competition in the development of EHS. We describe a case of a young amateur runner, admitted to the hospital due to loss of consciousness, further mental confusion, and increased body temperature above 40°C. Head scans excluded brain haemorrhage and stroke. Elevated troponin I levels suggested an acute coronary syndrome (ACS) or myocarditis. An increase of procalcitonin levels, signs of rhabdomyolysis and severe liver injury resulted in evaluation for infection and acute hepatic damage. Subsequently, the patient's negative results pointed us to a diagnosis of EHS. In-depth anamnesis revealed that the patient's excessive effort during the race was linked to the male-female competition. EHS can present diagnostic challenges, as it mimics various diseases, such as stroke, myocarditis, ACS, infection, or liver dysfunction. In addition, the role of psychological components, such as unhealthy competition, in the development of EHS should be considered.

Unusual manifestation of heat stroke: Isolated trochlear nerve palsy.

Heat stroke is a life-threatening disease characterized by hyperthermia and neurological dysfunction. The central nervous system is highly sensitive to hyperthermia, which causes neurological complications due to the involvement of the cerebellum, basal ganglia, anterior horn cells, and peripheral nerves. Several studies reported about clinical symptoms and brain image findings of heat stroke. Isolated cranial nerve dysfunction caused by lacunar infarction is an extremely rare condition in patient with heat stroke. We experienced a rare case of trochlear nerve palsy due to midbrain infarction caused by heat stroke.

Emergency Medical Service Directors' Protocols for Exertional Heat Stroke.

Background and Objectives: Emergency Medical Service (EMS) protocols vary widely and may not implement best practices for exertional heat stroke (EHS). EHS is 100% survivable if best practices are implemented within 30 min. The purpose of this study is to compare EMS protocols to best practices for recognizing and treating EHS. Materials and Methods: Individuals (n = 1350) serving as EMS Medical or Physician Director were invited to complete a survey. The questions related to the EHS protocols for their EMS service. 145 individuals completed the survey (response rate = 10.74%). Chi-Squared Tests of Associations (χ2) with 95% confidence intervals (CI) were calculated. Prevalence ratios (PR) with 95% CI were calculated to determine the prevalence of implementing best practices based on location, working with an athletic trainer, number of EHS cases, and years of directing. All PRs whose 95% CIs excluded 1.00 were considered statistically significant; Chi-Squared values with p values < 0.05 were considered statistically significant. Results: A majority of the respondents reported not using rectal thermometry for the diagnosis of EHS (n = 102, 77.93%) and not using cold water immersion for the treatment of EHS (n = 102, 70.34%). If working with an athletic trainer, EMS is more likely to implement best-practice treatment (i.e., cold-water immersion and cool-first transport-second) (69.6% vs. 36.9%, χ2 = 8.480, p < 0.004, PR = 3.15, 95% CI = 1.38, 7.18). Conclusions: These findings demonstrate a lack of implementation of best-practice standards for EHS by EMS. Working with an athletic trainer appears to increase the likelihood of following best practices. Efforts should be made to improve EMS providers' implementation of best-practice standards for the diagnosis and management of EHS to optimize patient outcomes.

Diagnosis and Management of Heatstroke.

Heatstroke is a life-threatening  and the most severe form of heat-related illnesses, characterized by body temperature >40ºC and central nervous system dysfunction. Heatstroke is classified into Non-Exertional Heatstroke (NEHS) and Exertional Heatstroke (EHS). The pathophysiology of heatstroke involves a combination of direct heat effects on the host, the systemic inflammatory and coagulopathic response. The diagnosis of heatstroke based on Bouchama's definition or Japan Association of Acute Medicine (JAAM) criteria. The basic principle of heatstroke management is early resuscitation and immediate cooling. Cold water immersion or convection evaporation method can be implemented based on the specific patient characteristic. Preventive strategies are early recognition by health workers, socialization to vulnerable groups and adequate acclimatization.

[Comparison of different critical care scoring systems in prognosis evaluation of heat stroke].

Objective: To evaluate the prognostic value of different critical care scoring systems in 28-day survival rate of patients with heat stroke. Methods: A retrospective analysis was conducted on the clinical data of 71 patients with heat stroke admitted to the department of emergency medicine of Beijing Luhe Hospital. Capital Medical University from July 2015 to September 2018. The general information and the worst values of vital signs and related pathophysiological indicators within 24 hours were collected and the sequential organ failure assessment (SOFA) , multiple organ dysfunction (MODS) , simplified acute physiological scoreⅡ (SAPS Ⅱ) and acute physiology and chronic health evaluationⅡ (APACHE Ⅱ) were calculated. The patients were divided into the survival group (n=45) and the non-survival group (n=26) according to 28-day prognosis, and the clinical data and scores of the two groups were compared.The ROC curve was drawn to analyze the evaluation value of each scoring system on the survival rate of patients at 28-day. Kaplan-Meier method was used to plot the survival curve of patients. Results: There were no significant differences in age, sex, vital signs and laboratory parameters between two groups (P>0.05) . In non-survival patients, SOFA, SAPS Ⅱ, APACHE Ⅱ scores were significantly elevated in the survival group (P<0.05) . ROC curve analysis showed that the area under ROC curve (AUC) of SOFA score for predicting 28-day survival rate was the highest, which was significantly higher than the APACHE Ⅱ, SAPS Ⅱ, MODS score. When the best cut-off value of SOFA score was 9.0, the sensitivity was 84.6%, and the specificity was 71.1%. Kaplan-Meier survival analysis showed that 28-day survival rate after hospital discharge in patients with SOFA score<9 (n=27) was significantly higher than that in patients with SOFA score ≥9.0 (χ(2)=1.0, P<0.01) . Conclusion: SOFA, APACHE Ⅱ, SAPS Ⅱ on admission have been proved to have good prognostic ability to predict 28-day prognosis in heat stroke patients. Among them, SOFA score system has more accurate prediction value.