Risk factors for and outcomes of heatstroke-related intracerebral hemorrhage.

Some patients with heatstroke also experience intracerebral hemorrhage (ICH). However, clinical case reports of heatstroke-induced ICH are rare. The risk factors for cerebral hemorrhage after heatstroke remain unknown. The present study evaluated the clinical characteristics and risk factors of patients with heatstroke-related ICH. In this retrospective observational study, we collected data on all ICHs after heatstroke occurred between 2012 and 2022. The characteristics of patients with heatstroke-induced ICH were described. The risk factors for cerebral hemorrhage after heatstroke were examined using logistic regression analysis. In total, 177 patients were included in this study, and 11 patients with ICH secondary to heatstroke were identified. Variables with P values of <.05 in univariate models, comparing the cerebral hemorrhage and control groups, included heatstroke cause, temperature, heart rate, respiratory rate, vasopressor use, mechanical ventilation use, Acute Physiology and Chronic Health Evaluation II, total bilirubin, creatinine, platelet count, prothrombin time, procalcitonin, creatine kinase, disseminated intravascular coagulation (DIC) occurrence, and DIC score. Multivariate logistic regression showed that heatstroke patients with higher DIC scores (odds ratio, 18.402, 95% confidence interval, 1.384-244.763, P = .027) and higher creatine kinase levels (odds ratio, 1.021, 95% confidence interval, 1.002-1.041, P = .033) were at a higher risk of developing ICH. The death rate was higher in the cerebral hemorrhage group than in the control group (P = .042). Heatstroke-related cerebral hemorrhage may be associated with elevated creatinine levels and DIC severity (International Society on Thrombosis and Hemostasis score) after heatstroke, and heatstroke with cerebral hemorrhage may accelerate death.

Exertional heat stroke-induced changes in gut microbiota cause cognitive impairment in mice.

BACKGROUND: The incidence of exertional heat stroke (EHS) escalates during periods of elevated temperatures, potentially leading to persistent cognitive impairment postrecovery. Currently, effective prophylactic or therapeutic measures against EHS are nonexistent. METHODS: The selection of days 14 and 23 postinduction for detailed examination was guided by TEM of neuronal cells and HE staining of intestinal villi and the hippocampal regions. Fecal specimens from the ileum and cecum at these designated times were analyzed for changes in gut microbiota and metabolic products. Bioinformatic analyses facilitated the identification of pivotal microbial species and metabolites. The influence of supplementing these identified microorganisms on behavioral outcomes and the expression of functional proteins within the hippocampus was subsequently assessed. RESULTS: TEM analyses of neurons, coupled with HE staining of intestinal villi and the hippocampal region, indicated substantial recovery in intestinal morphology and neuronal injury on Day 14, indicating this time point for subsequent microbial and metabolomic analyses. Notably, a reduction in the Lactobacillaceae family, particularly Lactobacillus murinus, was observed. Functional annotation of 16S rDNA sequences suggested diminished lipid metabolism and glycan biosynthesis and metabolism in EHS models. Mice receiving this intervention (EHS + probiotics group) exhibited markedly reduced cognitive impairment and increased expression of BDNF/TrKB pathway molecules in the hippocampus during behavioral assessment on Day 28. CONCLUSION: Probiotic supplementation, specifically with Lactobacillus spp., appears to mitigate EHS-induced cognitive impairment, potentially through the modulation of the BDNF/TrKB signaling pathway within the hippocampus, illustrating the therapeutic potential of targeting the gut-brain axis.

Effects of isorhamnetin on liver injury in heat stroke-affected rats under dry-heat environments via oxidative stress and inflammatory response.

Isorhamnetin is a natural flavonoid compound, rich in brass, alkaloids, and sterols with a high medicinal value. This study investigated the effects of isorhamnetin on liver injury and oxidative and inflammatory responses in heat-stroke-affected rats in a dry-heat environment. Fifty Sprague Dawley rats were randomly divided into five groups: normal temperature control (NC, saline), dry-heat control (DHC, saline), low-dose isorhamnetin-pretreated (L-AS, 25 mg/Kg), medium-dose isorhamnetin-pretreated (M-AS, 50 mg/Kg), and high-dose isorhamnetin-pretreated (H-AS, 100 mg/Kg) group. Saline was administered to the NC and DHC groups and corresponding concentrations of isorhamnetin were administered to the remaining three groups for 1 week. Blood and liver tissue were analyzed for oxidative stress and inflammation. The liver histopathological injury score, serum liver enzyme (alanine transaminase, aspartate transaminase, and lactate dehydrogenase), liver oxidative stress index (superoxide dismutase [SOD], catalase [CAT], and malondialdehyde), and inflammation index (tumor necrosis factor α [TNF-α], interleukin [IL]-1ß, IL-6, and lipopolysaccharides) were significantly higher in the DHC group than in the NC group (P < 0.05). These index values in the L-AS, M-AS, and H-AS groups were significantly lower than those in the DHC group (P < 0.05). The index values decreased significantly with an increase in the concentration of isorhamnetin (P < 0.05), while the index values of CAT and SOD showed the opposite tendency (P < 0.05). The expression of liver tissue nuclear factor kappa B (NF-κB), caspase-3, and heat shock protein (HSP-70) was higher in the DHC group than in the NC group (P < 0.05). Comparison between the isorhamnetin and DHC groups revealed that the expression of NF-кB and caspase-3 was decreased, while that of HSP-70 continued to increase (P < 0.05). The difference was significant for HSP-70 among all the isorhamnetin groups (P < 0.05); however, the NF-кB and caspase-3 values in the L-AS and H-AS groups did not differ. In summary, isorhamnetin has protective effects against liver injury in heat-stroke-affected rats. This protective effect may be related to its activities concerning antioxidative stress, anti-inflammatory response, inhibition of NF-кB and caspase-3 expression, and enhancement of HSP-70 expression.

Hyperbaric oxygen preconditioning normalizes scrotal temperature, sperm quality, testicular structure, and erectile function in adult male rats subjected to exertional heat injury.

Testicular hyperthermia has been noted in men who work in high ambient temperatures. Scrotal temperatures above the normal range caused germ cell loss in the testes and resulted in male subfertility. In adult male rats, exercising at a higher environmental temperature (36 °C with relative humidity of 50%, 52 min) caused exertional heat stroke (EHS) characterized by scrotal hyperthermia, impaired sperm quality, dysmorphology in testes, prostates and bladders, and erectile dysfunction. Here, we aim to ascertain whether hyperbaric oxygen preconditioning (HBOP: 100% O2 at 2.0 atm absolute [ATA] for 2 h daily for 14 days consequently before the onset of EHS) is able to prevent the problem of EHS-induced sterility, testes, prostates, and bladders dysmorphology and erectile dysfunction. At the end of exertional heat stress compared to normobaric air (NBA or non-HBOP) rats, the HBOP rats exhibited lower body core temperature (40 °C vs. 43 °C), lower scrotal temperature (34 °C vs. 36 °C), lower neurological severity scores (2.8 vs. 5.8), higher erectile ability, (5984 mmHg-sec vs. 3788 mmHg-sec), higher plasma testosterone (6.8 ng/mL vs. 3.5 ng/mL), lower plasma follicle stimulating hormone (196.3 mIU/mL vs. 513.8 mIU/mL), lower plasma luteinizing hormone (131 IU/L vs. 189 IU/L), lower plasma adrenocorticotropic hormone (5136 pg/mL vs. 6129 pg/mL), lower plasma corticosterone (0.56 ng/mL vs. 1.18 ng/mL), lower sperm loss and lower values of histopathological scores for epididymis, testis, seminal vesicle, prostate, and bladder. Our data suggest that HBOP reduces body core and scrotal hyperthermia and improves sperm loss, testis/prostate/bladder dysmorphology, and erectile dysfunction after EHS in rats.

Gastrointestinal manifestations of critical ill heatstroke patients and their associations with outcomes: A multicentre, retrospective, observational study.

BACKGROUND: Extreme heat exposure is a growing health problem, and the effects of heat on the gastrointestinal (GI) tract is unknown. This study aimed to assess the incidence of GI symptoms associated with heatstroke and its impact on outcomes. AIM: To assess the incidence of GI symptoms associated with heatstroke and its impact on outcomes. METHODS: Patients admitted to the intensive care unit (ICU) due to heatstroke were included from 83 centres. Patient history, laboratory results, and clinically relevant outcomes were recorded at ICU admission and daily until up to day 15, ICU discharge, or death. GI symptoms, including nausea/vomiting, diarrhoea, flatulence, and bloody stools, were recorded. The characteristics of patients with heatstroke concomitant with GI symptoms were described. Multivariable regression analyses were performed to determine significant predictors of GI symptoms. RESULTS: A total of 713 patients were included in the final analysis, of whom 132 (18.5%) patients had at least one GI symptom during their ICU stay, while 26 (3.6%) suffered from more than one symptom. Patients with GI symptoms had a significantly higher ICU stay compared with those without. The mortality of patients who had two or more GI symptoms simultaneously was significantly higher than that in those with one GI symptom. Multivariable logistic regression analysis revealed that older patients with a lower GCS score on admission were more likely to experience GI symptoms. CONCLUSION: The GI manifestations of heatstroke are common and appear to impact clinically relevant hospitalization outcomes.

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.

Idiopathic segmental anhidrosis in an older patient presenting with recurrent dizziness.

Dizziness is one of the most common complaints encountered in the outpatient clinic, which is difficult to diagnose, especially in older patients because of the multifactorial nature of the disease. Although not commonly recognised, anhidrosis can also cause dizziness.We report a case of a woman in her 70s who presented with long-term recurrent dizziness. She had a history of frequent hospitalisations for heatstroke. Physical examination revealed markedly less sweating in the left axilla and soles than in the right. Minol test revealed that most of the left side of her body, including the face, was anhidrotic. She was diagnosed with idiopathic segmental anhidrosis. We administered steroid pulse therapy without observing any significant effects.Although anhidrosis is a rare disorder, a careful interview and physical examination should be conducted to confirm a history of heatstroke and the absence of sweating to avoid missing the disease.

Risk factors for brain injury in patients with exertional heatstroke: A 5-year experience.

PURPOSE: Minimal data exist on brain injury in patients with exertional heatstroke (EHS) in developing country. In this study, we explored the risk factors for brain injury induced by EHS 90-day after onset. METHODS: A retrospective cohort study of patients with EHS was conducted in the intensive care unit of the General Hospital of Southern Theater Command of PLA in China from April 2014 to June 2019. Patients were divided into non-brain injury (fully recovered) and brain injury groups (comprising deceased patients or those with neurological sequelae). The brain injury group was further subdivided into a death group and a sequela group for detailed analysis. General information, neurological performance and information on important organ injuries in the acute stage were recorded and analysed. Multivariable logistic regression was used to identify risk factors for brain injury after EHS and mortality risk factors for brain injury, and Kaplan-Meier survival curve was used to evaluate the effect of the neurological dysfunction on survival. RESULTS: Out of the 147 EHS patients, 117 were enrolled, of which 96 (82.1%) recovered, 13 (11.1%) died, and 8 (6.8%) experienced neurological sequelae. Statistically significant differences were found between non-brain injury and brain injury groups in age, hypotension, duration of consciousness disorders, time to drop core body temperature below 38.5°C, lymphocyte counts, platelet counts, procalcitonin, alanine aminotransferase, aspartate aminotransferase, creatinine, cystatin C, coagulation parameters, international normalized ratio, acute physiology and chronic health evaluation II scores, sequential organ failure assessment (SOFA) scores, and Glasgow coma scale scores (all p < 0.05). Multivariate logistic regression showed that age (OR = 1.090, 95% CI: 1.02 - 1.17, p = 0.008), time to drop core temperature (OR = 8.223, 95% CI: 2.30 - 29.40, p = 0.001), and SOFA scores (OR = 1.676, 95% CI: 1.29 - 2.18, p < 0.001) are independent risk factors for brain injury induced by EHS. The Kaplan-Meier curves suggest significantly prolonged survival (p < 0.001) in patients with early Glasgow coma scale score > 8 and duration of consciousness disorders ≤ 24 h. CONCLUSIONS: Advanced age, delayed cooling, and higher SOFA scores significantly increase the risk of brain injury post-EHS. These findings underscore the importance of rapid cooling and early assessment of organ failure to improve outcomes in EHS patients.

A newly proposed heatstroke-induced coagulopathy score in patients with heat illness: A multicenter retrospective study in China.

PURPOSE: In patients with heatstroke, disseminated intravascular coagulation (DIC) is associated with greater risk of in-hospital mortality. However, time-consuming assays or a complex diagnostic system may delay immediate treatment. Therefore, the present study proposes a new heatstroke-induced coagulopathy (HIC) score in patients with heat illness as an early warning indicator for DIC. METHODS: This retrospective study enrolled patients with heat illness in 24 Chinese hospitals from March 2021 to May 2022. Patients under 18 years old, with a congenital clotting disorder or liver disease, or using anticoagulants were excluded. Data were collected on demographic characteristics, routine blood tests, conventional coagulation assays and biochemical indexes. The risk factors related to coagulation function in heatstroke were identified by regression analysis, and used to construct a scoring system for HIC. The data of patients who met the diagnostic criteria for HIC and International Society on Thrombosis and Haemostasis defined-DIC were analyzed. All statistical analyses were performed using SPSS 26.0. RESULTS: The final analysis included 302 patients with heat illness, of whom 131 (43.4%) suffered from heatstroke, including 7 death (5.3%). Core temperature (OR = 1.681, 95% CI 1.291 - 2.189, p < 0.001), prothrombin time (OR = 1.427, 95% CI 1.175 - 1.733, p < 0.001) and D-dimer (OR = 1.242, 95% CI 1.049 - 1.471, p = 0.012) were independent risk factors for heatstroke, and therefore used to construct an HIC scoring system because of their close relation with abnormal coagulation. A total score ≥ 3 indicated HIC, and HIC scores correlated with the score for International Society of Thrombosis and Hemostasis -DIC (r = 0.8848, p < 0.001). The incidence of HIC (27.5%) was higher than that of DIC (11.2%) in all of 131 heatstroke patients. Meanwhile, the mortality rate of HIC (19.4%) was lower than that of DIC (46.7%). When HIC developed into DIC, parameters of coagulation dysfunction changed significantly: platelet count decreased, D-dimer level rose, and prothrombin time and activated partial thromboplastin time prolonged (p < 0.05). CONCLUSIONS: The newly proposed HIC score may provide a valuable tool for early detection of HIC and prompt initiation of treatment.

Extracellular histones exacerbate heat stroke-induced liver injury by triggering hepatocyte pyroptosis and liver injury via the TLR9-NLRP3 pathway.

BACKGROUND: Severe heat stroke is often complicated by multiple organ failure, including liver injury. Recent evidence indicates that the underlying mechanism constitutes sterile inflammation triggered by cell damage, in which hepatocyte NOD-like receptor family pyrin domain-containing 3 inflammasome activation and pyroptosis play key roles. As extracellular histones act as damage-associated molecular patterns and mediate tissue toxicity and inflammation, we aimed to investigate whether extracellular histones contribute to inducing hepatocyte pyroptosis following heat stroke, promoting the development of liver inflammation and injury, and elucidate the potential underlying mechanisms. METHODS: Exogenous histones were administered to AML-12 murine hepatocytes or male aged 8-12 week mice following hyperthermic treatment (at 39 °C in a chamber with 60 % relative humidity). Prior to heat exposure, endogenous histones were neutralized using neutralizing antibodies, inflammasomes were inhibited by RNA silencing, and Toll-like receptor 9 was modulated using a pharmacological agonist or antagonist. Inflammasome assembly, caspase-1 activation, histological changes, and liver enzyme levels were measured. Statistical comparison of more than two groups was performed using one-way ANOVA with Tukey's post-hoc testing. The correlations were analyzed using Pearson's correlation test. All experiments were repeated thrice. A p-value < 0.05 was considered significant. RESULTS: Heat stroke induced histone release into the extracellular space at levels correlating with liver injury. Moreover, extracellular histones augmented heat stroke-induced liver injury both in vitro and in vivo in a dose- and time-dependent manner, whereas neutralizing histones conferred protection following heat stroke. Histones mediated NOD-like receptor family pyrin domain-containing 3 inflammasome activation through the Toll-like receptor 9 signaling pathway, which resulted in hepatocyte pyroptosis and liver inflammation. CONCLUSIONS: Our findings show that histones are critical mediators of hepatocyte pyroptosis that aggravate liver injury in a heat stroke setting. Therefore, we suggest extracellular histones as potential therapeutic targets to limit heat stroke-induced cell death and liver injury.

A case report of near-missed heat stroke.

RATIONALE: Heat-related illnesses have protean manifestations that can mimic other life-threatening conditions. The diagnosis of heat stroke requires a high index of suspicion if the patient has been exposed to a high-temperature environment. Central nervous system dysfunction is a cardinal feature. Strict adherence to temperature criteria can potentially lead to misdiagnosis. PATIENT CONCERNS: A 37-year-old construction worker was brought in by his wife and coworker due to a sudden loss of consciousness while resting after completing his work. DIAGNOSES: Due to challenges faced during the coronavirus disease 2019 pandemic, as well as language barriers, a detailed history from the coworker who witnessed the patient's altered sensorium was not available. He was initially suspected of having encephalitis and brainstem stroke. However, subsequent investigations revealed multiorgan dysfunction with a normal brain computed tomography and cerebral computed tomography angiogram. In view of the multiple risk factors for heat stroke, pupillary constriction, and urine color suggestive of rhabdomyolysis, a diagnosis of heat stroke was made. INTERVENTIONS: Despite delayed diagnosis, the patient's multiorgan dysfunction recovered within days with basic supportive care. OUTCOMES: There were no noticeable complications on follow-up 14 months later. LESSONS: Heat stroke can be easily confused with other neurological pathologies, particularly if no history can be obtained from the patient or informant. When approaching a comatose patient, we propose that serum creatinine kinase should be considered as an initial biochemical screening test.

Reversible supraventricular tachycardia and left bundle branch block in a marathon runner with exertional heat stroke in the Po Valley.

We report the case of a 52-year-old marathon runner admitted to our emergency department for exertional heat stroke (EHS). The electrocardiogram (ECG) showed a supraventricular tachycardia, probably an atrial flutter with 2:1 block, conducted with left bundle branch block. After 10 minutes of aggressive fluid management and rapid external cooling, the ECG returned to normal. As the high-sensitivity cardiac troponin I was elevated, coronary angiography and an electrophysiological study were performed, revealing normal coronary arteries and excluding inducible arrhythmias. As reported in the current literature, our findings confirm that the electrocardiographic changes and elevation of cardiac markers in EHS do not reflect cardiac ischemia, but rather a myocardial injury due to the pathophysiological response to dehydration and hyperthermia, which markedly impaired stroke volume and cardiac output. EHS is a life-threatening condition with a complex pathophysiology caused by thermoregulatory failure. Diagnosis is not always straightforward, but early recognition and timely management (the "golden hour") with rapid cooling and intravenous fluids are crucial to prevent irreversible and fatal organ damage. EHS is defined by a rectal temperature > 40.5 °C with symptoms or signs of neurological dysfunction, such as confusion, drowsiness, or seizures, which can rapidly worsen with delirium, coma, and cardiac arrest. With this case report, we want to remind emergency physicians that early diagnosis and appropriate management of EHS can avoid death and inappropriate treatment. (www.actabiomedica.it).

[Analysis of clinical characteristics and risk factors of early heat stroke-related acute liver injury].

OBJECTIVE: To analyze the clinical characteristics and risk factors of early acute liver injury in patients with heat stroke (HS), and to provide basis for early identification of HS-related liver injury and its pathogenesis in clinical practice. METHODS: The clinical data of patients with HS admitted to the department of critical care medicine of Haian People's Hospital from June 2015 to August 2022 were retrospectively analyzed. The patients with HS were divided into early liver injury group and early non-liver injury group according to the occurrence of acute liver injury within 24 hours of admission. The differences of basic data, clinical data, laboratory indexes and clinical outcomes of the two groups were analyzed. Logistic regression was used to analyze the risk factors for early HS-related acute liver injury, and receiver operator characteristic (ROC) curves were drawn to evaluate their value in predicting the occurrence of early HS-related acute liver injury. RESULTS: A total of 76 patients with HS were enrolled, and 46 patients with acute liver injury, accounting for 60.53%. In the early liver injury group, 14 patients (30.43%) had elevated aminotransferase alone, 9 patients (19.57%) had elevated total bilirubin (TBil) alone, and 23 patients (50.00%) had elevated both aminotransferase and TBil. Among the patients with elevated aminotransferases, 24 patients (64.87%) had mild elevation, 5 patients (13.51%) had moderate elevation, 8 patients (21.62%) had severe elevation. Compared with the early non-liver injury group, acute physiology and chronic health evaluation II (APACHE II), sequential organ failure assessment (SOFA), arterial blood lactate (Lac), interleukin-6 (IL-6), procalcitonin (PCT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), TBil, γ-gamma glutamyl transferase (γ-GGT), lactate dehydrogenase (LDH), creatine kinase (CK), MB isoenzyme of creatine kinase (CK-MB), cardiac troponin I (cTnI), myoglobin (MYO), N-terminal B-type pro-brain natriuretic peptide (NT-proBNP), prothrombin time (PT), activated partial thromboplastin time (APTT), D-dimer in the early liver injury group were significantly increased, while platelet count (PLT) were significantly decreased within 24 hours after admission, the 28-day mortality was significantly increased [28.26% (13/46) vs. 6.67% (2/30)], and the differences were statistically significant (all P < 0.05). Univariate Logistic regression analysis showed that APACHE II score, SOFA score, PLT, Lac, IL-6, PCT, γ-GGT, LDH, CK, CK-MB, cTnI, MYO, PT, APTT, D-dimer were risk factors of early HS-related acute liver injury (all P < 0.05). Multivariate Logistic regression analysis showed that PLT, IL-6, and LDH were independent risk factors of early HS-related acute liver injury [odds ratio (OR) and 95% confidence interval (95%CI) were 0.986 (0.974-0.998), 1.027 (1.012-1.041), and 1.002 (1.000-1.004), all P < 0.05]. The ROC curve analysis showed that the area under the ROC curve (AUC) of PLT, IL-6 and LDH for predicting the occurrence of early HS-related acute liver injury was 0.672 (95%CI was 0.548-0.797), 0.897 (95%CI was 0.824-0.971) and 0.833 (95%CI was 0.739-0.927), respectively. IL-6 had the highest predictive value for early HS-related liver injury. When the optimal diagnostic threshold of IL-6 was 48.25 ng/L, the sensitivity was 95.7%, the specificity was 73.3%, and the predictive value of PLT was the lowest. CONCLUSIONS: The early HS-related liver injury is mainly manifested as the simultaneous elevation of aminotransferase and TBil, and most of cases are mild liver injury. PLT, IL-6 and LDH are independent risk factors of early HS-related acute liver injury.

Inhibition of the MLCK/MLC2 pathway protects against intestinal heat stroke-induced injury in rats.

Intestinal barrier dysfunction often exists in the heat stroke (HS) pathological process, which increases intestinal permeability and induces endotoxemia. The upregulation of MLCK is a crucial player affecting intestinal permeability. This study aimed to explore whether inhibiting myosin light chain kinase (MLCK) can improve HS-induced intestinal injury in rats. Twelve-week-old Wistar male rats were divided into three groups: the control group, the HS model group, and the treatment group [HS model + ML-7 (MLCK inhibitor)]. HS impaired the tight junctions in the rat gut and increased permeability. Additionally, increased inflammatory factors in serum, activation of apoptosis, and downregulation of tight junction proteins were observed in intestinal cells. ML-7 significantly inhibited the MLCK/p-MLC2 signaling pathway, increased the expression of tight junction proteins, reduced intestinal permeability, reduced apoptosis and alleviated the intestinal damage caused by HS. ML-7 inhibited HS-induced apoptosis of intestinal epithelial cells by regulating the ERK/p38/HSP70 axis. Furthermore, inhibition of MLCK upregulated HSP70 expression through activation of the ERK pathway and inhibited cell apoptosis by abolishing the p38 MAPK pathway. In conclusion, inhibiting the MLCK/p-MLC2 signaling pathway reduces HS-induced intestinal permeability and protects the intestinal mucosal barrier.

The association of standard base excess upon emergency admission with outcomes in patients with heat stroke.

OBJECTIVES: Standard base excess (SBE) is a quick and effective tool to identify acid-base disorders in critically ill patients, independent of respiratory factors. The predictive value of SBE for adverse outcomes in patients with heat stroke (HS) is still unclear. This study aimed to explore the prognostic significance of SBE for in-hospital mortality and other adverse outcomes in patients with HS. METHODS: A retrospective, observational multicenter cohort study with consecutive patients between 2021 and 2022 was conducted. The SBE was performed upon emergency department (ED) admission. The primary outcome was in-hospital mortality. Secondary outcomes included the use of vasoactive drugs in the ED, admission to the ICU, acute kidney failure, acute heart failure, acute respiratory failure, sepsis, and coagulation impairment. Logistic regression models and receiver operating characteristic (ROC) curves were used to estimate the association of SBE with outcomes in HS patients. Interaction and stratified analyses were also conducted. RESULTS: The median level of SBE was -4.70 (-8.05- -1.55) mmol/L. Overall hospital mortality in these 151 HS patients was 12.58%. SBE was independently associated with hospital mortality (OR 0.81, 95% CI 0.70-0.95, P = 0.011). Age and HS type played interactive roles in the relationship between SBE and in-hospital mortality. The OR between SBE and hospital mortality was 0.5 (95% CI, 0.3-0.9; p < 0.018) in classic HS participants and 0.62 (95% CI, 0.45-0.87; p = 0.005) in participants aged >65 years. The AUC of SBE to predict in-hospital mortality was 0.868 (95% CI: 0.704-0.962) and 0.883 (95% CI: 0.750-0.951) in these two groups, respectively. SBE was significantly associated with admission to the ICU, acute kidney failure, acute respiratory failure, sepsis, and coagulation impairment. CONCLUSION: SBE upon emergency admission was significantly associated with adverse outcomes in patients with HS.

Multiparametric cardiac magnetic resonance reveals persistent myocardial inflammation in patients with exertional heat illness.

OBJECTIVES: To explore the clinical potential of multiparametric cardiac magnetic resonance (CMR) in evaluating myocardial inflammation in patients with exertional heat illness (EHI). METHODS: This prospective study enrolled 28 males with EHI (18 patients with exertional heat exhaustion (EHE) and 10 with exertional heat stroke (EHS)) and 18 age-matched male healthy controls (HC). All subjects underwent multiparametric CMR, and 9 patients had follow-up CMR measurements 3 months after recovery from EHI. CMR-derived left ventricular geometry, function, strain, native T1, extracellular volume (ECV), T2, T2*, and late gadolinium enhancement (LGE) were obtained and compared among different groups. RESULTS: Compared with HC, EHI patients showed increased global ECV, T2, and T2* values (22.6% ± 4.1 vs. 19.7% ± 1.7; 46.8 ms ± 3.4 vs. 45.1 ms ± 1.2; 25.5 ms ± 2.2 vs. 23.8 ms ± 1.7; all p < 0.05). Subgroup analysis showed that ECV was higher in the EHS patients than those in EHE and HC groups (24.7% ± 4.9 vs. 21.4% ± 3.2, 24.7% ± 4.9 vs. 19.7% ± 1.7; both p < 0.05). Repeated CMR measurements at 3 months after baseline CMR showed persistently higher ECV than HC (p = 0.042). CONCLUSIONS: With multiparametric CMR, EHI patients demonstrated increased global ECV, T2, and persistent myocardial inflammation at 3-month follow-up after EHI episode. Therefore, multiparametric CMR might be an effective method in evaluating myocardial inflammation in patients with EHI. CLINICAL RELEVANCE STATEMENT: This study showed persistent myocardial inflammation after an exertional heat illness (EHI) episode demonstrated by multiparametric CMR, which is a potential promising method to evaluate the severity of myocardial inflammation and guide return to work, play, or duty in EHI patients. KEY POINTS: • EHI patients showed an increased global extracellular volume (ECV), late gadolinium enhancement, and T2 value, indicating myocardial edema and fibrosis. • ECV was higher in the exertional heat stroke patients than exertional heat exhaustion and healthy control groups (24.7% ± 4.9 vs. 21.4% ± 3.2, 24.7% ± 4.9 vs. 19.7% ± 1.7; both p < 0.05). • EHI patients showed persistent myocardial inflammation with higher ECV than healthy controls 3 months after index CMR (22.3% ± 2.4 vs. 19.7% ± 1.7, p = 0.042).