Association between prehospital shock index and mortality among patients with COVID-19 disease.

BACKGROUND: There exists a need for prognostic tools for the early identification of COVID-19 patients requiring intensive care unit (ICU) admission and mortality. Here we investigated the association between a clinical (initial prehospital shock index (SI)) and biological (initial prehospital lactatemia) tool and the ICU admission and 30-day mortality among COVID-19 patients cared for in the prehospital setting. METHODS: We retrospectively analysed COVID-19 patients initially cared for by a Paris Fire Brigade advanced (ALS) or basic life support (BLS) team in the prehospital setting between 2020, March 08th and 2020, May 30th. We assessed the association between prehospital SI and prehospital lactatemia and ICU admission and mortality using logistic regression model analysis after propensity score matching with Inverse Probability Treatment Weighting (IPTW) method. Covariates included in the IPTW propensity analysis were: age, sex, body mass index (BMI), initial respiratory rate (iRR), initial pulse oximetry without (SpO2i) and with oxygen supplementation (SpO2i.O2), initial Glasgow coma scale (GCSi) value, initial prehospital SI and initial prehospital lactatemia. RESULTS: We analysed 410 consecutive COVID-19 patients [254 males (62%); mean age, 64 ± 18 years]. Fifty-seven patients (14%) deceased on the scene, of whom 41 (72%) were male and were significantly older (71 ± 12 years vs. 64 ± 19 years; P 〈10-3). Fifty-three patients (15%) were admitted in ICU and 39 patients (11%) were deceased on day-30. The mean prehospital SI value was 1.5 ± 0.4 and the mean prehospital lactatemia was 2.0 ± 1.7 mmol.l-1. Multivariate logistic regression analysis on matched population after IPTW propensity analysis reported a significant association between ICU admission and age (adjusted Odd-Ratio (aOR), 0.90; 95% confidence interval (95%CI): 0.93-0.98;p = 10-3), SpO2i.O2 (aOR, 1.10; 95%CI: 1.02-1.20;p = 0.002) and BMI (aOR, 1.09; 95% CI: 1.03-1.16;p = 0.02). 30-day mortality was significantly associated with SpO2i.O2 (aOR, 0.92; 95% CI: 0.87-0.98;p = 0.01 P < 10-3) and GCSi (aOR, 0.90; 95% CI: 0.82-0.99;p = 0.04). Neither prehospital SI nor prehospital lactatemia were associated with ICU admission and 30-day mortality. CONCLUSION: Neither prehospital initial SI nor lactatemia were associated with ICU admission and 30-day mortality among COVID-19 patients initially cared for by a Paris Fire Brigade BLS or ALS team. Further prospective studies are needed to confirm these preliminary results.

Variations in the TRPV1 gene are associated to exertional heat stroke.

OBJECTIVES: Exertional Heat Stroke (EHS) is one of the top three causes of sudden death in athletes. Extrinsic and intrinsic risk factors have been identified but the genetic causes still remain unclear. Our aim was to identify genes responsible for EHS, which is a necessary step to identify patients at risk and prevent crises. DESIGN: Genetic and functional laboratory studies METHODS: Whole Exome Sequencing (WES) was performed to search for candidate genes in a cohort of 15 soldiers who had a documented EHS episode. In silico and in vitro functional studies were performed to evaluate the effect of mutations identified in the candidate gene TRPV1. RESULTS: WES led to the identification of two missense variations in the TRPV1 gene. These variations were very rare or unreported in control databases and located in critical domains of the protein. In vitro functional studies revealed that both variations induce a strong modification of the channel response to one of its natural agonist, the capsaicin. CONCLUSIONS: We evidenced mutations altering channel properties of the TRPV1 gene and demonstrated that TRPV1, which is involved in thermoregulation and nociception, is a new candidate gene for EHS. Our data provide the bases to explore genetic causes and molecular mechanisms governing the pathophysiology of EHS.

French Policies for Victim Management During Mass Radiological Accidents/Attacks.

In the current international context, emergency medical services have to be prepared for chemical, biological, radiological, and nuclear events. Emergency response to radiological or nuclear events requires coordination between many components: the fire brigade, emergency medical services (including nurses and physicians), police, hospitals, etc. To optimize efficiency, victim management in France is governed by specific policies and planned responses. This plan for radiological/nuclear event response is inspired by military chemical, biological, radiological, and nuclear victim management in the operational theatre and is based on extraction (removal to a safe environment), first triage, decontamination, second triage, treatment, substance identification, and training. It is also supported by specific equipment. Prehospital victim management in case of nuclear and radiological accident or attack will be described, as well as French-specific supplies. This response plan is constantly evolving due to the complexity of radiological and nuclear events.

Is there a link between exertional heat stroke and susceptibility to malignant hyperthermia?

OBJECTIVE: The identification of a predisposition toward malignant hyperthermia (MH) as a risk factor for exertional heat stroke (EHS) remains a matter of debate. Such a predisposition indicates a causal role for MH susceptibility (MHS) after EHS in certain national recommendations and has led to the use of an in vitro contracture test (IVCT) to identify the MHS trait in selected or unselected EHS patients. The aim of this study was to determine whether the MHS trait is associated with EHS. METHODS: EHS subjects in the French Armed Forces were routinely examined for MHS after experiencing an EHS episode. This retrospective study compared the features of IVCT-diagnosed MHS (iMHS) EHS subjects with those of MH-normal EHS patients and MH patients during the 2004-2010 period. MHS status was assessed using the European protocol. RESULTS: During the study period, 466 subjects (median age 25 years; 31 women) underwent MHS status investigation following an EHS episode. None of the subjects reported previous MH events. An IVCT was performed in 454 cases and was diagnostic of MHS in 45.6% of the study population, of MH susceptibility to halothane in 18.5%, of MH susceptibility to caffeine in 9.9%, and of MH susceptibility to halothane and caffeine in 17.2%. There were no differences in the clinical features, biological features or outcomes of iMHS EHS subjects compared with those of MH-normal or caffeine or halothane MHS subjects without known prior EHS episode. The recurrence rate was 12.7% and was not associated with MH status or any clinical or biological features. iMHS EHS patients exhibited a significantly less informative IVCT response than MH patients. CONCLUSIONS: The unexpected high prevalence of the MHS trait after EHS suggested a latent disturbance of calcium homeostasis that accounted for the positive IVCT results. This study did not determine whether EHS patients have an increased risk of MH, and it could not determine whether MH susceptibility is a risk factor for EHS.

Report of 182 cases of exertional heatstroke in the French Armed Forces.

OBJECTIVES: Exertional heatstroke (EHS) remains a major problem for the military. The aim of our study was to describe medical history and clinical and biological features of EHS in a large military cohort. METHODS: We conducted a retrospective study among military subjects admitted to the Military Teaching Hospital Laveran for EHS from 2004 to 2006. RESULTS: Of the 182 subjects, EHS occurred most often at the end (80%) of a timed race of 8 km in battle clothes (84%) between the months of May and October (87%). The subjects were physically fit. Motivation was the primary intrinsic factor reported. A previous episode of EHS was reported by 15.4% of the subjects. Comas or seizures occurred more frequently in subjects whose temperatures exceeded 41°C (p = 0.03). Alanine aminotransferase was consistently increased in subjects who experienced EHS. We observed acute renal failure in 31.3% of the subjects, liver insufficiency in 12%, and disseminated intravascular coagulation in 1%. High creatine kinase levels alone did not correlate with renal failure. CONCLUSIONS: Detection of severe EHS in the field before the onset of multiple organ failure is challenging. The determination of the factors contributing to recurrence is urgently needed as EHS remains a life-threatening condition.

Is muscle energy production disturbed in exertional heat stroke?

BACKGROUND: Exertional heat stroke (EHS) is a life-threatening disease that shares some clinical similarities with malignant hyperthermia (MH). By use of (31)Phosphorus magnetic resonance spectroscopy (MRS), EHS patients with MH susceptibility and MH patients shared common metabolic abnormalities. The aim of this study was to determine whether subjects who suffered from an EHS episode had disturbed muscle energetics. METHOD: This retrospective study was performed within the French database of military subjects that were explored from 2004 to 2010 after they suffered an EHS. All subjects had both in vitro contracture test to determine their MH susceptibility and (31)Phosphorus MRS at 4.7 Tesla to assess muscle energetics by means of MRS score, a composite score corresponding to the sum of metabolic abnormalities recorded during a standardized rest-exercise-recovery protocol. RESULTS: 437 subjects were investigated and 32.5% of them exhibited abnormal MRS score. MRS score did not segregate subjects on demographic, clinical, or biological grounds. No clear correlation could be done between MH status and MRS score. DISCUSSION: These results did not confirm the potential relationship between calcium homeostasis and muscle energetics previously reported. However, muscle energy production was disturbed in a significant number of EHS subjects.