Body temperature and mortality in patients with acute respiratory distress syndrome

Association Between Temperature During Intensive Care Unit and Mortality in Patients With Acute Respiratory Distress Syndrome

The relationship between body temperature changes and prognosis in patients with acute respiratory distress syndrome (ARDS) remains inconclusive. Our study aimed to investigate the clinical value of body temperature in the management of ARDS. Data from the Medical Information Mart for Intensive Care III database were collected. Adult patients with ARDS were enrolled and further grouped based on their temperature values in the intensive care unit. Both the maximum (temperaturemax) and minimum (temperaturemin) temperatures were used. The primary outcome was 28-day mortality rate. Polynomial regression, subgroup analysis, and logistic regression analysis were performed in the final analysis. A total of 3922 patients with ARDS were enrolled. There was a U-shaped relationship between 28-day mortality and body temperature. For patients with infection, the elevated temperaturemax (≥37.0°C) was associated with decreased mortality, with an odds ratio ranging from 0.39 to 0.49, using temperaturemax from 36.5°C to 36.9°C as reference. For patients without infection, a similar tendency was observed, but the protective effect was lost at extremely high temperatures (≥38.0°C, p < 0.05). Elevated temperaturemin (≥37.0°C) and decreased temperaturemin (<35.0°C) were associated with increased mortality, using the temperaturemin from 36.0°C to 36.9°C as a reference. Hypothermia was associated with increased mortality in patients with ARDS, while the effect of hyperthermia (≥37.0°C) on the mortality of patients with ARDS was not fully consistent in the infection and noninfection subgroups. Short-term and transient temperatures above 37.0°C would be beneficial to patients with ARDS, but extreme hyperthermia and persistent temperatures above 37.0°C should be avoided.

Development and validation of a clinical risk model to predict the hospital mortality in ventilated patients with acute respiratory distress syndrome: a population-based study

Background

Large variability in mortality exists in patients of acute respiratory distress syndrome (ARDS), especially those with invasive ventilation. The aim of this study was to develop a model to predict risk of in-hospital death in ventilated ARDS patients.

Methods

Ventilated patients with ARDS from two public databases (MIMIC-III and eICU-CRD) were randomly divided as training cohort and internal validation cohort. Least absolute shrinkage and selection operator (LASSO) and then Logistic regression was used to construct a predictive model with demographic, clinical, laboratory, comorbidities and ventilation variables ascertained at first 24 h of ICU admission and invasive ventilation. Our model was externally validated using data from another database (MIMIC-IV).

Results

A total of 1075 adult patients from MIMIC-III and eICU were randomly divided into training cohort (70%, n = 752) and internal validation cohort (30%, n = 323). 521 patients were included from MIMIC-IV. From 176 potential predictors, 9 independent predictive factors were included in the final model. Five variables were ascertained within the first 24 h of ICU admission, including age (OR, 1.02; 95% CI: 1.01–1.03), mean of respiratory rate (OR, 1.04; 95% CI: 1.01–1.08), the maximum of INR (OR, 1.14; 95% CI: 1.03–1.31) and alveolo-arterial oxygen difference (OR, 1.002; 95% CI: 1.001–1.003) and the minimum of RDW (OR, 1.17; 95% CI: 1.09–1.27). And four variables were collected within the first 24 h of invasive ventilation: mean of temperature (OR, 0.70; 95% CI: 0.57–0.86), the maximum of lactate (OR, 1.15; 95% CI: 1.09–1.22), the minimum of blood urea nitrogen (OR, 1.02; 95% CI: 1.01–1.03) and white blood cell counts (OR, 1.03; 95% CI: 1.01–1.06). Our model achieved good discrimination (AUC: 0.77, 95% CI: 0.73–0.80) in training cohort but the performance declined in internal (AUC: 0.75, 95% CI: 0.69–0.80) and external validation cohort (0.70, 95% CI: 0.65–0.74) and showed modest calibration.

Conclusions

A risk score based on routinely collected variables at the start of admission to ICU and invasive ventilation can predict mortality of ventilated ARDS patients, with a moderate performance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02057-0.

Energy Efficiency through the Implementation of an AI Model to Predict Room Occupancy Based on Thermal Comfort Parameters

Room occupancy prediction based on indoor environmental quality may be the breakthrough to ensure energy efficiency and establish an interior ambience tailored to each user. Identifying whether temperature, humidity, lighting, and CO2 levels may be used as efficient predictors of room occupancy accuracy is needed to help designers better utilize the readings and data collected in order to improve interior design, in an effort to better suit users. It also aims to help in energy efficiency and saving in an ever-increasing energy crisis and dangerous levels of climate change. This paper evaluated the accuracy of room occupancy recognition using a dataset with diverse amounts of light, CO2, and humidity. As classification algorithms, K-nearest neighbors (KNN), hybrid Adam optimizer–artificial neural network–back-propagation network (AO–ANN (BP)), and decision trees (DT) were used. Furthermore, this research is based on machine learning interpretability methodologies. Shapley additive explanations (SHAP) improve interpretability by estimating the significance values for each feature for classifiers applied. The results indicate that the KNN performs better than the DT and AO-ANN (BP) classification models have 99.5%. Though the two classifiers are designed to evaluate variations in interpretations, we must ensure that they have accurate detection. The results show that SHAP provides successful implementation following these metrics, with differences detected amongst classifier models that support the assumption that model complexity plays a significant role when predictability is taken into account.

Fever temperatures impair hemolysis caused by strains of Escherichia coli and Staphylococcus aureus

Hemolysis modulates susceptibility to bacterial infections and predicts poor sepsis outcome. Hemolytic bacteria use hemolysins to induce erythrocyte lysis and obtain the heme that is essential for bacterial growth. Hemolysins are however potent immunogens and infections with hemolytic bacteria may cause a reversible fever response from the host that will aid in pathogen clearance. We hypothesized that fever temperatures impact the growth and infectivity of two hemolytic bacteria that are known to evoke fever in patients. To that end, we used high-sensitivity microcalorimetry to measure the evolution of heat production in fever-inducing strains of Escherichia coli and Staphylococcus aureus, under different temperature conditions. We determined specific bacterial aggregation profiles at temperatures equal to or exceeding 38.5 °C. Two melting temperatures peaks ranged from 38 °C to 43 °C for either species, a feature that we assigned to the formation of hemolysin aggregates of different oligomerization order. In order to measure the role of fever temperatures on hemolysis, we incubated the pathogens on blood agar plates at relevant temperatures, measuring the presence of hemolysis at 37 °C and its absence at 40.5 °C, respectively. We conclude that fever temperatures affect the kinetics of hemolysin pore formation and subsequently the hemolysis of red blood cells in vitro. We reveal the potential of microcalorimetry to monitor heat response from fever inducing bacterial species. Furthermore, these results help establish an additional positive role of febrile temperatures in modulating the immune response to infections, through the abolishment of hemolysis.

Potential for Further Mismanagement of Fever During COVID-19 Pandemic: Possible Causes and Impacts

Fever remains an integral part of acute infectious diseases management, especially for those without effective therapeutics, but the widespread myths about "fevers" and the presence of confusing guidelines from different agencies, which have heightened during the coronavirus disease 2019 (COVID-19) pandemic and are open to alternate interpretation, could deny whole populations the benefits of fever. Guidelines suggesting antipyresis for 37.8-39°C fever are concerning as 39°C boosts the protective heat-shock and immune response (humoral, cell-mediated, and nutritional) whereas ≥40°C initiates/enhances the antiviral responses and restricts high-temperature adapted pathogens, e.g., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), strains of influenza, and measles. Urgent attention is accordingly needed to address the situation because of the potential public health consequences of the existence of conflicting guidelines in the public domain. We have in this article attempted to restate the benefits of fever in disease resolution, dispel myths, and underline the need for alignment of national treatment guidelines with that of the WHO, to promote appropriate practices and reduce the morbidity and mortality from infectious diseases, such as COVID-19.

Inhaled ACE2-engineered microfluidic microsphere for intratracheal neutralization of COVID-19 and calming of the cytokine storm

The SARS-CoV-2 pandemic spread worldwide unabated. However, achieving protection from the virus in the whole respiratory tract, avoiding blood dissemination, and calming the subsequent cytokine storm remains a major challenge. Here, we develop an inhaled microfluidic microsphere using dual camouflaged methacrylate hyaluronic acid hydrogel microspheres with a genetically engineered membrane from angiotensin-converting enzyme II (ACE2) receptor-overexpressing cells and macrophages. By timely competing with the virus for ACE2 binding, the inhaled microspheres significantly reduce SARS-CoV-2 infective effectiveness over the whole course of the respiratory system in vitro and in vivo. Moreover, the inhaled microspheres efficiently neutralize proinflammatory cytokines, cause an alternative landscape of lung-infiltrated immune cells, and alleviate hyperinflammation of lymph nodes and spleen. In an acute pneumonia model, the inhaled microspheres show significant therapeutic efficacy by regulation of the multisystem inflammatory syndrome and reduce acute mortality, suggesting a powerful synergic strategy for the treatment of patients with severe COVID-19 via non-invasive administration.

Acute respiratory distress syndrome: A study of autopsy findings

Context:

In this autopsy study, the various morphological patterns of acute respiratory distress syndrome (ARDS) have been analyzed and compared along with their etiopathogenesis.

Aims:

We aimed to study the prevalence and clinicopathological correlation of ARDS based on age, gender, hospital stay, symptoms, clinical diagnosis, gross, and microscopy findings.

Subjects and Methods:

Total 130 cases of ARDS were studied over a period of 5 years. Age, gender, hospital stay duration, symptoms, clinical diagnosis, gross and microscopic lung finding, clinicopathological correlation, and cause of death were documented and analyzed. Special stains were done whenever required.

Statistical Analysis:

This is an observational study, and simple statistics such as mean, median, and standard deviation have been used for continuous variables.

Results:

The prevalence of ARDS among the adult autopsy was 6.05%. Majority of the cases were in the age group of 18–30 years (36.9%), with a male: female ratio of 1.7:1. Chief complaints were fever (71%), breathlessness (54.6%), and chills (43.8%). The main clinical diagnoses were ARDS (41.6%), sepsis (28.3%), acute febrile illness (17%), and lower respiratory tract infection (12.5%). Most of the patients had a hospital stay of <1 day. Associated conditions mostly included chronic alcoholism (16.1%), pregnancy (16.1%), and chronic smoking (10.7%). Major findings on gross examination were intrapulmonary hemorrhage (38.5%), ARDS (33%), pulmonary edema (13%), and pneumonia (15.3%). On microscopy, major findings were hyaline membrane (84.6%), intrapulmonary hemorrhage (76.1%), pulmonary edema (75.3%), organizing fibrin (55.3%), and bronchopneumonia (36.2%).

Conclusion:

Infections were one of the major predisposing causes of ARDS. Due to the short interval, the underlying cause for ARDS often goes undiagnosed.

Fever management in critically ill COVID-19 patients: a retrospective analysis

BACKGROUND

Fever has been reported as a common symptom in COVID-19 patients. The aim of the study was to describe the characteristics of COVID-19 critically ill patients with fever and to assess if fever management had an impact on some physiologic variables.

METHODS

This is a retrospective monocentric cohort analysis of critically ill COVID-19 patients admitted to the Department of Intensive Care Unit (ICU) of Erasme Hospital, Brussels, Belgium, between March 2020 and May 2020. Fever was defined as body temperature ≥ 38° C during the ICU stay. We assessed the independent predictors of fever during ICU stay. We reported the clinical and physiological variables before and after the first treated episode of fever during the ICU stay.

RESULTS

A total of 72 critically ill COVID-19 patients were admitted to the ICU over the study period and were all eligible for the final analysis; 53 (74%) of them developed fever, after a median of 4 [0-13] hours since ICU admission. In the multivariable analysis, male gender (OR 5.41 [C.I. 95% 1.34-21.92]; p=0.02) and low PaO2/FiO2 ratio (OR 0.99 [C.I. 95% 0.99-1.00]; p=0.04) were independently associated with fever. After the treatment of the first febrile episode, heart rate and respiratory rate significantly decreased together with an increase in PaO2 and SaO2.

CONCLUSIONS

In our study, male gender and severe impairment of oxygenation were independently associated with fever in critically ill COVID-19 patients. Fever treatment reduced heart rate and respiratory rate and improved systemic oxygenation.

Predictors of critical illness and mortality based on symptoms and initial physical examination for patients with SARS-CoV-2: A retrospective cohort study

INTRODUCTION

An unidentified cluster of pneumonia was identified in Wuhan city of China in the last week of December 2019, named Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-COV-2). The current study explored the predictors associated with critical illness and mortality based on symptoms at the time of admission and initial physical examination findings in patients with SARS-CoV-2.

MATERIAL AND METHODS

A total of 249 records of laboratory-confirmed SARS-COV-2 patients were analyzed. Demographic profile and findings of initial physical examination were collected and analyzed. Bivariate logistic and multivariable stepwise forward regression analysis was used to identify the predictors of critical illness and mortality.

RESULTS

A total of 249 records of SARS-COV-2 patients were retrospectively studied, of whom 66 (26.5%) developed a critical illness, and 58 (23.29%) died. The mean age of patients was 45.15 (16.34) years; 171 (68.71%) were men. From 27 potential predictors for developing a critical illness, 15 were reported independent predictors for critical illness, and 13 were for increased risk of mortality. Stepwise forward regression reported dyspnea as a single strongest predictor (OR, 5.800, 95% CI-2.724-12.346; p = 0.001, R2 = 0.272) to develop critical illness. Likewise, the respiratory rate was alone reported as a strong predictor (OR, 1.381, 95% CI- 1.251-1.525; p = 0.000, R2 = 0.329) for mortality.

CONCLUSIONS

Coronavirus disease is a new challenge to the medical fraternity, leading to significant morbidity and mortality. Knowledge of potential risk factors could help clinicians assess patients' risk with unfavourable outcomes and improve hospitalization decisions in the early stage.

Emergency department utilization and risk factors for mortality in older patients: an analysis of Korean National Emergency Department Information System data

Objective

With trends in population aging an increasing number of older patients are visiting the emergency department (ED). This study aimed to identify the characteristics of ED utilization and risk factors for in-hospital mortality in older patients who visited EDs.

Methods

This nationwide observational study used National Emergency Department Information System data collected during a 2-year period from January 2016 to December 2017. The characteristics of older patients aged 70 years or older were compared with those of younger patients aged 20 to 69 years. Risk factors associated with in-hospital mortality were analyzed by multivariable logistic regression.

Results

A total of 6,596,423 younger patients and 1,737,799 older patients were included. In the medical and nonmedical older patient groups, significantly higher proportions of patients were transferred from another hospital, utilized emergency medical services, had Korean Triage and Acuity Scale scores of 1 and 2, required hospitalization, and required intensive care unit admission in the older patient group than in the younger patient group. ED and post-hospitalization mortality rates increased with age; in particular, older medical patients aged 90 or older had an in-hospital mortality rate of 9%. Older age, male sex, transfer from another hospital, emergency medical service utilization, a high Korean Triage and Acuity Scale score, systolic blood pressure <100 mmHg, respiratory rate >20/min, heart rate >100/min, body temperature <36°C, and altered mental status were associated with in-hospital mortality.

Conclusion

Development of appropriate decision-making algorithms and treatment protocols for high risk older patients visiting the ED might facilitate appropriate allocation of medical resources to optimize outcomes.

Thermal inactivation scaling applied for SARS-CoV-2

Based on a model of protein denaturation rate limited by an entropy-related barrier, we derive a simple formula for virus inactivation time as a function of temperature. Loss of protein structure is described by two reaction coordinates: conformational disorder of the polymer and wetting by the solvent. These establish a competition between conformational entropy and hydrophobic interaction favoring random coil or globular states, respectively. Based on the Landau theory of phase transition, the resulting free energy barrier is found to decrease linearly with the temperature difference T - Tm, and the inactivation rate should scale as U to the power of T - Tm. This form recalls an accepted model of thermal damage to cells in hyperthermia. For SARS-CoV-2 the value of U in Celsius units is found to be 1.32. Although the fitting of the model to measured data is practically indistinguishable from Arrhenius law with an activation energy, the entropy barrier mechanism is more suitable and could explain the pronounced sensitivity of SARS-CoV-2 to thermal damage. Accordingly, we predict the efficacy of mild fever over a period of ∼24 h in inactivating the virus.

Fever Management of Critically Ill Patients with COVID-19 Infection: Less is More?

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Moderate Fever Cycles as a Potential Mechanism to Protect the Respiratory System in COVID-19 Patients

Mortality in COVID-19 patients predominantly results from an acute respiratory distress syndrome (ARDS), in which lungs alveolar cells undergo programmed cell death. Mortality in a sepsis-induced ARDS rat model is reduced by adenovirus over-expression of the HSP70 chaperone. A natural rise of body temperature during mild fever can naturally accumulate high cellular levels of HSP70 that can arrest apoptosis and protect alveolar lung cells from inflammatory damages. However, beyond 1-2 h of fever, no HSP70 is being further produced and a decreased in body temperature required to the restore cell's ability to produce more HSP70 in a subsequent fever cycle. We suggest that antipyretics may be beneficial in COVID-19 patients subsequent to several hours of mild (<38.8°C) advantageous fever, allowing lung cells to accumulate protective HSP70 against damages from the inflammatory response to the virus SARS-CoV-2. With age, the ability to develop fever and accumulate HSP70 decreases. This could be ameliorated, when advisable to do so, by thermotherapies and/or physical training.

Clinical characteristics, laboratory outcome characteristics, comorbidities, and complications of related COVID-19 deceased: a systematic review and meta-analysis

Background

At present, novel coronavirus disease 2019 (COVID-19) has become a serious global public health problem. The current meta-analysis aimed to find risk factors for the COVID-19-related death, helping to enhance the efficacy and reduce the mortality of COVID-19.

Methods

We searched PubMed, Embase, medRxiv, and Cochrane Library for articles published between January 1, 2020, and April 13, 2020. We statistically analyzed the risk factors of the COVID-19 deceased with meta-analysis.

Results

A total of 2401 patients in 15 articles were included in this study. Meta-analysis showed that 66.6% of COVID-19 deceased were male, with a median age of 69.9 years. Common symptoms of deceased included fever (70.6–100%), dyspnea (38.89–85.7%), cough (22.4–78%), and fatigue (22–61.9%). The incidence of hypertension, chronic cardiovascular disease, diabetes, and chronic cerebrovascular disease among the COVID-19 deceased were 38.56% (95% confidence interval (CI) 25.84 ~ 52.12%), 17.54% (95% CI 13.38 ~ 21.69%), 22.2% (95% CI 19.30 ~ 25.10%), and 15.58% (95% CI 10.05 ~ 21.12%), respectively. Compared with the surviving COVID-19 patients, the deceased had lower platelet levels (mean difference (MD) = − 39.35, 95% CI − 55.78 ~ − 22.93) and higher C-reactive protein (CRP) (MD = 80.85, 95% CI 62.53 ~ 99.18) and lactate dehydrogenase (LDH) (MD = 246.65, 95% CI 157.43 ~ 335.88) at admission. The most common complications of the deceased were acute respiratory distress syndrome (ARDS) (OR = 100.36, 95% CI 64.44 ~ 156.32) and shock (OR = 96.60, 95% CI 23.80 ~ 392.14).

Conclusion

Most of the COVID-19 deceased were elderly males. Fever, dyspnea, dry cough, fatigue, hypertension, chronic cardiovascular and cerebrovascular disease, diabetes, and laboratory examinations showed low levels of platelet content, increased CRP and LDH were associated with the risk of dying. ARDS and shock were risk factors for death in COVID-19 patients.

The Association of Fever and Antipyretic Medication With Outcomes in Mechanically Ventilated Patients: A Cohort Study

BACKGROUND

Fever is common in mechanically ventilated patients and may be uniquely detrimental in those with lung injury because of its injurious effects on pulmonary vascular permeability and alveolar epithelium. We evaluated the association of fever and antipyretic medication with mortality in mechanically ventilated emergency department (ED) patients.

METHODS

This is a retrospective cohort study of 1,264 patients requiring mechanical ventilation initiated in the ED with subsequent admission to an intensive care unit. Maximum body temperature was recorded for the first 24 h after ED admission and categorized into four categories: <37°C, 37°C to 38.2°C, 38.3°C to 39.4°C, and ≥39.5°C. The primary outcome was 28-day mortality. We conducted a planned subgroup analysis of patients with sepsis at the time of intubation. Multivariable Cox proportional hazard ratios (HRs) were used to assess the relationship between temperature, antipyretics, and mortality.

RESULTS

Multivariable Cox proportional HRs demonstrated that a maximum temperature ≥39.5°C was associated with increased mortality (adjusted hazard ratio [aHR] 1.59 [95% confidence interval, CI, 1.05-2.39]). In the subgroup of patients with sepsis, a maximum temperature of 38.3°C to 39.4°C was associated with survival (aHR 0.61 [95% CI, 0.39-0.99]). There was no difference in 28-day mortality between patients who did and did not receive antipyretic medication in either the overall cohort or the septic subgroup.

CONCLUSION

High fever (≥39.5°C) was associated with increased risk for mortality in mechanically ventilated patients. However, in patients with sepsis, moderate fever (38.3°C-39.4°C) was protective. Antipyretic medication was not associated with changes in outcome. This suggests that fever may have different implications in septic versus nonseptic mechanically ventilated patients.

Non-Cardiogenic Pulmonary Oedema Following the use of Gadolinium-Based Contrast Medium: A Case Report

Non-cardiogenic pulmonary oedema can be life threatening and requires prompt treatment. While gadolinium-based contrast is generally considered safe with a low risk of severe side effects, non-cardiogenic pulmonary oedema has become increasingly recognised as a rare, but possibly life-threatening complication. We present a case of a usually well, young 23-year-old female who developed non-cardiogenic pulmonary oedema with a moderate oxygenation impairment and no mucosal or cutaneous features of anaphylaxis following the administration of gadolinium-based contrast. She did not respond to treatment of anaphylaxis but made a rapid recovery following the commencement of positive pressure ventilation. Our case highlights the importance of recognising the rare complication of non-cardiogenic pulmonary oedema following gadolinium-based contrast administration in order to promptly implement the appropriate treatment.

Risk Factors Associated With Acute Respiratory Distress Syndrome and Death in Patients With Coronavirus Disease 2019 Pneumonia in Wuhan, China

IMPORTANCE

Coronavirus disease 2019 (COVID-19) is an emerging infectious disease that was first reported in Wuhan, China, and has subsequently spread worldwide. Risk factors for the clinical outcomes of COVID-19 pneumonia have not yet been well delineated.

OBJECTIVE

To describe the clinical characteristics and outcomes in patients with COVID-19 pneumonia who developed acute respiratory distress syndrome (ARDS) or died.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of 201 patients with confirmed COVID-19 pneumonia admitted to Wuhan Jinyintan Hospital in China between December 25, 2019, and January 26, 2020. The final date of follow-up was February 13, 2020.

EXPOSURES

Confirmed COVID-19 pneumonia.

MAIN OUTCOMES AND MEASURES

The development of ARDS and death. Epidemiological, demographic, clinical, laboratory, management, treatment, and outcome data were also collected and analyzed.

RESULTS

Of 201 patients, the median age was 51 years (interquartile range, 43-60 years), and 128 (63.7%) patients were men. Eighty-four patients (41.8%) developed ARDS, and of those 84 patients, 44 (52.4%) died. In those who developed ARDS, compared with those who did not, more patients presented with dyspnea (50 of 84 [59.5%] patients and 30 of 117 [25.6%] patients, respectively [difference, 33.9%; 95% CI, 19.7%-48.1%]) and had comorbidities such as hypertension (23 of 84 [27.4%] patients and 16 of 117 [13.7%] patients, respectively [difference, 13.7%; 95% CI, 1.3%-26.1%]) and diabetes (16 of 84 [19.0%] patients and 6 of 117 [5.1%] patients, respectively [difference, 13.9%; 95% CI, 3.6%-24.2%]). In bivariate Cox regression analysis, risk factors associated with the development of ARDS and progression from ARDS to death included older age (hazard ratio [HR], 3.26; 95% CI 2.08-5.11; and HR, 6.17; 95% CI, 3.26-11.67, respectively), neutrophilia (HR, 1.14; 95% CI, 1.09-1.19; and HR, 1.08; 95% CI, 1.01-1.17, respectively), and organ and coagulation dysfunction (eg, higher lactate dehydrogenase [HR, 1.61; 95% CI, 1.44-1.79; and HR, 1.30; 95% CI, 1.11-1.52, respectively] and D-dimer [HR, 1.03; 95% CI, 1.01-1.04; and HR, 1.02; 95% CI, 1.01-1.04, respectively]). High fever (≥39 °C) was associated with higher likelihood of ARDS development (HR, 1.77; 95% CI, 1.11-2.84) and lower likelihood of death (HR, 0.41; 95% CI, 0.21-0.82). Among patients with ARDS, treatment with methylprednisolone decreased the risk of death (HR, 0.38; 95% CI, 0.20-0.72).

CONCLUSIONS AND RELEVANCE

Older age was associated with greater risk of development of ARDS and death likely owing to less rigorous immune response. Although high fever was associated with the development of ARDS, it was also associated with better outcomes among patients with ARDS. Moreover, treatment with methylprednisolone may be beneficial for patients who develop ARDS.

The Use of Core Warming as a Treatment for Coronavirus Disease 2019 (COVID-19): an Initial Mathematical Model

Background: Increasing data suggest that elevated body temperature may be helpful in resolving a variety of diseases, including sepsis, acute respiratory distress syndrome (ARDS), and viral illnesses. SARS-CoV-2, which causes coronavirus disease 2019 (COVID-19), may be more temperature sensitive than other coronaviruses, particularly with respect to the binding affinity of its viral entry via the ACE2 receptor. A mechanical provision of elevated temperature focused in a body region of high viral activity in patients undergoing mechanical ventilation may offer a therapeutic option that avoids arrhythmias seen with some pharmaceutical treatments. We investigated the potential to actively provide core warming to the lungs of patients with a commercially available heat transfer device via mathematical modeling, and examine the influence of blood perfusion on temperature using this approach. Methods: Using the software Comsol Multiphysics, we modeled and simulated heat transfer in the body from an intraesophageal warming device, taking into account the airflow from patient ventilation. The simulation was focused on heat transfer and warming of the lungs and performed on a simplified geometry of an adult human body and airway from the pharynx to the lungs. Results: The simulations were run over a range of values for blood perfusion rate, which was a parameter expected to have high influence in overall heat transfer, since the heat capacity and density remain almost constant. The simulation results show a temperature distribution which agrees with the expected clinical experience, with the skin surface at a lower temperature than the rest of the body due to convective cooling in a typical hospital environment. The highest temperature in this case is the device warming water temperature, and that heat diffuses by conduction to the nearby tissues, including the air flowing in the airways. At the range of blood perfusion investigated, maximum lung temperature ranged from 37.6°C to 38.6°C. Conclusions: The provision of core warming via commercially available technology currently utilized in the intensive care unit, emergency department, and operating room can increase regional temperature of lung tissue and airway passages. This warming may offer an innovative approach to treating infectious diseases from viral illnesses such as COVID-19, while avoiding the arrhythmogenic complications of currently used pharmaceutical treatments.

COVID-19: A review of therapeutics under investigation

The COVID-19 outbreak has disrupted global health care networks and caused thousands of deaths and an international economic downturn. Multiple drugs are being used on patients with COVID-19 based on theoretical and in vitro therapeutic targets. Several of these therapies have been studied, but many have limited evidence behind their use, and clinical trials to evaluate their efficacy are either ongoing or have not yet begun. This review summarizes the existing evidence for medications currently under investigation for treatment of COVID-19, including remdesivir, chloroquine/hydroxychlorquine, convalescent plasma, lopinavir/ritonavir, IL-6 inhibitors, corticosteroids, and angiotensin-converting enzyme inhibitors.

Impact of Accidental Hypothermia on Pulmonary Complications in Multiply Injured Patients With Blunt Chest Trauma - A Matched-pair Analysis

BACKGROUND/AIM

Blunt chest trauma is one of the major injuries in multiply injured patients and is associated with an increased risk of acute respiratory distress syndrome (ARDS) and ventilator-associated pneumonia (VAP). Accidental hypothermia is a common accompaniment of multiply injured patients. The objective of this study was to analyze the influence of accidental hypothermia on pulmonary complications in multiply injured patients with blunt chest trauma.

PATIENTS AND METHODS

Multiply injured patients [injury severity score (ISS) ≥16] with severe blunt chest trauma [abbreviated injury scale of the chest (AISchest) ≥3] were analyzed. Hypothermia was defined as body core temperature <35°C. The primary endpoint was the development of ARDS and VAP. Propensity score matching was performed.

RESULTS

Data were analyzed for 238 patients, with a median ISS of 26 (interquartile range=12). A total of 67 patients (28%) were hypothermic on admission. Hypothermic patients were injured more severely (median ISS 34 vs. 24, p<0.001) and had a higher transfusion requirement (p<0.001). Their mortality rate was consequently increased (10% vs. 1%, p=0.002); After propensity score matching, the mortality rate was still higher (10% vs. 2%, p=0.046). However, hypothermia was not an independent predictor of mortality. Hypothermic patients had to be ventilated longer (p=0.02). However, there were no differences in occurrence of ARDS and VAP. Hypothermia was not identified as an independent predictor of ARDS and VAP.

CONCLUSION

Among multiply injured patients with severe blunt chest trauma, accidental hypothermia is not an independent predictor of ARDS and VAP and is more likely to be an accompaniment of injury severity and hemorrhage.

Hypothesis: Fever control, a niche for alpha-2 agonists in the setting of septic shock and severe acute respiratory distress syndrome?

During severe septic shock and/or severe acute respiratory distress syndrome (ARDS) patients present with a limited cardio-ventilatory reserve (low cardiac output and blood pressure, low mixed venous saturation, increased lactate, low PaO2/FiO2 ratio, etc.), especially when elderly patients or co-morbidities are considered. Rescue therapies (low dose steroids, adding vasopressin to noradrenaline, proning, almitrine, NO, extracorporeal membrane oxygenation, etc.) are complex. Fever, above 38.5-39.5°C, increases both the ventilatory (high respiratory drive: large tidal volume, high respiratory rate) and the metabolic (increased O2 consumption) demands, further limiting the cardio-ventilatory reserve. Some data (case reports, uncontrolled trial, small randomized prospective trials) suggest that control of elevated body temperature ("fever control") leading to normothermia (35.5-37°C) will lower both the ventilatory and metabolic demands: fever control should simplify critical care management when limited cardio-ventilatory reserve is at stake. Usually fever control is generated by a combination of general anesthesia ("analgo-sedation", light total intravenous anesthesia), antipyretics and cooling. However general anesthesia suppresses spontaneous ventilation, making the management more complex. At variance, alpha-2 agonists (clonidine, dexmedetomidine) administered immediately following tracheal intubation and controlled mandatory ventilation, with prior optimization of volemia and atrio-ventricular conduction, will reduce metabolic demand and facilitate normothermia. Furthermore, after a rigorous control of systemic acidosis, alpha-2 agonists will allow for accelerated emergence without delirium, early spontaneous ventilation, improved cardiac output and micro-circulation, lowered vasopressor requirements and inflammation. Rigorous prospective randomized trials are needed in subsets of patients with a high fever and spiraling toward refractory septic shock and/or presenting with severe ARDS.

The Association of Fever with Total Mechanical Ventilation Time in Critically Ill Patients

This research aims to investigate the impact of fever on total mechanical ventilation time (TVT) in critically ill patients. Subgroup analysis was conducted using a previous prospective, multicenter observational study. We included mechanically ventilated patients for more than 24 hours from 10 Korean and 15 Japanese intensive care units (ICU), and recorded maximal body temperature under the support of mechanical ventilation (MAX(MV)). To assess the independent association of MAX(MV) with TVT, we used propensity-matched analysis in a total of 769 survived patients with medical or surgical admission, separately. Together with multiple linear regression analysis to evaluate the association between the severity of fever and TVT, the effect of MAX(MV) on ventilator-free days was also observed by quantile regression analysis in all subjects including non-survivors. After propensity score matching, a MAX(MV) ≥ 37.5°C was significantly associated with longer mean TVT by 5.4 days in medical admission, and by 1.2 days in surgical admission, compared to those with MAX(MV) of 36.5°C to 37.4°C. In multivariate linear regression analysis, patients with three categories of fever (MAX(MV) of 37.5°C to 38.4°C, 38.5°C to 39.4°C, and ≥ 39.5°C) sustained a significantly longer duration of TVT than those with normal range of MAX(MV) in both categories of ICU admission. A significant association between MAX(MV) and mechanical ventilator-free days was also observed in all enrolled subjects. Fever may be a detrimental factor to prolong TVT in mechanically ventilated patients. These findings suggest that fever in mechanically ventilated patients might be associated with worse mechanical ventilation outcome.

Hospitalized acute patients with fever and severe infection have lower mortality than patients with hypo- or normothermia: a follow-up study

OBJECTIVES

Severe infection is a frequent cause of admission to an acute medical unit (AMU). However, not all infected patients present with fever. The aim was to assess differences in 30-day mortality among patients hospitalized with community-acquired severe infection presenting with hypothermia, normothermia or fever.

METHODS

A retrospective single-center follow-up at an AMU from August 1, 2009 to August 31, 2011. Patients were included the first time they presented with severe infection within the study period. Temperature was categorized into hypothermia (<36.0ºC), normothermia (36.0ºC-38.0ºC) and fever (>38.0ºC). Severe infection was defined as a discharge diagnosis indicating infection combined with organ failure within the first 24 h after arrival. Multivariable Cox regression analysis was computed to assess the association between temperature and 30-day mortality.

RESULTS

A total of 2128 patients with severe infection were included. 3.0% (N  =  64) were hypothermic, 57.1% (N  =  1216) normothermic and 39.9% (N  =  848) had fever at arrival. Crude 30-day mortality was 16.1% (N  =  342, 95%CI 14.5-17.7%); 37.5% (N  =  24, 95% CI 25.7-50.5%) for hypothermic patients, 18.3% (N  =  223, 95%CI 16.2-20.6%) for normothermic patients and 11.2% (N = 95, 95%CI 9.2-13.5%) for patients with fever. Compared to normothermic patients, the adjusted hazard ratio of 30-day mortality among hypothermic patients was 1.62 (95%CI 1.06-2.49) and 0.74 (95%CI 0.58-0.94) among patients with fever.

CONCLUSIONS

Over half of the patients admitted to an AMU with severe infection were normothermic at arrival. Hypothermia was associated with an increased risk of short-term mortality, whereas patients with fever were associated with a lower risk compared to those with normothermia.

Controversies in the temperature management of critically ill patients

Although body temperature is a classic primary vital sign, its value has received little attention compared with the others (blood pressure, heart rate, and respiratory rate). This may result from the fact that unlike the other primary vital signs, aging and diseases rarely affect the thermoregulatory system. Despite this, when humans are exposed to various anesthetics and analgesics and acute etiologies of non-infectious and infectious diseases in perioperative and intensive care settings, abnormalities may occur that shift body temperature up and down. A recent upsurge in clinical evidence in the perioperative and critical care field resulted in many clinical trials in temperature management. The results of these clinical trials suggest that aggressive body temperature modifications in comatose survivors after resuscitation from shockable rhythm, and permissive fever in critically ill patients, are carried out in critical care settings to improve patient outcomes; however, its efficacy remains to be elucidated. A recent, large multicenter randomized controlled trial demonstrated contradictory results, which may disrupt the trends in clinical practice. Thus, updated information concerning thermoregulatory interventions is essential for anesthesiologists and intensivists. Here, recent controversies in therapeutic hypothermia and fever management are summarized, and their relevance to the physiology of human thermoregulation is discussed.

Melatonin alleviates acute lung injury through inhibiting the NLRP3 inflammasome

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are clinically severe respiratory disorders, and there are currently no Food and Drug Administration-approved drug therapies. Melatonin is a well-known anti-inflammatory molecule, which has proven to be effective in ALI induced by many conditions. Emerging studies suggest that the NLRP3 inflammasome plays a critical role during ALI. How melatonin directly blocks activation of the NLRP3 inflammasome in ALI remains unclear. In this study, using an LPS-induced ALI mouse model, we found intratracheal (i.t.) administration of melatonin markedly reduced the pulmonary injury and decreased the infiltration of macrophages and neutrophils into lung. During ALI, the NLRP3 inflammasome is significantly activated with a large amount of IL-1β and the activated caspase-1 occurring in the lung. Melatonin inhibits the activation of the NLRP3 inflammasome by both suppressing the release of extracellular histones and directly blocking histone-induced NLRP3 inflammasome activation. Notably, i.t. route of melatonin administration opens a more efficient therapeutic approach for treating ALI.

Targeted temperature management in intensive care - Do we let nature take its course?

Should we aim to intervene and control fever in the critically ill patient? The answer is not straightforward and there is certainly no universal agreement on the subject. This article aims to discuss whether we should over-ride nature and disallow it to take it's course, particularly where it appears that this evolutionary response to invading pathogens is actually becoming harmful to the patient. Also discussed here are the physiology of temperature control and the scope of our current understanding of the impact of fever in patients manifesting systemic inflammatory response syndrome (SIRS) and sepsis in ICU, the possible interventions to combat fever (both physical and pharmacological) and the evidence for anti-pyretic drug therapy. The final section examines the potential role of targeted temperature management in the management of sepsis / SIRS in the critically ill.