Fever is associated with delayed ventilator liberation in acute lung injury. Ann Am Thorac Soc. 2013;10:608-615. [PMID: 24024608 DOI: 10.1513/annalsats.201303-052oc]

Protocol for fever control using external cooling in mechanically ventilated patients with septic shock: SEPSISCOOL II randomised controlled trial

INTRODUCTION

Fever treatment is commonly applied in patients with sepsis but its impact on survival remains undetermined. Patients with respiratory and haemodynamic failure are at the highest risk for not tolerating the metabolic cost of fever. However, fever can help to control infection. Treating fever with paracetamol has been shown to be less effective than cooling. In the SEPSISCOOL pilot study, active fever control by external cooling improved organ failure recovery and early survival. The main objective of this confirmatory trial is to assess whether fever control at normothermia can improve the evolution of organ failure and mortality at day 60 of febrile patients with septic shock. This study will compare two strategies within the first 48 hours of septic shock: treatment of fever with cooling or no treatment of fever.

METHODS AND ANALYSIS

SEPSISCOOL II is a pragmatic, investigator-initiated, adaptive, multicentre, open-label, randomised controlled, superiority trial in patients admitted to the intensive care unit with febrile septic shock. After stratification based on the acute respiratory distress syndrome status, patients will be randomised between two arms: (1) cooling and (2) no cooling. The primary endpoint is mortality at day 60 after randomisation. The secondary endpoints include the evolution of organ failure, early mortality and tolerance. The target sample size is 820 patients.

ETHICS AND DISSEMINATION

The study is funded by the French health ministry and was approved by the ethics committee CPP Nord Ouest II (Amiens, France). The results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04494074.

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.

Design and rationale of the CHILL phase II trial of hypothermia and neuromuscular blockade for acute respiratory distress syndrome

The Cooling to Help Injured Lungs (CHILL) trial is an open label, two group, parallel design multicenter, randomized phase IIB clinical trial assessing the efficacy and safety of targeted temperature management with combined external cooling and neuromuscular blockade to block shivering in patients with early moderate-severe acute respiratory distress syndrome (ARDS). This report provides the background and rationale for the clinical trial and outlines the methods using the Consolidated Standards of Reporting Trials guidelines. Key design challenges include: [1] protocolizing important co-interventions; [2] incorporation of patients with COVID-19 as the cause of ARDS; [3] inability to blind the investigators; and [4] ability to obtain timely informed consent from patients or legally authorized representatives early in the disease process. Results of the Reevaluation of Systemic Early Neuromuscular Blockade (ROSE) trial informed the decision to mandate sedation and neuromuscular blockade only in the group assigned to therapeutic hypothermia and proceed without this mandate in the control group assigned to a usual temperature management protocol. Previous trials conducted in National Heart, Lung, and Blood Institute ARDS Clinical Trials (ARDSNet) and Prevention and Early Treatment of Acute Lung Injury (PETAL) Networks informed ventilator management, ventilation liberation and fluid management protocols. Since ARDS due to COVID-19 is a common cause of ARDS during pandemic surges and shares many features with ARDS from other causes, patients with ARDS due to COVID-19 are included. Finally, a stepwise approach to obtaining informed consent prior to documenting critical hypoxemia was adopted to facilitate enrollment and reduce the number of candidates excluded because eligibility time window expiration.

Design, synthesis, and SAR study of novel 4,5-dihydropyrazole-Thiazole derivatives with anti-inflammatory activities for the treatment of sepsis

Systemic inflammatory response syndrome is a major feature of sepsis which is one of the major causes of death worldwide. It has been reported that 3,5-diaryl-4,5-dihydropyrazole and thiazole derivatives have many biological functions, especially in the aspect of anti-inflammation. According to the strategy of pharmacophore combination, we introduced thiazole moiety into dihydropyrazole skeleton to design and synthesize a novel series of 2-(3,5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl)-4-methylthiazole derivatives, and evaluated their anti-inflammatory activities for sepsis treatment. Preliminary structure-activity relationship (SAR) analysis was conducted by their inhibitory activities against nitric oxide (NO) release in LPS-induced RAW264.7 cells, and the optimal compound E26 exhibited more potent anti-inflammatory activity than the positive control treatment indomethacin and dexamethasone. In further mechanism study, our results showed that compound E26 significantly suppressed the production of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), NO and inhibited the expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) through blocking MAPKs signaling pathway. In addition, in vivo administration of compound E26 resulted in a significant improvement of LPS-induced sepsis in C57BL/6J mice, with reducing toxicity in multiple organs. Taken together, this study demonstrated the compound E26 could be a promising agent for the treatment of sepsis.

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.

Effect of a fever in viral infections — the ‘Goldilocks’ phenomenon?

Acute infections, including those due to Coronaviridae and other viruses, often stimulate a febrile response. A mild fever appears to improve outcome; it appears to diminish viral replication by several mechanisms, including virion entry into host cells and genome transcription, and improving host defence mechanisms against the pathogen. However, a fever may also damage host cellular and tissue function and increase metabolic demands. At temperatures at the lower end of the febrile range, the benefit of the fever appears to outweigh the detrimental effects. However, at higher temperatures, the outcome worsens, suggesting that the disadvantages of fever on the host predominate. A non-infective fever is associated with a worse outcome at lower temperatures, suggesting that hyperthermia carries less benefit in the absence of infection. This review discusses the risks and benefits of a fever on the host response, focusing on the effects of a fever on viral replication and host response, and the detrimental effect on the host.

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.

[Fever in the critically ill : To treat or not to treat]

Fever, arbitrarily defined as a core body temperature >38.3 °C, is present in 20-70 % of intensive care unit patients. Fever caused by infections is a physiologic reset of the thermostatic set-point and is associated with beneficial consequences, but may have negative sequelae with temperatures >39.5 °C. Fever of non-infectious and neurologic origin affects about 50 % of patients with elevated body temperature, presents as a pathologic loss of thermoregulation, and may be associated with untoward side effects at temperatures above 38.5-39.0 °C. Cooling can be achieved by physical and pharmacologic means. Evidence-based recommendations are not available. The indication for a cooling therapy can only be based on the physiologic reserve and the neurologic, hemodynamic, and respiratory state. The temperature should be lowered to the normothermic range. Hyperthermia syndromes require immediate physical cooling (and dantrolen when indicated).

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.

Exposure to febrile-range hyperthermia potentiates Wnt signalling and epithelial-mesenchymal transition gene expression in lung epithelium

BACKGROUND

As environmental and body temperatures vary, lung epithelial cells experience temperatures significantly different from normal core temperature. Our previous studies in human lung epithelium showed that: (i) heat shock accelerates wound healing and activates profibrotic gene expression through heat shock factor-1 (HSF1); (ii) HSF1 is activated at febrile temperatures (38-41 °C) and (iii) hypothermia (32 °C) activates and hyperthermia (39.5 °C) reduces expression of a subset of miRNAs that target protein kinase-Cα (PKCα) and enhance proliferation.

METHODS

We analysed the effect of hypo- and hyperthermia exposure on Wnt signalling by exposing human small airway epithelial cells (SAECs) and HEK293T cells to 32, 37 or 39.5 °C for 24 h, then analysing Wnt-3a-induced epithelial-mesenchymal transition (EMT) gene expression by qRT-PCR and TOPFlash reporter plasmid activity. Effects of miRNA mimics and inhibitors and the HSF1 inhibitor, KNK437, were evaluated.

RESULTS

Exposure to 39.5 °C for 24 h increased subsequent Wnt-3a-induced EMT gene expression in SAECs and Wnt-3a-induced TOPFlash activity in HEK293T cells. Increased Wnt responsiveness was associated with HSF1 activation and blocked by KNK437. Overexpressing temperature-responsive miRNA mimics reduced Wnt responsiveness in 39.5 °C-exposed HEK293T cells, but inhibitors of the same miRNAs failed to restore Wnt responsiveness in 32 °C-exposed HEK293T cells.

CONCLUSIONS

Wnt responsiveness, including expression of genes associated with EMT, increases after exposure to febrile-range temperature through an HSF1-dependent mechanism that is independent of previously identified temperature-dependent miRNAs. This process may be relevant to febrile fibrosing lung diseases, including the fibroproliferative phase of acute respiratory distress syndrome (ARDS) and exacerbations of idiopathic pulmonary fibrosis (IPF).

Higher mini-BAL total protein concentration in early ARDS predicts faster resolution of lung injury measured by more ventilator-free days

The protein concentration of alveolar edema fluid in acute respiratory distress syndrome (ARDS) is dynamic. It reflects alveolar flooding during acute injury, as well as fluid and protein clearance over time. We hypothesized that among ARDS patients treated with low tidal volume ventilation, higher concentrations of protein in mini-bronchoalveolar lavage (mBAL) samples would predict slower resolution of lung injury and worse clinical outcomes. Total protein and IgM concentrations in day 0 mBAL samples from 79 subjects enrolled in the aerosolized albuterol (ALTA) ARDS Network Albuterol Trial were measured by colorimetric assay and ELISA, respectively. Linear regression models were used to test the association of mBAL proteins with clinical outcomes and measures of length of illness, including ventilator-free days (VFDs). Median mBAL total protein concentration was 1,740 μg/ml [interquartile range (IQR): 890-3,170]. Each 500 μg/ml increase in day 0 mBAL total protein was associated with an additional 0.8 VFDs [95% confidence interval (CI): 0.05-1.6, P value = 0.038]. Median mBAL IgM concentration was 410 ng/ml (IQR: 340-500). Each 50 ng/ml increase in mBAL IgM was associated with an additional 1.1 VFDs (95% CI 0.2-2.1, P value = 0.022). These associations remained significant and were not attenuated in multivariate models adjusted for age, serum protein concentration, and vasopressor use in the 24 h before enrollment. Thus, higher mBAL total protein and IgM concentrations at day 0 are associated with more VFDs in patients with ARDS and may identify patients with preserved alveolar epithelial mechanisms for net alveolar fluid clearance.

Inadvertent hypothermia and mortality in critically ill adults: Systematic review and meta-analysis

OBJECTIVE

Considering that inadvertent hypothermia (IH) is common in Intensive Care Unit (ICU) patients and can be followed by severe complications, this systematic review identified, appraised and synthesised the published literature about the association between IH and mortality in adults admitted to the ICU.

DATA SOURCES

By using key terms, literature searches were conducted in Pubmed, CINAHL, Cochrane Library, Web of Science and EMBASE.

REVIEW METHODS

According to PRISMA guidelines, articles published between 1980-2016 in English-language, peer-reviewed journals were considered. IH was defined as core temperature of <36.5°C or lower, present on ICU admission or manifested during ICU stay. Outcome measure included ICU, hospital or 28-day mortality. Selected cohort studies were evaluated with the Newcastle-Ottawa Scale. Extracted data were summarised in tables and synthesised qualitatively and quantitatively, with adjusted odds ratios (ORs) for mortality being combined in meta-analyses.

RESULTS

Eighteen observational studies met inclusion criteria. All of them had high methodological quality. In twelve out of fifteen studies, unadjusted mortality was significantly higher in hypothermic patients compared to non-hypothermic ones. Likewise, in thirteen out of sixteen studies, IH or lowest core temperature was independently associated with significantly higher mortality. High severity and long duration of IH were also associated with higher mortality. Mortality was significantly higher in patients with core temperature <36.0°C (pooled OR 2.093, 95% CI 1.704-2.570), and in those with core temperature <35.0°C (pooled OR 2.945, 95% CI 2.166-4.004).

CONCLUSIONS

These findings indicate that IH predicts mortality in critically ill adults and pose suspicion that this may contribute to adverse patient outcome.

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.

An interdisciplinary computational/experimental approach to evaluate drug-loaded gold nanoparticle tumor cytotoxicity

AIM

Clinical translation of cancer nanotherapy has largely failed due to the infeasibility of optimizing the complex interaction of nano/drug/tumor/patient parameters. We develop an interdisciplinary approach modeling diffusive transport of drug-loaded gold nanoparticles in heterogeneously-vascularized tumors.

MATERIALS & METHODS

Evaluated lung cancer cytotoxicity to paclitaxel/cisplatin using novel two-layer (hexadecanethiol/phosphatidylcholine) and three-layer (with high-density-lipoprotein) nanoparticles. Computer simulations calibrated to in-vitro data simulated nanotherapy of heterogeneously-vascularized tumors.

RESULTS

Evaluation of free-drug cytotoxicity between monolayer/spheroid cultures demonstrates a substantial differential, with increased resistance conferred by diffusive transport. Nanoparticles had significantly higher efficacy than free-drug. Simulations of nanotherapy demonstrate 9.5% (cisplatin) and 41.3% (paclitaxel) tumor radius decrease.

CONCLUSION

Interdisciplinary approach evaluating gold nanoparticle cytotoxicity and diffusive transport may provide insight into cancer nanotherapy.

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.

Body temperature and mortality in patients with acute respiratory distress syndrome

BACKGROUND

Little is known about the relationship between body temperature and outcomes in patients with acute respiratory distress syndrome (ARDS). A better understanding of this relationship may provide evidence for fever suppression or warming interventions, which are commonly applied in practice.

OBJECTIVE

To examine the relationship between body temperature and mortality in patients with ARDS.

METHODS

Secondary analysis of body temperature and mortality using data from the ARDS Network Fluid and Catheter Treatment Trial (n = 969). Body temperature at baseline and on study day 2, primary cause of ARDS, severity of illness, and 90-day mortality were analyzed by using multiple logistic regression.

RESULTS

Mean baseline temperature was 37.5°C (SD, 1.1°C; range, 27.2°C-40.7°C). At baseline, fever (≥ 38.3°C) was present in 23% and hypothermia (< 36°C) in 5% of the patients. Body temperature was a significant predictor of 90-day mortality after primary cause of ARDS and score on the Acute Physiology and Chronic Health Evaluation III were adjusted for. Higher temperature was associated with decreased mortality: for every 1°C increase in baseline temperature, the odds of death decreased by 15% (odds ratio, 0.85; 95% CI, 0.73-0.98, P = .03). When patients were divided into 5 temperature groups, mortality was lower with higher temperature (P for trend = .02).

CONCLUSIONS

Early in ARDS, fever is associated with improved survival rates. Fever in the acute phase response to lung injury and its relationship to recovery may be an important factor in determining patients' outcome and warrants further study.