Temperature control in sepsis

Impact of thermoneutral acclimation on a murine model of polymicrobial peritonitis

To examine the effects of ambient temperature on the reproducibility and translation of a murine sepsis model, we hypothesized that acclimation of mice in temperatures within their thermoneutral zone would alter immune responses and outcomes compared to standard housing temperatures. Mice housed for one week in thermoneutral (30°C) as compared to standard (22°C) conditions displayed lower counts of circulating neutrophils (0.52 ± 0.20 vs. 1.10 ± 0.54 x103/μL; p = 0.011) and peritoneal macrophages (0.80 ± 0.57 vs. 1.62 ± 0.62 x 105/μL; p = 0.002) as well as reduced in vitro production of IFN-γ by stimulated splenocytes (0.38 ± 0.68 vs 2.55 ± 0.76 x104 pg/mL, respectively, p = 0.004). After one week of temperature acclimation followed by CLP, the 7-day mortality was significantly lower under thermoneutral as compared to standard temperatures (80% vs 30%, respectively; p = 0.012), although core body temperature was preserved (average for 24 hours: 36.4 ± 1.3°C vs 31.7 ± 4.7°C; p < 0.0001). The lower survival was accompanied by increased systemic IL-6 levels (3.8 ± 3.3 vs 1.9 ± 1.3 x103 pg/mL; p = 0.04) and less robust influx of neutrophils into the peritoneum (1.68 ± 1.07 vs. 4.20 ± 2.46 x105/μL, respectively; p = 0.0003). Overall, thermoneutral temperatures impacted innate immune parameters before and after CLP, producing distinctly different outcomes. Therefore, ambient temperature is an important variable that could impact model reproducibility and should be reported for the acclimation period and experimentation phases of murine sepsis studies.

Evaluating Sepsis Management and Patient Outcomes: A Comprehensive Retrospective Study of Clinical and Treatment Data

Background/Objectives: Sepsis, as a major cause of mortality worldwide, requires timely diagnosis and prompt treatment to improve patient outcomes. In this study, we evaluated sepsis management strategies and their impact on clinical outcomes in hospitalized patients. Methods: A retrospective study was conducted by analyzing clinical and treatment data from the electronic records of sepsis patients who had been admitted to tertiary care hospitals in eastern Saudi Arabia. Using systematic sampling, the details of eligible patients were obtained. Data were collected on patient demographics, vital signs, Sequential Organ Failure Assessment (SOFA) and laboratory parameters, treatment (antibiotic therapy, vasopressor use, or fluid resuscitation), and outcomes (survival in hospital). Statistical analyses were performed to assess the association between clinical and treatment strategies and patient outcomes. Results: A total of 234 sepsis cases were analyzed, of which 70.9% were survivors and 29.1% were non-survivors. Patients aged 60 years and above were the most affected. Statistically significant differences were observed across all of the measured vital sign variables and outcomes (p < 0.0001). Based on SOFA scores, 56.41% of patients were assessed as having a moderate risk. Through our comparison of clinical and laboratory parameters between survivors and non-survivors, significant differences were found in all of the measured variables (p < 0.0001). The odds of survival were significantly higher in those who received early administration of broad-spectrum antibiotics (OR = 4.9449, p = 0.0001), vasopressor therapy (OR = 1.9408, p = 0.0262), and fluid resuscitation OR = 11.035, p = 0.0001). Conclusions: The results of this study highlight the importance of early sepsis recognition, prompt antibiotic therapy, and standardized protocol adherence in improving patient outcomes and reducing mortality and morbidity.

Development and application of an early prediction model for risk of bloodstream infection based on real-world study

BACKGROUND

Bloodstream Infection (BSI) is a severe systemic infectious disease that can lead to sepsis and Multiple Organ Dysfunction Syndrome (MODS), resulting in high mortality rates and posing a major public health burden globally. Early identification of BSI is crucial for effective intervention, reducing mortality, and improving patient outcomes. However, existing diagnostic methods are flawed by low specificity, long detection times and high demands on testing platforms. The development of artificial intelligence provides a new approach for early disease identification. This study aims to explore the optimal combination of routine laboratory data and clinical monitoring indicators, and to utilize machine learning algorithms to construct an early, rapid, and universally applicable BSI risk prediction model, to assist in the early diagnosis of BSI in clinical practice.

METHODS

Clinical data of 2582 suspected BSI patients admitted to the Chongqing University Central Hospital, from January 1, 2021 to December 31, 2023 were collected for this study. The data were divided into a modeling dataset and an external validation dataset based on chronological order, while the modeling dataset was further divided into a training set and an internal validation set. The occurrence rate of BSI, distribution of pathogens, and microbial primary reporting time were analyzed within the training set. During the feature selection stage, univariate regression and ML algorithms were applied. First, Univariate logistic regression was used to screen for predictive factors of BSI. Then, the Boruta algorithm, Lasso regression, and Recursive Feature Elimination with Cross-validation (RFE-CV) were employed to determine the optimal combination of predictors for predicting BSI. Based on the optimal combination, six machine learning algorithms were used to construct an early BSI risk prediction model. The best model was selected by models' performance, and the Shapley Additive Explanations (SHAP) method was used to explain the model. The external validation set was used to evaluate the predictive performance and generalizability of the selected model, and the research findings were ultimately applied in clinical practice.

RESULTS

The incidence of BSI among inpatients at the Chongqing University Central Hospital was 12.91%. Following further feature selection, a set of 5 variables was determined, including white blood cell count, standard bicarbonate, base excess of extracellular fluid, interleukin-6, and body temperature. BSI early risk prediction models were constructed using six machine learning algorithms, with the XGBoost model demonstrating the best performance, achieving an AUC value of 0.782 in the internal validation set and an AUC value of 0.776 in the external validation set. This model is made publicly available as an online webpage tool for clinical use.

CONCLUSIONS

This study successfully identified a set of 5 features by analyzing routine laboratory data clinical monitoring indicators among hospitalized patients. Based on this set, a machine learning-based early risk prediction model for BSI was constructed. The model is capable of early and rapid differentiation between BSI and non-BSI patients. The inclusion of minimal risk prediction factors enhances its applicability in clinical settings, particularly at the primary care level. To further improve the model's real-world applicability and more convenient for clinical use, the online application of the model could greatly improve the efficiency of BSI diagnosis and reducing patients' mortality.

Improved Sixty-Day Mortality in Candidemia with Antifungal Treatment Within 72 Hours of Fever Onset: A Single-Center Retrospective Study in Rural Japan

Introduction: Prognostic factor investigations for candidemia have been conducted in large-scale facilities, leading to significant evidence, including early administration of echinocandin antifungal agents and removal of central venous catheters (CVCs). In departments that provide aggressive chemotherapy or transplantation, candidiasis markers are regularly evaluated, and preemptive treatments may be initiated. However, in resource-limited facilities, candidemia detection largely relies on vital signs like fever and blood cultures. This study assessed whether evidence from large-scale facilities applies to such settings. Additionally, while prior studies indicate that early antifungal treatment is based on positive blood cultures, no established criteria exist for early administration based on fever as an indicator. Methods: This study analyzed cases of candidemia from blood cultures at Fukui General Hospital (2014-2024). Patients aged 18 or older with at least one positive blood culture for Candida species and clinical signs of infection were included, while contamination cases were excluded. The patients were categorized into survival and death groups based on 60-day survival from fever onset. The variables collected included age, gender, duration from admission to fever onset, time from fever onset to blood culture collection and antifungal treatment initiation, antifungal treatment within 72 h, serum albumin levels, history of cancer, diabetes, empiric echinocandin treatment, CVC insertion, duration of CVC insertion until fever onset, use of total parenteral nutrition, broad-spectrum antibiotic use, and sequential organ failure assessment (SOFA) score. Fever was defined as a body temperature of 38.0 °C or higher, guiding blood culture collection. Results: Of 30 candidemia cases, 29 were analyzed. Survival was significantly associated with younger age (average 73.3 ± 13.3 vs. 83.1 ± 9.1 years, p = 0.038) and antifungal treatment within 72 h of fever onset (9 vs. 3, p = 0.025). CVC use was of marginal significance (8 vs. 13, p = 0.108). There was a significant difference in the duration (in days) of CVC insertion until fever onset (median [IQR]: 15.5 [11.75-19.5] vs. 30.0 [19.0-39.0], p = 0.027). Logistic regression identified early antifungal treatment (OR = 0.065, p = 0.035) and CVC use (OR = 21.8, p = 0.024) as independent predictors of mortality. Conclusions: Early antifungal treatment within 72 h of fever onset and CVC use were independent predictors of mortality in candidemia. The importance of early antifungal treatment was reaffirmed even in smaller facilities. The impact of CVC insertion on 60-day survival cannot be readily generalized due to the limited sample size. Further research is needed to clarify the impact of fever-based antifungal initiation and CVC use on 60-day survival.

Wearable 3D-Printed Microneedle Sensor for Intradermal Temperature Monitoring

Accurate temperature monitoring plays a crucial role in understanding the physiological status of patients and the early diagnosis of diseases commonly associated with local and global infections. Intradermal temperature measurement is, in principle, more precise than skin surface detection, as it prevents interference from environmental temperature changes and skin secretions. However, to date, precise and reliable intradermal temperature monitoring in a real-time and continuous manner remains a challenge. We propose herein high-resolution 3D printing to fabricate a mechanically robust and biocompatible hollow microneedle, filled with a temperature-responsive conducting polymer (poly(3,4-ethylenedioxythiophene): polystyrenesulfonate, PEDOT:PSS) to develop a microneedle temperature sensor (T-MN). The significance is 2-fold: rational design of robust MNs with high resolution in the micrometer domain and the implementation of a conducting polymer in a MN format for temperature sensing. The analytical performance of the developed T-MN is in vitro evaluated under mimicked intradermal conditions, demonstrating good sensitivity (-0.74%° C-1), resolution (0.2 °C), repeatability (RSD = 2%), reproducibility (RSD = 2%), reversibility, and medium-term stability. On-body temperature monitoring is performed on six euthanized rats for 80 min. The results presented good agreement with those obtained using a commercial optical temperature probe, which was intradermally inserted into the rat skin. The reliability of utilizing the T-MN for precise and continuous intradermal temperature monitoring was successfully demonstrated, noting its potential use for patient monitoring in the near future but also temperature compensation for MN (bio)sensors that may need it.

[A systematic review on the safety and efficacy of metamizole sodium as a therapy for the treatment of fever in children and adults]

AIM

To systematically analyze existing publications from available scientific databases (PubMed, Cochrane, eLibrary) for the period from 2018 to 2023 on the treatment of fever in children and adults with metamizole sodium (MS).

MATERIALS AND METHODS

A systematic review of scientific publications on the efficacy and safety of MS therapy for fever in adults and children compared to non-steroidal anti-inflammatory drugs was conducted. Six randomized clinical trials involving 884 patients (101 adults and 783 children) were included in the analysis.

RESULTS

In all studies, MS has been demonstrated to be effective in reducing fever in both children and adults when used for short-term therapy. MS is superior to paracetamol, ibuprofen, acetylsalicylic acid and not inferior to nimesulide and propacetamol in terms of effectiveness in reducing body temperature between 1.5 and 6.0 hours after oral intake. It has been shown that treatment of fever with MS is a safer strategy compared to other non-steroidal anti-inflammatory drugs, as it has no clinically significant risks of gastric mucosal irritation, development of gastrointestinal bleeding and erosions. It has been established that therapeutic doses of MS do not lead to an increase in blood pressure, and in some cases contribute to hypotensive effect, especially in fever in adult comorbid patients with arterial hypertension.

CONCLUSION

MS is an effective treatment for fever in children and adults.

Severe intensive care unit-acquired hypernatraemia: Prevalence, risk factors, trajectory, management, and outcome

Background

Severe intensive care unit-acquired hypernatraemia (ICU-AH) is a serious complication of critical illness. However, there is no detailed information on how this condition develops.

Objectives

The objective of this study was to study the prevalence, risk factors, trajectory, management, and outcome of severe ICU-AH (≥155 mmol·L-1).

Methods

A retrospective study was conducted in a 40-bed ICU in a university-affiliated hospital. Assessment of sodium levels, factors associated with severe ICU-AH, urinary electrolyte measurements, water therapy, fluid balance, correction rate, and delirium was made.

Results

We screened 11,642 ICU admissions and identified 109 patients with severe ICU-AH. The median age was 57 years, 63% were male, and the median Acute Physiology and Chronic Health Evaluation III score was 64 (52; 80). On the day of ICU admission, 64% of patients were ventilated; 71% received vasopressors, and 22% had acute kidney injury. The median peak sodium level was 158 (156; 161) mmolL-1 at a median of 4 (1; 11) days after ICU admission. Only eight patients (7%) had urine sodium measurement (median concentration: 17 mmol·L-1). On the day of peak hypernatraemia, 80% of patients were unable to drink due to invasive ventilation; 34% were on diuretics; 25% had fever, and 50% did not receive hypotonic fluids. When available, the median electrolyte-free water clearance was -1.1 L (-1.7; -0.5), representing half of the urine output. After peak hypernatraemia, the correction rate was -2.8 mmol·L-1 per day (95% confidence interval: [-2.9 to -2.6]) during the first 3 d.

Conclusions

Severe hypernatraemia occurred in the setting of inability to drink, near-absent measurement of urinary free water losses, diuretic therapy, fever, renal impairment, and near-absent or limited or delayed water administration. Correction was slow.

Thermoregulation and survival during sepsis: insights from the cecal ligation and puncture experimental model

BACKGROUND

Sepsis remains a major global health concern due to its high prevalence and mortality. Changes in body temperature (Tb), such as hypothermia or fever, are diagnostic indicators and play a crucial role in the pathophysiology of sepsis. This study aims to characterize the thermoregulatory mechanisms during sepsis using the cecal ligation and puncture (CLP) model and explore how sepsis severity and ambient temperature (Ta) influence Tb regulation and mortality. Rats were subjected to mild or severe sepsis by CLP while housed at thermoneutral (28 °C) or subthermoneutral (22 °C) Ta, and their Tb was monitored for 12 h. Blood and hypothalamus were collected for cytokines and prostaglandin E2 (PGE2) analysis.

RESULTS

At 28 °C, febrile response magnitude correlated with sepsis severity and inflammatory response, with tail vasoconstriction as the primary heat retention mechanism. At 22 °C, Tb was maintained during mild sepsis but dropped during severe sepsis, linked to reduced UCP1 expression in brown adipose tissue and less effective vasoconstriction. Despite differences in thermoregulatory responses, both Ta conditions induced a persistent inflammatory response and increased hypothalamic PGE2 production. Notably, mortality in severe sepsis was significantly higher at 28 °C (80%) compared to 22 °C (0%).

CONCLUSIONS

Our findings reveal that ambient temperature and the inflammatory burden critically influence thermoregulation and survival during early sepsis. These results emphasize the importance of considering environmental factors in preclinical sepsis studies. Although rodents in experimental settings are often adapted to cold environments, these conditions may not fully translate to human sepsis, where cold adaptation is rare. Thus, researchers should carefully consider these variables when designing experiments and interpreting translational implications.

How cold is too cold during maternal sepsis? Navigating between maternal hypothermia and fetal bradycardia

Hypothermia is a relatively rare condition in pregnancy and has been associated with fetal bradycardia. The management of maternal hypothermia resulting in fetal bradycardia presents a challenging dilemma for healthcare professionals. Currently, no evidence exists to advise on the duration of this condition before obstetric interventions are necessary for a safe outcome for both mother and infant. We discuss a case of a 26-year old primigravida with a gestational age of 32 weeks, who presented with clinical urosepsis, resulting in severe hypothermia up to 32 degrees Celsius. Active warming measures were taken and intravenous antibiotic treatment was started. Fetal evaluation on the cardiotocogram showed prolonged bradycardia (90 BPM) prompting consideration of a cesarean section. However, after multidisciplinary consultation, conservative treatment was proposed since there were no other signs of fetal hypoxia; no decelerations, good variability and accelerations. The patient started to show clinical improvement and had a body core temperature of 36 degrees Celsius after approximately 60 h of active rewarming measures. Fetal heartrate baseline normalized as the maternal temperature raised. Subsequently the patient was discharged in good clinical condition and had an uncomplicated vaginal delivery of a healthy newborn at term. In conclusion, when fetal bradycardia occurs due to maternal hypothermia, in the absence of signs for fetal hypoxia on the cardiotocogram, treatment of the underlying maternal condition instead of immediate obstetrics intervention is the best clinical option. This strategy aims to address the underlying cause of maternal hypothermia and consequently fetal bradycardia while ensuring the well-being of both mother and fetus and preventing unnecessary premature delivery.

Hypothermia and Influence of Rewarming Rates on Survival Among Patients Admitted to Intensive Care with Bloodstream Infection: A Multicenter Cohort Study

Although critically ill patients with bloodstream infections (BSIs) who present with hypothermia are at the highest risk for death, it is not known how rewarming rates may influence the outcomes. The objective of this study was to identify the occurrence and determinants of hypothermia among patients admitted to intensive care units (ICUs) with BSI and assess how the rate of temperature correction may influence 90-day all-cause case-fatality. A cohort of 3951 ICU admissions associated with BSI was assembled. The lowest temperature measured within the first 24 hours of admission was identified, and among those who were hypothermic (<36°C), the rewarming rate [(time difference between lowest and subsequent first temperature ≥36°C) divided by hypothermia severity (difference between lowest measured and 36°C)] was determined. Within the first 24 hours of admission to the ICU, 329 (8.4%) and 897 (22.7%) subjects had the lowest temperature measurements ranging <34.9°C and 35-35.9°C, respectively. Patients with lower temperatures were more likely to be admitted to tertiary care ICUs, have more comorbid illnesses, have greater severity of illness, and have a higher need for organ-supportive therapies. The 90-day all-cause case-fatality rate was 22.9% overall and was 45.3%, 24.8%, and 19.6% for those with the lowest 24 hours temperatures of <35°C, 35-35.9°C, and ≥36°C, respectively (p < 0.001). Among 1133 hypothermic patients with documented temperatures corrected to the normal range while admitted to the ICU, the median rate of temperature increase was 0.24 (interquartile range, 0.13-0.45)oC/hour. After controlling for the severity of illness and comorbidity, a faster rewarming rate was associated with significantly lower 90-day case-fatality. Hypothermia is a significant risk factor associated with death among critically ill patients with BSI that faster rates of rewarming may modify.

Comprehensive risk factor-based nomogram for predicting one-year mortality in patients with sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a frequent and severe complication in septic patients, characterized by diffuse brain dysfunction resulting from systemic inflammation. Accurate prediction of long-term mortality in these patients is critical for improving clinical outcomes and guiding treatment strategies. We conducted a retrospective cohort study using the MIMIC IV database to identify adult patients diagnosed with SAE. Patients were randomly divided into a training set (70%) and a validation set (30%). Least absolute shrinkage and selection operator regression and multivariate logistic regression were employed to identify significant predictors of 1-year mortality, which were then used to develop a prognostic nomogram. The model's discrimination, calibration, and clinical utility were assessed using the area under the receiver operating characteristic curve (AUC), calibration plots, and decision curve analysis, respectively. A total of 3,882 SAE patients were included in the analysis. The nomogram demonstrated strong predictive performance with AUCs of 0.881 (95% CI: 0.865, 0.896) in the training set and 0.859 (95% CI: 0.830, 0.888) in the validation set. Calibration plots indicated good agreement between predicted and observed 1-year mortality rates. The decision curve analysis showed that the nomogram provided greater net benefit across a range of threshold probabilities compared to traditional scoring systems such as Glasgow Coma Scale and Sequential Organ Failure Assessment. Our study presents a robust and clinically applicable nomogram for predicting 1-year mortality in SAE patients. This tool offers superior predictive performance compared to existing severity scoring systems and has significant potential to enhance clinical decision-making and patient management in critical care settings.

Management of spontaneous septic hypothermia in intensive care. A national survey of French intensive care units

The benefit of temperature control in sepsis or septic shock is still under debate in the literature. We developed a national survey to assess the current state of knowledge and the practical management of spontaneous septic hypothermia in French intensive care units. Out of more 764 intensivists who were contacted, 436 responded to the survey. The majority of doctors (52.4%) considered spontaneous septic hypothermia to be a frequently encountered situation in intensive care, and 62.1% were interested in this problem. Definition of spontaneous septic hypothermia among French intensivists was not consensual. More than half of the doctors questioned (57.1%) stated that they did not actively rewarm patients suffering from spontaneous septic hypothermia.