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Background: The distinction between culture-positive sepsis and culture-negative sepsis regarding clinical characteristics and outcomes remains contentious. We aimed to elucidate these differences using large-scale nationwide data. Methods: This prospective cohort study analyzed data from the Korean Sepsis Alliance registry, comprising 21 intensive care units (ICUs) across 20 hospitals from September 2019 to December 2021. Patients meeting the Sepsis-3 criteria were included. Results: Among 11,981 sepsis patients, 3501 were analyzed, all of whom were referred to the ICU through the emergency department (mean age: 72 ± 13 years; 1976 [56%] males). Of these, 2213 (63%) were culture-positive sepsis and 1288 (37%) were culture-negative sepsis. Compared to the culture-positive sepsis group, the culture-negative sepsis group exhibited less severe illness, with lower Sequential Organ Failure Assessment scores and less deteriorated vital signs. While pulmonary-origin sepsis was common in both groups, culture-negative patients primarily presented with pulmonary infections and had a higher incidence of respiratory failure. In comparison to the culture-positive sepsis group, blood cultures and the administration of empirical antibiotics were performed less promptly in the culture-negative sepsis group. Patients with culture-negative sepsis also showed lower compliance with fluid resuscitation (98.4% vs. 96.9%, p = 0.038; culture-positive sepsis vs. culture-negative sepsis) and received vasopressors earlier (31.1% vs. 35.9%, p = 0.012). In-hospital mortality did not differ significantly between the two groups (31.6% vs. 34.9%, p = 0.073); however, in patients with septic shock, culture-negative sepsis had higher mortality rates (37.6% vs. 45.1%, p = 0.029). The apparent appropriateness of empirical antibiotics in the culture-negative septic shock was higher than that of the culture-positive septic shock (85.2% vs. 96.8%, p < 0.001). Culture-negativity independently predicted poor prognosis in septic shock patients (OR: 1.462, 95% CI [1.060–2.017], p = 0.021). Conclusion: In patients with septic shock, culture-negativity was associated with increased mortality, despite the paradoxically higher appropriateness of empirical antibiotics than culture-positive patients. These contradictory findings suggest that the current criteria for determining the appropriateness of empirical antibiotic therapy may not be valid for culture-negative sepsis. [ABSTRACT FROM AUTHOR]

In this paper, we conducted an analysis of the heliospheric current sheets (HCSs) in the heliosheath (HS), utilizing observations by Voyager 2 between 2008 and 2018. Employing rigorous criteria, we identified a total of 34 HCSs that indicate significant changes in magnetic polarity. These occurrences were more prevalent during solar maximum periods when the HCS expanded to higher latitudes, coinciding with the spacecraft positioned at an average latitude of −31° from the solar equator. We determined certain features of the large-scale structures of the identified HCSs. Most importantly, employing two distinct methods indicates that the thickness of the HCSs within the HS ranges from ∼0.003 to ∼0.4 au with an average thickness of ∼0.03 to ∼0.1 au, depending on methods of event selection and fitting techniques. This thickness surpasses that known near 1 au or other heliospheric distances. It is also notably thicker than the typical proton inertial length, implying unfavorable conditions for magnetic reconnection. Additionally, our analysis reveals a frequent tilt of HCS planes relative to the solar equatorial plane by a varying angle up to several tens of degrees, likely implying a common occurrence of a warped structure of the HCS within the HS. Longitudinally, the HCS planes closely align with the Parker spiral field direction expected in the HS. Finally, for a large fraction of the identified HCS events, the HCS planes are likely characterized by a rotational discontinuity. These findings are valid within the limits of the 1 hr resolution data used in this study. [ABSTRACT FROM AUTHOR]

Background: There is limited information about the outcomes of polymicrobial bloodstream infections in patients with sepsis. We aimed to investigate outcomes of polymicrobial bloodstream infections compared to monomicrobial bloodstream infections. Methods: This study used data from the Korean Sepsis Alliance Registry, a nationwide database of prospective observational sepsis cohort. Adult sepsis patients with bloodstream infections from September 2019 to December 2021 at 20 tertiary or university-affiliated hospitals in South Korea were analyzed. Results: Among the 3,823 patients with bloodstream infections, 429 of them (11.2%) had polymicrobial bloodstream infections. The crude hospital mortality of patients with sepsis with polymicrobial bloodstream infection and monomicrobial bloodstream infection was 35.7% and 30.1%, respectively (p = 0.021). However, polymicrobial bloodstream infections were not associated with hospital mortality in the proportional hazard analysis (HR 1.15 [0.97–1.36], p = 0.11). The inappropriate use of antibiotics was associated with increased mortality (HR 1.37 [1.19–1.57], p < 0.001), and source control was associated with decreased mortality (HR 0.51 [0.42–0.62], p < 0.001). Conclusions: Polymicrobial bloodstream infections per se were not associated with hospital mortality in patients with sepsis as compared to monomicrobial bloodstream infections. The appropriate use of antibiotics and source control were associated with decreased mortality in bloodstream infections regardless of the number of microbial pathogens. [ABSTRACT FROM AUTHOR]

Background: Data regarding the clinical effects of bacteremia on severe community-acquired pneumonia (CAP) are limited. Thus, we investigated clinical characteristics and outcomes of severe CAP patients with bacteremia compared with those of subjects without bacteremia. In addition, we evaluated clinical factors associated with bacteremia at the time of sepsis awareness. Methods: We enrolled sepsis patients diagnosed with CAP at emergency departments (EDs) from an ongoing nationwide multicenter observational registry, the Korean Sepsis Alliance, between September 2019 and December 2020. For evaluation of clinical factors associated with bacteremia, we divided eligible patients into bacteremia and non-bacteremia groups, and logistic regression analysis was performed using the clinical characteristics at the time of sepsis awareness. Result: During the study period, 1,510 (47.9%) sepsis patients were caused by CAP, and bacteremia was identified in 212 (14.0%) patients. Septic shock occurred more frequently in the bacteremia group than in the non-bacteremia group (27.4% vs. 14.8%; p < 0.001). In multivariable analysis, hematologic malignancies and septic shock were associated with an increased risk of bacteremia. However, chronic lung disease was associated with a decreased risk of bacteremia. Hospital mortality was significantly higher in the bacteremia group than in the non-bacteremia group (27.3% vs. 40.6%, p < 0.001). The most prevalent pathogen in blood culture was Klebsiella pneumoniae followed by Escherichia coli in gram-negative pathogens. Conclusion: The incidence of bacteremia in severe CAP was low at 14.0%, but the occurrence of bacteremia was associated with increased hospital mortality. In severe CAP, hematologic malignancies and septic shock were associated with an increased risk of bacteremia. [ABSTRACT FROM AUTHOR]

In this paper, an operational Dst index prediction model is developed by combining empirical and Artificial Neural Network (ANN) models. ANN algorithms are widely used to predict space weather conditions. While they require a large amount of data for machine learning, large-scale geomagnetic storms have not occurred sufficiently for the last 20 years, Advanced Composition Explorer (ACE) and Deep Space Climate Observatory (DSCOVR) mission operation period. Conversely, the empirical models are based on numerical equations derived from human intuition and are therefore applicable to extrapolate for large storms. In this study, we distinguish between Coronal Mass Ejection (CME) driven and Corotating Interaction Region (CIR) driven storms, estimate the minimum Dst values, and derive an equation for describing the recovery phase. The combined Korea Astronomy and Space Science Institute (KASI) Dst Prediction (KDP) model achieved better performance contrasted to ANN model only. This model could be used practically for space weather operation by extending prediction time to 24 h and updating the model output every hour.

Background: The optimal strategy for fluid management during the first few days of ICU in sepsis patients remains controversial. We aimed to investigate the impact of cumulative fluid balance during the first three days of ICU on the mortality of patients with sepsis. Methods: This study analyzed prospectively collected data from the Korean Sepsis Alliance Database, which registered 11,981 sepsis patients from 20 hospitals. We selected three propensity score-matched cohorts consisting of patients with a negative or positive cumulative fluid balance during the first three ICU days: from ICU admission to the first midnight as the D1 cohort, until the second midnight as the D2 cohort, and until the third midnight as the D3 cohort. The propensity score for fluid balance was calculated using covariates including the amount of fluid output during the first three ICU days. The primary outcome was mortality at day 28 in the ICU. Results: From a total of 11,981 patients, 2516 patients were included for propensity score matching. After matching in a 1:1 ratio, there were 483, 373, and 392 matched pairs of patients assigned to the D1, D2, and D3 cohorts, respectively. In the D1 cohort, there were no significant differences in mortality at day 28 (hazard ratio [HR], 1.17; 95% confidence interval [CI] 0.85–1.60; P = 0.354) between the two groups. The positive fluid groups in both the D2 (HR, 2.13; 95% CI 1.48–3.06; P < 0.001) and D3 (HR, 1.56; 95% CI 1.10–2.22; P = 0.012) cohorts had significantly higher mortality rates than the negative fluid groups. Conclusions: In patients with sepsis, a positive fluid balance on the first ICU day was not associated with mortality at day 28. In contrast, cumulative positive fluid balances on the second and third ICU days were associated with higher mortality at day 28. [ABSTRACT FROM AUTHOR]

Background: Numerous epidemiological studies investigating gender-dependent clinical outcomes in sepsis have shown conflicting evidence. This study aimed to investigate the effect of gender on in-hospital mortality due to sepsis according to age group. Methods: This study used data from the Korean Sepsis Alliance, an ongoing nationwide prospective multicenter cohort from 19 participating hospitals in South Korea. All adult patients diagnosed with sepsis in the emergency departments of the participating hospitals between September 2019 and December 2021 were included in the analysis. Clinical characteristics and outcomes were compared between male and female. Eligible patients were stratified by age into 19–50 years, 50–80 years, and ≥ 80 years old individuals. Results: During the study period, 6442 patients were included in the analysis, and 3650 (56.7%) were male. The adjusted odds ratio (OR) [95% confidence interval (CI)] for in-hospital mortality for male compared with female was 1.15 (95% CI = 1.02–1.29). Interestingly, in the age 19–50 group, the risk of in-hospital mortality for males was significantly lower than that of females [0.57 (95% CI = 0.35–0.93)]. For female, the risk of death remained relatively stable until around age 80 (P for linearity = 0.77), while in males, there was a linear increase in the risk of in-hospital death until around age 80 (P for linearity < 0.01). Respiratory infection (53.8% vs. 37.4%, p < 0.01) was more common in male, whereas urinary tract infection (14.7% vs. 29.8%, p < 0.01) was more common in female. For respiratory infection, male had significantly lower in-hospital mortality than female in the age 19–50 groups (adjusted OR = 0.29, 95% CI = 0.12–0.69). Conclusions: Gender may influence age-associated sepsis outcomes. Further studies are needed to replicate our findings and fully understand the interaction of gender and age on the outcomes of patients with sepsis. [ABSTRACT FROM AUTHOR]

Background: Based on sparse evidence, the current Surviving Sepsis Campaign guideline suggests that critically ill patients with sepsis be admitted to the intensive care unit (ICU) within 6 h. However, limited ICU bed availability often makes immediate transfer difficult, and it is unclear whether all patients will benefit from early admission to the ICU. Therefore, the purpose of this study was to determine the association between the timing of ICU admission and mortality in patients with hospital-onset sepsis. Methods: This nationwide prospective cohort study analyzed patients with hospital-onset sepsis admitted to the ICUs of 19 tertiary hospitals between September 2019 and December 2020. ICU admission was classified as either early (within 6 h) or delayed (beyond 6 h). The primary outcome of in-hospital mortality was compared using logistic regression adjusted for key prognostic factors in the unmatched and 1:1 propensity-score-matched cohorts. Subgroup and interaction analyses assessed whether in-hospital mortality varied according to baseline characteristics. Results: A total of 470 and 286 patients were included in the early and delayed admission groups, respectively. Early admission to the ICU did not significantly result in lower in-hospital mortality in both the unmatched (adjusted odds ratio [aOR], 1.35; 95% confidence interval [CI], 0.99–1.85) and matched cohorts (aOR, 1.38; 95% CI, 0.94–2.02). Subgroup analyses showed that patients with increasing lactate levels (aOR, 2.10; 95% CI, 1.37–3.23; P for interaction = 0.003), septic shock (aOR, 2.06; 95% CI, 1.31–3.22; P for interaction = 0.019), and those who needed mechanical ventilation (aOR, 1.92; 95% CI, 1.24–2.96; P for interaction = 0.027) or vasopressor support (aOR, 1.69; 95% CI, 1.17–2.44; P for interaction = 0.042) on the day of ICU admission had a higher risk of mortality with delayed admission. Conclusions: Among patients with hospital-onset sepsis, in-hospital mortality did not differ significantly between those with early and delayed ICU admission. However, as early intensive care may benefit those with increasing lactate levels, septic shock, and those who require vasopressors or ventilatory support, admission to the ICU within 6 h should be considered for these subsets of patients. [ABSTRACT FROM AUTHOR]

Background: Sepsis is the most common cause of death in hospitals, and intra-abdominal infection (IAI) accounts for a large portion of the causes of sepsis. We investigated the clinical outcomes and factors influencing mortality of patients with sepsis due to IAI. Methods: This post-hoc analysis of a prospective cohort study included 2126 patients with sepsis who visited 16 tertiary care hospitals in Korea (September 2019–February 2020). The analysis included 219 patients aged > 19 years who were admitted to intensive care units owing to sepsis caused by IAI. Results: The incidence of septic shock was 47% and was significantly higher in the non-survivor group (58.7% vs 42.3%, p = 0.028). The overall 28-day mortality was 28.8%. In multivariable logistic regression, after adjusting for age, sex, Charlson Comorbidity Index, and lactic acid, only coagulation dysfunction (odds ratio: 2.78 [1.47–5.23], p = 0.001) was independently associated, and after adjusting for each risk factor, only simplified acute physiology score III (SAPS 3) (p < 0.001) and continuous renal replacement therapy (CRRT) (p < 0.001) were independently associated with higher 28-day mortality. Conclusions: The SAPS 3 score and acute kidney injury with CRRT were independently associated with increased 28-day mortality. Additional support may be needed in patients with coagulopathy than in those with other organ dysfunctions due to IAI because patients with coagulopathy had worse prognosis. [ABSTRACT FROM AUTHOR]

Background: Hospital-onset sepsis is associated with a higher in-hospital mortality rate than community-onset sepsis. Many hospitals have implemented rapid response teams (RRTs) for early detection and timely management of at-risk hospitalized patients. However, the effectiveness of an all-day RRT over a non-all-day RRT in reducing the risk of in-hospital mortality in patient with hospital-onset sepsis is unclear. We aimed to determine the effect of the RRT's operating hours on in-hospital mortality in inpatient patients with sepsis.Methods: We conducted a nationwide cohort study of adult patients with hospital-onset sepsis prospectively collected from the Korean Sepsis Alliance (KSA) Database from 16 tertiary referral or university-affiliated hospitals in South Korea between September of 2019 and February of 2020. RRT was implemented in 11 hospitals, of which 5 (45.5%) operated 24-h RRT (all-day RRT) and the remaining 6 (54.5%) had part-day RRT (non-all-day RRT). The primary outcome was in-hospital mortality between the two groups.Results: Of the 405 patients with hospital-onset sepsis, 206 (50.9%) were admitted to hospitals operating all-day RRT, whereas 199 (49.1%) were hospitalized in hospitals with non-all-day RRT. A total of 73 of the 206 patients in the all-day group (35.4%) and 85 of the 199 patients in the non-all-day group (42.7%) died in the hospital (P = 0.133). After adjustments for co-variables, the implementation of all-day RRT was associated with a significant reduction in in-hospital mortality (adjusted odds ratio 0.57; 95% confidence interval 0.35-0.93; P = 0.024).Conclusions: In comparison with non-all-day RRTs, the availability of all-day RRTs was associated with reduced in-hospital mortality among patients with hospital-onset sepsis. [ABSTRACT FROM AUTHOR]

Background: Timely administration of antibiotics is one of the most important interventions in reducing mortality in sepsis. However, administering antibiotics within a strict time threshold in all patients suspected with sepsis will require huge amount of effort and resources and may increase the risk of unintentional exposure to broad-spectrum antibiotics in patients without infection with its consequences. Thus, controversy still exists on whether clinicians should target different time-to-antibiotics thresholds for patients with sepsis versus septic shock.Methods: This study analyzed prospectively collected data from an ongoing multicenter cohort of patients with sepsis identified in the emergency department. Adjusted odds ratios (ORs) were compared for in-hospital mortality of patients who had received antibiotics within 1 h to that of those who did not. Spline regression models were used to assess the association of time-to-antibiotics as continuous variables and increasing risk of in-hospital mortality. The differences in the association between time-to-antibiotics and in-hospital mortality were assessed according to the presence of septic shock.Results: Overall, 3035 patients were included in the analysis. Among them, 601 (19.8%) presented with septic shock, and 774 (25.5%) died. The adjusted OR for in-hospital mortality of patients whose time-to-antibiotics was within 1 h was 0.78 (95% confidence interval [CI] 0.61-0.99; p = 0.046). The adjusted OR for in-hospital mortality was 0.66 (95% CI 0.44-0.99; p = 0.049) and statistically significant in patients with septic shock, whereas it was 0.85 (95% CI 0.64-1.15; p = 0.300) in patients with sepsis but without shock. Among patients who received antibiotics within 3 h, those with septic shock showed 35% (p = 0.042) increased risk of mortality for every 1-h delay in antibiotics, but no such trend was observed in patients without shock.Conclusion: Timely administration of antibiotics improved outcomes in patients with septic shock; however, the association between early antibiotic administration and outcome was not as clear in patients with sepsis without shock. [ABSTRACT FROM AUTHOR]