Hemodynamic clinical phenotyping in septic shock

Applicability of an unsupervised cluster model developed on first wave COVID-19 patients in second/third wave critically ill patients

OBJECTIVE

To validate the unsupervised cluster model (USCM) developed during the first pandemic wave in a cohort of critically ill patients from the second and third pandemic waves.

DESIGN

Observational, retrospective, multicentre study.

SETTING

Intensive Care Unit (ICU).

PATIENTS

Adult patients admitted with COVID-19 and respiratory failure during the second and third pandemic waves.

INTERVENTIONS

None.

MAIN VARIABLES OF INTEREST

Collected data included demographic and clinical characteristics, comorbidities, laboratory tests and ICU outcomes. To validate our original USCM, we assigned a phenotype to each patient of the validation cohort. The performance of the classification was determined by Silhouette coefficient (SC) and general linear modelling. In a post-hoc analysis we developed and validated a USCM specific to the validation set. The model's performance was measured using accuracy test and area under curve (AUC) ROC.

RESULTS

A total of 2330 patients (mean age 63 [53-82] years, 1643 (70.5%) male, median APACHE II score (12 [9-16]) and SOFA score (4 [3-6]) were included. The ICU mortality was 27.2%. The USCM classified patients into 3 clinical phenotypes: A (n = 1206 patients, 51.8%); B (n = 618 patients, 26.5%), and C (n = 506 patients, 21.7%). The characteristics of patients within each phenotype were significantly different from the original population. The SC was -0.007 and the inclusion of phenotype classification in a regression model did not improve the model performance (0.79 and 0.78 ROC for original and validation model). The post-hoc model performed better than the validation model (SC -0.08).

CONCLUSION

Models developed using machine learning techniques during the first pandemic wave cannot be applied with adequate performance to patients admitted in subsequent waves without prior validation.

Advances and Challenges in Sepsis Management: Modern Tools and Future Directions

Sepsis, a critical condition marked by systemic inflammation, profoundly impacts both innate and adaptive immunity, often resulting in lymphopenia. This immune alteration can spare regulatory T cells (Tregs) but significantly affects other lymphocyte subsets, leading to diminished effector functions, altered cytokine profiles, and metabolic changes. The complexity of sepsis stems not only from its pathophysiology but also from the heterogeneity of patient responses, posing significant challenges in developing universally effective therapies. This review emphasizes the importance of phenotyping in sepsis to enhance patient-specific diagnostic and therapeutic strategies. Phenotyping immune cells, which categorizes patients based on clinical and immunological characteristics, is pivotal for tailoring treatment approaches. Flow cytometry emerges as a crucial tool in this endeavor, offering rapid, low cost and detailed analysis of immune cell populations and their functional states. Indeed, this technology facilitates the understanding of immune dysfunctions in sepsis and contributes to the identification of novel biomarkers. Our review underscores the potential of integrating flow cytometry with omics data, machine learning and clinical observations to refine sepsis management, highlighting the shift towards personalized medicine in critical care. This approach could lead to more precise interventions, improving outcomes in this heterogeneously affected patient population.

Surviving Sepsis After Burn Campaign

INTRODUCTION

The Surviving Sepsis Campaign was developed to improve outcomes for all patients with sepsis. Despite sepsis being the primary cause of death after thermal injury, burns have always been excluded from the Surviving Sepsis efforts. To improve sepsis outcomes in burn patients, an international group of burn experts developed the Surviving Sepsis After Burn Campaign (SSABC) as a testable guideline to improve burn sepsis outcomes.

METHODS

The International Society for Burn Injuries (ISBI) reached out to regional or national burn organizations to recommend members to participate in the program. Two members of the ISBI developed specific "patient/population, intervention, comparison and outcome" (PICO) questions that paralleled the 2021 Surviving Sepsis Campaign [1]. SSABC participants were asked to search the current literature and rate its quality for each topic. At the Congress of the ISBI, in Guadalajara, Mexico, August 28, 2022, a majority of the participants met to create "statements" based on the literature. The "summary statements" were then sent to all members for comment with the hope of developing an 80% consensus. After four reviews, a consensus statement for each topic was created or "no consensus" was reported.

RESULTS

The committee developed sixty statements within fourteen topics that provide guidance for the early treatment of sepsis in burn patients. These statements should be used to improve the care of sepsis in burn patients. The statements should not be considered as "static" comments but should rather be used as guidelines for future testing of the best treatments for sepsis in burn patients. They should be updated on a regular basis.

CONCLUSION

Members of the burn community from the around the world have developed the Surviving Sepsis After Burn Campaign guidelines with the goal of improving the outcome of sepsis in burn patients.

Bioimpedance and Duration of Organ Dysfunction in Septic Shock-A Prospective Observational Study

Rationale: Bioimpedance may be a useful tool to guide fluid treatment and avoid organ dysfunction related to fluid overload. Objective: We examined the correlation between bioimpedance and organ dysfunction in patients with septic shock. Methods: Prospective observational study of adult intensive care unit patients fulfilling the sepsis-3 criteria. Bioimpedance was measured using a body composition monitor (BCM) and BioScan Touch i8 (MBS). We measured impedance at inclusion and after 24 h and reported the impedance, change in impedance, bioimpedance-derived fluid balance, and changes in bioimpedance-derived fluid balance. Organ markers on respiratory, circulatory, and kidney function and overall disease severity were ascertained on days 1-7. The effect of bioimpedance on the change in organ function was assessed by mixed effects linear models. We considered P < .01 as significant. Measurements and Main Results: Forty-nine patients were included. None of the single baseline measurements or derived fluid balances were associated with the course of organ dysfunction. Changes in impedance were associated with the course of overall disease severity (P < .001; with MBS), and with changes in noradrenaline dose (P < .001; with MBS) and fluid balance (P < .001; with BCM). The changes in bioimpedance-derived fluid balance were associated with changes in noradrenaline dose (P < .001; with BCM), cumulative fluid balances (P < .001; with MBS), and lactate concentrations (P < .001; with BCM). Conclusions: Changes in bioimpedance were correlated with the duration of overall organ failure, circulatory failure, and fluid status. Single measurements of bioimpedance were not associated with any changes in organ dysfunction.

Clinical Sepsis Phenotypes in Critically Ill Patients

Sepsis, defined as the life-threatening dysregulated host response to an infection leading to organ dysfunction, is considered as one of the leading causes of mortality worldwide, especially in intensive care units (ICU). Moreover, sepsis remains an enigmatic clinical syndrome, with complex pathophysiology incompletely understood and a great heterogeneity both in terms of clinical expression, patient response to currently available therapeutic interventions and outcomes. This heterogeneity proves to be a major obstacle in our quest to deliver improved treatment in septic critical care patients; thus, identification of clinical phenotypes is absolutely necessary. Although this might be seen as an extremely difficult task, nowadays, artificial intelligence and machine learning techniques can be recruited to quantify similarities between individuals within sepsis population and differentiate them into distinct phenotypes regarding not only temperature, hemodynamics or type of organ dysfunction, but also fluid status/responsiveness, trajectories in ICU and outcome. Hopefully, we will eventually manage to determine both the subgroup of septic patients that will benefit from a therapeutic intervention and the correct timing of applying the intervention during the disease process.

Case report: A case of sepsis caused by rickettsial infection-induced hemophagocytic syndrome

Hemophagocytic lymphohistiocytosis (HLH) is a rare histiocytic disorder characterized by reactive hyperplasia of the mononuclear phagocytic system, which is primarily caused by dysfunction of cytotoxic killer cells and natural killer cells, leading to antigen clearance barriers and the overactivation of the mononuclear phagocytic system due to continuous antigen stimulation. HLH encompasses a group of clinical syndromes marked by the overproduction of inflammatory cytokines. A 68-year-old Chinese man presented with persistent fever, chills, nausea, and vomiting; the patient had no history of any underlying conditions. Laboratory investigations revealed decreased levels of red blood cells, white blood cells, and platelets, along with reduced natural killer cell activity, increased CD25, hyperferritinemia, and the detection of Rickettsia DNA in his blood, meeting the diagnostic criteria of the Histiocyte Society HLH-2004 guidelines. The patient was treated with antibiotics, improving anemia, glucocorticoid therapy, and continuous renal replacement therapy (CRRT), temporarily improving his condition. However, the patient died after 2 years from chronic renal failure caused by septic shock.

TRPM7 mediates endoplasmic reticulum stress and ferroptosis in sepsis-induced myocardial injury

Transient receptor potential melastatin 7 (TRPM7), a non-selective cation channel, was significantly upregulated in the blood of patients with sepsis. This study focuses on the preliminary exploration of the probable regulatory mechanism of TRPM7 in sepsis-induced myocardial injury (SIMI). HL-1 cardiac muscle cell line was treated with lipopolysaccharide (LPS) to mimic SIMI in vitro, and TRPM7 level was assessed. The impacts of TRPM7 knockdown on cellular inflammation response, oxidative stress, apoptosis, endoplasmic reticulum (ER) stress, and ferroptosis were identified. In order to explore the mechanism, ER stress agonist tunicamycin (TM) or ferroptosis inducer erastin was applied to treat HL-1 cells. The influences of TM and erastin on the aforementioned aspects were evaluated. TRPM7 was elevated in response to LPS stimulation, and its knockdown reduced the secretion of inflammatory factors and oxidative stress degree. Moreover, TRPM7 knockdown significantly suppressed cell apoptosis, ER stress, and ferroptosis. TM and erastin reversed the functions of TRPM7 knockdown, indicating ER stress and ferroptosis mediated in the regulation of TRPM7. This research proposes the possibility of TRPM7 as a marker or target for SIMI, and provides theoretical support for follow-up research.

Septic Cardiomyopathy: From Pathophysiology to the Clinical Setting

The onset of cardiomyopathy is a common feature in sepsis, with relevant effects on its pathophysiology and clinical care. Septic cardiomyopathy is characterized by reduced left ventricular (LV) contractility eventually associated with LV dilatation with or without right ventricle failure. Unfortunately, such a wide range of ultrasonographic findings does not reflect a deep comprehension of sepsis-induced cardiomyopathy, but rather a lack of consensus about its definition. Several echocardiographic parameters intrinsically depend on loading conditions (both preload and afterload) so that it may be challenging to discriminate which is primitive and which is induced by hemodynamic perturbances. Here, we explore the state of the art in sepsis-related cardiomyopathy. We focus on the shortcomings in its definition and point out how cardiac performance dynamically changes in response to different hemodynamic clusters. A special attention is also given to update the knowledge about molecular mechanisms leading to myocardial dysfunction and that recall those of myocardial hibernation. Ultimately, the aim of this review is to highlight the unsolved issue in the field of sepsis-induced cardiomyopathy as their implementation would lead to improve risk stratification and clinical care.

Septic Shock and Cardiac Arrest in Obstetrics: A Practical Simplified Clinical View

Septic shock and cardiac arrest during pregnancy, despite being uncommon, carry a high mortality rate among pregnant individuals. Basic initial management strategies are fundamental to improve clinical outcomes; obstetricians and maternal-fetal medicine specialists need to be familiar with such interventions.

Factors associated with left ventricular diastolic dysfunction in patients with septic shock

Purpose

To investigate risk factors associated with left ventricular diastolic dysfunction (LVDD) of patients with septic shock.

Materials and methods

Patients with septic shock concomitant with or without LVDD were retrospectively enrolled and divided into the LVDD group (n = 17) and control without LVDD (n = 85). The clinical and ultrasound data were analyzed.

Results

A significant (P < 0.05) difference existed between the two groups in serum creatinine, APACHE II score, serum glucose, triglyceride, BUN, FT4, LAVI, mitral E, average e’, E/average e’, septal e’, septal e’/septal s’, E/septal e’, lateral s’, lateral e’, and E/lateral e’. LAVI > 37 mL/m², septal e’ < 7 cm/s (OR 11.04, 95% CI 3.38–36.05), septal e’/septal s’ < 0.8 (OR 4.09, 95% CI 1.37–12.25), E/septal e’ > 15 (OR 22.86, 95% CI 6.09–85.79), lateral e’ < 8 cm/s (OR 9.16, 95% CI 2.70–31.07), E/lateral e’ > 13 (OR 52, 95% CI 11.99- 225.55), lateral s’ < 10 (OR 3.36, 95% CI 1.13–9.99), average e’ > 10, E/average e’ > 10 (OR 9.53, 95% CI 2.49–36.46), APACHE II score > 16 (OR 3.33, 95% CI 1.00–11.03), SOFA > 5 (or 3.43, 95% CI 1.11–10.60), BUN > 12 mmol/L (OR 3.37, 95% CI 1.15–9.87), serum creatinine > 146 μmol/L (OR 5.08, 95% CI 1.69–15.23), serum glucose > 8 mmol/L (OR 3.36, 95% CI 1.09–10.40), and triglyceride > 1.8 mmol/L were significant (P < 0.05) risk factors for LVDD. LAVI > 37 ml/m², lateral e’ < 8 cm/s, E/lateral e’ > 13, and SOFA > 5 were significant (P < 0.05) independent risk factors for LVDD. ROC curve analysis demonstrated that the cut-off value and AUC were 37.09 mL/m² and 0.85 for LAVI, 8.00 cm/s and 0.89 for lateral e’, 12.86 and 0.82 for E/lateral e’, and 5.00 and 0.69 for SOFA, respectively.

Conclusion

Left atrial volume index, mitral lateral e’, E/lateral e’, and SOFA score are significant independent risk factors for predicting left ventricular diastolic dysfunction in patients with septic shock.

Identification précoce des phénotypes cardiovasculaires chez les patients en insuffisance respiratoire aiguë au cours de la première pandémie Covid-19

Objectif : L'objectif principal était de comparer la prévalence de la dysfonction ventriculaire gauche (VG) et/ ou droite (VD) des patients admis au service d'urgence (SU) avec une insuffisance respiratoire aiguë (IRA) secondaire ou non à une pneumopathie à Covid-19.

Méthodes : Pendant un mois, nous avons inclus (24/7) de façon prospective les patients de l'unité de Covid-19 du SU qui présentaient une IRA. Pour chaque patient, un test RT-PCR, une tomodensitométrie thoracique et une échographie cardiaque de niveau 2 et pulmonaire étaient systématiquement réalisés avant toute intervention thérapeutique. Chaque patient était classé selon les phénotypes cardiovasculaires suivants : insuffisance VG, insuffisance VD, hypovolémie ± hyperkinésie et profil hémodynamique normal.

Résultats : Parmi les 517 patients admis pendant la période d'étude, 78 présentaient une IRA (15 %) et 62 ont bénéficié d'une échocardiographie de niveau 2 (âge : 73 ± 14 ans ; SpO2 : 90 ± 4 % ; lactate : 2,1 ± 1,3 mmol/l). Le diagnostic de la Covid-19 a été établi pour 22 patients (35 %). L'insuffisance VG (15 [38 %] vs 2 [9 %] ; p = 0,016) et celle VD (12 [30 %] vs 1 [5 %] ; p = 0,018) étaient plus souvent observées dans le groupe témoin que chez les patients ayant une pneumopathie à Covid-19. Inversement, les patients Covid-19 avaient plus fréquemment un profil hémodynamique normal ou une hypovolémie associée ou non à une vasoplégie (20 [91 %] vs 21 [53 %] ; p = 0,002). La mortalité intrahospitalière était de 18 % ( n = 11). Tous les patients atteints de la Covid-19 présentant une insuffisance VG et/ou VD précoce sont décédés pendant leur hospitalisation.

Conclusions : La dysfonction VG et celle VD étaient plus fréquentes chez les patients non atteints de la Covid-19, alors que les patients atteints de Covid-19 avaient un phénotype cardiovasculaire normal ou hypovolémique.

Hyperdynamic Left Ventricular Ejection Fraction in ICU Patients With Sepsis

OBJECTIVES

To evaluate the cause and prognosis of hyperdynamic left ventricular ejection fraction in critically ill patients with sepsis.

DESIGN

Retrospective, single-center cohort study.

SETTING

University Hospital ICU, Birmingham, United Kingdom.

PATIENTS

ICU patients who received a transthoracic echocardiogram within 7 days of sepsis between April 2016 and December 2019.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The 90-day mortality rates of normal (55-70%), depressed (< 55%), and hyperdynamic left ventricular ejection fraction (> 70%) were compared. Multivariate logistic regression analysis was performed to determine the association of left ventricular ejection fraction phenotypes with mortality and the association of clinical variables with left ventricular ejection fraction phenotypes. One thousand fourteen patients met inclusion criteria and were 62 years old (interquartile range, 47-72), with mostly respiratory infections (n = 557; 54.9%). Ninety-day mortality was 32.1% (n = 325). Patients with hyperdynamic left ventricular ejection fraction had a higher mortality than depressed and normal left ventricular ejection fraction cohorts (58.9% [n = 103] vs 34.0% [n = 55] vs 24.7% [n = 167]; p < 0.0001, respectively). After multivariate logistic regression, hyperdynamic left ventricular ejection fraction was independently associated with mortality (odds ratio, 3.90 [2.09-7.40]), whereas depressed left ventricular ejection fraction did not (odds ratio, 0.62 [0.28-1.37]). Systemic vascular resistance was inversely associated with hyperdynamic left ventricular ejection fraction (odds ratio, 0.79 [0.58-0.95]), and age, frailty, and ischemic heart disease were associated with depressed left ventricular ejection fraction.

CONCLUSIONS

Hyperdynamic left ventricular ejection fraction was associated with mortality in septic ICU patients and may reflect unmitigated vasoplegia from sepsis. Depressed left ventricular ejection fraction was not associated with mortality but was associated with cardiovascular disease.

[Resuscitation strategy for patients with sepsis and septic shock]

Fluid and vasopressor resuscitation is, along with antimicrobial therapy and control of the focus of infection, a basic issue of the treatment of sepsis and septic shock. There is currently no accepted protocol that we can follow for the resuscitation of these patients and the Surviving Sepsis Campaign proposes controversial measures and without sufficient evidence support to establish firm recommendations. We propose a resuscitation strategy adapted to the situation of each patient: in the patient in whom community sepsis is suspected, we consider that the early administration of 30mL/kg of crystalloids is effective and safe; in the patient with nosocomial sepsis, we must carry out a more in-depth evaluation before initiating aggressive resuscitation. In patients who do not respond to initial resuscitation, it is necessary to increase monitoring level and, depending on the hemodynamic profile, administer more fluids, a second vasopressor or inotropes.

[Pathophysiology of septic shock]

Sepsis and septic shock result from an inadequate host response to an infection, which causes organ dysfunction. The progression of this condition is manifested by the occurrence of successive clinical stages, resulting from the systemic inflammatory response secondary to the activation of different inflammatory mediators, leading to organ dysfunction. There is a high burden of evidence on the role of endotoxin in the pathogenesis of sepsis and its crucial role in triggering the inflammatory response in sepsis caused by gram-negative bacteria. The coagulation cascade activation in sepsis patients is part of the host's adaptive immune response to infection. The endothelium is the main target in sepsis, which is metabolically active and can.

Fluid Overload Phenotypes in Critical Illness-A Machine Learning Approach

BACKGROUND

The detrimental impact of fluid overload (FO) on intensive care unit (ICU) morbidity and mortality is well known. However, research to identify subgroups of patients particularly prone to fluid overload is scarce. The aim of this cohort study was to derive "FO phenotypes" in the critically ill by using machine learning techniques.

METHODS

Retrospective single center study including adult intensive care patients with a length of stay of ≥3 days and sufficient data to compute FO. Data was analyzed by multivariable logistic regression, fast and frugal trees (FFT), classification decision trees (DT), and a random forest (RF) model.

RESULTS

Out of 1772 included patients, 387 (21.8%) met the FO definition. The random forest model had the highest area under the curve (AUC) (0.84, 95% CI 0.79-0.86), followed by multivariable logistic regression (0.81, 95% CI 0.77-0.86), FFT (0.75, 95% CI 0.69-0.79) and DT (0.73, 95% CI 0.68-0.78) to predict FO. The most important predictors identified in all models were lactate and bicarbonate at admission and postsurgical ICU admission. Sepsis/septic shock was identified as a risk factor in the MV and RF analysis.

CONCLUSION

The FO phenotypes consist of patients admitted after surgery or with sepsis/septic shock with high lactate and low bicarbonate.