New clinical criteria for septic shock: serum lactate level as new emerging vital sign

A Point-of-Care Serum Lactate Level and Mortality in Adult Sepsis Patients: A Community Hospital Setting

Introduction:

Sepsis is a serious and emergency condition that may lead to acute circulatory failure associated with infection. Serum lactate level of over 4 mmol/L is associated with sepsis mortality. However, there is limited data on using a point of care (POC) for fingertip lactate level on sepsis mortality in community hospital setting. This study aimed to evaluate roles of POC for serum lactate with combination of clinical factors on mortality prediction in sepsis patients.

Methods:

This was a retrospective cohort study conducted at 7 community hospitals. The inclusion criteria were adult patients with diagnosis of sepsis who were tested for POC lactate level. Electronic chart reviews of eligible patients were performed. Predictors for mortality were computed using clinical factors and POC lactate level.

Results:

There were 1641 patients met the study criteria. The mortality rate was 8.96% (147 patients). There were 3 independent factors associated with mortality: age, co-morbid diseases, and POC lactate level. The adjusted odds ratio (95% CI) of POC lactate level was 1.025 (1.002, 1.048). The cut point of serum lactate was 1.6 mmol/L gave sensitivity of 79.59% and specificity of 32.10%.

Conclusion:

POC serum lactate level may be associated with mortality in sepsis patients at community hospitals. Lactate level of 1.6 mmol/L may be an indicator for mortality with good sensitivity. Physicians may consider more aggressive and prompt management in individuals with sepsis and POC serum lactate of 1.6 mmol/L or over.

Arterial or cuff pressure: Clinical predictors among patients in shock in a critical care resuscitation unit

OBJECTIVES

Blood pressure (BP) measurement is essential for managing patients with hypotension. There are differences between invasive arterial blood pressure (IABP) and noninvasive blood pressure (NIBP) measurements. However, the clinical applicability of these differences in patients with shock [need for vasopressor or serum lactate ≥ 4 millimole per liter (mmol/L)] has not been reported. This study investigated differences in IABP and NIBP as well as changes in clinical management in critically ill patients with shock.

METHODS

This was a retrospective study involving adult patients admitted to the Critical Care Resuscitation Unit (CCRU). Adult patients who received IABP upon admission between 01/01/2017-12/31/2017 with non-hypertensive diseases were eligible. The primary outcome, clinically relevant difference (CRD), was defined as difference of 10 mm of mercury (mmHg) between IABP and NIBP and change of blood pressure management according to goal mean arterial pressure (MAP) ≥ 65 mmHg. We performed forward stepwise multivariable logistic regression to measure associations.

RESULTS

Sample size calculation recommended 200 patients, and we analyzed 263. 121 (46%) patients had shock, 23 (9%) patients had CRD. Each mmol/L increase in serum lactate was associated with 11% higher likelihood of having CRD (OR 1.11, 95%CI 1.002-1.2). Peripheral artery disease and any kidney disease was significantly associated with higher likelihood of MAP difference ≥ 10 mmHg.

CONCLUSION

Approximately 9% of patients with shock had clinically-relevant MAP difference. Higher serum lactate was associated with higher likelihood of CRD. Until further studies are available, clinicians should consider using IABP in patients with shock.

A Graphene-Based Enzymatic Biosensor Using a Common-Gate Field-Effect Transistor for L-Lactic Acid Detection in Blood Plasma Samples

Lactate is an important organic molecule that is produced in excess during anaerobic metabolism when oxygen is absent in the human organism. The concentration of this substance in the body can be related to several medical conditions, such as hemorrhage, respiratory failure, and ischemia. Herein, we describe a graphene-based lactate biosensor to detect the concentrations of L-lactic acid in different fluids (buffer solution and plasma). The active surface (graphene) of the device was functionalized with lactate dehydrogenase enzyme using different substances (Nafion, chitosan, and glutaraldehyde) to guarantee stability and increase selectivity. The devices presented linear responses for the concentration ranges tested in the different fluids. An interference study was performed using ascorbic acid, uric acid, and glucose, and there was a minimum variation in the Dirac point voltage during detection of lactate in any of the samples. The stability of the devices was verified at up to 50 days while kept in a dry box at room temperature, and device operation was stable until 12 days. This study demonstrated graphene performance to monitor L-lactic acid production in human samples, indicating that this material can be implemented in more simple and low-cost devices, such as flexible sensors, for point-of-care applications.

Cellular Metabolites Regulate Central Nucleic Acid Sensing Pathways

Detection of pathogen-derived DNA or RNA species by cellular nucleic acid sensors prompts release of anti-microbial interferons and cytokines. In contrast to their protective anti-microbial functions, inappropriate or excessive activation of nucleic acid sensors can cause inflammatory diseases. Nucleic acid sensing is therefore tightly controlled by regulatory factors acting through both transcriptional and post-transcriptional mechanisms. Recently, it has become clearer that metabolic pathways-previously thought to be unconnected with immune responses-can influence nucleic acid sensing. This regulation can be observed when immune system cells undergo metabolic reprogramming in response to stimulation with pathogen-associated molecular patterns such as lipopolysaccharide from gram negative bacteria. Metabolic reprogramming leads to accumulation and secretion of metabolites, which have been mostly viewed as end-products of processes providing cellular energy and building blocks. However, metabolites have now been identified as important regulators of nucleic acid sensing. This mini-review aims to outline current knowledge on regulation of central nucleic acid sensing pathways by metabolites during metabolic reprogramming.

The sepsis induced defective aggravation of immune cells: a translational science underling chemico-biological interactions from altered bioenergetics and/or cellular metabolism to organ dysfunction

Sepsis is described as a systemic immune response of the body to an infectious process that might result in dysfunctional organs that may lead to death. In clinical practice, sepsis is considered a medical emergency. The initial event in sepsis caused by a deregulated host response towards harmful microorganisms that leads to an aggravated systemic inflammatory response syndrome (SIRS) to tackle with pathogen invasion and a compensatory anti-inflammatory response syndrome (CARS) that lasts for several days. The inflammatory response and the cellular damage as well as the risk of an organ dysfunction are in direct proportion. Even though, the pathogenesis of sepsis remains unclear, many studies have shown evidence of role of oxidants and antioxidants in sepsis. The altered innate and adaptive immune cell and upregulated production and release of cytokines and chemokines most probably due to involvement of JAK-STAT pathway, disturbance in redox homeostasis due to low clearance of lactate and other oxidative stressors, contributes to sepsis process to organ dysfunction which contribute to increase rates of mortality among these patients. Hence, the treatment strategies for sepsis include antibiotics, ventilator and blood glucose management and other strategies for resuscitation are rapidly progressing. In the current review, we mainly concentrate on throwing light on the main molecular aspects and chemico-biological interactions that shows involvement in pathways manipulating alteration in physiology of immune cells (innate and adaptive) that change the bioenergetics/cellular metabolism to organ dysfunction and correlation of these altered pathway, improve the understating for new therapeutic target for sepsis.

The Levels of Lactate, Troponin, and N-Terminal Pro-B-Type Natriuretic Peptide Are Predictors of Mortality in Patients with Sepsis and Septic Shock: A Retrospective Cohort Study

BACKGROUND Serum lactate, troponin, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) have been proposed to be useful prognostic indicators in patients with sepsis and septic shock. This study aimed to evaluate the predictive ability of these biomarkers and assess how their prognostic utility may be improved by using them in combination. MATERIAL AND METHODS A retrospective review of the medical records of 1242 patients with sepsis and septic shock who were admitted to the Richmond University Medical Center between June 1, 2018, and June 1, 2019, was carried out; 427 patients met the study criteria and were included in the study. The primary outcome measures included 30-day mortality, APACHE II scores, length of hospital stay, and admission to the Medical Intensive Care Unit (MICU). RESULTS High levels of lactate (>4 mmol/L), troponin (>0.45 ng/mL), and NT-proBNP (>8000 pg/mL) were independent predictors of 30-day mortality, with an adjusted odds ratio of mortality being 3.19 times, 2.13 times, and 2.5 times higher, respectively, compared with corresponding reference groups, at 95% confidence intervals. Elevated levels of lactate, troponin, and NT-proBNP were associated with 9.12 points, 7.70 points, and 8.88 points in higher APACHE II scores, respectively. Only elevated troponin levels were predictive of a longer length of hospital stay. In contrast, elevated lactate and troponin were associated with an increased chance of admission to the MICU. CONCLUSIONS Elevated levels of serum lactate, troponin, and NT-proBNP are independent predictors of mortality and higher APACHE II scores in patients with sepsis and septic shock.

Lactate Level as a Prediction Factor of Reperforation after Repairing Gastric Perforation

Reperforation after gastric perforation repair is a complication which increases the rate of morbidity and mortality in gastric perforation. The lack of ability of the tissue to use oxygen in septic condition causes anaerobic cellular metabolism and furthermore it will cause failure in closing the perforation. The production of anaerobic metabolism is lactic acid which can be measured from the blood. The aim of this study is to determine the cut-off point of blood lactate level as a predictor of reperforation after repairing gastric perforation. Forty-six patients diagnosed as gastric perforation, who were repaired in Dr Soetomo Hospital from October 2014 to October 2015 were recruited as samples. Serum lactate was taken one hour before repairing the perforation. After being repaired, the patients were observed until the 14th day to evaluate whether any reperforation would occur or not . The design of this research was cross-sectional, analytic observational. The data was analyzed using independent t-test and ROC for obtaining the cut-off point as a predictor of the reperforation after the gastric perforation was repaired. There was a significant difference in the mean of lactate level in the group with reperforation compared with that of the non-reperforation group, that is as big as 3.74±0.59 mmol/L and 2.60±0.76 mmol/L. Using ROC curve analysis, there was the cut-off point of lactate level for reperforation 3.35 mmol/L, with sensitivity 92.9%, specificity 84.4%, positive predictive value 72% and negative predictive Value 96.4%, accuracy 87.0% and in the AUC value 0.902.

Serum metabolic profiles of septic shock patients based upon co-morbidities and other underlying conditions

Diagnosis and management of patients with septic shock is still a significant challenge for clinicians with its high mortality amongst hospitalized patients. Septic shock is a heterogeneous condition and is usually accompanied by various underlying disease conditions. Dissecting the specific metabolic changes induced by these underlying disease conditions through metabolomics has shown the potential to improve our understanding of the disease's relevant pathophysiological mechanisms, leading to improved treatment. This study has shown the metabolic alterations caused due to co-morbid conditions like diabetes, hypertension, CAD, and CKD in septic shock. It has also shown the distinct metabolic profiles of septic shock patients with underlying respiratory illnesses and encephalopathy. Metabolic profiling of sera obtained from 50 septic shock patients and 20 healthy controls was performed using high-resolution 1D ¹H CPMG and diffusion-edited NMR spectra. Univariate and multivariate statistical analyses were performed to identify the potential molecular biomarkers. Noted dysregulations in amino acids, carbohydrates, and lipid metabolism were observed in septic shock patients. Further stratification within the septic shock patients based on co-morbid conditions and primary diagnosis has shown their role in causing metabolic alterations. Evaluation of these compounds during treatment will help design a personalized treatment protocol for the patients, improving therapeutics.

Functionalization of hybrid surface microparticles for in vitro cellular antigen classification

Hybrid material surfaces on microparticles are emerging as vehicles for many biomedical multiplexing applications. Functionalization of these hybrid surface microparticles to biomolecules presents unique challenges related to optimization of surface chemistries including uniformity, repeatability, and sample sparring. Hybrid interfaces between microlevel surfaces and individual biomolecules will provide different microenvironments impacting the surface functionalization optimization and efficiency. Here, we propose and validate the first demonstration of streptavidin adsorption-based antibody functionalization on unmodified, hybrid surface microparticles for in vitro analysis. We test this analytical technique and fabricate hybrid surface microparticles with a polystyrene core and aluminum oxide semi-coating. Additionally, we optimize the streptavidin-biotin functionalization chemistry in both assay implementation and sample sparring via analytical mass balances for these microparticles and subsequently conjugate anti-human CD11b antibodies. Result confirmation and characterization occurs from ultraviolet protein absorbance and ImageJ processing of fluorescence microscopy images. Additionally, we design and implement the multi-sectional imaging (MSI) approach to support functionalization uniformity on the hybrid surface microparticles. Finally, as a proof-of-concept performance, we validate anti-CD11b antibodies functionalization by visualizing hybrid surface microparticles conjugate to human neutrophils isolated from blood samples collected from potentially septic patients. Our study introduces and defines a category of functionalization for hybrid surface microparticles with the intent of minuscule sample volumes, low cost, and low environmental impact to be used for many cellular or proteomic in vitro multiplexing applications in the future. Graphical abstract.

Blood Lactate And Lactate Clearance: Refined Biomarker And Prognostic Marker In Burn Resuscitation

Adequate resuscitation of acute burn patients is important to ensure end organ perfusion and oxygenation. The ideal marker to the endpoint of burn resuscitation is still not established. We aimed to evaluate the role of blood lactate and lactate clearance in burn resuscitation and their association with mortality and sepsis in burn patients. The retrospective study included patients (18-50 years) with thermal and scald burns with total body surface area of 30% to 60% over a period of 9 months who had achieved target urine output of at least 0.5ml/kg/hr within 24 hours of resuscitation. Patients were divided based on their admission blood lactate levels (Group A < 2 mmol/L and Group B > 2 mmol/L). Group B was further subdivided into Group B1 in whom blood lactate levels reached less than 2 mmol/L within 24 hours of burn resuscitation and Group B2 in whom it did not. Total patients included were 203. Mortality (M) and sepsis (S) rates in subgroup B2 were higher (M=57.9%; S=43.5%) and rates in subgroup B1 (M=25.8%; S=27.4%) were comparable to Group A (M=27.8%; S=26.4%). Persistent lactic acidosis at 24 hours was independently associated with significantly increased mortality and sepsis. Our data suggests a correlation of blood lactate levels and lactate clearance within 24 hours of admission with mortality and sepsis related to burn injury.

Use and Evaluation of Computerized Clinical Decision Support Systems for Early Detection of Sepsis in Hospitals: Protocol for a Scoping Review

BACKGROUND

Sepsis is a leading cause of death in hospitals, with high associated costs for both patients and health care systems worldwide. Early detection followed by timely intervention is critical for successful sepsis management and, hence, can save lives. Health care institutions are increasingly leveraging clinical data captured in electronic health records for the development of computerized clinical decision support (CCDS) systems aimed at enhancing the early detection of sepsis. However, a comprehensive evidence base regarding sepsis CCDS systems to inform clinical practice, research, and policy is currently lacking.

OBJECTIVE

This scoping review aims to systematically describe studies reporting on the use and evaluation of CCDS systems for early detection of sepsis in hospitals.

METHODS

The methodology for conducting scoping reviews presented by the Joanna Briggs Institute Reviewer's Manual and the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) will be used and adapted as guides. A comprehensive literature search of 10 electronic databases will be conducted to identify all empirical quantitative and qualitative studies that investigate the use of CCDS systems for early detection of sepsis in hospitals. Detailed inclusion and exclusion criteria have been developed. Two reviewers will independently screen all articles based on these criteria. Any discrepancies will be resolved through discussion and further review by a third researcher if required.

RESULTS

Electronic database searches have retrieved 12,139 references after removing 10,051 duplicates. As of the submission date of this protocol, we have completed the title and abstract screening. A total of 372 references will be included for full-text screening. Only 15.9% (59/372) of these studies were focused on children: 11.0% (41/372) for pediatric and 4.8% (18/372) for neonatal patients. The scoping review and the manuscript will be completed by December 2020.

CONCLUSIONS

Results of this review will guide researchers in determining gaps and shortcomings in the current evidence base for CCDS system use and evaluation in the early detection of sepsis. The findings will be shared with key stakeholders in clinical care, research, policy, and patient advocacy.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/24899.

Machine Learning-Assisted Raman Spectroscopy for pH and Lactate Sensing in Body Fluids

This study presents the combination of Raman spectroscopy with machine learning algorithms as a prospective diagnostic tool capable of detecting and monitoring relevant variations of pH and lactate as recognized biomarkers of several pathologies. The applicability of the method proposed here is tested both in vitro and ex vivo. In a first step, Raman spectra of aqueous solutions are evaluated for the identification of characteristic patterns resulting from changes in pH or in the concentration of lactate. The method is further validated with blood and plasma samples. Principal component analysis is used to highlight the relevant features that differentiate the Raman spectra regarding their pH and concentration of lactate. Partial least squares regression models are developed to capture and model the spectral variability of the Raman spectra. The performance of these predictive regression models is demonstrated by clinically accurate predictions of pH and lactate from unknown samples in the physiologically relevant range. These results prove the potential of our method to develop a noninvasive technology, based on Raman spectroscopy, for continuous monitoring of pH and lactate in vivo.

Comparison of wavelength selection methods for in-vitro estimation of lactate: a new unconstrained, genetic algorithm-based wavelength selection

Biochemical and medical literature establish lactate as a fundamental biomarker that can shed light on the energy consumption dynamics of the body at cellular and physiological levels. It is therefore, not surprising that it has been linked to many critical conditions ranging from the morbidity and mortality of critically ill patients to the diagnosis and prognosis of acute ischemic stroke, septic shock, lung injuries, insulin resistance in diabetic patients, and cancer. Currently, the gold standard for the measurement of lactate requires blood sampling. The invasive and costly nature of this procedure severely limits its application outside intensive care units. Optical sensors can provide a non-invasive, inexpensive, easy-to-use, continuous alternative to blood sampling. Previous efforts to achieve this have shown significant potential, but have been inconclusive. A measure that has been previously overlooked in this context, is the use of variable selection methods to identify regions of the optical spectrum that are most sensitive to and representative of the concentration of lactate. In this study, several wavelength selection methods are investigated and a new genetic algorithm-based wavelength selection method is proposed. This study shows that the development of more accurate and parsimonious models for optical estimation of lactate is possible. Unlike many existing methods, the proposed method does not impose additional locality constraints on the spectral features and therefore helps provide a much more granular interpretation of wavelength importance.

Best-practice IgM- and IgA-enriched immunoglobulin use in patients with sepsis

Background

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Despite treatment being in line with current guidelines, mortality remains high in those with septic shock. Intravenous immunoglobulins represent a promising therapy to modulate both the pro- and anti-inflammatory processes and can contribute to the elimination of pathogens. In this context, there is evidence of the benefits of immunoglobulin M (IgM)- and immunoglobulin A (IgA)-enriched immunoglobulin therapy for sepsis. This manuscript aims to summarize current relevant data to provide expert opinions on best practice for the use of an IgM- and IgA-enriched immunoglobulin (Pentaglobin) in adult patients with sepsis.

Main text

Sepsis patients with hyperinflammation and patients with immunosuppression may benefit most from treatment with IgM- and IgA-enriched immunoglobulin (Pentaglobin). Patients with hyperinflammation present with phenotypes that manifest throughout the body, whilst the clinical characteristics of immunosuppression are less clear. Potential biomarkers for hyperinflammation include elevated procalcitonin, interleukin-6, endotoxin activity and C-reactive protein, although thresholds for these are not well-defined. Convenient biomarkers for identifying patients in a stage of immune-paralysis are still matter of debate, though human leukocyte antigen–antigen D related expression on monocytes, lymphocyte count and viral reactivation have been proposed. The timing of treatment is potentially more critical for treatment efficacy in patients with hyperinflammation compared with patients who are in an immunosuppressed stage. Due to the lack of evidence, definitive dosage recommendations for either population cannot be made, though we suggest that patients with hyperinflammation should receive an initial bolus at a rate of up to 0.6 mL (30 mg)/kg/h for 6 h followed by a continuous maintenance rate of 0.2 mL (10 mg)/kg/hour for ≥ 72 h (total dose ≥ 0.9 g/kg). For immunosuppressed patients, dosage is more conservative (0.2 mL [10 mg]/kg/h) for ≥ 72 h, without an initial bolus (total dose ≥ 0.72 g/kg).

Conclusions

Two distinct populations that may benefit most from Pentaglobin therapy are described in this review. However, further clinical evidence is required to strengthen support for the recommendations given here regarding timing, duration and dosage of treatment.

Identification and Quantitative Determination of Lactate Using Optical Spectroscopy-Towards a Noninvasive Tool for Early Recognition of Sepsis

Uninterrupted monitoring of serum lactate levels is a prerequisite in the critical care of patients prone to sepsis, cardiogenic shock, cardiac arrest, or severe lung disease. Yet there exists no device to continuously measure blood lactate in clinical practice. Optical spectroscopy together with multivariate analysis is proposed as a viable noninvasive tool for estimation of lactate in blood. As an initial step towards this goal, we inspected the plausibility of predicting the concentration of sodium lactate (NaLac) from the UV/visible, near-infrared (NIR), and mid-infrared (MIR) spectra of 37 isotonic phosphate-buffered saline (PBS) samples containing NaLac ranging from 0 to 20 mmol/L. UV/visible (300–800 nm) and NIR (800–2600 nm) spectra of PBS samples were collected using the PerkinElmer Lambda 1050 dual-beam spectrophotometer, while MIR (4000–500 cm⁻¹) spectra were collected using the Spectrum two FTIR spectrometer. Absorption bands in the spectra of all three regions were identified and functional groups were assigned. The concentration of lactate in samples was predicted using the Partial Least-Squares (PLS) regression analysis and leave-one-out cross-validation. The regression analysis showed a correlation coefficient (R²) of 0.926, 0.977, and 0.992 for UV/visible, NIR, and MIR spectra, respectively, between the predicted and reference samples. The RMSECV of UV/visible, NIR, and MIR spectra was 1.59, 0.89, and 0.49 mmol/L, respectively. The results indicate that optical spectroscopy together with multivariate models can achieve a superior technique in assessing lactate concentrations.

Use of adrenaline continuous infusion to treat hypotension during general anaesthesia in a cow and a calf

Background

Hypotension is one of the most common complications observed during inhalation anaesthesia in veterinary patients. Treatment of hypotension in cattle is more challenging than in other species, owing to the limited number of drugs licensed in food producing animals. The use of adrenaline as an infusion to support blood pressure has not been described previously in bovines.

Case presentation

A cow and a calf presented to University College Dublin Veterinary Hospital for bilateral mandibular fracture repair and bladder rupture repair respectively, developed severe anaesthetic related hypotension unresponsive to conventional treatments. In both cases an adrenaline infusion was started and slowly increased to effect, with infusion rates ranging from 0.01 to 0.25 μg/kg/min. Blood pressure increased as the adrenaline infusion rate increased, but clinically significant improvements in blood pressure were only observed with infusion rates exceeding 0.05 μg/kg/min. The side effect observed with adrenaline infusion was an increase in plasma lactate levels in both cases. Both animals were euthanised due to non-anaesthetic related complications.

Conclusions

Maintenance of normotension is important during bovine anaesthesia to prevent the development of post-anaesthetic complications. In the cases described here, adrenaline was effective as an additional treatment of anaesthetic related hypotension. Further research is required to establish the recommended infusion rates, cardiovascular effects and possible side effects of adrenaline infusion administration as a treatment for hypotension in bovines.

Clinical Utilization of Blood and Urine Cultures and Incidences of Bacteremia and Bacteriuria in a Hospital in Thailand

Background

To effectively treat sepsis and urinary tract infection (UTI), blood and urine cultures should be used appropriately and relative to incidences of bacteremia and bacteriuria. This study aimed to investigate the use of blood and urine cultures and incidences of bacteremia and bacteriuria in a hospital in Thailand.

Material/Methods

Medical records of patients admitted from 2016 to 2018 were randomly selected and data in the records were anonymously extracted for investigation.

Results

From 12 000 records, data on blood and urine cultures were extracted from 9% and 4% of them, respectively. The negative rate of blood culture was 87.48%. Bacteremia was detected in 10.22%. The positive rate of urine culture was 27.38% and the contamination rate was 31.26%. Escherichia coli was the most common cause of community-onset bacteremia and bacteriuria. Methicillin-resistant coagulase-negative staphylococci and Acinetobacter baumannii were the most common cause of hospital-acquired bacteremia while yeasts were the most common cause of hospital-acquired UTI.

Conclusions

A high negative rate of blood culture may result not only from its low sensitivity but also from liberal test use to identify sepsis in some conditions. Improper urine collection is the main problem with use of urine culture.

Biomarkers and newer laboratory investigations in the diagnosis of sepsis

Sepsis is a major cause of death in hospitalised patients accounting for mortality rates as high as 60% and, hence, is called 'a hidden public health disaster'. Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis is not a disease but is a clinical syndrome, where the initial features are nonspecific resulting in delayed diagnosis. Lack of specific laboratory tests to diagnose the syndrome adds to the diagnostic confusion. Failure to identify sepsis in the early stages itself delays effective treatment resulting in high morbidity and mortality. Various biomarkers and newer laboratory tests help to address these issues. However, to date there is no ideal test to diagnose sepsis. The most commonly used markers are C-reactive protein (CRP) and procalcitonin (PCT). There are around 180 biomarkers reported to be useful in sepsis. In addition to CRP and PCT, various emerging laboratory markers, such as like serum amyloid A, soluble triggering receptor expressed on myeloid cell-1, mannan and antimannan antibodies, and interferon γ inducible protein-10 etc., have been reviewed and their clinical usefulness discussed in this paper.

Is my patient ready for a safe transfer to a lower-intensity care setting? Nursing complexity as an independent predictor of adverse events risk after ICU discharge

BACKGROUND

Patients discharged from intensive care units (ICUs) are at risk for adverse events (AEs). Establishing safe discharge criteria is challenging. No available criteria consider nursing complexity among risk factors.

OBJECTIVES

To investigate whether nursing complexity upon ICU discharge is an independent predictor for AEs.

METHODS

Prospective observational study. The Patient Acuity and Complexity Score (PACS) was developed to measure nursing complexity. Its predictive power for AEs was tested using multivariate regression analysis.

RESULTS

The final regression model showed a very-good discrimination power (AUC 0.881; p<0.001) for identifying patients who experienced AEs. Age, ICU admission reason, PACS, cough strength, PaCO₂, serum creatinine and sodium, and transfer to Internal Medicine showed to be predictive of AEs. Exceeding the identified PACS threshold increased by 3.3 times the AEs risk.

CONCLUSIONS

The level of nursing complexity independently predicts AEs risk and should be considered in establishing patient's eligibility for a safe ICU discharge.

Systematic review on peri-operative lactate measurements to predict outcomes in patients undergoing liver resection

Lactate measurements have proven utility as a triage tool, therapeutic guide, and prognostic indicator, with broad use in Acute Care and transplantation. Its value in guiding therapy and predicting outcomes following liver resection is less well‐defined. This systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines assessed the relationship between peri‐operative lactate levels and morbidity and mortality after liver resection. Seven relevant studies comprising 2573 patients in total were identified. Six studies assessed intra‐operative or early postoperative lactate levels, one publication examined pre‐operative levels. All studies demonstrated a significant association between peri‐operative lactate levels and adverse outcomes. The influence of pre‐operative diabetes and cirrhosis on postoperative lactate levels was shown in one study each, no study assessed the association of lactate with post‐hepatectomy liver failure according to defined criteria. The heterogeneity of study measurements and end‐points precluded a meta‐analysis from being performed. Early postoperative lactate >3‐3.7 mmol/L is associated with mortality but validation of clear cut‐off levels for outcome prediction is pending. Literature suggests lactate is a useful predictive marker for outcomes post liver surgery, especially when measured in the early postoperative phase. Further research is required to standardize the use of lactate measurements in a meaningful therapeutic manner.

Determination of physiological lactate and pH by Raman spectroscopy

Lactate and pH values in human blood are important physiological parameters that can reflect serious pathological states as sepsis or hypoxia. In this study we demonstrate that we can determine lactate and pH values from blood samples by Raman spectroscopy combined with multivariate analysis at medically relevant resolution and reliability. The method prepares the base for new real-time in vivo analytics for a number of pathological cases and physiological control in competitive sports. We demonstrate the capability to resolve pH variations of 0.04 and lactate concentrations of 0.20 mM ex vivo.

Digital Alerting and Outcomes in Patients With Sepsis: Systematic Review and Meta-Analysis

BACKGROUND

The diagnosis and management of sepsis remain a global health care challenge. Digital technologies have the potential to improve sepsis care.

OBJECTIVE

The aim of this paper was to systematically review the evidence on the impact of digital alerting systems on sepsis related outcomes.

METHODS

The following databases were searched for studies published from April 1964 to February 12, 2019, with no language restriction: EMBASE, MEDLINE, HMIC, PsycINFO, and Cochrane. All full-text reports of studies identified as potentially eligible after title and abstract reviews were obtained for further review. The search was limited to adult inpatients. Relevant articles were hand searched for other studies. Only studies with clear pre- and postalerting phases were included. Primary outcomes were hospital length of stay (LOS) and intensive care LOS, whereas secondary outcomes were time to antibiotics and mortality. Studies based solely on intensive care, case reports, narrative reviews, editorials, and commentaries were excluded. All other trial designs were included. A qualitative assessment and meta-analysis were performed.

RESULTS

This review identified 72 full-text articles. From these, 16 studies met the inclusion criteria and were included in the final analysis. Of these, 8 studies reviewed hospital LOS, 12 reviewed mortality outcomes, 5 studies explored time to antibiotics, and 5 studies investigated intensive care unit (ICU) LOS. Both quantitative and qualitative assessments of the studies were performed. There was evidence of a significant benefit of digital alerting in hospital LOS, which reduced by 1.31 days (P=.014), and ICU LOS, which reduced by 0.766 days (P=.007). There was no significant association between digital alerts and mortality (mean decrease 11.4%; P=.77) or time to antibiotics (mean decrease 126 min; P=.13).

CONCLUSIONS

This review highlights that digital alerts can considerably reduce hospital and ICU stay for patients with sepsis. Further studies including randomized controlled trials are necessary to confirm these findings and identify the choice of alerting system according to the patient status and pathological cohort.

A Case of Linezolid Toxicity Presenting as a Sepsis Mimic

Linezolid is an efficacious and well tolerated antimicrobial but can have serious adverse effects including myelo-suppression, serotonin syndrome, neuropathy, hypoglycemia, liver dysfunction, and lactic acidosis. The side effects are generally duration dependent; linezolid use is not recommended for more than 28 days. Case. A 59-year-old female presented with malaise, loss of appetite, and altered mentation. She had multiple medical comorbidities and required long-term anticoagulation with warfarin for venous thromboembolism. She had multiple medication allergies. Prior to admission, she was on linezolid for cellulitis of foot due to Methicillin-resistant Staphylococcus aureus (MRSA). On physical exam, she was drowsy and required endotracheal intubation for airway protection. Initial laboratory parameters showed lactic acidosis, thrombocytopenia, supra-therapeutic coagulation profile, low blood glucose, and transaminitis. Her altered mentation was due to hypoglycemia. The interaction with warfarin led to altered coagulation profile. She developed shock and vasopressors were initiated. Given her presentation, she was managed as severe sepsis. There were no active infectious foci attributing to decline of her clinical status. Linezolid was discontinued and she was managed with intravenous polymyxin B, aztreonam, and vancomycin. Her hemodynamic status improved within one day. She was extubated on Day 5 of her presentation. Her laboratory parameters showed gradual improvement over 12 days after discontinuation of linezolid. Retrospective evaluation revealed linezolid toxicity as possible cause of presentation. Linezolid toxicity can present as sepsis mimic and should be considered as a differential diagnosis while managing sepsis with other antimicrobial agents.

Central venous pressure value can assist in adjusting norepinephrine dosage after the initial resuscitation of septic shock

BACKGROUND

New definitions for sepsis and septic shock (Sepsis-3) were published, but the strategy to adjust vasopressors after the initial guidelines is still unclear. We conducted a retrospective observational study to explore dosing strategy of norepinephrine (NE).

METHODS

A retrospective observational study in the 15-bed mixed intensive care unit of a tertiary care university hospital. The study was performed on septic shock patients after 30 mL/kg fluid resuscitation and mean arterial pressure (MAP) levels reached >65 mmHg requiring NE. We divided patients into NE dosage increase and decrease groups, and collected hemodynamic and tissue perfusion parameters before (T1) and after (T2) adjusting NE dosage.

RESULTS

In both NE increase and decrease groups, central venous pressure (CVP) and pressure difference between usual MAP and MAP (dMAP) at the T1 time point were associated with lactate clearance. In groups LC HM (CVP <10 mmHg, dMAP > 0 mmHg) and HC HM (CVP ≥ 10 mmHg, dMAP > 0 mmHg), decrease in NE dosage decreased lactate level, while in group HC LM (CVP ≥ 10 mmHg, dMAP ≤ 0 mmHg), both increase and decrease in NE dosage led to increase lactate level.

CONCLUSIONS

After patients with septic shock (Sepsis-3) resuscitated to reach the initial recovery target goals, combination of CVP and MAP refer to usual levels can help doctors make the next decision to make the correct choice of increase NE dosage or decrease NE dosage.

Fluid resuscitation in patients with end-stage renal disease on hemodialysis presenting with severe sepsis or septic shock: A case control study

Due to the potential risk of volume overload, physicians are hesitant to aggressively fluid-resuscitate septic patients with end-stage renal disease (ESRD) on hemodialysis (HD). Primary objective: To calculate the percentage of ESRD patients on HD (Case) who received ≥30 mL/Kg fluid resuscitation within the first 6 h compared to non-ESRD patients (Control) that presented with severe sepsis (SeS) or septic shock (SS). Secondary objectives: Effect of fluid resuscitation on intubation rate, need for urgent dialysis, hospital length of stay (LOS), intensive care unit (ICU) admission and LOS, need for vasopressors, and hospital mortality. Medical records of 715 patients with sepsis, SeS, SS, and ESRD were reviewed. We identified 104 Case and 111 Control patients. In the Case group, 23% of patients received ≥30 mL/Kg fluids compared to 60% in the Control group (p < 0.001). There was no significant difference in in-hospital mortality, need for urgent dialysis, intubation rates, ICU LOS, or hospital LOS between the two groups. Subgroup analysis between ESRD patients who received ≥30 mL/Kg (N = 80) vs those who received <30 mL/Kg (N = 24) showed no significant difference in any of the secondary outcomes. Compliance with 30 mL/Kg fluids was low for all patients but significantly lower for ESRD patients. Aggressive fluid resuscitation appears to be safe in ESRD patients.

Procalcitonin as a biomarker for critically ill patients with sepsis: Effects of vitamin D supplementation

Early diagnosis of sepsis is often difficult in clinical practice, whilst it can be vital for positive patient outcomes in sepsis management. Any delay in diagnosis and treatment may lead to significant organ failure and can be associated with elevated mortality rates. Early diagnosis and effective management of sepsis can allow for prompt antibiotic therapy and a potential reduction in mortality; it can also minimize the unnecessary use of antibiotics. Furthermore, vitamin D supplementation, which is commonly used in the intensive care units to reduce mortality, may interfere with the ability to use procalcitonin (PCT) as a means of assessing clinical progression. This paper aims to explore the diagnostic and prognostic value of serum levels of PCT as an early marker of sepsis and to assess whether it can be used as a guide for using antibiotic therapy. Several serum-based biomarkers such as C-reactive protein, lactate, presepsin, and cytokines, such as interleukin-1 (IL-1), and IL-6 have been evaluated as early indicators of sepsis but none have been proven sensitive and/or specific enough to make a definitive diagnosis. Finally the potential benefits and disadvantages of using serum levels of PCT to diagnose and monitor patients with sepsis and septic shock will be briefly discussed.

Association between pre-operative serum lactate concentrate with tumour cell proliferative index in primary brain tumour

BACKGROUND

Elevated preoperative lactate levels have been reported in patients admitted for resection of brain tumors. As histologic type and tumor grade have also been linked to lactate concentration, we hypothesized that preoperative lactate concentration in patients with brain tumors may be associated with tumor proliferation. We describe the relationship between preoperative plasma lactate levels, and the cell proliferation marker Ki-67 in brain tumor surgery.

METHODS

In this cross-sectional study, records of patients who underwent craniotomy between June 2017 and February 2018 at our Hospital were reviewed to select glioma and meningioma cases in which lactate concentrations in plasma and degree of cell proliferation were registered. Bivariable and linear regression analyses were used to assess the association between lactate concentrations and the Ki-67 index.

RESULTS

Lactate concentrations in plasma and Ki-67 index were available in 55 patients. Meningioma cases had a mean concentration of 1.2 (0.1) mmol/L compared to diffuse astrocytic and oligodendroglial tumours cases with 1.7 (0.1) mmol/L (p<.01). Both variables had a low positive correlation in meningiomas (Spearman's r, 0.29; 95% CI, -0.10-0.61; p=.13) and a high correlation in gliomas (Spearman's r, 0.64; 95% CI, 0.33-0.82; p<.01). The pooled analysis showed a high correlation index (Spearman's r, 0.61; 95% CI, 0.40-0.76; p<.01). A linear regression model showed that the Ki-67 index explained 43% of the variation in lactate (p<.01).

CONCLUSIONS

Brain tumors with higher rates of cell proliferation have higher plasma lactate levels. In this scenario, lactate concentrations may not only reflect systemic perfusion.

Relation Between Central Venous, Peripheral Venous and Arterial Lactate Levels in Patients With Sepsis in the Emergency Department

Background

Sepsis and multi-organ failure remain a major clinical problem with high morbidity and mortality worldwide. Lactate measurement remains part of the initial assessment and management of patients with sepsis. Although arterial blood is most commonly used for lactate measurement, there is increasing use of peripheral venous lactate for initial assessment and for monitoring of response to treatment in patients with sepsis. The aim of this study was to evaluate the relation between lactate levels measured from central line, peripheral vein and arterial line in patients treated for sepsis in the emergency department (ED).

Methods

This prospective study enrolled 31 patients with diagnosis of sepsis who were evaluated and treated in the ED of a university hospital. During initial resuscitation, blood samples from the artery, peripheral vein and central vein (when available) were collected and lactate concentrations were measured. Correlation between lactate values from the three different locations was assessed using Pearson correlation. Bland-Altman plots were used to evaluate agreement between lactate measurements in different sampling locations. All patients were eventually admitted to the Internal Medicine Department ward or to the intensive care unit (ICU) for further treatment.

Results

Our data showed strong, highly significant correlation between arterial and peripheral venous lactate levels (r = 0.880, P < 0.0001), between arterial and central venous blood lactate (r = 0.898, P < 0.0001) and between central and peripheral venous blood lactate (r = 0.941, P < 0.0001).

Conclusions

In this study we observed strong correlation between arterial, central vein and peripheral vein lactate concentrations in 31 patients assessed and treated for sepsis. We suggest that lactate measurement in peripheral venous blood could be used for screening and for monitoring response to therapy in sepsis patients. However, because this is a small study in only 31 patients and published data are limited, larger studies are needed in order to confirm the validity of our findings.

In vitro quantification of lactate in Phosphate Buffer Saline (PBS) samples

Continuous measurement of lactate levels in the blood is a prerequisite in intensive care patients who are susceptible to sepsis due to their suppressed immune system and increased metabolic demand. Currently, there exists no noninvasive tool for continuous measurement of lactate in clinical practice. The current mode of measurement is based on arterial blood gas analyzers which require sampling of arterial blood. In this work, we propose the use of Near Infra-Red (NIR) spectroscopy together with multivariate models as a means to non-invasively predict the concentration of lactate in the blood. As the first step towards this objective, we examined the possibility of accurately predicting concentrations of sodium lactate (NaLac) from the NIR spectra of 37 isotonic phosphate buffer saline (PBS) samples containing NaLac ranging from 0 to 20 mmol/L. NIR spectra of PBS samples were collected using the Lambda 1050 dual beam spectrometer over a spectral range of 800 - 2600 nm with a quartz cell of 1 mm optical path. Estimates and calibration of the lactate concentration with the NIR spectra were made using Partial Least-Squares (PLS) regression analysis and leave-one-out cross-validation on filtered spectra. The regression analysis showed a correlation coefficient of 0.977 and a standard error of 0.89 mmol/L between the predicted and prepared samples. The results suggest that NIR spectroscopy together with multivariate models can be a valuable tool for non-invasive assessment of blood lactate concentrations.

Clinical Approach to the Patient in Critical State Following Immunotherapy and/or Stem Cell Transplantation: Guideline for the On-Call Physician

: The initial management of the hematology patient in a critical state is crucial and poses a great challenge both for the hematologist and the intensive care unit (ICU) physician. After years of clinical practice, there is still a delay in the proper recognition and treatment of critical situations, which leads to late admission to the ICU. There is a much-needed systematic ABC (Airway, Breathing, Circulation) approach for the patients being treated on the wards as well as in the high dependency units because the underlying hematological disorder, as well as disease-related complications, have an increasing frequency. Focusing on score-based decision-making on the wards (Modified Early Warning Score (MEWS), together with Quick Sofa score), active sepsis screening with inflammation markers (C-reactive protein, procalcitonin, and presepsin), and assessment of microcirculation, organ perfusion, and oxygen supply by using paraclinical parameters from the ICU setting (lactate, central venous oxygen saturation (ScVO2), and venous-to-arterial carbon dioxide difference), hematologists can manage the immediate critical patient and improve the overall outcome.

The Duration of Intra-abdominal Hypertension and Increased Serum Lactate Level are Important Prognostic Markers in Critically Ill Surgical Patient's Outcome: A Prospective, Observational Study

Aim:

The present study analyzed the clinical significance of duration of intra-abdominal hypertension (IAH) associated with increased serum lactate in critically ill patients with severe sepsis.

Materials and Methods:

Our study was an observational, prospective study carried out in the Surgical Intensive Care Unit (ICU) at J.L.N Medical College, Ajmer, Rajasthan, India. In our study, we included a total of 100 patients and intra-abdominal pressure (IAP) was measured through intravesical route at the time of admission and after 6, 12, 24, 48, and 72 h via a urinary catheter filled with 25 ml of saline. Duration of ICU and hospital stay, need for ventilator support, initiation of enteral feeding, serum lactate level at time of admission and after 48 h, and 30-day mortality were noted as outcomes.

Results:

In our study, an overall incidence of IAH was 60%. Patients with cardiovascular surgery and renal and pulmonary dysfunction were 93.3%, 55%, and 60%, respectively, at the time of admission and 65%, 10%, and 10%, respectively, after 72 h of admission in the surgical ICU. Nonsurvivors had statistically significant higher IAP and serum lactate levels than survivors. Patients with longer duration of IAH had longer ICU and hospital stay, longer duration of vasopressors and ventilator support, and delayed enteral feeding.

Conclusion:

There is a strong relationship “risk accumulation” between duration of IAH associated with increased serum lactate and organ dysfunction. The duration of IAH was an independent predictor of 30-day mortality. Early recognition and prompt intervention for IAH and severe sepsis are essential to improve the patient outcomes.

Manifestations and Outcomes of Patients with Parkinson's Disease and Serious Infection in the Emergency Department

BACKGROUND

Several comorbidities contribute to an increased risk of infections in Parkinson's disease (PD) as the disease progresses. However, few studies have examined the correlation between sepsis and PD.

AIM

The aim of this study is to disclose the presentation and outcome of serious infection in patients with PD in the emergency department.

METHODS

This retrospective cohort study enrolled patients with PD who had serious infection and were admitted to the emergency department between January 2007 and December 2013. For clinical comparison, we compared the clinical features, laboratory data, and outcomes with those of age- and sex-matched patients who had serious infection but not PD.

RESULTS

There were a total of 1,200 episodes of infected PD patients and 2,400 age- and sex-matched infected patients without PD as disease controls. PD patients had fewer comorbidities and lower severity of infectious disease but longer hospital stays than control group patients. The incidences of respiratory tract and urinary tract infections were higher in PD patients. The levels of inflammatory and organ dysfunction biomarkers in PD were lower and compatible with the severity of infectious disease. A total of 86 (7.2%) infected PD patients died during the 28-day admission compared to 339 (14.1%) in non-PD patients. Serum C-reactive protein, bandemia, and lactate could be used to predict mortality in infected PD patients.

CONCLUSIONS

In infected patients with PD, respiratory and urinary tract infections were the two most common infectious sources. Empiric therapy based on experience could treat both respiratory and urinary tract infections. Early diagnosis and treatment are essential for survival.

Understanding fluid homoeostasis in infants and children: part 2

Part two of this article focuses on the care and management of infants and children who are seriously ill and who have lost so much fluid that they have entered a state of shock. The pathophysiology of shock is reviewed and the types and stages of shock are considered. The challenges of identifying shock are explored and the management of fluid resuscitation with colloids rather than crystalloids is analysed. An overview of the complex management of a young person in shock is provided using a case history format. The article offers the opportunity to extend readers' knowledge of some of the special tests that may be required to support the diagnosis of shock and provides an overview of the expected results.

Cardiovascular dysfunction in sepsis at the dawn of emerging mediators

Subcellular dysfunction and impaired metabolism derived from the complex interaction of cytokines and mediators with cellular involvement are on the basis of the cardiovascular response to sepsis. The lethal consequences of an infection are intimately related to its ability to spread to other organ sites and the immune system of the host. About one century ago, William Osler (1849-1919), a Canadian physician, remarkably defined the sequelae of the host response in sepsis: "except on few occasions, the patient appears to die from the body's response to infection rather than from it." Cardiac dysfunction has received considerable attention to explain the heart failure in patients progressing from infection to sepsis, but our understanding of the processes remains limited. In fact, most concepts are linked to a mechanical concept of the sarcomeric structure, and physiological data seems to be often disconnected. Cytokines, prostanoids, and nitric oxide release are high direct impact factors, but coronary circulation and cardiomyocyte physiology also play a prominent role in modulating the effects of monocyte adhesion and infiltration. Damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs) are involved in the host response. The identification of microRNAs, as well as the cyclic activation of the inflammatory cascade, has further added complexity to the scene. In this review, we delineate the current concepts of cellular dysfunction of the cardiomyocyte in the setting of sepsis and consider potential therapeutic strategies.