Lactate, a useful marker for disease mortality and severity but an unreliable marker of tissue hypoxia/hypoperfusion in critically ill patients

Clinical characteristics of extracorporeal cardiopulmonary resuscitation in China: a multicenter retrospective study

PURPOSE

Extracorporeal cardiopulmonary resuscitation (ECPR) might markedly increase the survival of selected patients with refractory cardiac arrest. But the application situation and indications remained unclear.

MATERIALS AND METHODS

We respectively reviwed all adult patients who underwent ECPR from January 2017 to March 2021. Patient characteristics, initiation and management of ECMO, complications, and outcomes were collected and compared between the survivors and nonsurvivors. LASSO regression was used to screen risk factors. Multivariate logistic regression was performed with several parameters screened by LASSO regression.

RESULTS

Data were reported from 42 ECMO centers covering 19 provinces of China. A total of 648 patients were included in the study, including 491 (75.8%) males. There were 11 ECPR centers in 2017, and the number increased to 42 in 2020. The number of patients received ECPR increased from 33 in 2017 to 274 in 2020, and the survival rate increased from 24.2% to 33.6%. Neurological complications, renal replacement therapy, epinephrine dosage after ECMO, recovery of spontaneous circulation before ECMO, lactate clearance and shockable rhythm were risk factors independently associated with outcomes of whole process. Sex, recovery of spontaneous circulation before ECMO, lactate, shockable rhythm and causes of arrest were pre-ECMO risk factors independently affecting outcomes.

CONCLUSIONS

From January 2017 to March 2021, the numbers of ECPR centers and cases in mainland China increased gradually over time, as well as the survival rate. Pre-ECMO risk factors, especially recovery of spontaneous circulation before ECMO, shockable rhythm and lactate, are as important as post-ECMO management,. Neurological complications are vital risk factors after ECMO that deserved close attention.

TRIAL REGISTRATION

NCT04158479, registered on 2019/11/08. https://clinicaltrials.gov/NCT04158479.

The use of venoarterial extracorporeal membrane oxygenation in cardiogenic shock: a narrative review

Aims

Cardiogenic shock (CS) develops in up to 10% of patients with acute myocardial infarction (AMI) and carries a 50% risk of mortality. Despite the paucity of evidence regarding its benefits, venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used in clinical practice in patients with AMI in CS (AMI-CS). This review aims to provide an in-depth description of the four available randomized controlled trials to date designed to evaluate the benefit of VA-ECMO in patients with AMI-CS.

Methods and results

The literature search was conducted on PubMed, Google Scholar, and clinicaltrials.gov to identify the four relevant randomized control trials from years of inception to October 2023. Despite differences in patient selection, nuances in trial conduction, and variability in trial endpoints, all four trials (ECLS-SHOCK I, ECMO-CS, EUROSHOCK, and ECLS-SHOCK) failed to demonstrate a mortality benefit with the use of VA-ECMO in AMI-CS, with high rates of device-related complications. However, the outcome of these trials is nuanced by the limitations of each study that include small sample sizes, challenging patient selection, and high cross-over rates to the intervention group, and lack of use of left ventricular unloading strategies.

Conclusion

The presented literature of VA-ECMO in CS does not support its routine use in clinical practice. We have yet to identify which subset of patients would benefit most from this intervention. This review emphasizes the need for designing adequately powered trials to properly assess the role of VA-ECMO in AMI-CS, in order to build evidence for best practices.

Mortality prediction model from combined serial lactate, procalcitonin and calprotectin levels in critically ill patients with sepsis: A retrospective study according to Sepsis-3 definition

OBJECTIVE

1) To evaluate the ability of baseline and on 24 h serum calprotectin, in comparison to canonical biomarkers (lactate and procalcitonin), for prognosis of 28-day mortality in critically ill septic patients; and 2) To develop a predictive model combining the three biomarkers.

DESIGN

A single-center, retrospective study.

SETTING

Intensive Care Unit of a university hospital.

PATIENTS OR PARTICIPANTS

One hundred and seventy three septic pacientes were included.

INTERVENTIONS

Measurement of baseline lactate, procalcitonin and calprotectin level and procalcitonin and calprotectin levels on 24 h.

MAIN VARIABLES OF INTEREST

Demographics and comorbidities, SOFA score on ICU admission, baseline lactate, procalcitonin and calprotectin on admission and on 24 h and 28-day mortality.

RESULTS

1) On ICU admission, lactate was the only biomarker achieving a significant accuracy (AUC: 0.698); 2) On 24 h, no differences were found on procalcitonin and calprotectin levels. Procalcitonin and calprotectin clearances were significantly lower in non-survivors and both achieved a moderate performance (AUCs: 0.668 and 0.664, respectively); 3) A biomarker based-model achieved a significant accuracy (AUC: 0.766), trending to increase (AUC: 0.829) to SOFA score alone; y 4) Baseline lactate levels and procalcitonin and calprotectin clearance were independent predictors for the outcome.

CONCLUSIONS

1) Baseline and on 24 h calprotectina and procalcitonin levels lacked ability in predicting 28-day mortality; 2) Accuracy of clearance of both biomarkers was moderate; and 3) Combination of SOFA score and the predictive biomarker based-model showed a high prognostic accuracy.

The predictive value of serum lactate to forecast injury severity in trauma-patients increases taking age into account

BACKGROUND

Two-tier trauma team activation (TTA)-protocols often fail to safely identify severely injured patients. A possible amendment to existing triage scores could be the measurement of serum lactate. The aim of this study was to determine the ability of the combination of serum lactate and age to predict severe injuries (ISS > 15).

METHODS

We conducted a retrospective cohort study in a single level one trauma center in a 20 months study-period and analyzed every trauma team activation (TTA) due to the mechanism of injury (MOI). Primary endpoint was the correlation between serum lactate (and age) and ISS and mortality. The validity of lactate (LAC) and lactate contingent on age (LAC + AGE) were assessed using the area under the curve (AUC) of the receiver operating characteristics (ROC) curve. We used a logistic regression model to predict the probability of an ISS > 15.

RESULTS

During the study period we included 325 patients, 75 met exclusion criteria. Mean age was 43 years (Min.: 11, Max.: 90, SD: 18.7) with a mean ISS of 8.4 (SD: 8.99). LAC showed a sensitivity of 0.82 with a specificity of 0.62 with an optimal cutoff at 1.72 mmol/l to predict an ISS > 15. The AUC of the ROC for LAC was 0.764 (95% CI: 0.67-0.85). The LAC + AGE model provided a significantly improved predictive value compared to LAC (0.765 vs. 0.828, p < 0.001).

CONCLUSIONS

The serum lactate concentration is able to predict injury severity. The prognostic value improves significantly taking the patients age into consideration. The combination of serum lactate and age could be a suitable Ad-on to existing two-tier triage protocols to minimize undertriage.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

Association between prehospital ROX index with 30-day mortality among septic shock

PURPOSE

Respiratory dysfunction is one of the most frequent symptoms observed during sepsis reflecting hypoxemia and/or acidosis that may be assessed by the ROX index (ratio of oxygen saturation by pulse oximetry/fraction of inspired oxygen to respiratory rate). This study aimed to describe the relationship between the prehospital ROX index and 30-day mortality rate among septic shock patients cared for in the prehospital setting by a mobile intensive care unit (MICU).

METHODS

From May 2016 to December 2021, 530 septic shock patients cared for by a prehospital MICU were retrospectively analysed. Initial ROX index value was calculated at the first contact with MICU. A Cox regression analysis after propensity score matching was performed to assess the relationship between 30-day mortality rate and a ROX index ≤ 10.

RESULTS

Pulmonary, digestive and urinary sepsis were suspected among 43%, 25% and 17% patients, respectively. The 30-day overall mortality reached 31%. Cox regression analysis showed a significant association between 30-day mortality and a ROX index ≤ 10: adjusted hazard ratio of 1.54 [1.08-2.31], p < 0.05.

CONCLUSIONS

During the prehospital stage of septic shock patients cared for by a MICU, ROX index is significantly associated with 30-day mortality. A prehospital ROX ≤ 10 value is associated with a 1.5-fold 30-day mortality rate increase. Prospective studies are needed to confirm the ability of prehospital ROX to predict sepsis outcome since the prehospital setting.

Randomized comparison between a forced air system and warm water bath for resuscitation of neonatal hypothermic calves with or without oral administration of caffeine

BACKGROUND

Hypothermia is a cause of neonatal calf death in cold climates. Practical and effective rewarming methods are important for bovine health within affected regions.

HYPOTHESIS/OBJECTIVES

To compare the rewarming rate and blood analytes (glucose, lactate, and cortisol) of calves resuscitated with forced air with warm water bath, with or without oral administration of caffeine.

ANIMALS

Twenty healthy neonatal Holstein bull calves.

METHODS

In this randomized, prospective study, calves born healthy and without history of dystocia were cooled to 32°C rectal temperature then thermally resuscitated using either forced air rewarming or warm water bath (40°C) with or without oral administration of caffeine. Rectal temperatures were used to quantify recovery rate. Measurements of glucose, lactate, and cortisol were recorded for every 2°C change in rectal temperature.

RESULTS

Rectal temperature decline (0.03°C per minute) and total cooling time (191.0 ± 33.3 minutes) did not significantly differ among treatment groups. Calves were successfully resuscitated to 38°C by either method. Time required to euthermia using warm water was significantly faster (0.1°C per minute; 64.3 ± 17.8 minute; P < .05) than forced air (0.05°C per minute; 123.1 ± 20.0 minutes). Caffeine had no significant effect on resuscitation rate (P = .14; 95% CI, -0.002 to 0.024) in either treatment; however, caffeine was associated with reduced time to euthermia by 8.3 and 10.8 minutes, respectively. Changes in metabolic variables (glucose, lactate, and cortisol), were inversely related to rectal temperature with no statistical significance among rewarming methods.

CONCLUSIONS AND CLINICAL IMPORTANCE

Although warm water submersion is faster, forced air rewarming is an effective alternative for restoration of euthermia.

Effects of restrictive fluid therapy on the time to resolution of hyperlactatemia in ICU patients with septic shock. A secondary post hoc analysis of the CLASSIC randomized trial

PURPOSE

The aim of this study was to examine the effects of intravenous (IV) fluid restriction on time to resolution of hyperlactatemia in septic shock. Hyperlactatemia in sepsis is associated with worse outcome. Sepsis guidelines suggest targeting lactate clearance to guide fluid therapy despite the complexity of hyperlactatemia and the potential harm of fluid overload.

METHODS

We conducted a post hoc analysis of serial plasma lactate concentrations in a sub-cohort of 777 patients from the international multicenter clinical CLASSIC trial (restriction of intravenous fluids in intensive care unit (ICU) patients with septic shock). Adult ICU patients with septic shock had been randomized to restrictive (n = 385) or standard (n = 392) intravenous fluid therapy. The primary outcome, time to resolution of hyperlactatemia, was analyzed with a competing-risks regression model. Death and discharge were competing outcomes, and administrative censoring was imposed 72 h after randomization if hyperlactatemia persisted. The regression analysis was adjusted for the same stratification variables and covariates as in the original CLASSIC trial analysis.

RESULTS

The hazard ratios (HRs) for the cumulative probability of resolution of hyperlactatemia, in the restrictive vs the standard group, in the unadjusted analysis, with time split, were 0.94 (confidence interval (CI) 0.78-1.14) at day 1 and 1.21 (0.89-1.65) at day 2-3. The adjusted analyses were consistent with the unadjusted results.

CONCLUSION

In this post hoc retrospective analysis of a multicenter randomized controlled trial (RCT), a restrictive intravenous fluid strategy did not seem to affect the time to resolution of hyperlactatemia in adult ICU patients with septic shock.

Pulse pressure variation guided goal-direct fluid therapy decreases postoperative complications in elderly patients undergoing laparoscopic radical resection of colorectal cancer: a randomized controlled trial

OBJECTIVE

The use of goal-directed fluid therapy (GDFT) has been shown to reduce complications and improve prognosis in high-risk abdominal surgery patients. However, the utilization of pulse pressure variation (PPV) guided GDFT in laparoscopic surgery remains a subject of debate. We hypothesized that utilizing PPV guidance for GDFT would optimize short-term prognosis in elderly patients undergoing laparoscopic radical resection for colorectal cancer compared to conventional fluid therapy.

METHODS

Elderly patients undergoing laparoscopic radical resection of colorectal cancer were randomized to receive either PPV guided GDFT or conventional fluid therapy and explore whether PPV guided GDFT can optimize the short-term prognosis of elderly patients undergoing laparoscopic radical resection of colorectal cancer compared with conventional fluid therapy.

RESULTS

The incidence of complications was significantly lower in the PPV group compared to the control group (32.8% vs. 57.1%, P = .009). Additionally, the PPV group had a lower occurrence of gastrointestinal dysfunction (19.0% vs. 39.3%, P = .017) and postoperative pneumonia (8.6% vs. 23.2%, P = .033) than the control group.

CONCLUSION

Utilizing PPV as a monitoring index for GDFT can improve short-term prognosis in elderly patients undergoing laparoscopic radical resection of colorectal cancer.

REGISTRATION NUMBER

ChiCTR2300067361; date of registration: January 5, 2023.

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.

Real-Time Measurements of Oral Mucosal Carbon Dioxide (POMCO2) Reveals an Inverse Correlation With Blood Pressure in a Porcine Model of Coagulopathic Junctional Hemorrhage

INTRODUCTION

Shock states that occur during, for example, profound hemorrhage can cause global tissue hypoperfusion leading to organ failure. There is an unmet need for a reliable marker of tissue perfusion during hemorrhage that can be followed longitudinally. Herein, we investigated whether longitudinal POMCO2 tracks changes in hemodynamics in a swine model of coagulopathic uncontrolled junctional hemorrhage.

MATERIALS AND METHODS

Female Yorkshire-crossbreed swine (n = 7, 68.1 ± 0.7 kg) were anesthetized and instrumented for continuous measurement of mean arterial pressure (MAP). Coagulopathy was induced by the exchange of 50 to 60% of blood volume with 6% Hetastarch over 30 minutes to target a hematocrit of <15%. A 4.5-mm arteriotomy was made in the right common femoral artery with 30 seconds of free bleeding. POMCO2 was continuously measured from baseline through hemodilution, hemorrhage, and a subsequent 3-h intensive care unit period. Rotational thromboelastometry and blood gases were measured.

RESULTS

POMCO2 and MAP showed no significant changes during the hemodilution phase of the experiment, which produced coagulopathy evidenced by prolonged clot formation times. However, POMCO2 increased because of the uncontrolled hemorrhage by 11.3 ± 3.1 mmHg and was inversely correlated with the drop (17.9 ± 5.9 mmHg) in MAP (Y = -0.4122*X + 2.649, P = .02, r2 = 0.686). In contrast, lactate did not significantly correlate with the changes in MAP (P = .35) or POMCO2 (P = .37).

CONCLUSIONS

Despite the logical appeal of measuring noninvasive tissue CO2 measurement as a surrogate for gastrointestinal perfusion, prior studies have only reported snapshots of this readout. The present investigation shows real-time longitudinal measurement of POMCO2 to confirm that MAP inversely correlates to POMCO2 in the face of coagulopathy. The simplicity of measuring POMCO2 in real time can provide an additional practical option for military or civilian medics to monitor trends in hypoperfusion during hemorrhagic shock.

The Effectiveness of Prehospital Subcutaneous Continuous Lactate Monitoring in Adult Trauma: A Systematic Review

INTRODUCTION

Existing diagnostics for polytrauma patients continue to rely on non-invasive monitoring techniques with limited sensitivity and specificity for critically unwell patients. Lactate is a known diagnostic and prognostic marker used in infection and trauma and has been associated with mortality, need for surgery, and organ dysfunction. Point-of-care (POC) testing allows for the periodic assessment of lactate levels; however, there is an associated expense and equipment burden associated with repeated sampling, with limited feasibility in prehospital care. Subcutaneous lactate monitoring has the potential to provide a dynamic assessment of physiological lactate levels and utilize these trends to guide management and response to given treatments.

STUDY OBJECTIVE

The aim of this study was to appraise the current literature on dynamic subcutaneous continuous lactate monitoring (SCLM) in adult trauma patients and its use in lactate-guided therapy in the prehospital environment.

METHODS

The systematic review was conducted in accordance with the PRISMA guidelines and registered with PROSPERO. Searched databases included PubMed, EMBASE via Ovid SP, Cochrane Library, and Web of Science. Databases were searched from inception to March 29, 2022. Relevant manuscripts were further scrutinized for reference citations to interrogate the fullness of the adjacent literature.

RESULTS

Searches returned 600 studies, including 551 unique manuscripts. Following title and abstract screening, 14 manuscripts met the threshold for full-text sourcing. Subsequent to the scrutiny of all 14 manuscripts, none fully met the specified eligibility criteria. Following careful examination, no article was found to cover the exact area of scientific inquiry due to disparity in technological or environmental characteristics.

CONCLUSION

Little is known about the utility of dynamic subcutaneous lactate monitoring, and this review highlights a clear gap in current literature. Novel subcutaneous lactate monitors are in development, and the literature describing the prototype experimentation has been summarized. These studies demonstrate device accuracy, which shows a close correlation with venous lactate while providing dynamic readings without significant lag times. Their availability and cost remain barriers to implementation at present. This represents a clear target for future feasibility studies to be conducted into the clinical use of dynamic subcutaneous lactate monitoring in trauma and resuscitation.

Association of initial lactate levels and red blood cell transfusion strategy with outcomes after severe trauma: a post hoc analysis of the RESTRIC trial

BACKGROUND

The appropriateness of a restrictive transfusion strategy for those with active bleeding after traumatic injury remains uncertain. Given the association between tissue hypoxia and lactate levels, we hypothesized that the optimal transfusion strategy may differ based on lactate levels. This post hoc analysis of the RESTRIC trial sought to investigate the association between transfusion strategies and patient outcomes based on initial lactate levels.

METHODS

We performed a post hoc analysis of the RESTRIC trial, a cluster-randomized, crossover, non-inferiority multicenter trials, comparing a restrictive and liberal red blood cell transfusion strategy for adult trauma patients at risk of major bleeding. This was conducted during the initial phase of trauma resuscitation; from emergency department arrival up to 7 days after hospital admission or intensive care unit (ICU) discharge. Patients were grouped by lactate levels at emergency department arrival: low (< 2.5 mmol/L), middle (≥ 2.5 and < 4.0 mmol/L), and high (≥ 4.0 mmol/L). We compared 28 days mortality and ICU-free and ventilator-free days using multiple linear regression among groups.

RESULTS

Of the 422 RESTRIC trial participants, 396 were analyzed, with low (n = 131), middle (n = 113), and high (n = 152) lactate. Across all lactate groups, 28 days mortality was similar between strategies. However, in the low lactate group, the restrictive approach correlated with more ICU-free (β coefficient 3.16; 95% CI 0.45 to 5.86) and ventilator-free days (β coefficient 2.72; 95% CI 0.18 to 5.26) compared to the liberal strategy. These findings persisted even after excluding patients with severe traumatic brain injury.

CONCLUSIONS

Our results suggest that restrictive transfusion strategy might not have a significant impact on 28-day survival rates, regardless of lactate levels. However, the liberal transfusion strategy may lead to shorter ICU- and ventilator-free days for patients with low initial blood lactate levels.

Cardiac output monitoring in children: a review

Cardiac output monitoring enables physiology-directed management of critically ill children and aids in the early detection of clinical deterioration. Multiple invasive techniques have been developed and have demonstrated ability to improve clinical outcomes. However, all require invasive arterial or venous catheters, with associated risks of infection, thrombosis and vascular injury. Non-invasive monitoring of cardiac output and fluid responsiveness in infants and children is an active area of interest and several proven techniques are available. Novel non-invasive cardiac output monitors offer a promising alternative to echocardiography and have proven their ability to influence clinical practice. Assessment of perfusion remains a challenge; however, technologies such as near-infrared spectroscopy and photoplethysmography may prove valuable clinical adjuncts in the future.

Association of the type of metabolic acidosis and non-survival of horses with colitis

Background

Metabolic acidosis (MA) is the most common acid-base disorder reported in horses with colitis but its association with survival is yet to be determined.

Objective

Investigate the types of MA in horses with colitis to determine effects of various anions on fatality rates.

Animals and procedures

We studied 158 horses with colitis. Horses were classified into 4 groups depending on the anion contributing to MA: i) no MA, ii) lactic acidosis (LA), iii) unmeasured strong ion (USI) acidosis, and iv) hyperchloremic acidosis (HA).

Results

Sixty percent (95/158) of horses had no MA, 22% (34/158) had LA, 12% (19/158) had HA, and 6% (10/158) had USI acidosis. The fatality rate of horses without MA was 20% (20/95), whereas the rates for those with LA, USI, and HA were 53% (18/34), 30% (3/10), and 16% (3/19), respectively. Horses with LA were more likely to die or be euthanized than horses without MA (OR: 4.2, 95% CI: 1.83 to 9.72, P < 0.001) and HA (OR: 5.9, 95% CI: 1.47 to 24.4, P < 0.01).

Conclusion and clinical relevance

Lactic acidosis was the most common type of MA in horses with colitis, and it was associated with non-survival.

Biomarkers to predict mortality in patients with Fournier's gangrene admitted to the intensive care unit after surgery in South Korea

BACKGROUND

The use of biomarkers to predict patient outcomes may be crucial for patients admitted to the intensive care unit (ICU) following surgery because biomarkers guide clinicians in tailoring treatment plans accordingly. Therefore, we aimed to identify potential biomarkers to predict the prognosis of patients with Fournier's gangrene (FG) admitted to the ICU after surgery.

METHODS

We enrolled patients with FG admitted to our Hospital between January 2013 and December 2022. We retrospectively analyzed patient characteristics, factors related to management, scores known to be associated with the prognosis of FG, and laboratory data.

RESULTS

The study population included 28 survivors and 13 nonsurvivors. The initial serum lactate level taken in the emergency department; white blood cell, neutrophil, and platelet counts; delta neutrophil index and international normalized ratio; albumin, glucose, HCO3, and postoperative lactate levels; and the laboratory risk indicator for necrotizing fasciitis differed between survivors and nonsurvivors. Postoperative lactate and initial albumin levels were independent predictors of mortality in patients with FG. In the receiver operating characteristic curve analysis, the postoperative lactate level was the best indicator of mortality (area under the curve, 0.877; 95% confidence interval, 0.711-1.000). The optimal cutoff postoperative lactate level for predicting mortality was 3.0 mmol/L (sensitivity, 80.0%; specificity, 95.0%).

CONCLUSIONS

Postoperative lactate and initial albumin levels could be potential predictors of mortality in patients with FG admitted to the ICU after surgery, and the optimal cutoff postoperative lactate and initial albumin levels to predict mortality were 3.0 mmol/L and 3.05 g/dl, respectively. Large-scale multicenter prospective studies are required to confirm our results.

Prehospital pulse pressure and mortality of septic shock patients cared for by a mobile intensive care unit

BACKGROUND

Septic shock medical treatment relies on a bundle of care including antibiotic therapy and hemodynamic optimisation. Hemodynamic optimisation consists of fluid expansion and norepinephrine administration aiming to optimise cardiac output to reach a mean arterial pressure of 65mmHg. In the prehospital setting, direct cardiac output assessment is difficult because of the lack of invasive and non-invasive devices. This study aims to assess the relationship between 30-day mortality and (i) initial pulse pressure (iPP) as (ii) pulse pressure variation (dPP) during the prehospital stage among patients cared for SS by a prehospital mobile intensive care unit (MICU).

METHODS

From May 09th, 2016 to December 02nd, 2021, septic shock patients requiring MICU intervention were retrospectively analysed. iPP was calculated as the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP) at the first contact between the patient and the MICU team prior to any treatment and, dPP as the difference between the final PP (the difference between SBP and DBP at the end of the prehospital stage) and iPP divided by prehospital duration. To consider cofounders, the propensity score method was used to assess the relationship between (i) iPP < 40mmHg, (ii) positive dPP and 30-day mortality.

RESULTS

Among the 530 patients analysed, pulmonary, digestive, and urinary infections were suspected among 43%, 25% and 17% patients, respectively. The 30-day overall mortality rate reached 31%. Cox regression analysis showed an association between 30-day mortality and (i) iPP < 40mmHg; aHR of 1.61 [1.03-2.51], and (ii) a positive dPP; aHR of 0.56 [0.36-0.88].

CONCLUSION

The current study reports an association between 30-day mortality rate and iPP < 40mmHg and a positive dPP among septic shock patients cared for by a prehospital MICU. A negative dPP could be helpful to identify septic shock with higher risk of poor outcome despite prehospital hemodynamic optimization.

Peripheral immune cell death in sepsis based on bulk RNA and single-cell RNA sequencing

Background

Immune cell activation in early sepsis is beneficial to clear pathogens, but immune cell exhaustion during the inflammatory response induces immunosuppression in sepsis. Here, we studied the relationship between immune cell survival status and the prognosis of sepsis patients.

Methods

Sepsis patients admitted to our hospital with a diagnosis time of less than 24 h were recruited. RNA sequencing technologies were used to study functional alterations in various immune cells in peripheral blood mononuclear cells (PBMCs) from sepsis patients. Flow cytometry and electron microscopy were performed to study cell apoptosis and morphological alterations.

Results

A total of 68 sepsis patients with complete data were enrolled and divided into survival (45 patients) and death (23 patients) groups according to their prognosis. Patients in the death group had significantly increased lactic acid levels compared with those in the survival group, but there was no significant difference in other physiological and coagulation functional indicators between the two groups. Bulk RNA sequencing showed that cell death-related pathways and biomarkers were highly enriched and activated in the PBMCs of the death group than that in the survival group. Signs of mitochondrial damage, autophagosomes, cell surface damage and cell surface pore forming were also more pronounced in PBMCs from the death group under electron microscopy. Further single-cell RNA sequencing revealed that cell death occurred mainly in myeloid cells rather than lymphocytes at the early stage of sepsis; cell death patterns of destructive necrosis and pyroptosis were predominant in neutrophils, and apoptosis, autophagy and ferroptosis with less damage to the surroundings were predominant in monocytes.

Conclusion

Cell death mainly occurs in monocytes and neutrophils in the PBMCs of sepsis at the early stage. The study provides a perspective for the immunotherapy of early sepsis targeting immune cell death.

Distinct subsets of neutrophils crosstalk with cytokines and metabolites in patients with sepsis

Sepsis is a life-threatening condition caused by a dysregulated host response to infection. Despite continued efforts to understand the pathophysiology of sepsis, no effective therapies are currently available. While singular components of the aberrant immune response have been investigated, comprehensive studies linking different data layers are lacking. Using an integrated systems immunology approach, we evaluated neutrophil phenotypes and concomitant changes in cytokines and metabolites in patients with sepsis. Our findings identify differentially expressed mature and immature neutrophil subsets in patients with sepsis. These subsets correlate with various proteins, metabolites, and lipids, including pentraxin-3, angiopoietin-2, and lysophosphatidylcholines, in patients with sepsis. These results enabled the construction of a statistical model based on weighted multi-omics linear regression analysis for sepsis biomarker identification. These findings could help inform early patient stratification and treatment options, and facilitate further mechanistic studies targeting the trifecta of surface marker expression, cytokines, and metabolites.

THE INITIAL ION SHIFT INDEX AS A PROGNOSTIC INDICATOR TO PREDICT PATIENT SURVIVAL IN TRAUMATIC DAMAGE CONTROL LAPAROTOMY PATIENTS

ABSTRACT

Objective: The ion shift index (ISI), which considers extracellular fluid ions such as phosphate, calcium, and magnesium, represents the ion shift following ischemia; concentrations of these ions are maintained within narrow normal ranges by adenosine triphosphate-dependent homeostasis. The ISI is defined as follows: {potassium (mmol/L-1) + phosphate (mmol/L-1) + Mg (mmol/L-1)}/calcium (mmol/L-1). This study investigated the possibility of predicting the 30-day survival rate of patients who underwent traumatic damage control laparotomy by comparing ISI and other laboratory findings, as well as the initial Trauma and Injury Severity Score (TRISS) and shock indices. Methods: Among the 134 patients who underwent damage control surgery between November 2012 and December 2021, 115 patients were enrolled in this study. Data regarding injury mechanism, age, sex, laboratory findings, vital signs, Glasgow Coma Scale score, Injury Severity Score, Abbreviated Injury Scale score, blood component transfusion, type of surgery, postoperative laboratory outcomes, morbidity, mortality rates, fluids administered, and volume of transfusions were collected and analyzed. Results: In univariate analysis, the odds ratio of the initial ISI was 2.875 (95% confidence interval, 1.52-5.43; P = 0.04), which showed a higher correlation with mortality compared with other indices. The receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) were derived from different multivariable logistic regression models. The initial ISI had high sensitivity and specificity in predicting patient mortality (AUC, 0.7378). In addition, in the model combining the initial ISI, crystalloids, and TRISS, the AUC showed a high value (AUC, 0.8227). Conclusion: The ISI evaluated using electrolytes immediately after admission in patients undergoing traumatic damage control surgery may be a predictor of patient mortality.

Clinical parameter-guided initial resuscitation in adult patients with septic shock: A systematic review and network meta-analysis

Aim

To identify the most useful tissue perfusion parameter for initial resuscitation in sepsis/septic shock adults using a network meta-analysis.

Methods

We searched major databases until December 2022 for randomized trials comparing four tissue perfusion parameters or against usual care. The primary outcome was short-term mortality up to 90 days. The Confidence in Network Meta-Analysis web application was used to assess the quality of evidence.

Results

Seventeen trials were identified. Lactate-guided therapy (risk ratios, 0.59; 95% confidence intervals [0.45-0.76]; high certainty) and capillary refill time-guided therapy (risk ratios, 0.53; 95% confidence intervals [0.33-0.86]; high certainty) were significantly associated with lower short-term mortality compared with usual care, whereas central venous oxygen saturation-guided therapy (risk ratio, 1.50; 95% confidence intervals [1.16-1.94]; moderate certainty) increased the risk of short-term mortality compared with lactate-guided therapy.

Conclusions

Lactate or capillary refill time-guided initial resuscitation for sepsis/septic shock patients may decrease short-term mortality. More research is essential to personalize and optimize treatment strategies for septic shock resuscitation.

Postoperative Lactate Predicts In-Hospital Death in Patients with Acute Type A Aortic Dissection

Several studies have found that lactate correlates with surgical outcomes in patients with heart disease. However, the prognostic value of postoperative lactate in patients with acute type A aortic dissection (AAAD) remains unclear. This study aimed to investigate the relationship between postoperative lactate and in-hospital mortality in patients with AAAD. Patients who underwent AAAD surgery at Fujian Cardiac Medical Center from February 2020 to January 2022 were enrolled in this retrospective study. Correlations between in-hospital mortality and various parameters, including lactate, were investigated. A total of 357 patients were included in this study, 58 of which died. Multivariate logistic regression analysis revealed that body mass index (BMI) (odds ratio [OR] = 1.099, 95% confidence interval [CI]: 1.017-1.188, P = 0.017), cardiopulmonary bypass (CPB) time (OR = 1.005; 95% CI: 1.000-1.010, P = 0.039), and lactate (OR = 1.291, 95% CI: 1.182-1.409, P < 0.001) were independent risk factors for in-hospital mortality in AAAD patients. Receiver operating characteristic (ROC) curve analysis showed that lactate had a moderate power for in-hospital mortality (area under the curve [AUC] = 0.729, 95% CI: 0.647-0.810, P < 0.001). Furthermore, the combination of lactate, BMI, and CPB time showed better performance (AUC = 0.780; 95% CI: 0.706-0.854, P < 0.001) in predicting in-hospital mortality than in using these variables independently. Among patients undergoing AAAD surgery, postoperative lactate was significantly associated with in-hospital mortality. Lactate can be used as a potential predictor of in-hospital mortality. The combination of lactate, BMI, and CPB time showed better performance in predicting in-hospital mortality than using single one.

Trans- and Multigenerational Maternal Social Isolation Stress Programs the Blood Plasma Metabolome in the F3 Generation

Metabolic risk factors are among the most common causes of noncommunicable diseases, and stress critically contributes to metabolic risk. In particular, social isolation during pregnancy may represent a salient stressor that affects offspring metabolic health, with potentially adverse consequences for future generations. Here, we used proton nuclear magnetic resonance (¹H NMR) spectroscopy to analyze the blood plasma metabolomes of the third filial (F3) generation of rats born to lineages that experienced either transgenerational or multigenerational maternal social isolation stress. We show that maternal social isolation induces distinct and robust metabolic profiles in the blood plasma of adult F3 offspring, which are characterized by critical switches in energy metabolism, such as upregulated formate and creatine phosphate metabolisms and downregulated glucose metabolism. Both trans- and multigenerational stress altered plasma metabolomic profiles in adult offspring when compared to controls. Social isolation stress increasingly affected pathways involved in energy metabolism and protein biosynthesis, particularly in branched-chain amino acid synthesis, the tricarboxylic acid cycle (lactate, citrate), muscle performance (alanine, creatine phosphate), and immunoregulation (serine, threonine). Levels of creatine phosphate, leucine, and isoleucine were associated with changes in anxiety-like behaviours in open field exploration. The findings reveal the metabolic underpinnings of epigenetically heritable diseases and suggest that even remote maternal social stress may become a risk factor for metabolic diseases, such as diabetes, and adverse mental health outcomes. Metabolomic signatures of transgenerational stress may aid in the risk prediction and early diagnosis of non-communicable diseases in precision medicine approaches.

Mucormycosis, a post-COVID infection: possible adjunctive herbal therapeutics for the realigning of impaired immune-metabolism in diabetic subjects

Cytokine storm is believed as a major root cause for multi-organ failure and death in severely infected diabetic patients with COVID-19. This condition is treated with anti-inflammatory drugs, mainly steroids, to recover people from critical conditions. However, steroid therapy causes immune suppression and uncontrolled hyper-glycaemia in post-COVID. This altered immune-metabolism provides a fertile environment for the infection of a black fungus, Rhizopus arrhizus which causes mucormycosis in diabetic patients. It is a life-threatening infection causing death in different countries. It is treated either with anti-fungal drugs, surgical debridement, or adjunctive therapies. The available therapies for mucormycosis have been associated with several drawbacks. Thus, the present review has explored and suggested herbs-spices based adjunctive therapy for possible realignment of the impaired immune system in the post-COVID diabetic subjects. The consumption of herbal therapeutics after COVID-19 could realign the impaired immune-metabolism in the post-COVID and thereby exert prophylactic effects against mucormycosis. Furthermore, the suggested herbal sources could help in the discovery of novel therapeutics against the COVID-19 associated mucormycosis.

Association between prehospital shock index variation and 28-day mortality among patients with septic shock

PURPOSE

Septic shock (SS) hyperdynamic phase is characterized by tachycardia and low-blood pressure reflecting the relative hypovolemia. Shock index (SI), the ratio between heart rate and systolic blood pressure, is a simple objective tool, usable for SS prognosis assessment. This study aims to evaluate the relationship between prehospital SI variation and 28-day mortality of SS patients initially cared for in prehospital setting by a mobile intensive care unit (mICU).

METHODS

From April 6^th, 2016 to December 31^st, 2020, 406 patients with SS requiring prehospital mICU were retrospectively analyzed. Initial SI, i.e. first measurement after mICU arrival to the scene, and final SI, i.e. last measurement of the prehospital stage, were used to calculate delta SI (initial SI-final SI) and to define positive and negative delta SI. A survival analysis after propensity score matching compared the 28-day mortality of SS patients with positive/negative delta SI.

RESULTS

The main suspected origins of infection were pulmonary (42%), digestive (25%) and urinary (17%). The 28-day overall mortality reached 29%. Cox regression analysis revealed a significant association between 28-day mortality and delta SI. A negative delta SI was associated with an increase in mortality (adjusted hazard ratio (HRa) of 1.88 [1.07-3.31] (p = 0.03)), whereas a positive delta SI was associated with a mortality decrease (HRa = 0.53 [0.30-0.94] (p < 10^-3)).

CONCLUSION

Prehospital hemodynamic delta SI among SS patients cared for by a mICU is associated with 28-day mortality. A negative prehospital delta SI could help physicians to identify SS with higher risk of 28-day mortality.

Using Machine Learning to Develop and Validate an In-Hospital Mortality Prediction Model for Patients with Suspected Sepsis

Background: Early recognition of sepsis and the prediction of mortality in patients with infection are important. This multi-center, ED-based study aimed to develop and validate a 28-day mortality prediction model for patients with infection using various machine learning (ML) algorithms. Methods: Patients with acute infection requiring intravenous antibiotic treatment during the first 24 h of admission were prospectively recruited. Patient demographics, comorbidities, clinical signs and symptoms, laboratory test data, selected sepsis-related novel biomarkers, and 28-day mortality were collected and divided into training (70%) and testing (30%) datasets. Logistic regression and seven ML algorithms were used to develop the prediction models. The area under the receiver operating characteristic curve (AUROC) was used to compare different models. Results: A total of 555 patients were recruited with a full panel of biomarker tests. Among them, 18% fulfilled Sepsis-3 criteria, with a 28-day mortality rate of 8%. The wrapper algorithm selected 30 features, including disease severity scores, biochemical parameters, and conventional and few sepsis-related biomarkers. Random forest outperformed other ML models (AUROC: 0.96; 95% confidence interval: 0.93–0.98) and SOFA and early warning scores (AUROC: 0.64–0.84) in the prediction of 28-day mortality in patients with infection. Additionally, random forest remained the best-performing model, with an AUROC of 0.95 (95% CI: 0.91–0.98, p = 0.725) after removing five sepsis-related novel biomarkers. Conclusions: Our results demonstrated that ML models provide a more accurate prediction of 28-day mortality with an enhanced ability in dealing with multi-dimensional data than the logistic regression model.

An Evaluation of the Predictive Value of Sepsis Patient Evaluation in the Emergency Department (SPEED) Score in Estimating 28-Day Mortality Among Patients With Sepsis Presenting to the Emergency Department: A Prospective Observational Study

Background and objective

Sepsis is a life-threatening medical emergency and a significant cause of mortality. Risk stratification scores for sepsis can be unsuitable for use in the emergency department (ED) due to their complexity, and an appropriate solution has yet to be found. In this study, the predictive value of the Sepsis Patient Evaluation in the Emergency Department (SPEED) score in estimating 28-day mortality was assessed among patients with sepsis presenting to the ED, in order to determine its suitability as an efficient risk stratification system.

Materials and methods

This was a single-center, prospective observational study conducted at an urban tertiary care center. We included patients presenting to the ED with suspected or confirmed sepsis who met the inclusion and exclusion criteria of our study. The patients were evaluated with the following scoring systems on arrival: the SPEED score; Predisposition, Infection, Response, and Organ dysfunction (PIRO) score; and Mortality in Emergency Department Sepsis (MEDS) score; the patients were subsequently followed up on the 28th day to record the final outcomes with regard to mortality and discharge rates.

Results

This study included 127 patients in total. The median age of the study population was 49 years, and the 28-day mortality rate was 50.4%. The area under the receiver operating characteristic (AUROC) curve for the SPEED score for predicting mortality was 0.899 (95% CI: 0.847-0.951). In comparison, the AUROC for MEDS and PIRO scores was 0.857 (95% CI: 0.793-0.92) and 0.895 (95% CI: 0.838-0.951), respectively. Based on the DeLong test, no significant difference was found in the diagnostic performances with respect to these scores.

Conclusion

The SPEED score is a simple and handy parameter that can be used for the early and appropriate risk stratification of patients with sepsis in the ED.

Integration of Metabolomic and Clinical Data Improves the Prediction of Intensive Care Unit Length of Stay Following Major Traumatic Injury

Recent advances in emergency medicine and the co-ordinated delivery of trauma care mean more critically-injured patients now reach the hospital alive and survive life-saving operations. Indeed, between 2008 and 2017, the odds of surviving a major traumatic injury in the UK increased by nineteen percent. However, the improved survival rates of severely-injured patients have placed an increased burden on the healthcare system, with major trauma a common cause of intensive care unit (ICU) admissions that last ≥10 days. Improved understanding of the factors influencing patient outcomes is now urgently needed. We investigated the serum metabolomic profile of fifty-five major trauma patients across three post-injury phases: acute (days 0–4), intermediate (days 5–14) and late (days 15–112). Using ICU length of stay (LOS) as a clinical outcome, we aimed to determine whether the serum metabolome measured at days 0–4 post-injury for patients with an extended (≥10 days) ICU LOS differed from that of patients with a short (<10 days) ICU LOS. In addition, we investigated whether combining metabolomic profiles with clinical scoring systems would generate a variable that would identify patients with an extended ICU LOS with a greater degree of accuracy than models built on either variable alone. The number of metabolites unique to and shared across each time segment varied across acute, intermediate and late segments. A one-way ANOVA revealed the most variation in metabolite levels across the different time-points was for the metabolites lactate, glucose, anserine and 3-hydroxybutyrate. A total of eleven features were selected to differentiate between <10 days ICU LOS vs. >10 days ICU LOS. New Injury Severity Score (NISS), testosterone, and the metabolites cadaverine, urea, isoleucine, acetoacetate, dimethyl sulfone, syringate, creatinine, xylitol, and acetone form the integrated biomarker set. Using metabolic enrichment analysis, we found valine, leucine and isoleucine biosynthesis, glutathione metabolism, and glycine, serine and threonine metabolism were the top three pathways differentiating ICU LOS with a p < 0.05. A combined model of NISS and testosterone and all nine selected metabolites achieved an AUROC of 0.824. Differences exist in the serum metabolome of major trauma patients who subsequently experience a short or prolonged ICU LOS in the acute post-injury setting. Combining metabolomic data with anatomical scoring systems allowed us to discriminate between these two groups with a greater degree of accuracy than that of either variable alone.

Is Serum Lactate a Good Predictor of Mortality in Children Aged 2 Months to 5 Years With Pneumonia in Central Vietnam

Pneumonia is a major cause of morbidity and mortality in children globally. Lactate, a product of anaerobic cellular metabolism, has been used as an indicator of poor tissue oxygenation and cellular hypoxia. Our objective was to determine whether serum lactate concentration at hospital admission predicted mortality in children aged 2 months to 5 years with pneumonia. Two hundred and eighty-one pediatric patients admitted to the Department of Pediatrics of a provincial hospital with WHO-defined pneumonia and severe pneumonia were included; of whom, 8 died during hospital stay. The median serum lactate concentration was 4.8 mmol/l (IQR 2.6-6.9) among children who died and 3.6 mmol/l (IQR 2.8-4.3) among children who survived (P > .05); 4.1 mmol/l (IQR 2.7-4.7) among children with severe pneumonia and 3.5 mmol/l (IQR 2.8-4.3) among children with pneumonia (P > .05). Serum lactate concentration had a low value in predicting pneumonia-related mortality (AUC 0.68, 95% CI 0.62-0.73); and the concentration cut-off of >4.06 mmol/l had the best sensitivity and specificity (75% and 68.9%, respectively) with a 2.4-fold risk of death (LR+ 2.4; 95% CI 1.6-3.7). Although hyperlactatemia was associated with severity and mortality in children 2 months to 5 years of age with pneumonia, its benefit was unclear.

PcvCO2-PaCO2/CaO2-CcvO2 Ratio: The Holy Grail in Resuscitation!

How to cite this article: Abraham S. PcvCO2-PaCO2/CaO2-CcvO2 Ratio: The Holy Grail in Resuscitation! Indian J Crit Care Med 2021; 25(12):1337-1338.

Utilization and Efficacy of Resuscitation Endpoints in Trauma and Burn Patients: A Review Article

Shock is a sequelae in trauma and burn patients that substantially increases the risk for morbidity and mortality. The use of resuscitation endpoints allows for improved management of these patients, with the potential to prevent further morbidity/mortality. We conducted a review of the current literature on the efficacy of hemodynamic, metabolic, and regional resuscitation endpoints for use in trauma and burn patients. Hemodynamic endpoints included mean arterial pressure (MAP), heart rate (HR), urinary output (UO), compensatory reserve index (CRI), intrathoracic blood volume, and stroke volume variation (SVV). Metabolic endpoints measure cellular responses to decreased oxygen delivery and include serum lactic acid (LA), base deficit (BD), bicarbonate, anion gap, apparent strong ion difference, and serum pH. Mean arterial pressure, HR, UO, and LA are the most established markers of trauma and burn resuscitation. The evidence suggests LA is a superior metabolic endpoint marker. Newer resuscitation endpoint technologies such as point-of-care ultrasound (PoCUS), thromboelastography (TEG), and rotational thromboelastometry (ROTEM) may improve patient outcomes; however, additional research is needed to establish the efficacy in trauma and burn patients. The endpoints discussed have situational strengths and weaknesses and no single universal resuscitation endpoint has yet emerged. This review may increase knowledge and aid in guideline development. We recommend clinicians continue to integrate multiple endpoints with emphasis on MAP, HR, UO, LA, and BD. Future investigation should aim to standardize endpoints for each clinical presentation. The search for universal and novel resuscitation parameters in trauma and burns should also continue.

Elevated serum lactate levels and age are associated with an increased risk for severe injury in trauma team activation due to trauma mechanism

BACKGROUND

The identification of risk factors for severe injury is crucial in trauma triage and trauma team activation (TTA) depends on a sufficient triage. The aim of this study was to determine whether or not elevated serum lactate levels and age are risk factors for severe injury in TTA due to trauma mechanism.

METHODS

We conducted a retrospective cohort study in a single level one trauma center between September 2019 and May 2021 and analysed every TTA due to trauma mechanism. Primary endpoint of interest was the association of serum lactate as well as age with injury severity assessed by the injury severity score (ISS).

RESULTS

During the study period, we included 250 patients. Mean age was 43.3 years (Min.: 11, Max.: 90, SD: 18.7) and the initial lactate level was 1.7 mmol/L (SD: 0.95) with a mean ISS of 8.4 (SD: 8.99). The adjusted odds ratio (OR) for age > 65 being associated with an ISS > 16 is 9.7 (p < 0.001; 95% CI 4.01-25.58) and for lactate > 2.2 mmol/L being associated with an ISS > 16 is 6.29 (p < 0.001; 95% CI 2.93-13.48). A lactate level of > 4 mmol/L results in a 36-fold higher risk of severe injury with an ISS > 16 (OR 36.06; 95% CI 4-324.29).

CONCLUSION

This study identifies age (> 65) and lactate (> 2.2 mmol/L) as independent risk factors for severe injury in a TTA due to trauma mechanism. Existing triage protocols might benefit from congruous amendments.

3D localized lactate detection in muscle tissue using double-quantum filtered 1 H MRS with adiabatic refocusing pulses at 7 T

PURPOSE

Lactate is a key metabolite in skeletal muscle and whole-body physiology. Its MR visibility in muscle is affected by overlapping lipid signals and fiber orientation. Double-quantum filtered (DQF) ¹ H MRS selectively detects lactate at 1.3 ppm, but at ultra-high field the efficiency of slice-selective 3D-localization with conventional RF pulses is limited by bandwidth. This novel 3D-localized ¹ H DQF MRS sequence uses adiabatic refocusing pulses to unambiguously detect lactate in skeletal muscle at 7 T.

METHODS

Lactate double-quantum coherences were 3D-localized using slice-selective Shinnar-Le Roux optimized excitation and adiabatic refocusing pulses (similar to semi-LASER). DQF MR spectra were acquired at 7 T from lactate phantoms, meat specimens with injected lactate (exploring multiple TEs and fiber orientations), and human gastrocnemius in vivo during and after exercise (without cuff ischemia).

RESULTS

Lactate was readily detected, achieving the full potential of 50% signal with a DQF, in solution. The effects of fiber orientation and TE on the lactate doublet (peak splitting, amplitude, and phase) were in good agreement with theory and literature. Exercise-induced lactate accumulation was detected with 30 s time resolution.

CONCLUSION

This novel 3D-localized ¹ H DQF MRS sequence can dynamically detect glycolytically generated lactate in muscle during exercise and recovery at 7 T.

Calcium and lactate in the fetal-to-neonatal transition

OBJECTIVE

To explore the relationship between calcium and lactate in arterial cord blood of healthy term neonates in response to the stress of labor.

METHODS

This was a prospective cohort study of consecutive, vaginal, term births in a community medical center (April 2029 to February 2020). Calcium and lactate were measured in cord blood gas analysis immediately after delivery.

RESULTS

In the arterial cord blood of 480 neonates, calcium levels were 1.5 (1.4; 1.5) mmol/L and lactate levels were 3.8 (2.9; 4.9) mmol/L. Calcium and lactate showed a statistically significant positive correlation (Pearson's correlation, r = 0.15, p = .001). Calcium levels had a significant positive correlation with PaCO₂ and a significant negative correlation with pH, PaO₂, HCO₃^-, and ABE levels. Multivariable analysis models confirmed that calcium levels were associated with HCO₃^-, gestational age, and birth weight, all accounting for 7% of the variability.

CONCLUSION

In healthy term vaginally delivered neonates, it was found that calcium and lactate were strongly correlated, together pointing to a neonatal response to the stress of labor and delivery. Cord blood calcium regulation may have an ancillary role in defining neonatal adaptation to extrauterine life.

Can Lactate Clearance Predict Mortality in Critically Ill Children?

Serial evaluation of blood lactate, including lactate clearance, may have greater value over single measurement at the time of presentation. The rationale of the current study was to evaluate the use of lactate clearance after 6 hours of admission to pediatric intensive care unit (PICU) as a predictor of mortality in critically ill children. A prospective observational study was conducted in a nine-bed PICU of a tertiary care teaching hospital over a period of 6 months. Lactate levels were measured in arterial blood samples of 76 patients at the time of admission and 6 hours later. According to calculated lactate clearance, patients were divided into group A (lactate clearance more than 0) which included 71% of patients and group B (lactate clearance ≤0) which included 29% of patients. Lactate level at admission was a poor predictor of mortality (area under receiver operating characteristic curve [AUC] = 0.519, p = 0.789). Lactate clearance after 6 hours of admission was a significant predictor of mortality (AUC = 0.766, p < 0.001). Using Kaplan–Meier survival curve, overall survival was significantly better among group A (p < 0.001). Using multivariate logistic regression model, lactate clearance after 6 hours (odds ratio = 0.98, 95% confidence interval [CI]: 0.96–0.99) and The Pediatric Index of Mortality 2 (PIM2) score (odds ratio = 4.7, 95% CI: 1.85–12.28) had independent prognostic significance as regard to mortality (p = 0.030, 0.001 respectively). We conclude that lactate clearance after 6 hours of admission can predict mortality in critically ill children.

Classification of the Gut Microbiota of Patients in Intensive Care Units During Development of Sepsis and Septic Shock

The gut microbiota of intensive care unit (ICU) patients displays extreme dysbiosis associated with increased susceptibility to organ failure, sepsis, and septic shock. However, such dysbiosis is difficult to characterize owing to the high dimensional complexity of the gut microbiota. We tested whether the concept of enterotype can be applied to the gut microbiota of ICU patients to describe the dysbiosis. We collected 131 fecal samples from 64 ICU patients diagnosed with sepsis or septic shock and performed 16S rRNA gene sequencing to dissect their gut microbiota compositions. During the development of sepsis or septic shock and during various medical treatments, the ICU patients always exhibited two dysbiotic microbiota patterns, or ICU-enterotypes, which could not be explained by host properties such as age, sex, and body mass index, or external stressors such as infection site and antibiotic use. ICU-enterotype I (ICU E1) comprised predominantly Bacteroides and an unclassified genus of Enterobacteriaceae, while ICU-enterotype II (ICU E2) comprised predominantly Enterococcus. Among more critically ill patients with Acute Physiology and Chronic Health Evaluation II (APACHE II) scores > 18, septic shock was more likely to occur with ICU E1 (P = 0.041). Additionally, ICU E1 was correlated with high serum lactate levels (P = 0.007). Therefore, different patterns of dysbiosis were correlated with different clinical outcomes, suggesting that ICU-enterotypes should be diagnosed as independent clinical indices. Thus, the microbial-based human index classifier we propose is precise and effective for timely monitoring of ICU-enterotypes of individual patients. This work is a first step toward precision medicine for septic patients based on their gut microbiota profiles.

Differences in Tolerance to Hypoxia: Physiological, Biochemical, and Molecular-Biological Characteristics

Hypoxia plays an important role in the development of many infectious, inflammatory, and tumor diseases. The predisposition to such disorders is mostly provided by differences in basic tolerance to oxygen deficiency, which we discuss in this review. Except the direct exposure of different-severity hypoxia in decompression chambers or in highland conditions, there are no alternative methods for determining organism tolerance. Due to the variability of the detection methods, differences in many parameters between tolerant and susceptible organisms are still not well-characterized, but some of them can serve as biomarkers of susceptibility to hypoxia. At the moment, several potential biomarkers in conditions after hypoxic exposure have been identified both in experimental animals and humans. The main potential biomarkers are Hypoxia-Inducible Factor (HIF)-1, Heat-Shock Protein 70 (HSP70), and NO. Due to the different mechanisms of various high-altitude diseases, biomarkers may not be highly specific and universal. Therefore, it is extremely important to conduct research on hypoxia susceptibility biomarkers. Moreover, it is important to develop a method for the evaluation of organisms' basic hypoxia tolerance without the necessity of any oxygen deficiency exposure. This can contribute to new personalized medicine approaches' development for diagnostics and the treatment of inflammatory and tumor diseases, taking into account hypoxia tolerance differences.

Is lactate lower in septic patients who are prescribed beta blockers? Retrospective cohort study of an intensive care population

OBJECTIVE

Elevated serum lactate has long been considered an important marker of sepsis severity. Increasing evidence supports catecholamine-stimulated aerobic glycolysis being a major contributor to the hyperlactataemia seen in sepsis. Beta-blockade may blunt such catecholamine mediated rise in lactate analogous to the way it can mask tachycardia. This could impact the way we evaluate sepsis severity and adequacy of initial treatment. The objective of this study is to investigate whether septic patients who were on beta-blocker treatment at presentation have lower serum lactate level.

METHODS

Using a retrospective cohort design we gathered data on patients admitted to our base hospital intensive care unit with APACHE III diagnosis of sepsis and septic shock during the 2017 calendar year. Serum lactate, current medications, presenting vital signs, illness severity scores, laboratory data and mortality outcome were extracted from patients' medical record and the unit's clinical database.

RESULTS

Of 189 records analysed, 49 patients were concurrently prescribed beta-blockers. More beta-blocked patients were male, beta-blocked patients were older, and a greater proportion of beta blocked patients had their first lactate measured as an inpatient. After regression to correct for identified significant covariates mean serum lactate was 0.87 (95% confidence interval 0.05-1.69) mmol/L lower in those prescribed beta blockers.

CONCLUSIONS

In our cohort pre-existing beta blocker treatment was associated with lower serum lactate measurements in patients presenting with sepsis. Pre-existing beta blocker treatment may reduce serum lactate at presentation in patients with sepsis.

Lactate and lactate clearance in critically burned patients: usefulness and limitations as a resuscitation guide and as a prognostic factor

OBJECTIVE

Lactate levels to guide resuscitation in critically burned patients are controversial. The purpose of our study was to determine whether absolute lactate values or lower lactate clearance predict mortality, and whether these are useful tools in the resuscitation phase.

METHODS

We conducted a prospective, unicentric, observational study of a cohort of 214 burn patients admitted in the Burn Intensive Care Unit. We collected demographic and laboratory data, complications, absolute lactate levels and lactate clearance every 8 h since admission to 72 h. In critical patients we monitored hemodynamic parameters with transpulmonary thermodilution. We used Student's t-test or nonparametric tests, mixed models and Pearson and Spearman methods, Fisher's exact and chi-squared test.

RESULTS

Of the 214 patients, 76.6% were male, mean age were 46 ± 15 years and 23.0 ± 19.5% of Total Basal Surface Area (TBSA) burned. Initial mean absolute levels of lactate were 2.02 ± 1.62 mmol/L in survivors vs. 4.05 ± 3.90 mmol/L in nonsurvivors. Initial elevated lactate levels increased mortality (p < .001), length of ICU stay, mechanical ventilation and shock. In the subgroup of burned TBSA < 20%, lowering the lactate cut-off point from 2.0 to 1.8 mmol/L improved the mortality prediction (OR:9.3). We found no relationship between lactate clearance in the first 24 h and mortality. In more severe patients (> 20% TBSA burned and initial lactate levels > 2), a good correlation was found between lactate and cardiac index; but not with intrathoracic blood volume index (ITBVI). Patients with low ITBVI preload (< 600 mL/m²) did not show significant differences in lactate clearance compared with those with ITBVI > 600.

CONCLUSIONS

Initial elevated lactate levels are a factor of poor prognosis and the cut-off point that best predicts mortality should be adjusted in the patients with TBSA burned < 20%. The global clearance of lactate in the first 24 h, unlike what occurs in other injuries, does not correlate with mortality. Monitoring lactate can ensure adequate peripheral perfusion during resuscitation with lower than normal fluid preload values.

The rise of bio-inspired polymer compartments responding to pathology-related signals

Self-organized nano- and microscale polymer compartments such as polymersomes, giant unilamellar vesicles (GUVs), polyion complex vesicles (PICsomes) and layer-by-layer (LbL) capsules have increasing potential in many sensing applications. Besides modifying the physicochemical properties of the corresponding polymer building blocks, the versatility of these compartments can be markedly expanded by biomolecules that endow the nanomaterials with specific molecular and cellular functions. In this review, we focus on polymer-based compartments that preserve their structure, and highlight the key role they play in the field of medical diagnostics: first, the self-assembling abilities that result in preferred architectures are presented for a broad range of polymers. In the following, we describe different strategies for sensing disease-related signals (pH-change, reductive conditions, and presence of ions or biomolecules) by polymer compartments that exhibit stimuli-responsiveness. In particular, we distinguish between the stimulus-sensitivity contributed by the polymer itself or by additional compounds embedded in the compartments in different sensing systems. We then address necessary properties of sensing polymeric compartments, such as the enhancement of their stability and biocompatibility, or the targeting ability, that open up new perspectives for diagnostic applications.

Central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio as an indicator of tissue oxygenation: a narrative review

The central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio (Pcv-aCO2/Ca-cvO2) has been proposed as a surrogate for respiratory quotient and an indicator of tissue oxygenation. Some small observational studies have found that a Pcv-aCO2/Ca-cvO2 > 1.4 was associated with hyperlactatemia, oxygen supply dependency, and increased mortality. Moreover, Pcv-aCO2/Ca-cvO2 has been incorporated into algorithms for tissue oxygenation evaluation and resuscitation. However, the evidence for these recommendations is quite limited and of low quality. The goal of this narrative review was to analyze the methodological bases, the pathophysiologic foundations, and the experimental and clinical evidence supporting the use of Pcv-aCO2/Ca-cvO2 as a surrogate for respiratory quotient. Physiologically, the increase in respiratory quotient secondary to critical reductions in oxygen transport is a life-threatening and dramatic event. Nevertheless, this event is easily noticeable and probably does not require further monitoring. Since the beginning of anaerobic metabolism is indicated by the sudden increase in respiratory quotient and the normal range of respiratory quotient is wide, the use of a defined cutoff of 1.4 for Pcv-aCO2/Ca-cvO2 is meaningless. Experimental studies have shown that Pcv-aCO2/Ca-cvO2 is more dependent on factors that modify the dissociation of carbon dioxide from hemoglobin than on respiratory quotient and that respiratory quotient and Pcv-aCO2/Ca-cvO2 may have distinct behaviors. Studies performed in critically ill patients have shown controversial results regarding the ability of Pcv-aCO2/Ca-cvO2 to predict outcome, hyperlactatemia, microvascular abnormalities, and oxygen supply dependency. A randomized controlled trial also showed that Pcv-aCO2/Ca-cvO2 is useless as a goal of resuscitation. Pcv-aCO2/Ca-cvO2 should be carefully interpreted in critically ill patients.

Early antituberculosis drug exposure in hospitalized patients with human immunodeficiency virus-associated tuberculosis

AIMS

Patients hospitalized at the time of human immunodeficiency virus-associated tuberculosis (HIV-TB) diagnosis have high early mortality. We hypothesized that compared to outpatients, there would be lower anti-TB drug exposure in hospitalized HIV-TB patients, and amongst hospitalized patients exposure would be lower in patients who die or have high lactate (a sepsis marker).

METHODS

We performed pharmacokinetic sampling in hospitalized HIV-TB patients and outpatients. Plasma rifampicin, isoniazid and pyrazinamide concentrations were measured in samples collected predose and at 1, 2.5, 4, 6 and 8 hours on the third day of standard anti-TB therapy. Twelve-week mortality was ascertained for inpatients. Noncompartmental pharmacokinetic analysis was performed.

RESULTS

Pharmacokinetic data were collected in 59 hospitalized HIV-TB patients and 48 outpatients. Inpatient 12-week mortality was 11/59 (19%). Rifampicin, isoniazid and pyrazinamide exposure was similar between hospitalized and outpatients (maximum concentration [C_max ]: 7.4 vs 8.3 μg mL^-1 , P = .223; 3.6 vs 3.5 μg mL^-1 , P = .569; 50.1 vs 46.8 μg mL^-1 , P = .081; area under the concentration-time curve from 0 to 8 hours: 41.0 vs 43.8 mg h L^-1 , P = 0.290; 13.5 vs 12.4 mg h L^-1 , P = .630; 316.5 vs 292.2 mg h L^-1 , P = .164, respectively) and not lower in inpatients who died. Rifampicin and isoniazid C_max were below recommended ranges in 61% and 39% of inpatients and 44% and 35% of outpatients. Rifampicin exposure was higher in patients with lactate >2.2 mmol L^-1 .

CONCLUSION

Mortality in hospitalized HIV-TB patients was high. Early anti-TB drug exposure was similar to outpatients and not lower in inpatients who died. Rifampicin and isoniazid C_max were suboptimal in 61% and 39% of inpatients and rifampicin exposure was higher in patients with high lactate. Treatment strategies need to be optimized to improve survival.

Determinants of prehospital lactate in trauma patients: a retrospective cohort study

Background

Point of care serum lactate measurement is emerging as an adjunct to prehospital clinical assessment and has the potential to guide triage and advanced treatment decision-making. In this study we aimed to assess which factors potentially affect prehospital lactate levels.

Methods

We performed a retrospective cohort study of all trauma patients attended by the Air Ambulance, Kent, Surrey & Sussex (AAKSS) between July 2017 and April 2018 in whom a pre-hospital lactate was measured. Lactate was measured before AAKSS treatments were commenced, but generally after prehospital treatment by ground ambulance crews was initiated. Primary endpoint of interest was the association of various patient- and treatment characteristics with prehospital lactate levels.

Results

During the study period, lactate was measured in 156 trauma patients. Median lactate was 3.0 [2.0–4.1] mmol/l. Patients with an elevated lactate more often had deranged indices of end organ perfusion- and oxygenation (shock index 0.80 [0.58–1.03] vs 0.61 [0.40–0.82], p < 0.001, SpO₂ 96 [89–100%] vs 98 [96–100%], p = 0.025). They more often suffered from head injuries (62% vs 41%, p = 0.008), and received less analgesia prior to arrival of the AAKSS team (51.6% vs 67.2%, p = 0.03). In multivariate analysis, indices of end organ perfusion- and oxygenation only explained 15% of the variation in lactate levels.

Conclusions

Prehospital lactate levels are not solely associated with indices of end organ perfusion- and oxygenation. Injury type, treatments given on scene and many other (unmeasured) factors likely play an important role as well. This should be taken into account when lactate is used in clinical algorithms to guide prehospital triage or treatment.

Role of Biomarkers in the Prediction of Serious Adverse Events after Syncope in Prehospital Assessment: A Multi-Center Observational Study

Syncope is defined as the nontraumatic, transient loss of awareness of rapid onset, short duration and with complete spontaneous recovery, and accounts for 1%–3% of all visits to the emergency department. The objective of this study was to evaluate the predictive capacity of the National Early Warning Score 2 (NEWS2) and prehospital lactate (pLA), individually and combined, at the prehospital level to detect patients with syncope at risk of early mortality (within 48 h) in the hospital environment. A prospective, multicenter cohort study without intervention was carried out on syncope patients aged over 18 who were given advanced life support and taken to the hospital. Our study included a total of 361 cases. Early mortality affected 21 patients (5.8%). The combined score formed by the NEWS2 and the pLA (NEWS2-L) obtained an AUC of 0.948 (95% CI: 0.88–1) and an odds ratio of 86.25 (95% CI: 11.36–645.57), which is significantly higher than that obtained by the NEWS2 or pLA in isolation (p = 0.018). The NEWS2-L can help stratify the risk in patients with syncope treated in the prehospital setting, with only the standard measurement of physiological parameters and pLA.

Differences in the Clinical and Hematological Characteristics of COVID-19 Patients with and without Type 2 Diabetes

OBJECTIVE

To examine whether comorbidity with type 2 diabetes (T2D) affects the clinical and hematological parameters of coronavirus disease 2019 (COVID-19) patients.

METHODS

We retrospectively investigated the clinical, imaging, and laboratory characteristics of patients with confirmed COVID-19 who were hospitalized from January 30, 2020 to March 17, 2020, at the Renmin Hospital of Wuhan University. A detailed clinical record was kept for each subject, including the medical history of COVID-19 and physical and laboratory examinations. A total of 164 subjects were eligible for the study, among which 40 patients were comorbid with T2D. Further analysis was conducted in two subcohorts of sex- and age-matched patients with and without T2D to identify hematological and biochemical differences. The laboratory tests, including routine blood tests, serum biochemistry, and coagulation function, were performed upon admission.

RESULTS

The two groups showed no significant differences in baseline parameters, including age, sex, chest X-ray, or computed tomography (CT) findings, upon admission. However, patients with T2D showed an increased incidence of diarrhea. T2D patients required more recovery time from pneumonia, as shown by follow-up CT findings, which might contribute to the prolonged hospitalization. Comorbidity with T2D also increased risk of secondary bacterial infection during COVID-19. The T2D group had significantly higher white blood cell and neutrophil counts compared with the nondiabetic group, but T2D patients suffered from more severe lymphocytopenia and inflammation (P < 0.05). Most biochemical parameters showed no significant differences between the two groups (P > 0.05). However, patients with T2D seemed to have a significantly higher risk of developing hyperlactatemia, hyponatremia, and hypocalcemia.

CONCLUSIONS

COVID-19 patients comorbid with T2D demonstrated distinguishing clinical features and hematological parameters during the infection. It is necessary to develop a different clinical severity scoring system for COVID-19 patients with T2D. This study may provide helpful clues for the assessment and management of COVID-19 in T2D patients.