Evolutive standard base excess and serum lactate level in severe sepsis and septic shock patients resuscitated with early goal-directed therapy: still outcome markers?

Clinical features and risk factors analysis for poor outcomes of severe community-acquired pneumonia in children: a nomogram prediction model

Background

Pneumonia remains the leading cause of death among children aged 1-59 months. The early prediction of poor outcomes (PO) is of critical concern. This study aimed to explore the risk factors relating to PO in severe community-acquired pneumonia (SCAP) and build a PO-predictive nomogram model for children with SCAP.

Methods

We retrospectively identified 300 Chinese pediatric patients diagnosed with SCAP who were hospitalized in the Affiliated Hospital of Southwest Medical University from August 1, 2018, to October 31, 2021. Children were divided into the PO and the non-PO groups. The occurrence of PO was designated as the dependent variable. Univariate and multivariate logistic regression analyses were used to identify the risk factors of PO. A nomogram model was constructed from the multivariate logistic regression analysis and internally validated for model discrimination and calibration. The performance of the nomogram was estimated using the concordance index (C-index).

Results

According to the efficacy evaluation criteria, 56 of 300 children demonstrated PO. The multivariate logistic regression analysis resulted in the following independent risk factors for PO: co-morbidity (OR: 8.032, 95% CI: 3.556-18.140, P < 0.0001), requiring invasive mechanical ventilation (IMV) (OR: 7.081, 95% CI: 2.250-22.282, P = 0.001), and ALB < 35 g/L (OR: 3.203, 95% CI: 1.151-8.912, P = 0.026). Results of the internal validation confirmed that the model provided good discrimination (concordance index [C-index], 0.876 [95% CI: 0.828-0.925]). The calibration plots in the nomogram model were of high quality.

Conclusion

The nomogram facilitated accurate prediction of PO in children diagnosed with SCAP and could be helpful for clinical decision-making.

Correlation of the Changing Trends of ScvO2, Serum Lactate, Standard Base Excess and Anion Gap in Patients with Severe Sepsis and Septic Shock Managed by Early Goal Directed Therapy (EGDT): A Prospective Observational Study

BACKGROUND

To observe the correlation of central venous oxygen saturation (ScvO₂), serum lactate, standard base excess (SBE), and anion gap (AG) in septic and septic shock patients resuscitated with early goal-directed therapy (EGDT).

MATERIALS AND METHODS

A review was made of 130 severe septic shock patients (15-65 years) according to the consensus conference criteria admitted in intensive care unit. Blood samples were obtained from arterial and central venous line for ScvO_2, serum lactate, SBE, and AG on admission and after achieving all aims of EGDT i.e.; mean arterial pressure >65 mmHg, central venous pressure = 8-12 mmHg, ScvO₂ >70%, and urine output >0.5 mL.kg^-1.h^-1, and on 12 and 24 h. The statistical analysis was done using SPSS for windows version 16 software. For comparison, Pearson test was used. A P < 0.05 was considered as statistically significant.

RESULTS

There were a positive correlation between ScvO₂ and SBE, a negative correlation between ScvO₂ and AG, a negative correlation between ScvO₂ and lactate, a negative correlation between SBE and AG, a negative correlation between AG and lactate, and a negative correlation between SBE and lactate. The ScvO₂ was initially low but was in an improving trend after a resuscitative period, SBE was initially low and correction of SBE was linear. AG was high in the beginning and goes on decreasing after resuscitation. Lactate level was also high initially and in decreasing trend after a resuscitative period.

CONCLUSIONS

ScvO₂ and SBE are correlated and can be used as a surrogate marker. ScvO₂ and AG are related but not absolutely codependent. ScvO₂ and lactate are correlated but they are not absolutely codependent. SBE and AG are correlated and can be used as a surrogate marker. AG and lactate are not related to each other. Hence, AG cannot be considered as a surrogate for lactate testing. SBE and lactate are related and can be used as a surrogate marker.

Methylene Blue to Neonatal Septic Shock treatment in neonate pigs. Clinics (Sao Paulo) 2022;77:100139. [PMID: 36459779 PMCID: PMC9706526 DOI: 10.1016/j.clinsp.2022.100139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

OBJECTIVE

The authors design an animal model of neonatal sepsis to analyze the treatment of neonatal septic shock with Methylene Blue (MB) in a swine model.

METHODS

The study design included twenty male newborn pigs divided into four groups: 1) The control group; 2) The sepsis group (induced with lipopolysaccharide); 3) The MB group, and 4) The MB-treated sepsis group. Septic shock was defined as Blood Pressure (BP) dropping 20% below the baseline value. Continuous Blood Pressure (BP), Nitric Oxide (NO) levels, cyclic Guanosine Monophosphate (cGMP), malondialdehyde acid, base excess, lactate, arterial blood gases, hematocrit, and echocardiography were analyzed.

RESULTS

The BP of the sepsis group treated with MB showed a slight improvement in the first hour after treatment; however, a significant difference was not observed compared to the untreated sepsis group. Besides hemodynamic stability, the current study did not show symptomatic pulmonary hypertension, suggesting that MB was safe in neonates and children. An improvement in Base Excel (BE) levels after MB administration in septic animals may indicate a possible improvement in microcirculation.

CONCLUSION

The MB improved biomarkers related to septic shock prognosis, although an improvement in the blood levels could not be detected. MB might be a beneficial drug for hemodynamic instability in infants.

Higher Acid-Base Imbalance Associated with Respiratory Failure Could Decrease the Survival of Patients with Scrub Typhus during Intensive Care Unit Stay: A Gene Set Enrichment Analysis

Ninety percent of patients with scrub typhus (SC) with vasculitis-like syndrome recover after mild symptoms; however, 10% can suffer serious complications, such as acute respiratory failure (ARF) and admission to the intensive care unit (ICU). Predictors for the progression of SC have not yet been established, and conventional scoring systems for ICU patients are insufficient to predict severity. We aimed to identify simple and robust indicators to predict aggressive behaviors of SC. We evaluated 91 patients with SC and 81 non-SC patients who were admitted to the ICU, and 32 cases from the public functional genomics data repository for gene expression analysis. We analyzed the relationships between several predictors and clinicopathological characteristics in patients with SC. We performed gene set enrichment analysis (GSEA) to identify SC-specific gene sets. The acid-base imbalance (ABI), measured 24 h before serious complications, was higher in patients with SC than in non-SC patients. A high ABI was associated with an increased incidence of ARF, leading to mechanical ventilation and worse survival. GSEA revealed that SC correlated to gene sets reflecting inflammation/apoptotic response and airway inflammation. ABI can be used to indicate ARF in patients with SC and assist with early detection.

Can Base Excess be Used for Prediction to Early Diagnosis of Neonatal Sepsis in Preterm Newborns?

Background

Neonatal sepsis remains an important and potentially life-threatening clinical syndrome and a major cause of neonatal mortality and morbidity. The aim of this study to investigate whether values of base excess before the onset of clinical signs and symptoms of sepsis indicate infection in the early diagnosis of neonatal sepsis.

Methods

In this study, a total of 118 infants were enrolled. The infants were classified into two groups: group 1 (sepsis, n=49) and group 2 (control, n=69). Blood gas analysis investigated for the screening of neonatal sepsis.

Results

A total of 49 newborns with neonatal sepsis and 69 healthy controls were enrolled. Comparison of markers of sepsis revealed C-reactive protein, interleukin-6 level to be significantly higher and pH, pCO₂, HCO_3, and base excess values to be significantly lower in newborns with sepsis compared healthy controls (p<0.01). The optimum cut-off value in the diagnosis of neonatal sepsis was found to be -5 mmol/L for base excess. Sensitivity, specificity, positive predictive value and negative predictive value of this base excess cut-off for neonatal sepsis were 75, 91, 86 and 84% respectively.

Conclusion

This is the first study to determine the relationship between the decreased value of the base excess and early stage of neonatal sepsis. If the value of base excess <-5 mmol/L without an underlying another reason, may need close follow up of infants for neonatal sepsis and it may help early diagnosis.

Prognostic Value of Arterial Blood Gas Indices Regarding the Severity of Traumatic Injury and Fractures of the Femur and Pelvis

Objective:

To evaluate the prognostic value of arterial blood gas (ABG) indices, especially base excess (BE), regarding the severity of traumatic injury.

Methods:

A total number of 96 trauma patients with fractures of femur and pelvis were included in this study. Demographic characteristics and clinical information of samples were recorded. The results of ABG test and hemoglobin (Hb) were evaluated at two time intervals (on admission and 6 hours later). The outcome of the patients was evaluated at the end of the study (dead or alive). The ABG indices included O2 saturation (O2Sat), PH, PO2, PCO2, bicarbonate (HCO3) and base excess (BE). The mean of the hemodynamic and ABG indices were compared between those who were discharged and mortality cases. The confounders were compensated using a multivariate logistic regression model.

Results:

Overall 94 trauma patients with long and pelvic fractures were included. There were 69 (73.4%) men and 25 (26.6%) women among the patients with mean age of 37.43 ± 20.07 years. The mortality rate was 10 (10.6%). The most common mechanism of injury was motorcycle accident in 41 (43.6%) and car collision in 43 (45.7%) patients. We found that mortality was significantly associated with amount of FFP transfusion (p=0.005), but was not associated with amount of transfused packed cells (p=0.113). We also found that mortality was associated with lower BP after 6 hours of admission (p=0.001), higher HR on admission (p=0.036), lower HR after 6 hours (p=0.017), lower O2Sat on admission (p<0.001), higher PCO2 after 6 hours and lower BE on admission (p=0.025).    

Conclusion:

The ABG indices including O2Sat, BE and PCO2 are considered prognostic determinants of outcome in trauma patients with long and pelvic fractures. These findings can be considered as fundamental studies to achieve new diagnostic methods.  

Respiratory gas exchange as a new aid to monitor acidosis in endotoxemic rats: relationship to metabolic fuel substrates and thermometabolic responses

This study introduces the respiratory exchange ratio (RER; the ratio of whole‐body CO₂ production to O₂ consumption) as an aid to monitor metabolic acidosis during the early phase of endotoxic shock in unanesthetized, freely moving rats. Two serotypes of lipopolysaccharide (lipopolysaccharide [LPS] O55:B5 and O127:B8) were tested at shock‐inducing doses (0.5–2 mg/kg). Phasic rises in RER were observed consistently across LPS serotypes and doses. The RER rise often exceeded the ceiling of the quotient for oxidative metabolism, and was mirrored by depletion of arterial bicarbonate and decreases in pH. It occurred independently of ventilatory adjustments. These data indicate that the rise in RER results from a nonmetabolic CO₂ load produced via an acid‐induced equilibrium shift in the bicarbonate buffer. Having validated this new experimental aid, we asked whether acidosis was interconnected with the metabolic and thermal responses that accompany endotoxic shock in unanesthetized rats. Contrary to this hypothesis, however, acidosis persisted regardless of whether the ambient temperature favored or prevented downregulation of mitochondrial oxidation and regulated hypothermia. We then asked whether the substrate that fuels aerobic metabolism could be a relevant factor in LPS‐induced acidosis. Food deprivation was employed to divert metabolism away from glucose oxidation and toward fatty acid oxidation. Interestingly, this intervention attenuated the RER response to LPS by 58%, without suppressing other key aspects of systemic inflammation. We conclude that acid production in unanesthetized rats with endotoxic shock results from a phasic activation of glycolysis, which occurs independently of physiological changes in mitochondrial oxidation and body temperature.

Frequency and outcomes of severe hyperlactatemia after elective cardiac surgery

BACKGROUND

Hyperlactatemia is relatively common in the cardiac surgical patient and is usually considered a marker of illness severity. The frequency and impact of severe hyperlactatemia after elective cardiac surgery has not been described, and prognosis may be different compared with that for other surgical or medical critically ill patient populations.

METHODS

We conducted a retrospective study to evaluate the hospital course and outcomes of patients who developed severe postoperative hyperlactatemia (SPHL; lactate >10 mmol/L) after elective cardiac surgery, from January 1, 2008 to December 31, 2012, at a large, academic, tertiary referral center.

RESULTS

Of 9580 cardiac surgical patients who met inclusion criteria, 121 (1.26%) developed SPHL. The most common cause was cardiogenic shock (53.8%). In-hospital mortality was 40.5% but varied widely based on the cause of the SPHL. All patients with definite mesenteric ischemia (n = 5) or extremity compartment syndrome (n = 6) at the time of SPHL died in the hospital. Forty patients (33.1%) were discharged to home, whereas 32 (26.4%) were discharge to a skilled-care facility.

CONCLUSIONS

Severe postoperative hyperlactatemia is rare after elective cardiac surgery. Although this phenomenon continues to be associated with mortality, >50% of patients survived to hospital discharge, a more favorable prognosis, compared with other patient populations based on lactate levels alone. Important exceptions were patients who had extremity compartment syndrome or mesenteric ischemia, which were associated with in-hospital death in all cases. In all other etiologic groups, a substantial proportion of patients were discharged to home.

Effect of Hypotensive Resuscitation with a Novel Combination of Fluids in a Rabbit Model of Uncontrolled Hemorrhagic Shock

Objective

The aim of this study was to compare the effects of hypotensive and normotensive resuscitation with a novel combination of fluids via lactate Ringer’s solution (LRS), 6% hydroxyethyl starch 130/0.4 solution (HES), and 7.5% hypertonic saline solution (HSS) at early stage of uncontrolled hemorrhagic shock (UHS) before hemostasis.

Methods

New Zealand white rabbits (n = 32) underwent UHS by transecting the splenic parenchyma, followed by blood withdrawal via the femoral artery to target mean arterial pressure (MAP) of 40–45 mmHg. Animals were distributed randomly into 4 groups (n = 8): in group Sham, sham operation was performed; in group HS, UHS was untreated; in group HS-HR, UHS was treated by hypotensive resuscitation with HSS and LRS+HES (ratio of 2∶1) to MAP of 50–55 mmHg; in group HS-NR, UHS was treated by normotensive resuscitation with HSS and LRS+HES (ratio of 2∶1) to MAP of 75–80 mmHg. Outcomes of hemodynamics, inflammatory and oxidative response, and other metabolic variables were measured and the histopathological studies of heart, lung and kidney were performed at the end of resusucitation.

Results

Hypotensive resuscitation with the novel combination of fluids for UHS rabbits decreased blood loss, maintained better stabilization of hemodynamics, and resulted in relatively higher hematocrit and platelet count, superior outcomes of blood gas, and lower plasma lactate concentration. Besides, hypotensive resuscitation attenuated the inflammatory and oxidative response significantly in UHS rabbits.

Conclusion

Hypotensive resuscitation with the novel combination of fluids via HSS and LRS+HES (ratio of 2∶1) has an effective treatment at early stage of UHS before hemostasis.

Factors related to post-operative metabolic acidosis following major abdominal surgery

BACKGROUND

Metabolic acidosis is frequently observed in perioperative patients, especially those who undergo major surgery. The aim of this study was to evaluate the factors related to post-operative metabolic acidosis and to attempt to identify the clinical effect of metabolic acidosis following major abdominal surgery.

METHODS

We included 172 patients admitted to a surgical intensive care unit (ICU) following major abdominal surgery. All cases were divided into either the acidosis or the normal group using immediate post-operative standard base excess (SBE). The following clinical data were retrospectively obtained from the chart and ICU database: basic clinical characteristics, operative data, type and volume of fluid infused during the operation, post-operative arterial blood gas analysis, lactate, and central venous oxygen saturation.

RESULTS

The predominant intraoperative fluid was either 0.9% saline or lactated Ringer's solution. The operation length, estimated blood loss, total fluid infused, total saline infused, lactate and corrected chloride were significantly higher in the acidosis group; however, central venous oxygen saturation was lower in the normal group. Among these factors, total infused saline and lactate level were independent factors related to metabolic acidosis. The comparison between the types of fluid revealed that the saline group had a significantly lower SBE, strong ion difference and higher corrected chloride. SBE was significantly correlated with lactate and total infused saline. ICU and hospital length of stay were significantly longer in the acidosis group.

CONCLUSIONS

Post-operative metabolic acidosis following major abdominal surgery was closely related to both hyperchloremic acidosis associated with large saline infusion and lactic acidosis caused by lactataemia.

Does lactate measurement performed on admission predict clinical outcome on the intensive care unit? A concise systematic review

Background

There is a need for practical, efficient and effective prognostic markers for patients admitted to the intensive care unit (ICU) with sepsis, to identify patients at highest risk and guide and monitor treatment. Although many biomarkers and scoring systems have been advocated, none have yet achieved this elusive combination. Most ICUs already use blood lactate concentrations to monitor patients but the evidence base for this application is unclear.

Methods

A systematic review of the last five years of evidence of effectiveness of lactate measurement in prediction of outcome in ICUs was performed.

Results

It was found that there is a lack of high-quality evidence, and no specific studies of prognostic accuracy. d- or l-Lactate concentrations measured in plasma, serum, whole blood or colonic washings were raised at admission in almost all patient groups, and were higher in patient groups who had the worst outcomes (in-hospital mortality, sequential organ failure). However, there was significant overlap in individual concentrations measured in those who died within 28 days of admission, or who developed multiple organ failure, and those who did not. For serum l-lactate concentrations, no specific cut-off value capable of predicting in-hospital mortality or sequential organ failure could be recommended.

Conclusions

The evidence reviewed suggested that whole blood, plasma or serum lactate measurement could not provide specific prognostic information for individual patients. There may be a role for monitoring for normalization of serum d- or l-lactate concentrations during goal-directed therapy in the ICU but further good-quality studies are needed. Measurement of the d-lactate stereoisomer shows promise, such that further studies are warranted.

Failure to reduce C-reactive protein levels more than 25% in the last 24 hours before intensive care unit discharge predicts higher in-hospital mortality: a cohort study

PURPOSE

To discharge a patient from the intensive care unit (ICU) is a complex decision-making process because in-hospital mortality after critical illness may be as high as up to 27%. Static C-reactive protein (CRP) values have been previously evaluated as a predictor of post-ICU mortality with conflicting results. Therefore, we evaluated the CRP ratio in the last 24 hours before ICU discharge as a predictor of in-hospital outcomes.

METHODS

A retrospective cohort study was performed in 409 patients from a 6-bed ICU of a university hospital. Data were prospectively collected during a 4-year period. Only patients discharged alive from the ICU with at least 72 hours of ICU length of stay were evaluated.

RESULTS

In-hospital mortality was 18.3% (75/409). Patients with reduction less than 25% in CRP concentrations at 24 hours as compared with 48 hours before ICU discharge had a worse prognosis, with increased mortality (23% vs 11%, P = .002) and post-ICU length of stay (26 [7-43] vs 11 [5-27] days, P = .036). Moreover, among hospital survivors (n = 334), patients with CRP reduction less than 25% were discharged later (hazard ratio, 0.750; 95% confidence interval, 0.602-0.935; P = .011).

CONCLUSIONS

In this large cohort of critically ill patients, failure to reduce CRP values more than 25% in the last 24 hours of ICU stay is a strong predictor of worse in-hospital outcomes.

Goal-directed therapy in small animal critical illness

Monitoring critically ill patients can be a daunting task even for experienced clinicians. Goal-directed therapy is a technique involving intensive monitoring and aggressive management of hemodynamics in patients with high risk of morbidity and mortality. The aim of goal-directed therapy is to ensure adequate tissue oxygenation and survival. This article reviews commonly used diagnostics in critical care medicine and what the information gathered signifies and discusses clinical decision making on the basis of diagnostic test results. One example is early goal-directed therapy for severe sepsis and septic shock. The components and application of goals in early goal-directed therapy are discussed.

Lactate and base deficit are predictors of mortality in critically ill patients with cancer

OBJECTIVE

Cancer patients frequently require admission to intensive care unit. However, there are a few data regarding predictive factors for mortality in this group of patients. The aim of this study was to evaluate whether arterial lactate or standard base deficit on admission and after 24 hours can predict mortality for patients with cancer.

METHODS

We evaluated 1,129 patients with severe sepsis, septic shock, or postoperative after high-risk surgery. Lactate and standard base deficit collected at admission and after 24 hours were compared between survivors and non-survivors. We evaluated whether these perfusion markers are independent predictors of mortality.

RESULTS

There were 854 hospital survivors (76.5%). 24 h lactate > 1.9 mmol/L and standard base deficit < -2.3 were independent predictors of intensive care unit mortality. 24 h lactate >1.9 mmol/L and 24 h standard base deficit < -2.3 mmol/Lwere independent predictors of hospital death.

CONCLUSION

Our findings suggest that lactate and standard base deficit measurement should be included in the routine assessment of patients with cancer admitted to the intensive care unit with sepsis, septic shock or after high-risk surgery. These markers may be useful in the adequate allocation of resources in this population.

Hemodynamic and perfusion end points for volemic resuscitation in sepsis

Sepsis is the systemic inflammatory response syndrome secondary to a local infection, and severe sepsis and septic shock are the more devastating scenarios of this disease. In the last decade, considerable achievements were obtained in sepsis knowledge, and an international campaign was developed to improve the treatment of this condition. However, sepsis is still one of the most important causes of death in intensive care units. The early stages of sepsis are characterized by a variety of hemodynamic derangements that induce a systemic imbalance between tissue oxygen supply and demand, leading to global tissue hypoxia. This dysfunction, which may occur in patients presenting normal vital signs, can be accompanied by a significant increase in both morbidity and mortality. The early identification of high-risk sepsis patients through tissue perfusion markers such as lactate and venous oxygen saturation is crucial for prompt initiation of therapeutic support, which includes early goal-directed therapy as necessary. The purpose of this article was to review the most commonly used hemodynamic and perfusion parameters for hemodynamic optimization in sepsis, emphasizing the physiological background for their use and the studies that demonstrated their effectiveness as goals of volemic resuscitation.

The role of serum lactate in the acute care setting

Acute care services are increasingly faced with the double burden of high patient acuity and limited resources. Early identification of patients who are sick or who have the potential to deteriorate rapidly is crucial so that these resources may be allocated to those in greatest need. Traditional measures of illness and end points of resuscitation, such as vital signs, often fail to identify occult hypoperfusion with certain disease processes associated with high morbidity and mortality. Thus, biochemical markers that may predict illness earlier are becoming more relevant. We present a review of the evidence behind use of the serum lactate level in this setting.

Relative hyperlactatemia and hospital mortality in critically ill patients: a retrospective multi-centre study

Introduction

Higher lactate concentrations within the normal reference range (relative hyperlactatemia) are not considered clinically significant. We tested the hypothesis that relative hyperlactatemia is independently associated with an increased risk of hospital death.

Methods

This observational study examined a prospectively obtained intensive care database of 7,155 consecutive critically ill patients admitted to the Intensive Care Units (ICUs) of four Australian university hospitals. We assessed the relationship between ICU admission lactate, maximal lactate and time-weighted lactate levels and hospital outcome in all patients and also in those patients whose lactate concentrations (admission n = 3,964, maximal n = 2,511, and time-weighted n = 4,584) were under 2 mmol.L^-1 (i.e. relative hyperlactatemia).

Results

We obtained 172,723 lactate measurements. Higher admission and time-weightedlactate concentration within the reference range was independently associated with increased hospital mortality (admission odds ratio (OR) 2.1, 95% confidence interval (CI) 1.3 to 3.5, P = 0.01; time-weighted OR 3.7, 95% CI 1.9 to 7.00, P < 0.0001). This significant association was first detectable at lactate concentrations > 0.75 mmol.L^-1. Furthermore, in patients whose lactate ever exceeded 2 mmol.L^-1, higher time-weighted lactate remained strongly associated with higher hospital mortality (OR 4.8, 95% CI 1.8 to 12.4, P < 0.001).

Conclusions

In critically ill patients, relative hyperlactataemia is independently associated with increased hospital mortality. Blood lactate concentrations > 0.75 mmol.L^-1 can be used by clinicians to identify patients at higher risk of death. The current reference range for lactate in the critically ill may need to be re-assessed.

Effect of PaCO2 variation on standard base excess value in critically ill patients

PURPOSE

The aim of this study was to investigate the impact of acute Paco(2) temporal variation on the standard base excess (SBE) value in critically ill patients.

METHODS

A total of 265 patients were prospectively observed; 158 were allocated to the modeling group, and 107 were allocated to the validation group. Two models were developed in the modeling group (one including and one excluding Paco(2) as a variable determinant of SBE), and both were tested in the validation group.

RESULTS

In the modeling group, the mathematical model including SIDai, SIG, l-lactate, albumin, phosphate, and Paco(2) had a predictive superiority in comparison with the model without Paco(2) (R(2) = 0.978 and 0.916, respectively). In the validation group, the results were confirmed with significant F change statistics (R(2) change = 0.059, P < .001) between the model with and without Paco(2). A high correlation (R = 0.99, P < .001) and agreement (bias = -0.25 mEq/L, limits of agreement 95% = -0.72 to 0.22 mEq/L) were found between the model-predicted SBE value and the SBE calculated using the Van Slyke equation.

CONCLUSIONS

Acute Paco(2) temporal variation is related to SBE changes in critically ill patients.

Differences in acid-base behavior between intensive care unit survivors and nonsurvivors using both a physicochemical and a standard base excess approach: a prospective, observational study

PURPOSE

This study aimed to test the hypothesis that intensive care unit survivors and nonsurvivors differ with regard to type and severity of acid-base disorders.

MATERIALS AND METHODS

Prospective, observational, cohort study of 107 consecutive patients admitted in a 7-bed intensive care unit during a 6-month period that stayed at least 4 days. All acid-base variables for the first 3 days and the day of discharge were analyzed.

RESULTS

Survivors had significant metabolic acidosis upon admission, which was due to hyperlactatemia, an excess of unmeasured anions, and principally, hyperchloremia. A progressive decrease in these anions in the presence of constant hypoalbuminemia led to normal standard base excess at discharge. Nonsurvivors had greater metabolic acidosis upon admission with acidifying variables in similar proportions to that of the survivors. On the day of death, nonsurvivors had a similar degree of metabolic acidosis but a different proportion of the anions (less chloride and more lactate) compared with the day of admission. Unmeasured anions were greater in nonsurvivors both on the day of admission and on the day of death.

CONCLUSIONS

Intensive care unit survivors and nonsurvivors differed in the severity of metabolic acidosis; however, the proportion of the different anions causing the acidosis on admission was similar between these 2 groups.

Epidemiology of severe sepsis in the emergency department and difficulties in the initial assistance

BACKGROUND

The aim of this study was to determine the occurrence rate, demographics, clinical characteristics, and outcomes of patients with severe sepsis admitted to the emergency department.

METHODS

A prospective study evaluating all patients admitted to the emergency department unit in a public hospital of tertiary complexity in a six-month period was conducted. During this period, the emergency team was trained to diagnose sepsis. Patients who met the diagnostic criteria for severe sepsis were followed until their discharge from the hospital.

RESULTS

A total of 5,332 patients were admitted to the emergency department, and 342 met the criteria for severe sepsis/septic shock. The median (interquartile range) age of patients was 74 (65-84) years, and 52.1% were male. The median APACHE II and SOFA scores at diagnosis were 19 (15-25) and 5 (3-7), respectively. The median number of dysfunctional organ systems per patient was 2 (1-3). The median hospital length of stay was 10 (4.7-17) days, and the hospital mortality rate was 64%. Only 31% of the patients were diagnosed by the emergency department team as septic. About 33.5% of the 342 severe sepsis patients admitted to the emergency department were referred to an ICU, with a median time delay of 24 (12-48) hours. Training improved diagnosis and decreased the time delay for septic patients in arriving at the ICU.

CONCLUSIONS

The occurrence rate of severe sepsis in the emergency department was 6.4%, and the rate of sepsis diagnosed by the emergency department team as well as the number of patients transferred to the ICU was very low. Educational campaigns are important to improve diagnosis and, hence, treatment of severe sepsis.

Effects of early changes in organ dysfunctions on the outcomes of critically ill patients in need of renal replacement therapy

INTRODUCTION

Acute kidney injury usually develops in critically ill patients in the context of multiple organ dysfunctions.

OBJECTIVE

To evaluate the effect of changes in associated organ dysfunctions over the first three days of renal replacement therapy on the outcomes of patients with acute kidney injury.

METHODS

Over a 19-month period, we evaluated 260 patients admitted to the intensive care units of three tertiary-care hospitals who required renal replacement therapy for > 48 h. Organ dysfunctions were evaluated by SOFA score (excluding renal points) on the first (D1) and third (D3) days of renal replacement therapy. Absolute (A-SOFA) and relative (Delta-SOFA) changes in SOFA scores were also calculated.

RESULTS

Hospital mortality rate was 75%. Organ dysfunctions worsened (A-SOFA>0) in 53%, remained unchanged (A-SOFA=0) in 17% and improved (A-SOFA<0) in 30% of patients; and mortality was lower in the last group (80% vs. 84% vs. 61%, p=0.003). SOFA on D1 (p<0.001), SOFA on D3 (p<0.001), A-SOFA (p=0.019) and Delta-SOFA (p=0.016) were higher in non-survivors. However, neither A-SOFA nor Delta-SOFA discriminated survivors from non-survivors on an individual basis. Adjusting for other covariates (including SOFA on D1), A-SOFA and Delta-SOFA were associated with increased mortality, and patients in whom SOFA scores worsened or remained unchanged had poorer outcomes.

CONCLUSIONS

In addition to baseline values, early changes in SOFA score after the start of renal replacement therapy were associated with hospital mortality. However, no prognostic score should be used as the only parameter to predict individual outcomes.

Sepsis: from bench to bedside

Sepsis is a syndrome related to severe infections. It is defined as the systemic host response to microorganisms in previously sterile tissues and is characterized by end-organ dysfunction away from the primary site of infection. The normal host response to infection is complex and aims to identify and control pathogen invasion, as well as to start immediate tissue repair. Both the cellular and humoral immune systems are activated, giving rise to both anti-inflammatory and proinflammatory responses. The chain of events that leads to sepsis is derived from the exacerbation of these mechanisms, promoting massive liberation of mediators and the progression of multiple organ dysfunction. Despite increasing knowledge about the pathophysiological pathways and processes involved in sepsis, morbidity and mortality remain unacceptably high. A large number of immunomodulatory agents have been studied in experimental and clinical settings in an attempt to find an efficacious anti-inflammatory drug that reduces mortality. Even though preclinical results had been promising, the vast majority of these trials actually showed little success in reducing the overwhelmingly high mortality rate of septic shock patients as compared with that of other critically ill intensive care unit patients. Clinical management usually begins with prompt recognition, determination of the probable infection site, early administration of antibiotics, and resuscitation protocols based on "early-goal" directed therapy. In this review, we address the research efforts that have been targeting risk factor identification, including genetics, pathophysiological mechanisms and strategies to recognize and treat these patients as early as possible.

Characterization of an animal model of severe sepsis associated with respiratory dysfunction

PURPOSE

Pathophysiological studies in humans regarding sepsis are difficult to perform due to ethical and methodological concerns. In this context, animal models of sepsis can be useful to better understand this condition and to test therapeutic strategies. The purpose of this study was to characterize a feasible and clinically relevant model of sepsis in pigs that could be useful for testing different therapeutic interventions.

METHODS

5 White Large pigs were anesthetized, arterial and pulmonary catheters were introduced, and sepsis was induced by fecal peritonitis. Several biochemical indicators of organ dysfunction and infectious parameters were measured. The pigs were monitored until death, when fragments of organs were removed for pathology. Three animals without peritonitis served as controls and were sacrificed 24 hours after surgery without developing significant changes in organ function.

RESULTS

Septic pigs survived 17 hours on average (range, 16-18 h), and Escherichia coli was recovered from blood cultures. They developed a significant decrease in left ventricular work and a nonsignificant reduction in mixed venous oxygen saturation. Respiratory dysfunction was characterized by a decrease in the PaO2/FiO2 ratio and respiratory compliance. Pathology of the lungs revealed areas of pulmonary collapse, hemorrhage, pulmonary congestion, and discrete neutrophil infiltrate.

CONCLUSIONS

Fecal peritonitis in pigs is a clinically relevant model of sepsis associated with acute lung injury without direct pulmonary insult. This model may prove to be useful for studying pathogenic aspects of secondary lung injury as well as for validating ventilatory or pharmacologic interventions.

Noninvasive Hemodynamic Monitoring in the Intensive Care Unit

This article reviews the clinically available devices that have been approved for noninvasive hemodynamic monitoring in critically ill patients. In addition this article reviews some of the surrogate markers that can be used to assess adequacy of cardiac output.