Transfusion requirements in septic shock (TRISS) trial - comparing the effects and safety of liberal versus restrictive red blood cell transfusion in septic shock patients in the ICU: protocol for a randomised controlled trial

Jehovah's Witness Needing Critical Care: A Narrative Review on the Expanding Arsenal

Present day Jehovah's Witness (JW) religion accounts for 8.5 million followers. A tenant feature of the JW faith is religious objection to transfusions of blood and blood products. Interpatient variability, as it pertains to blood and blood products may occur; hence, a confidential interview will determine which products individual may consent to (Marsh and Bevan, 2002). This belief and practice place great restrictions on treating medical professionals in scenarios of life-threatening anaemia and active haemorrhage. The review to follow explores the physiological and pathophysiological consequences of severe anaemia. Non-blood transfusion practices are explored, many of which are potentially lifesaving. Particular attention is drawn to the evolving science involving artificial oxygen carriers and their use in emergency situations. A greater safety profile ensures its future use amongst religious objectors to be greatly beneficial. Intravenous iron supplementation has enjoyed a lively debate within the critical care community. A review of recent systematic and meta-analysis supports its use in the ICU; however, more investigation is needed into the complementary use of hepcidin.

Appropriateness of Allogeneic Red Blood Cell Transfusions in Non-Bleeding Patients in a Large Teaching Hospital: A Retrospective Study

In hemodynamically stable patients, both anemia and red blood cell (RBC) transfusion may be detrimental to patients; hence, a decision regarding RBC transfusion should be based on thorough risk-benefit assessment. According to hematology and transfusion medicine organizations, RBC transfusion is indicated when recommended hemoglobin (Hb) triggers are met, and symptoms of anemia are present. The aim of our study was to examine the appropriateness of RBC transfusions in non-bleeding patients at our institution. We performed a retrospective analysis of all RBC transfusions performed between January 2022 and July 2022. The appropriateness of RBC transfusion was based on the most recent Association for the Advancement of Blood and Biotherapies (AABB) guidelines and some additional criteria. The overall incidence of RBC transfusions at our institution was 10.2 per 1000 patient-days. There were 216 (26.1%) RBC units appropriately transfused and 612 (73.9%) RBC units that were transfused with no clear indications. The incidence of appropriate and inappropriate RBC transfusions were 2.6 and 7.5 per 1000 patient-days, respectively. The most frequent clinical situations when RBC transfusion was classified as appropriate were: Hb < 70 g/L plus cognitive problems/headache/dizziness (10.1%), Hb < 60 g/L (5.4%), and Hb < 70 g/L plus dyspnea despite oxygen therapy (4.3%). The most frequent causes of inappropriate RBC transfusions were: no Hb determination pre-RBC transfusion (n = 317) and, among these, RBC transfused as a second unit in a single-transfusion episode (n = 260); absence of anemia sings/symptoms pre-transfusion (n = 179); and Hb concentration ≥80 g/L (n = 80). Although the incidence of RBC transfusions in non-bleeding inpatients in our study was generally low, the majority of RBC transfusions were performed outside recommended indications. Red blood cell transfusions were evaluated as inappropriate mainly due to multiple-unit transfusion episodes, absence of anemia signs and/or symptoms pre- transfusion, and liberal transfusion triggers. There is still the need to educate physicians on appropriate indications for RBC transfusion in non-bleeding patients.

Racial differences in red blood cell transfusion in hospitalized patients with anemia

BACKGROUND

Guidelines recommend transfusion of red blood cells (RBC's) when a hospitalized patient's hemoglobin (Hb) drops below a restrictive transfusion threshold, either at 7 or 8 g. Hospitals have implemented transfusion policies to encourage compliance with guidelines and reduce variation in transfusion practice. However, variation in transfusion practice remains. The purpose of this study was to examine whether there is variation in the receipt of transfusion by patient race.

METHODS

Hospitalized general medicine patients with anemia (Hb < 10 g/dL) were eligible. Chi-squared tests were used to compare the percent of patients receiving a transfusion by race overall and within strata of their nadir Hb. Linear regression was used to test the association between a patient's race, their nadir Hb, receipt of an RBC transfusion, and the number of units transfused.

RESULTS

Four thousand nine hundred and fifty-one patients consented, including 1363 (28%) who received a transfusion. 71% of patients were African American, 25% were White, and 4% were Other Race. Overall African Americans were less likely to be transfused compared to Whites (25% vs. 30%, p < .01), and within Hb strata below a Nadir Hb of 9 g/dL (Hb 8.0-8.9 g/dL 1% vs. 7%, p < .01; 7.0-7.9 g/dL 15% vs. 28%, p < .01; <7 g/dL 80% vs. 86%, p < .01). African Americans also received fewer units of RBC's (β = -.17, p < .01) overall and at lower Hb levels (β = .14, p < .01) compared to Whites.

DISCUSSION

The Hb level at which patients are transfused at and the total number of RBC units received during hospitalization differ by patient race.

Effects of simulated sample sizes on the mortality effect estimates in three randomized intensive care unit trials

BACKGROUND

Randomized clinical trials (RCTs) are occasionally stopped prematurely before reaching their planned sample sizes. It has been suggested that early stopped RCTs are associated with under- and overestimation of the effect estimates. We simulated the effect of hypothetical premature stopping of three large RCTs done in the intensive care unit (ICU) setting.

METHODS

In this post hoc study, we simulated the impact of stopping trials early by calculating mortality effect estimates continuously after the inclusion of each individual patient in three large RCTs, that is the 6S trial on hydroxyethyl starch vs Ringer's acetate in sepsis in ICU, the TRISS trial on lower vs higher haemoglobin threshold for transfusion in septic shock in ICU and the SUP-ICU trial on pantoprazole in patients at risk for gastrointestinal bleeding in the ICU.

RESULTS

The three trials included a total of 5087 patients; 798 from the 6S trial, 998 from the TRISS trial and 3291 patients from the SUP-ICU trial. The premature mortality effect estimates showed considerable fluctuations until at least 20%-30% of the sample size was included. The premature estimates became stable after inclusion of 205 patients (26% of the final sample size) in the 6S trial, 133 patients(13%) in the TRISS trial and 1926 patients(59%) in the SUP-ICU trial.

CONCLUSIONS

In this post hoc study of three international RCTs within intensive care, we found that the simulated interim mortality effect estimates showed considerable fluctuations until at least 20%-30% of the sample size was included, but remained instable until the final sample sizes had been included. Thus, this study illustrates the necessity for cautious interpretations of prematurely stopped trials.

A Physiologic Approach to Hemodynamic Monitoring and Optimizing Oxygen Delivery in Shock Resuscitation

The approach to shock resuscitation focuses on all components of oxygen delivery, including preload, afterload, contractility, hemoglobin, and oxygen saturation. Resuscitation focused solely on preload and fluid responsiveness minimizes other key elements, resulting in suboptimal patient care. This review will provide a physiologic and practical approach for the optimization of oxygen delivery utilizing available hemodynamic monitoring technologies. Venous oxygen saturation (SvO₂) and lactate will be discussed as indicators of shock states and endpoints of resuscitation within the framework of resolving oxygen deficit and oxygen debt.

Heterogenous treatment effects of transfusion thresholds by patient age: Post-hoc analysis of the TRISS trial

BACKGROUND

Use of a lower haemoglobin (Hb) threshold to guide red blood cell (RBC) transfusion is now generally recommended in critically ill patients, but uncertainty remains regarding the optimal Hb threshold for RBC transfusion in patients of different ages.

METHODS

We conducted a post-hoc analysis of 998 patients with septic shock and anaemia randomised to RBC transfusion at a Hb threshold of 7 g/dl [4.3 mmol/l] vs 9 g/dl [5.6 mmol/l] in the Transfusion Requirements in Septic Shock (TRISS) trial. We assessed if there were heterogeneous effects between the allocated Hb threshold and patient age categorised and on the continuous scale. The primary outcome was 1-year mortality; the secondary outcome was 90-day mortality. Both outcomes were analysed using logistic regression models and in sensitivity analyses with additional adjusting for site of enrolment, presence of haematological malignancy and the Sequential Organ Failure Assessment (SOFA) score. The secondary analyses were Kaplan-Meier curves with corresponding log-rank tests.

RESULTS

We found no heterogeneity between patient age and the allocated Hb thresholds for RBC transfusion for 1-year mortality or 90-day mortality in the primary analyses. The sensitivity analyses suggested heterogeneity between age groups regarding 90-day mortality, however, this was not consistent for 1-year mortality or when assessing age on the continuous scale.

CONCLUSION

In this post-hoc study of ICU patients with septic shock, we found no reliable heterogeneous effects of transfusion at a Hb threshold of 7 vs 9 g/dl according to patient age on mortality. However, due to low power, this study should only be considered as hypothesis generating.

Sublingual microcirculation does not reflect red blood cell transfusion thresholds in the intensive care unit-a prospective observational study in the intensive care unit

Purpose

Hemoglobin (Hb) transfusion thresholds are established in intensive care units. A restrictive transfusion threshold (Hb 70–75 g/l) is recommended in septic patients, and a liberal transfusion threshold (Hb 90 g/l) for cardiogenic shock. It is unclear whether these historically adopted transfusion thresholds meet the challenges of individual patients.

Methods

We evaluated microvascular flow index (MFI) and proportion of perfused vessels (PPV) in the sublingual microcirculation with CytoCam-IDF microscopy and near-infrared spectroscopy (NIRS). A study team-independent, treating intensivist assigned a total of 64 patients to 1 of 2 two transfusion thresholds, 43 patients to the Hb 75 g/l threshold and 21 patients to the Hb 90 g/l threshold, at a surgical intensive care unit. We performed microcirculatory measurements 1 h before and 1 h after transfusion of 1 unit of red blood cells.

Results

Microcirculatory flow variables correlated negatively with pre-transfusion flow variables (ΔMFI: ρ = − 0.821, p <  0.001; ΔPPV: ρ = − 0.778, p <  0.001). Patients with good initial microcirculation (cutoffs: MFI > 2.84, PPV > 88%) showed a deteriorated microcirculation after red blood cell transfusion. An impaired microcirculation improved after transfusion. At both transfusion thresholds, approximately one third of the patients showed an initially impaired microcirculation. In contrast, one third in every group had good microcirculation above the cutoff variables and did not profit from the transfusion.

Conclusion

The data suggest that the established transfusion thresholds and other hemodynamic variables do not reflect microcirculatory perfusion of patients. Blood transfusion at both thresholds 75 g/l and 90 g/l hemoglobin can either improve or harm the microcirculatory blood flow, questioning the concept of arbitrary transfusion thresholds.

Contemporary Transfusion Science and Challenges

Health care professionals must understand the impact of blood product transfusions and transfusion therapy procedures to ensure high-quality patient care, positive outcomes, and wise use of resources in blood management programs. Understanding transfusions of blood and blood products is also important because of the number of treatments performed, which affects individual patients and health care system resources. This article reviews research findings to acquaint health care professionals with the most successful protocols for blood, blood product, and coagulation factor transfusions. Damage control resuscitation in bleeding trauma patients, protocols for patients without trauma who are undergoing surgical procedures that place them at risk for excessive bleeding, and protocols for patients with sepsis are addressed. Emerging research continues to help guide mass transfusion treatments (restrictive vs liberal, balanced, and goal-directed treatment). Although available study results provide some guidance, questions remain. Additional research by health care professionals is needed.

Storage time of red blood cells among ICU patients with septic shock

BACKGROUND

We aimed to describe the exposure to blood transfusions and mortality among patients with septic shock.

METHODS

We did a retrospective cohort study of two cohorts-patients with septic shock registered in a Danish ICU database (2008-2010) and patients from the Transfusion Requirements in Septic Shock (TRISS) trial (2011-2013). We extracted information on blood transfusions issued to all patients. We investigated the number of patients receiving very fresh blood (less than 7 days), very old blood (more than 24 days) and blood with a mixture of storage time.

RESULTS

In the Danish cohort, 1637 patients were included of whom 1394 (85%) received 20,239 blood units from 14 days prior the ICU admission to 90 days after; 33% were transfused before, 77% in the ICU and 36% after ICU. The exposure to exclusively very fresh or very old blood was 3% and 4%, respectively. In the TRISS cohort, 77% of the 937 patients received 5047 RBC units; 3% received exclusively very fresh and 13% very old blood. The point estimate of mortality was higher among patients receiving large amounts of exclusively very fresh and very old blood, but the number of patients were very small.

CONCLUSIONS

Patients with septic shock were transfused both before and after ICU. Exposure to blood of less than 7 days or more than 24 days old were limited. We were not able to detect higher mortality among the limited number of patients with septic shock transfused with very fresh or very old blood.

Lower vs higher transfusion threshold in septic shock patients of different ages: A study protocol

BACKGROUND

Current evidence indicates that it is safe to use a lower haemoglobin (Hb) threshold for red blood cell (RBC) transfusion as compared to a higher Hb-threshold. However, the recent Transfusion Requirements in Cardiac Surgery (TRICS-3) trial reported a significant interaction between patient age and the effect of lower vs higher Hb-thresholds for RBC transfusion. The interaction between patient age and transfusion strategy appears to differ between trials.

METHODS

This is the protocol and statistical analysis plan for a post hoc analysis of the Transfusion Requirements in Septic Shock (TRISS) trial. We will assess the effect of a lower vs a higher Hb-threshold for RBC transfusion in patients of different ages with septic shock. The primary and secondary outcomes are 1-year mortality and 90-day mortality respectively. We will assess age divided into six age groups and as a continuous variable and present baseline characteristics and odds ratios derived from both simple and adjusted (for the Sequential Organ Failure Assessment score, haematological malignancy, age and trial site) logistic regression models and P-values for the test-of-interaction. Furthermore, we will compare outcomes according to Hb-threshold in each age group using Kaplan-Meier curves and log-rank tests.

DISCUSSION

The outlined study will make a detailed assessment of potential interaction of patient age with transfusion strategy in patients with septic shock. This may inform future trials on the benefits and harms of RBC transfusion.

Review of available evidence supporting different transfusion thresholds in different patient groups with anemia

In patients with anemia, transfusion of red blood cells (RBCs) can save lives and improve quality of life. The choice to transfuse should be cautiously made owing to risks of transfusion, economic costs, and limitations on the blood supply. Until the 1980s, the decision for RBC transfusion was guided by Hb threshold, with the aim of maintaining the patient's blood Hb level over 100 grams per liter. Since then, multiple randomized controlled trials and key systematic reviews have provided evidence-based guidelines as to appropriate transfusion thresholds in a number of clinical settings. Here, we aimed to address the outcome of defining different anemia criteria in specific clinical populations exclusively on the basis of the need for RBC transfusion based on Hb concentration. We focused on the patient populations, where there were the most available data on differing transfusion thresholds, which looked at transfusing to a higher or liberal transfusion threshold in comparison with a lower or restrictive transfusion threshold. These included patients in intensive care with or without septic shock, hip fracture surgery, cardiovascular surgery, and upper gastrointestinal bleeding, the pediatric population, and also those with malaria, by reviewing key randomized controlled trials and systematic reviews. Twenty-four randomized controlled studies and 12 systematic reviews have been included, and these are discussed below.

The effect of red-blood-cell transfusion on fatigue in hospitalized patients with anaemia

BACKGROUND AND OBJECTIVE

Guidelines suggest that red-blood-cell transfusion decisions for most hospitalized patients be based on haemoglobin (Hb) concentration and the presence of symptoms of anaemia, including fatigue. However, studies differ in whether transfusion is associated with improvements in fatigue. One explanation is that the benefit of transfusion varies by baseline fatigue levels, which existing studies have not examined. The objective of this study was to determine whether the association between transfusion during hospitalization and improvements in fatigue 30 days postdischarge varies by baseline fatigue level.

METHODS

A prospective observational study of hospitalized general medicine patients with any Hb <9 g/dl. Patients with sickle cell anaemia and gastrointestinal bleeding were excluded since these diagnoses have alternative transfusion practices. Patients with depression were excluded because their fatigue is not primarily due to anaemia. Fatigue was measured during an in-person interview and a 30-day postdischarge phone interview. Hb values and receipt of a transfusion were collected from hospital administrative data. Linear regression was used to test associations between 'change in fatigue', Hb concentration and receipt of a transfusion.

RESULTS

Transfusion interacted with nadir Hb was associated with reduced fatigue postdischarge for patients with higher baseline fatigue (20% most fatigued: β = 12, P = 0·02; 10% most fatigued: β = 17, P = 0·02). Patients <50 years old with high baseline fatigue had large reductions in fatigue from transfusion (20%: β = 23, P = 0·02; 10%: β = 29, P = 0·03).

CONCLUSIONS

Transfusion during hospitalization is associated with reduced fatigue 30 days postdischarge in patients with higher levels of baseline fatigue.

Monitoring microcirculation in critical illness

PURPOSE OF REVIEW

Critical illness includes a wide range of conditions from sepsis to high-risk surgery. All these diseases are characterized by reduced tissue oxygenation. Macrohemodynamic parameters may be corrected by fluids and/or vasoactive compounds; however, the microcirculation and its tissues may be damaged and remain hypoperfused. An evaluation of microcirculation may enable more physiologically based approaches for understanding the pathogenesis, diagnosis, and treatment of critically ill patients.

RECENT FINDINGS

Microcirculation plays a pivotal role in delivering oxygen to the cells and maintains tissue perfusion. Negative results of several studies, based on conventional hemodynamic resuscitation procedures to achieve organ perfusion and decrease morbidity and mortality following conditions of septic shock and other cardiovascular compromise, have highlighted the need to monitor microcirculation. The loss of hemodynamic coherence between the macrocirculation and microcirculation, wherein improvement of hemodynamic variables of the systemic circulation does not cause a parallel improvement of microcirculatory perfusion and oxygenation of the essential organ systems, may explain why these studies have failed.

SUMMARY

Critical illness is usually accompanied by abnormalities in microcirculation and tissue hypoxia. Direct monitoring of sublingual microcirculation using hand-held microscopy may provide a more physiological approach. Evaluating the coherence between macrocirculation and microcirculation in response to therapy seems to be essential in evaluating the efficacy of therapeutic interventions.

[International guidelines from the Surviving Sepsis Campaign : 2016 update]

An update to the international guidelines for sepsis therapy was published by the Surviving Sepsis Campaign (SSC) in March 2017. The guidelines have been completely restructured and comprehensively deal with new evidence. The guidelines discuss sepsis-specific therapeutic measures and provide detailed recommendations on general intensive care measures for sepsis. This article summarizes the most important amendments and suggests delving deeper into the guidelines.

Factors associated with non-response at health-related quality of life follow-up in a septic shock trial

BACKGROUND

Follow-up of intensive care unit (ICU) patients often includes health-related quality of life (HRQoL) surveying, but non-responders hamper the interpretation. Our aim was to assess factors for non-response to HRQoL survey in ICU patients with septic shock at follow-up in a clinical trial.

METHODS

In a post hoc follow-up registry study, we assessed all the Danish survivors in the Transfusion-Requirements in Septic Shock trial patients, who were mailed the Short Form 36-item Survey (SF-36) 1-year after randomization. We used covariates from the trial database merged with covariates from nation-wide registries using the unique national identification number to explore possible factors for not responding. Five covariates were pre-specified to be included in the primary multivariate analysis: age, number of days in hospital from randomization to follow-up, level of education, cohabitation and employment status at follow-up. We compared the mortality from 1-year survival (2012-2014) till end of final follow-up (January 2016) between non-responders and responders.

RESULTS

We assessed 308 survivors of whom 108 (35%) were non-responders. In the primary analysis lower age (odds ratio 1.03, 95% CI [1.01-1.05]), more admission days in hospital (1.006 [1.001-1.011]) and living alone (4.33 [2.46-7.63]) were associated with non-responding, whereas the level of education and employment status were not. Non-responders had a hazard ratio of 1.63 [0.97-2.72] for mortality from 1-year follow-up to final follow-up as compared to the responders.

CONCLUSION

Being younger, spending more days in hospital and living alone were all associated with non-response at 1-year HRQoL follow-up among ICU patients with septic shock.

Epidemiology of donors and recipients: lessons from the SCANDAT database

With the development of several 'vein-to-vein' databases, which capture data on the entire donor-recipient continuum and link this data to health outcomes, there has been an increasing number of studies investigating the health effects of all aspects of the practice of transfusion medicine. The Scandinavian Donations and Transfusions (SCANDAT) database is one of several such databases, which includes all electronically available data on blood donors, donations and transfusions since the late 1960s in Sweden and the early 1980s in Denmark. The SCANDAT database has been used to characterise disease occurrence among blood donors and transfused patients, as well as to investigate possible health effects of blood donations, aspects of transfusion care and possible transfusion transmission of disease. Recent publications include studies on recipient mortality associated with the storage lesion, studies on the effects of donor demographics on patient mortality and health effects of frequent blood donation. Although this research approach is clearly very powerful, the appropriate analysis of such real-world data is complex and requires close methodological attention. The purpose of this review is to present some of the research conducted within the SCANDAT collaboration. We hope more international collaboration may help improve our understanding of the important remaining questions about donor and recipient health.

Association Between Anemia and Fatigue in Hospitalized Patients: Does the Measure of Anemia Matter?

OBJECTIVE

To assess multiple Hb-based measures of anemia in hospitalized patients and test whether these are associated with fatigue.

DESIGN

Prospective observational study.

SETTING

Urban, academic medical center.

PATIENTS

Hospitalized general medicine patients, age =50 years, with any Hb < 9 g/dL.

MEASUREMENTS

Measures of anemia were created for each patient based on the Hb values from their hospitalization (mean, median, minimum, maximum, admission, and discharge). Fatigue was measured using the Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue subscale.

RESULTS

Seven hundred eighty-four patients participated. Minimum Hb was strongly associated with fatigue. Patients with a minimum Hb of < 8 g/dL had higher fatigue levels (mean FACIT [standard deviation] Hb < 7 g/dL: 25 [13], 7 g/ dL = Hb <8 g/dL: 25 [14] Hb =8 g/dL: 29 [14], P = 0.001) and were more likely to report high levels of fatigue (FACIT-Fatigue < 27) (56% vs 41%; P = 0.002). Mean Hb had a less robust association with fatigue than minimum Hb, and no other measure of Hb was associated with patients' fatigue levels.

CONCLUSIONS

Minimum Hb is associated with fatigue while hospitalized and may help identify patients for interventions to address anemia-related fatigue.

Daily Lowest Hemoglobin and Risk of Organ Dysfunctions in Critically Ill Patients

OBJECTIVES

To determine the association between hemoglobin levels and the daily risk of individual organ dysfunctions in critically ill patients.

DESIGN

Post hoc analysis of prospectively collected data.

SETTING

Vanderbilt University Medical Center and Saint Thomas Hospital Medical and Surgical ICUs.

PATIENTS

Medical and surgical ICU patients admitted with respiratory failure or shock.

INTERVENTIONS

Baseline demographic data, and detailed in-ICU and hospital data, including daily lowest hemoglobin, were collected up to hospital day 30. We assessed patients daily for brain dysfunction (delirium, using Confusion Assessment Method for ICU), for renal and respiratory dysfunction (using the ordinal renal and respiratory Sequential Organ Failure Assessment score), and for ICU mortality. Associations between the lowest hemoglobin on a given day and organ dysfunctions the following day were assessed using multivariable regressions, adjusting for age, Acute Physiology and Chronic Health Evaluation II score, Charlson comorbidity index, Framingham Stroke Risk Profile, ICU day, ICU type, sepsis, and current organ dysfunction status. A sensitivity analysis further adjusted for daily transfusions and fluid balance in a subset of our patients.

MEASUREMENTS AND MAIN RESULTS

We enrolled 821 patients with a median (interquartile range) age of 61 (51-71) years, Acute Physiology and Chronic Health Evaluation II score of 25 (19-31), and hemoglobin level of 10.0 (9.0-11.1) g/dL. There was no evidence of an association between lowest daily hemoglobin and brain dysfunction (p = 0.69 for delirium), renal dysfunction (p = 0.30), or ICU mortality (p = 0.95). The lowest hemoglobin on a given day was significantly associated with the respiratory Sequential Organ Failure Assessment score the following day; for each increasing hemoglobin unit, the odds of worsened respiratory Sequential Organ Failure Assessment score the following day were decreased by 36% (OR, 0.64; 95% CI, 0.53-0.77; p < 0.001). The sensitivity analysis including daily transfusions and fluid balance (in a subset of 518 patients) did not qualitatively change any of these associations.

CONCLUSIONS

In this study in ICU patients, lower hemoglobin was associated with a higher probability of worsening respiratory dysfunction scores the following day. There was no evidence of association between hemoglobin and brain or renal dysfunction, or ICU mortality. The possible differential effects of anemia on organ dysfunctions seen in this hypothesis-generating study will have to be studied in a larger prospective study before any alterations to present restrictive transfusion guidelines can be recommended.

Higher vs. lower haemoglobin threshold for transfusion in septic shock: subgroup analyses of the TRISS trial

BACKGROUND

Using a restrictive transfusion strategy appears to be safe in sepsis, but there may be subgroups of patients who benefit from transfusion at a higher haemoglobin level. We explored if subgroups of patients with septic shock and anaemia had better outcome when transfused at a higher vs. a lower haemoglobin threshold.

METHODS

In post-hoc analyses of the full trial population of 998 patients from the Transfusion Requirements in Septic Shock (TRISS) trial, we investigated the intervention effect on 90-day mortality in patients with severe comorbidity (chronic lung disease, haematological malignancy or metastatic cancer), in patients who had undergone surgery (elective or acute) and in patients with septic shock as defined by the new consensus definition: lactate above 2 mmol/l and the need for vasopressors to maintain a mean arterial pressure above 65 mmHg.

RESULTS

The baseline characteristics were mostly similar between the two intervention groups in the different subgroups. There were no differences in the intervention effect on 90-day mortality in patients with chronic lung disease (test of interaction P = 0.31), haematological malignancy (P = 0.47), metastatic cancer (P = 0.51), in those who had undergone surgery (P = 0.99) or in patients with septic shock by the new definition (P = 0.20).

CONCLUSION

In exploratory analyses of a randomized trial in patients with septic shock and anaemia, we observed no survival benefit in any subgroups of transfusion at a haemoglobin threshold of 90 g/l vs. 70 g/l.

Long-term outcomes in patients with septic shock transfused at a lower versus a higher haemoglobin threshold: the TRISS randomised, multicentre clinical trial

PURPOSE

We assessed the predefined long-term outcomes in patients randomised in the Transfusion Requirements in Septic Shock (TRISS) trial.

METHODS

In 32 Scandinavian ICUs, we randomised 1005 patients with septic shock and haemoglobin of 9 g/dl or less to receive single units of leuko-reduced red cells when haemoglobin level was 7 g/dl or less (lower threshold) or 9 g/dl or less (higher threshold) during ICU stay. We assessed mortality rates 1 year after randomisation and again in all patients at time of longest follow-up in the intention-to-treat population (n = 998) and health-related quality of life (HRQoL) 1 year after randomisation in the Danish patients only (n = 777).

RESULTS

Mortality rates in the lower- versus higher-threshold group at 1 year were 53.5 % (268/501 patients) versus 54.6 % (271/496) [relative risk 0.97; 95 % confidence interval (CI) 0.85-1.09; P = 0.62]; at longest follow-up (median 21 months), they were 56.7 % (284/501) versus 61.0 % (302/495) (hazard ratio 0.88; 95 % CI 0.75-1.03; P = 0.12). We obtained HRQoL data at 1 year in 629 of the 777 (81 %) Danish patients, and mean differences between the lower- and higher-threshold group in scores of physical HRQoL were 0.4 (95 % CI -2.4 to 3.1; P = 0.79) and in mental HRQoL 0.5 (95 % CI -3.1 to 4.0; P = 0.79).

CONCLUSIONS

Long-term mortality rates and HRQoL did not differ in patients with septic shock and anaemia who were transfused at a haemoglobin threshold of 7 g/dl versus a threshold of 9 g/dl. We may reject a more than 3 % increased hazard of death in the lower- versus higher-threshold group at the time of longest follow-up.

Association between fluid balance and mortality in patients with septic shock: a post hoc analysis of the TRISS trial

BACKGROUND

Several studies have shown an association between a positive fluid balance and increased mortality in patients with septic shock. This may have led to a more restrictive use of intravenous fluids. The association between fluid accumulation and mortality in the setting of a more restrictive use of intravenous fluids, however, is uncertain. We therefore aimed to investigate the association between a cumulative fluid balance 3 days after randomization and 90-day mortality in a recent Nordic multicentre cohort of patients with septic shock.

METHODS

A post hoc analysis of patients from the Transfusion Requirements in Septic Shock (TRISS) trial treated for 3 days or more in the ICU after randomization. The patients were categorized into four groups depending on their weight-adjusted cumulative fluid balance after 3 days. We performed multivariable Cox regression analysis, adjusting for important prognostics (study site, age, chronic cardiovascular and chronic lung disease, haematologic malignancy, chronic dialysis, source of infection, baseline SOFA score and plasma lactate).

RESULTS

The median cumulative fluid balance of the 841 included patients was 2480 ml (IQR 47-5045). The median time from ICU admission to inclusion in the trial was 22 h. The overall 90-day mortality was 52%. There was no statistically significant association between fluid balance 3 days from inclusion and 90-day mortality after the adjustment for the prognostics (P = 0.37).

CONCLUSION

In our cohort of patients with septic shock and a comparably low cumulative fluid balance, there was no association between fluid balance and mortality. However, the study design and the limited power preclude strong conclusions. There is an urgent need for high-quality trials assessing the benefit and harm of different fluid volume strategies in patients with septic shock.

Whole Blood Reveals More Metabolic Detail of the Human Metabolome than Serum as Measured by 1H-NMR Spectroscopy: Implications for Sepsis Metabolomics

Serum is a common sample of convenience for metabolomics studies. Its processing time can be lengthy and may result in the loss of metabolites including those of red blood cells (RBCs). Unlike serum, whole blood (WB) is quickly processed, minimizing the influence of variable hemolysis while including RBC metabolites. To determine differences between serum and WB metabolomes, both sample types, collected from healthy volunteers, were assayed by H-NMR (proton nuclear magnetic resonance) spectroscopy. A total of 34 and 50 aqueous metabolites were quantified from serum and WB, respectively. Free hemoglobin (Hgb) levels in serum were measured, and the correlation between Hgb and metabolite concentrations was determined. Most metabolites detected in serum were at higher concentrations in WB with the exception of acetoacetate and propylene glycol. The 18 unique metabolites of WB included adenosine, AMP, ADP, and ATP, which are associated with RBC metabolism. The use of serum results in the underrepresentation of a number of metabolic pathways including branched-chain amino acid degradation and glycolysis and gluconeogenesis. The range of free Hgb in serum was 0.03 to 0.01 g/dL, and eight metabolites were associated (P ≤ 0.05) with free Hgb. The range of free Hgb in serum samples from 18 sepsis patients was 0.02 to 0.46 g/dL. Whole blood and serum have unique aqueous metabolite profiles, but the use of serum may introduce potential pathway bias. Use of WB for metabolomics may be particularly important for studies in diseases such as sepsis in which RBC metabolism is altered, and mechanical and sepsis-induced hemolysis contributes to variance in the metabolome.

STROBE-compliant article: Blood Transfusions within the First 24 Hours of Hospitalization Did Not Impact Mortality Among Patients with Severe Sepsis

Transfusion of packed red blood cells is common during resuscitation of critically ill patients. However, the association between in-hospital mortality and blood transfusion among patients with severe sepsis during the first 24  hours of hospitalization has not yet been determined. A cohort study was conducted of adult nontrauma patients who visited the emergency department of a tertiary hospital and were diagnosed with severe sepsis. Propensity score (PS) matching was conducted, based on patient demographics, underlying illnesses, laboratory results, and vital signs presented at the emergency department, and multivariate logistic regression was performed to adjust for potential residual confounding between the 2 transfused and nontransfused groups to assess the risk of in-hospital mortality. Of 3448 patients included in this study, 265 underwent blood transfusion during the first 24  hours of hospitalization. Despite comparable severity of sepsis, patients who received transfusions tended to have lower mean arterial pressures (86 vs 98  mmHg) and hemoglobin levels (7.6 vs 11.2  g/dL), and were more likely to have chronic kidney disease (12% vs 6%) and hematologic organ dysfunction (57% vs 35%, all P < 0.001). Transfused patients tended to have higher mortality rates (26% vs 9%, respectively, P < 0.001). After PS matching, 177 pairs of transfused and nontransfused patients were analyzed. After adjusting for residual confounding factors by multivariate logistic regression in the matched patient pairs, no significant differences in in-hospital mortality were observed (odds ratio [OR] = 1.52, 95% confidence interval: 0.92-2.51). In this PS-matched cohort study of adult nontrauma patients with severe sepsis, the in-hospital mortality rate was not significantly different in patients who received blood transfusions during the first 24  hours of hospitalization.

Blood Products

Perioperative hemorrhage, anemia, thrombocytopenia, and coagulopathy are common in the surgical intensive care unit. As a result, blood product transfusion occurs frequently. While red blood cell, plasma, and platelet transfusions have a lifesaving role in the resuscitation of patients with trauma and hemorrhagic shock, their application in other settings is under scrutiny. Current data would suggest a conservative approach be taken, thus avoiding unnecessary transfusion and associated potential adverse events. New and developmental products such as prothrombin complex concentrates offer appealing alternatives to traditional transfusion practice—potentially with fewer risks—however, further investigation into their safety and efficacy is required before practice change can take place.

Variability in targeted arterial oxygenation levels in patients with severe sepsis or septic shock

BACKGROUND

Supplemental oxygen therapy is used for intensive care (ICU) patients with severe sepsis, but with no general guidelines and few safety data. The aim of this observational study was to describe the variability in oxygen administration as well as the association between partial pressure of arterial oxygen (PaO2 ) and mortality.

METHODS

We extracted data from two Scandinavian clinical trials of ICU patients with severe sepsis or septic shock. We calculated average PaO2 and fraction of inspired oxygen (FiO2 ) from trial inclusion and the following 5 days, and assessed the association between PaO2 and 90-day mortality.

RESULTS

The median PaO2 was 9.8 kPa [5-95% range 6.4-19.9] and FiO2 was 0.51 [5-95% range 0.27-1.00], respectively. Eight hundred and five of 1,770 patients (45%) died. The relative risk of mortality was 1.43 [95% CI: 1.19-1.65] in patients with average PaO2 < 8 kPa and 1.29 [95% CI: 0.84-1.68] in patients with average PaO2 ≥ 16 kPa, as compared to patients with average PaO2 10-12 kPa. The relative risk of mortality was 1.38 [95% CI: 1.17-1.58] in patients with an average FiO2 0.60-0.80 and 2.10 [95% CI: 1.88-2.23] in patients with an average FiO2  ≥ 0.80 as compared to patients with an average FiO2  ≤ 0.40.

CONCLUSION

Administration of oxygen in patients with severe sepsis resulted in a wide range of PaO2 . Significantly higher mortality was observed in patients with an average PaO2 < 8 kPa and FiO2 ≥ 0.60. The results do not imply causation and the associations between average PaO2 and adverse outcomes have to be assessed further.

Severe sepsis and septic shock: clinical overview and update on management

Sepsis is among the oldest themes in medicine; however, despite modern advances, it remains a leading cause of death in the United States. Every clinician should be able to recognize the signs and symptoms of sepsis, along with early management strategies, to expeditiously provide appropriate care and decrease resultant morbidity and mortality. This review addresses the definitions, pathogenesis, clinical manifestations, management, and outcomes of patients with sepsis, severe sepsis, and septic shock.

Lower versus higher hemoglobin threshold for transfusion in septic shock

BACKGROUND

Blood transfusions are frequently given to patients with septic shock. However, the benefits and harms of different hemoglobin thresholds for transfusion have not been established.

METHODS

In this multicenter, parallel-group trial, we randomly assigned patients in the intensive care unit (ICU) who had septic shock and a hemoglobin concentration of 9 g per deciliter or less to receive 1 unit of leukoreduced red cells when the hemoglobin level was 7 g per deciliter or less (lower threshold) or when the level was 9 g per deciliter or less (higher threshold) during the ICU stay. The primary outcome measure was death by 90 days after randomization.

RESULTS

We analyzed data from 998 of 1005 patients (99.3%) who underwent randomization. The two intervention groups had similar baseline characteristics. In the ICU, the lower-threshold group received a median of 1 unit of blood (interquartile range, 0 to 3) and the higher-threshold group received a median of 4 units (interquartile range, 2 to 7). At 90 days after randomization, 216 of 502 patients (43.0%) assigned to the lower-threshold group, as compared with 223 of 496 (45.0%) assigned to the higher-threshold group, had died (relative risk, 0.94; 95% confidence interval, 0.78 to 1.09; P=0.44). The results were similar in analyses adjusted for risk factors at baseline and in analyses of the per-protocol populations. The numbers of patients who had ischemic events, who had severe adverse reactions, and who required life support were similar in the two intervention groups.

CONCLUSIONS

Among patients with septic shock, mortality at 90 days and rates of ischemic events and use of life support were similar among those assigned to blood transfusion at a higher hemoglobin threshold and those assigned to blood transfusion at a lower threshold; the latter group received fewer transfusions. (Funded by the Danish Strategic Research Council and others; TRISS ClinicalTrials.gov number, NCT01485315.).

Effect of ERK1/2 signaling pathway in electro-acupuncture mediated up-regulation of heme oxygenase-1 in lungs of rabbits with endotoxic shock

Background

The anti-oxidative and anti-inflammatory activities of electro-acupuncture (EA), a traditional clinical method, are widely accepted, but its mechanisms are not yet well defined. In this study, we investigated the role of extracellular signal-regulated kinases1/2 (ERK1/2) pathways on electro-acupuncture – mediated up-regulation of heme oxygenase-1 (HO-1) in rabbit lungs injured by LPS-induced endotoxic shock.

Material/Methods

Seventy rabbits were randomly divided into 7 groups: group C, group M, group D, group SEAM, group EAM, group EAMPD, and group PD98059. Male New England white rabbits were given EA treatment on both sides once a day on days 1–5, and then received LPS to replicate the experimental model of injured lung induced by endotoxic shock. Then, they were killed by exsanguination at 6 h after LPS administration. The blood samples were collected for serum examination, and the lungs were removed for pathology examination, determination of wet-to-dry weight ratio, MDA content, SOD activity, serum tumor necrosis factor-α, determination of HO-1 protein and mRNA expression, and determination of ERK1/2 protein.

Results

The results revealed that after EA treatment, expression of HO-1and ERK1/2 was slightly increased compared to those in other groups, accompanied with less severe lung injury as indicated by lower index of lung injury score, lower wet-to-dry weight ratio, MDA content, and serum tumor necrosis factor-α levels, and greater SOD activity (p<0.05 for all). After pretreatment with ERK1/2 inhibitor PD98059, the effect of EA treatment and expression of HO-1 were suppressed (p<0.05 for all).

Conclusions

After electro-acupuncture stimulation at ST36 and BL13, severe lung injury during endotoxic shock was attenuated. The mechanism may be through up-regulation of HO-1, mediated by the signal transductions of ERK1/2 pathways. Thus, the regulation of ERK1/2 pathways via electro-acupuncture may be a therapeutic strategy for endotoxic shock.

Red blood cell transfusion in septic shock - clinical characteristics and outcome of unselected patients in a prospective, multicentre cohort

Background

Treating anaemia with red blood cell (RBC) transfusion is frequent, but controversial, in patients with septic shock. Therefore we assessed characteristics and outcome associated with RBC transfusion in this group of high risk patients.

Methods

We did a prospective cohort study at 7 general intensive care units (ICUs) including all adult patients with septic shock in a 5-month period.

Results

Ninety-five of the 213 included patients (45%) received median 3 (interquartile range 2–5) RBC units during shock. The median pre-transfusion haemoglobin level was 8.1 (7.4–8.9) g/dl and independent of shock day and bleeding. Patients with cardiovascular disease were transfused at higher haemoglobin levels. Transfused patients had higher Simplified Acute Physiology Score (SAPS) II (56 (45-69) vs. 48 (37-61), p = 0.0005), more bleeding episodes, lower haemoglobin levels days 1 to 5, higher Sepsis-related Organ Failure Assessment (SOFA) scores (days 1 and 5), more days in shock (5 (3-10) vs. 2 (2-4), p = 0.0001), more days in ICU (10 (4-19) vs. 4 (2-8), p = 0.0001) and higher 90-day mortality (66 vs. 43%, p = 0.001). The latter association was lost after adjustment for admission category and SAPS II and SOFA-score on day 1.

Conclusions

The decision to transfuse patients with septic shock was likely affected by disease severity and bleeding, but haemoglobin level was the only measure that consistently differed between transfused and non-transfused patients.