Comprehensive Analysis of Liberal and Restrictive Transfusion Strategies in Pediatric Intensive Care Unit

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2024

The 2024 revised edition of the Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock (J-SSCG 2024) is published by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine. This is the fourth revision since the first edition was published in 2012. The purpose of the guidelines is to assist healthcare providers in making appropriate decisions in the treatment of sepsis and septic shock, leading to improved patient outcomes. We aimed to create guidelines that are easy to understand and use for physicians who recognize sepsis and provide initial management, specialized physicians who take over the treatment, and multidisciplinary healthcare providers, including nurses, physical therapists, clinical engineers, and pharmacists. The J-SSCG 2024 covers the following nine areas: diagnosis of sepsis and source control, antimicrobial therapy, initial resuscitation, blood purification, disseminated intravascular coagulation, adjunctive therapy, post-intensive care syndrome, patient and family care, and pediatrics. In these areas, we extracted 78 important clinical issues. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 42 GRADE-based recommendations, 7 good practice statements, and 22 information-to-background questions were created as responses to clinical questions. We also described 12 future research questions.

Single centre analysis of factors influencing surgical treatment of splenic trauma in children

OBJECTIVE

This study aims to investigate determinants impacting the surgical management of splenic trauma in paediatric patients by scrutinizing age distribution, etiological factors and concomitant injuries. The analysis seeks to establish a foundation for delineating optimal operative timing.

METHODS

A cohort of 262 paediatric cases presenting with splenic trauma at our institution from January 2011 to December 2021 underwent categorization into either the conservative or operative group.

RESULTS

Significantly disparate attributes between the two groups included age, time of presentation, blood pressure, haemoglobin levels, blood transfusion requirements, thermal absorption, American Association for the Surgery of Trauma (AAST) classification and associated injuries. Logistic regression analysis revealed age, haemoglobin levels, AAST classification and blood transfusion as autonomous influencers of surgical intervention (OR = 1.024, 95% CI: 1.011-1.037; OR = 1.067, 95% CI: 1.01-1.127; OR = 0.2760, 95% CI: 0.087-0.875; OR = 7.873, 95% CI: 2.442-25.382; OR = 0.016, 95% CI: 0.002-0.153). The AAST type and age demonstrated areas under the receiver operating characteristic (ROC) curve of 0.782 and 0.618, respectively.

CONCLUSION

Age, haemoglobin levels, AAST classification and blood transfusion independently influence the decision for surgical intervention in paediatric patients with splenic trauma. Age and AAST classification emerge as viable parameters for assessing and prognosticating the likelihood of surgical intervention in this patient cohort.

Post-operative anemia in children undergoing elective neurosurgery: An analysis of incidence, risk factors, and outcomes

Objectives

Pediatric neurosurgeries carry a considerable risk of intraoperative bleeding and, subsequently, anemia in the post-operative period. Postoperative anemia is often multifactorial with several factors contributing to its occurrence. The present study aims to quantify the incidence of postoperative anemia, identify potential risk factors, and assess the impact of post-operative anemia on clinical outcomes in the pediatric neurosurgery population.

Materials and Methods

This was a single-center and retrospective cohort study which included children <18 years of age undergoing elective neurosurgery. The data were extracted from the electronic and physical patient health records. Post-operative anemia was defined for this study as a hemoglobin value below 10 g/dL at any time up to 3 days after surgery.

Results

A total of 300 children were recruited during the study period. The incidence of post-operative anemia after elective pediatric neurosurgery was 21.33%. Children in the post-operative anemia group were younger (P = 0.004), had lower pre-operative hemoglobin values (P < 0.001), belonged to higher American Society of Anesthesiologists (ASA) physical status (P = 0.023), underwent predominantly supratentorial (P = 0.041) and non-tumor surgeries (0.004), and received lesser intraoperative blood transfusion (P = 0.010) compared to no post-operative anemia group. The factors that remained predictive of post-operative anemia on multivariate analysis were ASA physical status (P = 0.018, odds ratio [OR] = 1.94, 95% confidence interval [CI] of 1.12-3.36), pre-operative hemoglobin (P < 0.001, OR = 0.64, 95% CI of 0.50-0.82), and intraoperative transfusion (P = 0.028, OR = 0.45, 95% CI of 0.22-0.92).

Conclusion

Optimization of modifiable risk factors is essential to reduce the occurrence of post-operative anemia and improve outcomes in pediatric neurosurgical patients.

Red Blood Cell Transfusion: 2023 AABB International Guidelines

Importance

Red blood cell transfusion is a common medical intervention with benefits and harms.

Objective

To provide recommendations for use of red blood cell transfusion in adults and children.

Evidence Review

Standards for trustworthy guidelines were followed, including using Grading of Recommendations Assessment, Development and Evaluation methods, managing conflicts of interest, and making values and preferences explicit. Evidence from systematic reviews of randomized controlled trials was reviewed.

Findings

For adults, 45 randomized controlled trials with 20 599 participants compared restrictive hemoglobin-based transfusion thresholds, typically 7 to 8 g/dL, with liberal transfusion thresholds of 9 to 10 g/dL. For pediatric patients, 7 randomized controlled trials with 2730 participants compared a variety of restrictive and liberal transfusion thresholds. For most patient populations, results provided moderate quality evidence that restrictive transfusion thresholds did not adversely affect patient-important outcomes. Recommendation 1: for hospitalized adult patients who are hemodynamically stable, the international panel recommends a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (strong recommendation, moderate certainty evidence). In accordance with the restrictive strategy threshold used in most trials, clinicians may choose a threshold of 7.5 g/dL for patients undergoing cardiac surgery and 8 g/dL for those undergoing orthopedic surgery or those with preexisting cardiovascular disease. Recommendation 2: for hospitalized adult patients with hematologic and oncologic disorders, the panel suggests a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (conditional recommendations, low certainty evidence). Recommendation 3: for critically ill children and those at risk of critical illness who are hemodynamically stable and without a hemoglobinopathy, cyanotic cardiac condition, or severe hypoxemia, the international panel recommends a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (strong recommendation, moderate certainty evidence). Recommendation 4: for hemodynamically stable children with congenital heart disease, the international panel suggests a transfusion threshold that is based on the cardiac abnormality and stage of surgical repair: 7 g/dL (biventricular repair), 9 g/dL (single-ventricle palliation), or 7 to 9 g/dL (uncorrected congenital heart disease) (conditional recommendation, low certainty evidence).

Conclusions and Relevance

It is good practice to consider overall clinical context and alternative therapies to transfusion when making transfusion decisions about an individual patient.

Measuring Mitochondrial Oxygen Tension during Red Blood Cell Transfusion in Chronic Anemia Patients: A Pilot Study

In light of the associated risks, the question has been raised whether the decision to give a blood transfusion should solely be based on the hemoglobin level. As mitochondria are the final destination of oxygen transport, mitochondrial parameters are suggested to be of added value. The aims of this pilot study were to investigate the effect of a red blood cell transfusion on mitochondrial oxygenation as measured by the COMET device in chronic anemia patients and to explore the clinical usability of the COMET monitor in blood transfusion treatments, especially the feasibility of performing measurements in an outpatient setting. To correct the effect of volume load on mitochondrial oxygenation, a red blood cell transfusion and a saline infusion were given in random order. In total, 21 patients were included, and this resulted in 31 observations. If patients participated twice, the order of infusion was reversed. In both the measurements wherein a blood transfusion was given first and wherein 500 mL of 0.9% saline was given first, the median mitochondrial oxygen tension decreased after red blood cell transfusion. The results of this study have strengthened the need for further research into the effect of blood transfusion tissue oxygenation and the potential role of mitochondrial parameters herein.

Impact of restrictive versus liberal transfusion and clinical outcomes in critically ill children: A retrospective observational study

Background and Aims

Critically ill children with anemia often requires blood transfusion, which can cause several complications. It is important to decide when to start the red blood cell (RBC) transfusion; however, the guidelines is still lacking. The aim of this study was to compare restrictive and liberal transfusion strategy.

Methods

This is an observational retrospective study of critically-ill children who receive RBC transfusion. Subjects categorized into two groups by initial hemoglobin (Hb), that is, restrictive (Hb ≤ 7 g/dl) and liberal (Hb ≤ 9.5 g/dl) strategy. In each group, subjects categorized based on: (1) Hb increment: high (increased ≥2.5 g/dl) and low (increase <2.5 g/dl) and (2) final Hb level: low (<7.0 mg/dl), moderate (7.0-10.0 mg/dl), and high (>10.0 mg/dl). Patient with hematologic or congenital disorder, severe malnutrition, chronic infection-related anemia, and transfusion in Hb level ≥9.5 g/dl were exclude. Each patients were evaluated for the clinical outcome, which is: intensive care length of stay (IC-LOS), length of mechanical ventilation (LoMV), and mortality rate.

Results

Clinical outcome and mortality rates of both transfusion strategies are similar. The mortality rates were lower in higher Hb increment and final Hb level (p = 0.04 and p = 0.01, respectively). Multivariate analysis in all groups revealed mortality rate had moderate correlation with Hb increment (odds ratio [OR] = 0.694, 95% confidence interval [CI] 0.549-0.878; p = 0.002) and moderate correlation (OR = 0.642, 95% CI 0.519-0.795; p = 0.000) with final Hb level. The similar results was found after categorization based on transfusion strategy.

Conclusion

We conclude the restrictive and liberal transfusion strategy have a similar effect to IC-LOS, LoMV, and mortality rate. High Hb increment (≥2.5 g/dl) and moderate-high final Hb (≥7.0 g/dl) after transfusion reduce the mortality rate.

Transfusion thresholds for guiding red blood cell transfusion

BACKGROUND

The optimal haemoglobin threshold for use of red blood cell (RBC) transfusions in anaemic patients remains an active field of research. Blood is a scarce resource, and in some countries, transfusions are less safe than in others because of inadequate testing for viral pathogens. If a liberal transfusion policy does not improve clinical outcomes, or if it is equivalent, then adopting a more restrictive approach could be recognised as the standard of care.  OBJECTIVES: The aim of this review update was to compare 30-day mortality and other clinical outcomes for participants randomised to restrictive versus liberal red blood cell (RBC) transfusion thresholds (triggers) for all clinical conditions. The restrictive transfusion threshold uses a lower haemoglobin concentration as a threshold for transfusion (most commonly, 7.0 g/dL to 8.0 g/dL), and the liberal transfusion threshold uses a higher haemoglobin concentration as a threshold for transfusion (most commonly, 9.0 g/dL to 10.0 g/dL).

SEARCH METHODS

We identified trials through updated searches: CENTRAL (2020, Issue 11), MEDLINE (1946 to November 2020), Embase (1974 to November 2020), Transfusion Evidence Library (1950 to November 2020), Web of Science Conference Proceedings Citation Index (1990 to November 2020), and trial registries (November 2020). We  checked the reference lists of other published reviews and relevant papers to identify additional trials. We were aware of one trial identified in earlier searching that was in the process of being published (in February 2021), and we were able to include it before this review was finalised.

SELECTION CRITERIA

We included randomised trials of surgical or medical participants that recruited adults or children, or both. We excluded studies that focused on neonates. Eligible trials assigned intervention groups on the basis of different transfusion schedules or thresholds or 'triggers'. These thresholds would be defined by a haemoglobin (Hb) or haematocrit (Hct) concentration below which an RBC transfusion would be administered; the haemoglobin concentration remains the most commonly applied marker of the need for RBC transfusion in clinical practice. We included trials in which investigators had allocated participants to higher thresholds or more liberal transfusion strategies compared to more restrictive ones, which might include no transfusion. As in previous versions of this review, we did not exclude unregistered trials published after 2010 (as per the policy of the Cochrane Injuries Group, 2015), however, we did conduct analyses to consider the differential impact of results of trials for which prospective registration could not be confirmed.   DATA COLLECTION AND ANALYSIS: We identified trials for inclusion and extracted data using Cochrane methods. We pooled risk ratios of clinical outcomes across trials using a random-effects model. Two review authors independently extracted data and assessed risk of bias. We conducted predefined analyses by clinical subgroups. We defined participants randomly allocated to the lower transfusion threshold as being in the 'restrictive transfusion' group and those randomly allocated to the higher transfusion threshold as being in the 'liberal transfusion' group.

MAIN RESULTS

A total of 48 trials, involving data from 21,433 participants (at baseline), across a range of clinical contexts (e.g. orthopaedic, cardiac, or vascular surgery; critical care; acute blood loss (including gastrointestinal bleeding); acute coronary syndrome; cancer; leukaemia; haematological malignancies), met the eligibility criteria. The haemoglobin concentration used to define the restrictive transfusion group in most trials (36) was between 7.0 g/dL and 8.0 g/dL.  Most trials included only adults; three trials focused on children. The included studies were generally at low risk of bias for key domains including allocation concealment and incomplete outcome data. Restrictive transfusion strategies reduced the risk of receiving at least one RBC transfusion by 41% across a broad range of clinical contexts (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.53 to 0.66; 42 studies, 20,057 participants; high-quality evidence), with a large amount of heterogeneity between trials (I² = 96%). Overall, restrictive transfusion strategies did not increase or decrease the risk of 30-day mortality compared with liberal transfusion strategies (RR 0.99, 95% CI 0.86 to 1.15; 31 studies, 16,729 participants; I² = 30%; moderate-quality evidence) or any of the other outcomes assessed (i.e. cardiac events (low-quality evidence), myocardial infarction, stroke, thromboembolism (all high-quality evidence)). High-quality evidence shows that the liberal transfusion threshold did not affect the risk of infection (pneumonia, wound infection, or bacteraemia). Transfusion-specific reactions are uncommon and were inconsistently reported within trials. We noted less certainty in the strength of evidence to support the safety of restrictive transfusion thresholds for the following predefined clinical subgroups: myocardial infarction, vascular surgery, haematological malignancies, and chronic bone-marrow disorders.

AUTHORS' CONCLUSIONS

Transfusion at a restrictive haemoglobin concentration decreased the proportion of people exposed to RBC transfusion by 41% across a broad range of clinical contexts. Across all trials, no evidence suggests that a restrictive transfusion strategy impacted 30-day mortality, mortality at other time points, or morbidity (i.e. cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. Despite including 17 more randomised trials (and 8846 participants), data remain insufficient to inform the safety of transfusion policies in important and selected clinical contexts, such as myocardial infarction, chronic cardiovascular disease, neurological injury or traumatic brain injury, stroke, thrombocytopenia, and cancer or haematological malignancies, including chronic bone marrow failure.  Further work is needed to improve our understanding of outcomes other than mortality. Most trials compared only two separate thresholds for haemoglobin concentration, which may not identify the actual optimal threshold for transfusion in a particular patient. Haemoglobin concentration may not be the most informative marker of the need for transfusion in individual patients with different degrees of physiological adaptation to anaemia. Notwithstanding these issues, overall findings provide good evidence that transfusions with allogeneic RBCs can be avoided in most patients with haemoglobin thresholds between the range of 7.0 g/dL and 8.0 g/dL. Some patient subgroups might benefit from RBCs to maintain higher haemoglobin concentrations; research efforts should focus on these clinical contexts.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Sepsis-related anemia in a pediatric intensive care unit: transfusion-associated outcomes

BACKGROUND

Pediatric patients with sepsis in intensive care units are at high risk of developing anemia, which might have adverse effects on their prognosis. This study aimed to evaluate the impact of red blood cell (RBC) transfusion on the outcomes of patients admitted to a pediatric intensive care unit (PICU) with sepsis.

METHODS

We conducted a prospective randomized clinical trial, enrolling 67 children, aged 2 to 144 months who were admitted to a PICU with a new episode of sepsis from November 2017 to April 2018. Patients were allocated randomly to two groups: Group 1, liberal transfusion strategy group, including 33 patients who had initial hemoglobin (Hb) between 7 or greater and less than 10 g/dL and received an RBC top-up transfusion to 12 g/dL; and Group 2, restrictive strategy group, including 34 patients who had the same Hb range and did not receive RBCs. Patients with Hb less than 7 or greater than 10 g/dL were excluded.

RESULTS

Of 33 patients who received liberal transfusions, 31 (93.94%) required ventilation, and 29 (87.88%) had multiorgan dysfunction. They had a significantly lengthier hospital stay and a higher incidence of acute respiratory distress syndrome and acute lung injury. Moreover, mortality was significantly higher in the liberal transfusion group (42.4% vs. 17.6%).

CONCLUSIONS

Compared to the restrictive transfusion strategy, liberal transfusion might be associated with a worse outcome. However, the possible role of other known and unknown confounding factors and minor protocol violations should be taken into consideration. We recommend minimizing factors worsening anemia in PICU patients to reduce the need for transfusion.

The Comparison of Hemoglobin Values Measured by Blood and Continuous Non-Invasive Monitoring (SpHb) in Newborn Infants

OBJECTIVE

Hemoglobin (Hb) measurement is one of the most commonly used laboratory tests in medical practice. Unnecessary blood sampling, especially in neonatal intensive care units (NICUs), contributes to iatrogenic anemia. Continuous non-invasive monitoring of total Hb (SpHb) was compared with invasive venous blood samples (tHb) in NICU patients.

METHODS

Three hundred and ten patients were identified in NICU. Non-invasive Hb measurement was performed immediately before venous blood sampling and comparison of invasive with non-invasive values was undertaken.

RESULTS

There was a strongly positive correlation between SpHb and tHb (r = 0.965, p < 0.001). Bland-Altman analysis was performed in 95% limits of agreement for Hb values measured by both methods. The mean bias between tHb and SpHb measurements was 0.05 g/dl (-1.85 to 1.96). In Passing-Bablok regression analysis, the CUSUM test p value was found to be 0.98 for Hb levels measured by SpHb and tHb; and the difference between the methods was not significant.

CONCLUSION

In newborns, SpHb method offers reliable Hb values, which are comparable with the more traditional tHb method. Continuous non-invasive monitoring of total Hb may help prevent unnecessary blood sampling and iatrogenic anemia. Further clinical studies are required for the effectiveness of the method in critically ill patients with circulatory disorders.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

7 Is the New 8: Improving Adherence to Restrictive PRBC Transfusions in the Pediatric ICU

Up to 30%-40% of children admitted to the pediatric intensive care unit (PICU) have anemia, and approximately 15% receive packed red blood cell (pRBC) transfusions. Current literature supports a pRBC transfusion threshold of hemoglobin less than or equal to seven for most PICU patients. Our objective was to determine pRBC transfusion rates, assess compliance with transfusion guidelines, understand patient-level variables that affect transfusion practices, and use cross-industry innovation to implement a practice strategy. This was a pre-post study of pediatric patients admitted to our PICU. We collected baseline data on pRBC transfusion practices. Next, we organized an innovation platform, which generated multi-industry ideas and produced an awareness campaign to effect pRBC ordering behavior. Innovative educational interventions were implemented, and postintervention transfusion practices were monitored. Statistical analysis was performed using linear mixed models. A p value < .05 was considered statistically significant. At baseline, 41% of pRBC transfusions met restrictive transfusion guidelines with a pretransfusion hemoglobin less than or equal to 7 g/dl. In the postintervention period, 53% of transfusions met restrictive transfusion guidelines (odds ratio 1.66, 95% confidence interval 1.21-2.28). Implementation of a behavioral campaign using multi-industry innovation led to improved adherence to pRBC transfusion guidelines in a tertiary care PICU.

Liberal Transfusion versus Restrictive Transfusion and Outcomes in Critically Ill Adults: A Meta-Analysis

Objective

We aimed to determine whether the restrictive red-cell transfusion strategy was superior to the liberal one in reducing all-cause mortality in critically ill adults.

Methods

The MEDLINE, EMBASE, PubMed, Web of Science, and Cochrane Library Central Register of Controlled Trials databases were searched from inception to January 2019 to identify meta-analyses or systematic reviews and published randomized controlled trials which were restrictive versus liberal blood transfusion with mortality as the endpoint in critically ill adults. We used two search routes whereby one search was restricted to systematic reviews, reviews, or meta-analysis, and the other was not restricted. There were no date restrictions, but language was limited to English and the population was restricted to critically ill adults. The data of study methods, participant characteristics, and outcomes were extracted and analyzed independently by 2 reviewers. The main outcome was all-cause mortality.

Results

Through screening the obtained records, we enrolled 7 randomized clinical trials that included information on restrictive versus liberal red-cell transfusion and mortality of intensive care unit (ICU) patients. Involving a total of 7,363 ICU adult patients, ICU mortality (risk ratio [RR] 0.82, 95% confidence interval [CI] 0.62, 1.08, p = 0.15), 28/30-day mortality (RR 0.98, 95% CI 0.84, 1.13, p = 0.74), 60-day mortality (RR 1.01, 95% CI 0.87, 1.16, p = 0.91), 90-day mortality (RR 1.02, 95% CI 0.92, 1.14, p = 0.69), 120-day mortality (RR 1.29, 95% CI 0.67, 2.47, p = 0.44), and 180-day mortality (RR 0.91, 95% CI 0.75, 1.12, p = 0.38) were not statistically significantly different when the restrictive transfusion strategy was compared with the liberal transfusion strategy. However, we surprisingly discovered that 112 out of 469 (24%) patients who received a unit RBC transfusion when hemoglobin was less than 7 g/dL, and 142 out of 469 (30.3%) who received a unit of RBC transfused with hemoglobin less than 9 g/dL, had died during hospitalization (RR 0.79, 95% CI 0.64, 0.97, p = 0.03). The results showed that the restrictive transfusion strategy could decrease in-hospital mortality compared with the liberal transfusion strategy. It was safe to utilize a restrictive transfusion threshold of less than 7 g/dL in stable critically ill adults.

Conclusions

In this study, we found that the restrictive red-cell transfusion strategy potentially reduced in-hospital mortality in critically ill adults with anemia compared with the liberal strategy.

Clinical trials evaluating red blood cell transfusion thresholds: An updated systematic review and with additional focus on patients with cardiovascular disease

BACKGROUND

Several new trials evaluating transfusion strategies in patients with cardiovascular disease have recently been published, increasing the number of enrolled patients by over 30%. The objective was to evaluate transfusion thresholds in patients with cardiovascular disease.

METHODS

We conducted an updated systematic review of randomized trials that compared patients assigned to maintain a lower (restrictive transfusion strategy) or higher (liberal transfusion strategy) hemoglobin concentration. We focused on new trial data in patients with cardiovascular disease. The primary outcome was 30-day mortality. Specific subgroups were patients undergoing cardiac surgery and with acute myocardial infarction.

RESULTS

A total of 37 trials that enrolled 19,049 patients were appraised. In cardiac surgery, mortality at 30days was comparable between groups (risk ratio 0.99; 95% confidence interval 0.74-1.33). In 2 small trials (n=154) in patients with myocardial infarction, the point estimate for the mortality risk ratio was 3.88 (95% CI, 0.83-18.13) favoring the liberal strategy. Overall, from 26 trials enrolling 15,681 patients, 30-day mortality was not different between restrictive and liberal transfusion strategies (risk ratio 1.0, 95% CI, 0.86-1.16). Overall and in the cardiovascular disease subgroup, there were no significant differences observed across a range of secondary outcomes.

CONCLUSIONS

New trials in patients undergoing cardiac surgery establish that a restrictive transfusion strategy of 7 to 8g/dL is safe and decreased red cell use by 24%. Further research is needed to define the optimal transfusion threshold in patients with acute myocardial infarction.