Transfusion Thresholds Research Articles

Measurement of lead, mercury, and cadmium in blood donors in Canada.

Fetal and neonatal exposure to lead is associated with irreversible adverse effects on neural development. There is no reliable threshold for lead effect, so limiting exposure is recommended. A significant correlation has been reported between post-transfusion blood lead level (BLL) in infants and lead levels in transfused RBC units. We measured levels of lead, mercury, and cadmium, in Canadian donor blood to investigate if concerning levels for neonatal transfusion exist. Whole blood samples from blood donors (n = 2529) were shipped cold within 7 days of donation. All permanent blood donation clinics across Canada were sampled. Twelve of these permanent clinics and 8 mobile clinics with a greater potential for having higher lead or mercury levels were oversampled. Heavy metals were measured by inductively coupled plasma mass spectrometry. Of all donations, 2.2% (lead) and 0.4% (mercury) had levels higher than the recommended thresholds for safe neonatal transfusion. BLLs were higher in males but there was no significant difference in the blood mercury levels of males versus females. Cadmium levels were higher in females. There was a positive correlation between donor age and levels of heavy metals, with lead having the strongest correlation (r = 0.47, p < .0001). Three clinics in close proximity to two lead-producing mines were among the clinics with the highest BLLs. Significantly higher blood mercury levels were observed in coastal clinics. Our data on donor blood heavy metal levels supports considering blood transfusion as an exposure source to heavy metals and encourages informed selection of blood units for transfusion to vulnerable groups.

Prediction of anemia in real-time using a smartphone camera processing conjunctival images.

Anemia is defined as a low hemoglobin (Hb) concentration and is highly prevalent worldwide. We report on the performance of a smartphone application (app) that records images in RAW format of the palpebral conjunctivae and estimates Hb concentration by relying upon computation of the tissue surface high hue ratio. Images of bilateral conjunctivae were obtained prospectively from a convenience sample of 435 Emergency Department patients using a dedicated smartphone. A previous computer-based and validated derivation data set associating estimated conjunctival Hb (HBc) and the actual laboratory-determined Hb (HBl) was used in deriving Hb estimations using a self-contained mobile app. Accuracy of HBc was 75.4% (95% CI 71.3, 79.4%) for all categories of anemia, and Bland-Altman plot analysis showed a bias of 0.10 and limits of agreement (LOA) of (-4.73, 4.93 g/dL). Analysis of HBc estimation accuracy around different anemia thresholds showed that AUC was maximized at transfusion thresholds of 7 and 9 g/dL which showed AUC values of 0.92 and 0.90 respectively. We found that the app is sufficiently accurate for detecting severe anemia and shows promise as a population-sourced screening platform or as a non-invasive point-of-care anemia classifier.

Parallel Cerebrospinal Fluid and Serum Temporal Profile Assessment of Axonal Injury Biomarkers Neurofilament-Light Chain and Phosphorylated Neurofilament-Heavy Chain: Associations With Patient Outcome in Moderate-Severe Traumatic Brain Injury.

Neurofilament-light chain (NF-L) and phosphorylated neurofilament-heavy chain (pNF-H) are axonal proteins that have been reported as potential diagnostic and prognostic biomarkers in traumatic brain injury (TBI). However, detailed temporal profiles for these proteins in blood, and interrelationships in the acute and chronic time periods post-TBI have not been established. Our objectives were: 1) to characterize acute-to-chronic serum NF-L and pNF-H profiles after moderate-severe TBI, as well as acute cerebrospinal fluid (CSF) levels; 2) to evaluate CSF and serum NF-L and pNF-H associations with each other; and 3) to assess biomarker associations with global patient outcome using both the Glasgow Outcome Scale-Extended (GOS-E) and Disability Rating Scale (DRS). In this multi-cohort study, we measured serum and CSF NF-L and pNF-H levels in samples collected from two clinical cohorts (University of Pittsburgh [UPITT] and Baylor College of Medicine [BCM]) of individuals with moderate-severe TBI. The UPITT cohort includes 279 subjects from an observational cohort study; we obtained serum (n = 277 unique subjects) and CSF (n = 95 unique subjects) daily for 1 week, and serum every 2 weeks for 6 months. The BCM cohort included 103 subjects from a previous randomized clinical trial of erythropoietin and blood transfusion threshold after severe TBI, which showed no effect on neurological outcome between treatment arms; serum (n = 99 unique subjects) and CSF (n = 54 unique subjects) NF-L and pNF-H levels were measured at least daily during Days (D) 0-10 post-injury. GOS-E and DRS were assessed at 6 months (both cohorts) and 12 months (UPITT cohort only). Results show serum NF-L and pNF-H gradually rise during the first 10 days and peak at D20-30 post-injury. In the UPITT cohort, acute (D0-6) NF-L and pNF-H levels correlate within CSF and serum (Spearman r = 0.44-0.48; p < 0.05). In the UPITT cohort, acute NF-L CSF and serum levels, as well as chronic (Months [M]2-6) serum NF-L levels, were higher among individuals with unfavorable GOS-E and worse DRS at 12 months (p < 0.05, all comparisons). In the BCM cohort, higher acute serum NF-L levels were also associated with unfavorable GOS-E. Higher pNF-H serum concentrations (D0-6 and M2-6), but not CSF pNF-H, were associated with unfavorable GOS-E and worse DRS (p < 0.05, all comparisons) in the UPITT cohort. Relationships between biomarker levels and favorable outcome persisted after controlling for age, sex, and Glasgow Coma Scale. This study shows for the first time that serum levels of NF-L and pNF-H peak at D20-30 post-TBI. Serum NF-L levels, and to a lesser extent pNF-H levels, are robustly associated with global patient outcomes and disability after moderate-severe TBI. Further studies on clinical utility as prognosis and treatment-response indicators are needed.

European practices on antithrombotic management during percutaneous mechanical circulatory support in adults: an international survey of the ACVC Association of the ESC joint with EuroELSO

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Fonds Wetenschappelijk Onderzoek Flanders. Background/introduction Bleeding and thrombotic complications impair the outcomes of patients on percutaneous mechanical circulatory support (pMCS) with veno-arterial extracorporeal membrane oxygenation (V-A ECMO) and/or microaxial flow pumps such as the Impella™. Very recent MCS-trials still show a 23.9% moderate/major bleeding incidence during V-A ECMO. Antithrombotic practices are an important determinant of the meticulous coagulopathic risk management, but guidelines here are non-existing. Purpose Providing an overview of the current European practices in antithrombotic management in adults on pMCS is a first but crucial step to design trials, standardize practice and improve outcome. Methods This online cross-sectional survey was distributed via a digital newsletter and social media platforms through the Association of Acute Cardiovascular Care (ACVC) and the European Extracorporeal Life Support Organization (EuroELSO). The survey was accessible between 17.04 and 23.05.2023. The target population were European clinicians involved in adult critical care and pMCS-management. Results We included responses from 105 different units from 26 European countries. 72.4% Of the European responders have an institutional anticoagulation protocol installed. Unfractionated heparin is the predominantly used anticoagulant (Impella™: 97.0% and V-A ECMO: 96.1%). Argatroban is the preferred alternative in case of heparin-induced thrombocytopenia (Impella™: 52.3% and V-A ECMO: 50.7%). 10.8% And 14.5% of the anticoagulation protocols rely on anti-factor-Xa assay with activated partial thromboplastin time (APTT) in parallel for Impella™ and V-A ECMO, respectively. Up to 43.1% (Impella™) and 32.9% (V-A ECMO) of the European respondents rely on a monitoring strategy with APTT alone. Anticoagulant targets for heparin vary significantly between institutions. 54.0% And 42.7% of the European survey participants administer dual antiplatelet therapy (DAPT) during Impella™ and V-A ECMO support after acute coronary syndrome without percutaneous coronary intervention (PCI), increasing to 93.7% and 84.0% after recent PCI, respectively. Typical thresholds for transfusion or administration of blood products without acute bleeding also vary substantially and are frequently not predefined. Conclusion Large heterogeneity in antithrombotic practices is observed across Europe. Consequently, device-associated coagulopathic complications may largely vary due to non-standardized management and heterogeneity between institutions. This survey underpins the importance of urgent prospective trials investigating important basic questions concerning antithrombotic therapy during pMCS (anticoagulation targets, monitoring strategy, concomitant use of DAPT among others).

Timing of Red Blood Cell Transfusions and Occurrence of Necrotizing Enterocolitis

Observational studies often report that anemia and red blood cell (RBC) transfusions are associated with a higher risk of necrotizing enterocolitis (NEC) among extremely low-birthweight (ELBW) infants. To evaluate whether there is a temporal association between 72-hour hazard periods of exposure to RBC transfusions and NEC among ELBW infants randomized to either higher or lower hemoglobin transfusion thresholds. This post hoc secondary analysis of 1690 ELBW infants who survived to postnatal day 10 enrolled in the Transfusion of Prematures (TOP) randomized multicenter trial between December 1, 2012, and April 12, 2017, was performed between June 2021 and July 2023. First, the distribution of RBC transfusions and the occurrence of NEC up to postnatal day 60 were examined. Second, 72-hour posttransfusion periods were categorized as hazard periods and the pretransfusion periods of variable duration as control periods. Then, the risk of NEC in posttransfusion hazard periods was compared with that in pretransfusion control periods, stratifying the risk based on randomization group (higher or lower hemoglobin transfusion threshold group). The primary outcome was incidence of NEC stage 2 or 3. Secondary outcomes included the incidence rates of NEC within five 10-day intervals, taking into account the number of days at risk. Of 1824 ELBW infants randomized during the TOP trial, 1690 were included in the present analysis (mean [SD] gestational age, 26.0 [1.5] weeks; 899 infants [53.2%] were female). After categorizing 4947 hazard periods and 5813 control periods, we identified 133 NEC cases. Fifty-nine of these cases (44.4%) occurred during hazard periods. Baseline and clinical characteristics of infants with NEC during hazard periods did not differ from those of infants with NEC during control periods. The risk of NEC was 11.9 per 1000 posttransfusion hazard periods and 12.7 per 1000 control periods (adjusted risk ratio, 0.95; 95% CI, 0.68-1.32; P = .74). This risk did not differ significantly between randomization groups, but the incidence rate of NEC per 1000 days peaked between postnatal days 20 and 29 in the lower hemoglobin transfusion threshold group. The findings of this post hoc analysis suggest that, among ELBW infants with the hemoglobin ranges occurring in the TOP trial, exposure to RBC transfusions was not temporally associated with a higher risk of NEC during 72-hour posttransfusion hazard periods. Given that the incidence rate of NEC peaked between postnatal days 20 and 29 among infants with lower hemoglobin values, a more in-depth examination of this at-risk period using larger data sets is warranted. ClinicalTrials.gov Identifier: NCT01702805.

Anticoagulation during extracorporeal membrane oxygenation: A narrative review.

Extracorporeal Membrane Oxygenation (ECMO) is a technology that offers organ support for critically ill patients with respiratory and/or cardiac failure. Despite improvements in recent years in technology and the biocompatibility of circuits, patients on ECMO remain at high risk of hematologic complications, such as bleeding or thrombosis. Anticoagulation is required in most cases to limit the risk of clotting, but questions persist regarding the optimal anticoagulation strategy. More precisely, there is still debate around the best anticoagulation agent and monitoring tools as well as on the transfusion thresholds and appropriate corrective measures when faced with complications. This narrative review provides an overview of hemostasis on ECMO and the impact of circuit size and coating. The benefits and downsides of unfractionated heparin (UHF) and Direct Thrombin Inhibitors (DTIs) as anticoagulation agents are reviewed. Finally, commonly available coagulation tests (activated clotting time, activated partial thrombin time, anti-Xa, and viscoelastic tests) and their limitations are addressed. In conclusion, future research is needed to determine the best anticoagulation strategy for patients on ECMO.

Impact of restrictive platelet transfusion strategies on transfusion rates: A cohort study in very preterm infants.

Evidence supports a restrictive platelet transfusion threshold in preterm neonates. We aimed to describe the effect of implementing this threshold on transfusion rates. This retrospective observational cohort study included all very preterm infants (born <32 weeks' gestation) admitted to a neonatal intensive care unit between 2004 and 2022, divided into three epochs. Platelet transfusion thresholds changed from 30 × 109/L for stable neonates and 50 × 109/L for unstable neonates (January 2004 to December 2009) to 20 × 109/L for stable neonates and 50 × 109/L for unstable neonates (January 2010 to June 2019) to 25 × 109/L for non-bleeding neonates and 50 × 109/L for neonates with major bleeding (July 2019 to July 2022). The primary outcome was the percentage of transfused neonates in each epoch. Secondary outcomes included the median number of transfusions per neonate, the percentage of transfusions given above 25 or 50 × 109/L, and major bleeding and mortality rates. The percentage of neonates transfused was 12.2% (115/939), 5.8% (96/1660), and 4.8% (25/525) in Epoch I, II, and III, respectively (p < .001), a relative reduction of 61%. The median number of transfusions per transfused neonate was 2.0 (interquartile range [IQR]: 1.0-3.0) in Epoch I, and 1.0 (IQR: 1.0-2.0) in subsequent Epochs (p = .04). The percentage of infants receiving at least one transfusion above 50 × 109/L in Epoch I, II, and III was 51.3% (59/115), 17.7% (17/96), and 20.0% (5/25; p < .001). Mortality and bleeding rates did not significantly differ between epochs. Implementation of restrictive platelet guidelines led to reduction of the rate and number of platelet transfusions.

Peripheral perfusion index stratifies risk in patients with intraoperative anemia: A multicentre cohort study

Study objectiveEvidence for red blood cell (RBC) transfusion thresholds in the intraoperative setting is limited, and current perioperative recommendations may not correspond with individual intraoperative physiological demands. Hemodynamics relevant for the decision to transfuse may include peripheral perfusion index (PPI). The objective of this prospective study was to assess the associations of PPI and hemoglobin levels with the risk of postoperative morbidity and mortality. DesignMulticenter cohort study. SettingBispebjerg and Hvidovre University Hospitals, Copenhagen, Denmark. PatientsWe included 741 patients who underwent acute high risk abdominal surgery or hip fracture surgery. InterventionsNo interventions were carried out. MeasurementsPrincipal values collected included measurements of peripheral perfusion index and hemoglobin values. MethodsThe study was conducted using prospectively obtained data on adults who underwent emergency high-risk surgery. Subjects were categorized into high vs. low subgroups stratified by pre-defined PPI levels (PPI: > 1.5 vs. < 1.5) and Hb levels (Hb: > 9.7 g/dL vs. < 9.7 g/dL). The study assessed mortality and severe postoperative complications within 90 days. Main resultsWe included 741 patients. 90-day mortality was 21% (n = 154), frequency of severe postoperative complications was 31% (n = 231).Patients with both low PPI and low Hb had the highest adjusted odds ratio for both 90-day severe postoperative complications (2.95, [1.62–5.45]) and 90-day mortality (3.13, [1.45–7.11]).A comparison of patients with low PPI and low Hb to those with high PPI and low Hb detected significantly higher 90-day mortality risk in the low PPI and low Hb group (OR 8.6, [1.57–162.10]). ConclusionHigh PPI in acute surgical patients who also presents with anemia was associated with a significantly better outcome when compared with patients with both low PPI and anemia. PPI should therefore be further investigated as a potential parameter to guide intraoperative RBC transfusion therapy.

Improvement of Transfusion Practice in Cardiothoracic Surgery Through Implementing a Patient Blood Management Program.

In this study, we examined the impact of a patient blood management (PBM) program on red blood cell (RBC) transfusion practices in cardiothoracic surgery. The PBM program had 3 components: monitoring transfusions through an order communication system checklist, educating the medical team about PBM, and providing feedback to ordering physicians on the appropriateness of transfusion. The retrospective analysis examined changes in the hemoglobin levels triggering transfusion and the proportions of appropriate RBC transfusions before, during, and after PBM implementation. Further analysis was focused on patients undergoing cardiac surgery, with outcomes including 30-day mortality, durations of intensive care unit and hospital stays, and rates of pneumonia, sepsis, and wound complications. The study included 2,802 patients admitted for cardiothoracic surgery. After the implementation of PBM, a significant decrease was observed in the hemoglobin threshold for RBC transfusion. This threshold dropped from 8.7 g/dL before PBM to 8.3 g/dL during the PBM education phase and 8.0 g/dL during the PBM feedback period. Additionally, the proportion of appropriate RBC transfusions increased markedly, from 23.9% before PBM to 34.9% and 58.2% during the education and feedback phases, respectively. Among the 381 patients who underwent cardiac surgery, a significant reduction was noted in the length of hospitalization over time (p<0.001). However, other clinical outcomes displayed no significant differences. PBM implementation effectively reduced the hemoglobin threshold for RBC transfusion and increased the rate of appropriate transfusion in cardiothoracic surgery. Although transfusion practices improved, clinical outcomes were comparable to those observed before PBM implementation.

Leading digit bias in hemoglobin thresholds for red cell transfusion.

Leading digit bias is a heuristic whereby humans overemphasize the left-most digit when evaluating numbers (e.g., 9.99 vs. 10.00). The bias might affect the interpretation of hemoglobin results and influence red cell transfusion in hospitalized patients. Adults who received a red cell transfusion while registered at the University Health Network (Toronto, Canada) between January 1, 2016 and January 1, 2022 (n = 6 years) were included. The primary analysis excluded apheresis, red cell disorders, radiology suites, and operating rooms. The primary comparison was a regression discontinuity analysis of transfusion occurrence above and below the hemoglobin threshold of 79 g/L (local units). Additional analyses tested other leading digit and control thresholds (71, 81, and 91 g/L). Secondary analyses explored temporal covariates and clinical subgroups. A total of 211,872 red cell transfusions were identified over the study period (median pre-transfusion hemoglobin 76 g/L; interquartile range = 69-92 g/L), with 107,790 inpatient transfusions in the primary analysis. The 79 g/L threshold showed 815 fewer red cell units above the threshold (95% confidence interval [CI]: -1215 to -415). The 69 g/L threshold showed 2813 fewer transfused units (95% CI: -4407 to -1220), and 89 g/L showed 40 fewer units (95% CI: -408 to 328). The effect was accentuated during daytime, weekday, and May-June months, persisted in analyses including all transfusions, and was absent at control thresholds. Leading digit bias might have a modest influence on the decision to transfuse red cells. The findings may inform practice guidelines and quasi-experimental study design in transfusion research.

Red blood cell transfusion in neurocritical patients: a systematic review and meta-analysis

BackgroundAnemia can lead to secondary brain damage by reducing arterial oxygen content and brain oxygen supply. Patients with acute brain injury have impaired self-regulation. Brain hypoxia may also occur even in mild anemia. Red blood cell (RBC) transfusion is associated with increased postoperative complications, poor neurological recovery, and mortality in critically ill neurologic patients. Balancing the risks of anemia and red blood cell transfusion-associated adverse effects is challenging in neurocritical settings.MethodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and MEDLINE (PubMed) from inception to January 31, 2024. We included all randomized controlled trials (RCTs) assessing liberal versus restrictive RBC transfusion strategies in neurocritical patients. We included all relevant studies published in English. The primary outcome was mortality at intensive care unit (ICU), discharge, and six months.ResultsOf 5195 records retrieved, 84 full-text articles were reviewed, and five eligible studies were included. There was no significant difference between the restrictive and liberal transfusion groups in ICU mortality (RR: 2.53, 95% CI: 0.53 to 12.13), in-hospital mortality (RR: 2.34, 95% CI: 0.50 to 11.00), mortality at six months (RR: 1.42, 95% CI: 0.42 to 4.78) and long-term mortality (RR: 1.22, 95% CI: 0.64 to 2.33). The occurrence of neurological adverse events and most major non-neurological complications was similar in the two groups. The incidence of deep venous thrombosis was lower in the restrictive strategy group (RR: 0.41, 95% CI: 0.18 to 0.91).ConclusionsDue to the small sample size of current studies, the evidence is insufficiently robust to confirm definitive conclusions for neurocritical patients. Therefore, further investigation is encouraged to define appropriate RBC transfusion thresholds in the neurocritical setting.

Preoperative Blood Transfusion Requirements for Hemorrhoidal Severe Anemia: A Retrospective Study of 128 Patients.

BACKGROUND Severe anemia caused by hemorrhoidal hematochezia is typically treated preoperatively with reference to severe anemia treatment strategies from other etiologies. This retrospective cohort study included 128 patients with hemorrhoidal severe anemia admitted to 3 hospitals from September 1, 2018, to August 1, 2023, and aimed to evaluate preoperative blood transfusion requirements. MATERIAL AND METHODS Of 5120 patients with hemorrhoids, 128 (2.25%; male/female: 72/56) experienced hemorrhoidal severe anemia, transfusion, and Milligan-Morgan surgery. Patients were categorized into 2 groups based on their preoperative hemoglobin (PHB) levels after transfusion: PHB ≥70 g/L as the liberal-transfusion group (LG), and PHB <70 as the restrictive-threshold group (RG). The general condition, bleeding duration, hemoglobin level on admission, transfusion volume, length of stay, immune transfusion reaction, surgical duration, and hospitalization cost were compared between the 2 groups. RESULTS Patients with severe anemia (age: 41.07±14.76) tended to be younger than those with common hemorrhoids (age: 49.431±15.59 years). The LG had a significantly higher transfusion volume (4.77±2.22 units), frequency of immune transfusion reactions (1.22±0.58), and hospitalization costs (16.69±3.31 thousand yuan) than the RG, which had a transfusion volume of 3.77±2.09 units, frequency of immune transfusion reactions of 0.44±0.51, and hospitalization costs of 15.00±3.06 thousand yuan. Surgical duration in the LG (25.69±14.71 min) was significantly lower than that of the RG (35.24±18.72 min). CONCLUSIONS Patients with hemorrhoids with severe anemia might require a lower preoperative transfusion threshold than the currently recognized threshold, with an undifferentiated treatment effect and additional benefits.

Adherence to a restrictive red blood cell transfusion strategy in critically ill patients: An observational study.

Randomized controlled trials relatively consistently show that restrictive red blood cell (RBC) transfusion strategies are safe and associated with similar outcomes compared to liberal transfusion strategies in critically ill patients. Based on these data, the general threshold for RBC transfusion was changed to 70 g/L at a 9-bed tertiary level intensive care unit in September 2020. Implementation measures included lectures, webinars and feedback during clinical practice. The aim of this study was to investigate how implementation of a restrictive transfusion strategy influenced RBC usage, haemoglobin trigger levels and adherence to prescribed trigger levels. In this registry-based, observational study, critically ill adult patients without massive bleeding were included and divided into a pre-cohort, with admissions prior to the change of transfusion strategy, and a post-cohort, with admissions following the change of transfusion strategy. These cohorts were compared regarding key RBC transfusion-related variables. In total 5626 admissions were included in the analyses (pre-cohort n = 4373, post-cohort n = 1253). The median volume (interquartile range, IQR) of RBC transfusions per 100 admission days, in the pre-cohort was 6120 (4110-8110) mL versus 3010 (2890-4970) mL in the post-cohort (p < .001). This corresponds to an estimated median saving of 1128 € per 100 admission days after a restrictive RBC transfusion strategy was implemented. In total, 26% of the admissions in the pre-cohort and 19% in the post-cohort (p < .001) received RBC transfusion(s) during days 0-10. Both median (IQR) prescribed trigger levels (determined by intensivist) and actual haemoglobin trigger levels (i.e., levels prior to actual administration of transfusion) were higher in the pre- versus post-cohort (90 [80-100] vs. 80 [72-90] g/L, p < .001 and 89 [82-96] g/L vs. 83 [79-94], p < .001, respectively). Percentage of days without compliance with the prescribed transfusion trigger was higher in the pre-cohort than in the post-cohort (23% vs. 14%, p < .001). Sensitivity analyses, excluding patients with traumatic brain injury, ischemic heart disease and COVID-19 demonstrated similar results. Implementation of a restrictive transfusion trigger in a critical care setting resulted in lasting decreased RBC transfusion use and costs, decreased prescribed and actual haemoglobin trigger levels and improved adherence to prescribed haemoglobin trigger levels.

Transfusion strategies for neonates: current perspectives.

Blood transfusion intervention has been proven to be a crucial therapeutic aid for preterm infants with serious morbidities such as sepsis, intraventricular hemorrhage, and cardiopulmonary insufficiencies. However, blood transfusion practices have also been shown to cause significant adverse outcomes, which may negate the therapeutic effect of the intervention. To address the varying policies regarding the administration of blood products, healthcare professionals have adopted a consensus-based approach. The absence of a standard protocol has resulted in conflicting outcomes in previous clinical studies. This study aimed to evaluate the effectiveness of blood transfusion practices in preterm infants by analyzing past clinical research and identifying the current trends that have emerged as a result of recent trials. Recent trials have demonstrated comparable trends in mortality rates and other primary outcomes, including retinopathy of prematurity, intraventricular hemorrhage, bronchopulmonary dysplasia, and brain injury, following transfusion of blood products in both groups. Nevertheless, employing restrictive thresholds rather than adopting a liberal approach can reduce these outcomes. The current literature does not provide clear support for either technique as opposing and contradictory results are evident. However, there is a slight inclination toward the restrictive transfusion threshold due to recent trials, which warrants further in-depth investigation into this issue.

The Effect of Albumin Administration in Critically Ill Patients: A Retrospective Single-Center Analysis.

The aim of this study was to analyze the development of albumin administration in patients admitted to the adult ICU. In addition, we assessed the impact of albumin administration on serum hemoglobin concentration. We conducted a retrospective single-center study including all patients who were admitted to the ICU from January 2013 to December 2021 and stayed at least 24 hours. The study was conducted in an academic hospital (University Hospital Basel, Switzerland). A total of 20,927 admissions were included, of which 3748 received albumin at least once during their ICU stay. To analyze volume expansion, 2006 admissions met the inclusion criteria, namely at least two hemoglobin measurements within 12 hours, one albumin delivery, and experienced no bleeding, dialysis, or transfusions during this period. None. We examined the hemoglobin levels before and after albumin administration and compared them with a matched control group to assess the amount and duration of volume expansion. From 2013 to 2021 the proportion of critically ill patients treated with albumin rose from 5.0% to 32.5%. An overproportioned increase in albumin use could be seen in surgical patients (4.7-47.2%) and in those receiving RBC transfusion (13.7-72.6%). In those patients receiving albumin, a significant drop in hemoglobin of around 5 g/L on average could be observed following treatment with albumin. Hemodilution was observable for at least 12 hours after albumin administration and may have caused a decrease in hemoglobin concentration of greater than 8 g/L when isooncotic albumin solution (5%, 25 g in 500 mL) was administered. This makes albumin, especially in its isooncotic form, an ideal colloid to achieve long-lasting volume expansion. However, RBC transfusions may increase under albumin therapy, as transfusion thresholds may be undershot after albumin administration.

Feasibility and accuracy of noninvasive continuous hemoglobin monitoring using transesophageal photoplethysmography in porcine model

BackgroundContinuous and noninvasive hemoglobin (Hb) monitoring during surgery is essential for anesthesiologists to make transfusions decisions. The aim of this study was to investigate the feasibility and accuracy of noninvasive and continuous Hb monitoring using transesophageal descending aortic photoplethysmography (dPPG) in porcine model.MethodsNineteen landrace pigs, aged 3 to 5 months and weighing 30 to 50 kg, were enrolled in this study. A homemade oximetry sensor, including red (660 nm) and infrared (940 nm) lights, was placed in the esophagus for dPPG signal detection to pair with the corresponding reference Hb values (Hbi−STAT) measured by blood gas analysis. The decrease and increase changes in Hb concentration were achieved by hemodilution and transfusion. Metrics, including alternating current (AC), direct current (DC), and AC/DC for both red and infrared light were extracted from the dPPG signal. A receiver operating characteristic (ROC) curve was built to evaluate the performance of dPPG metrics in predicting the Hb “trigger threshold” of transfusion (Hb < 60 g/L and Hb > 100 g/L). Agreement and trending ability between Hb measured by dPPG (HbdPPG) and by blood gas analysis were analyzed by Bland-Altman method and polar plot graph. Error grid analysis was also performed to evaluate clinical significance of HbdPPG measurement.ResultsThe dPPG signal was successfully detected in all of the enrolled experimental pigs, without the occurrence of a continuous loss of dPPG signal for 2 min during the entire measurement. A total of 376 pairs of dPPG signal and Hbi−STAT were acquired. ACred/DCred and ACinf/DCinf had moderate correlations with Hbi−STAT, and the correlation coefficients were 0.790 and 0.782, respectively. The areas under the ROC curve for ACred/DCred and ACinf/DCinf in predicting Hbi−STAT < 60 g/L were 0.85 and 0.75, in predicting Hbi−STAT > 100 g/L were 0.90 and 0.83, respectively. Bland-Altman analysis and polar plot showed a small bias (1.69 g/L) but a wide limit of agreement (-26.02–29.40 g/L) and a poor trend ability between HbdPPG and Hbi−STAT. Clinical significance analysis showed that 82% of the data lay within the Zone A, 18% within the Zone B, and 0% within the Zone C.ConclusionIt is feasible to establish a noninvasive and continuous Hb monitoring by transesophageal dPPG signal. The ACred/DCred extracted from the dPPG signal could provide a sensitive prediction of the Hb threshold for transfusion. The Hb concentration measured by dPPG signal has a moderate correlation with that measured by blood gas analysis. This animal study may provide an experimental basis for the development of bedside HbdPPG monitoring in the future.

Ultra-restrictive red blood cell transfusion strategies in extensively burned patients

In recent years, due to the shortage of blood products, some extensive burn patients were forced to adopt an “ultra-restrictive” transfusion strategy, in which the hemoglobin levels of RBC transfusion thresholds were < 7 g/dl or even < 6 g/dl. This study investigated the prognostic impacts of ultra-restrictive RBC transfusion in extensive burn patients. This retrospective multicenter cohort study recruited extensive burns (total body surface area ≥ 50%) from three hospitals in Eastern China between 1 January 2016 and 30 June 2022. Patients were divided into an ultra-restrictive transfusion group and a restrictive transfusion group depending on whether they received timely RBC transfusion at a hemoglobin level < 7 g/dl. 1:1 ratio propensity score matching (PSM) was performed to balance selection bias. Modified Poisson regression and linear regression were conducted for sensitive analysis. Subsequently, according to whether they received timely RBC transfusion at a hemoglobin level < 6 g/dl, patients in the ultra-restrictive transfusion group were divided into < 6 g/dl group and 6–7 g/dl group to further compare the prognostic outcomes. 271 eligible patients with extensive burns were included, of whom 107 patients were in the ultra-restrictive transfusion group and 164 patients were in the restrictive transfusion group. The ultra-restrictive transfusion group had a significantly lower RBC transfusion volume than the restrictive transfusion group (11.5 [5.5, 21.5] vs 17.3 [9.0, 32.5] units, p = 0.004). There were no significant differences between the two groups in terms of in-hospital mortality, risk of infection, hospital length of stay, and wound healing time after PSM or multivariate adjustment (p > 0.05). Among the ultra-restrictive transfusion group, patients with RBC transfusion threshold < 6 g/dl had a significantly higher hospital mortality than 6–7 g/dl (53.1% vs 21.3%, p = 0.001). For extensive burn patients, no significant adverse effects of ultra-restrictive RBC transfusion were found in this study. When the blood supply is tight, it is acceptable to adopt an RBC transfusion threshold of < 7 g/dL but not < 6 g/dL.

Consequences of anemia in geriatric hip fractures: how low is too low?

BackgroundThe transfusion threshold for low hemoglobin (Hgb) in geriatric patients with hip fractures is widely debated. In certain populations, low Hgb is associated with poor outcomes. Our objective was to...

Machine learning in the prediction of massive transfusion in trauma: a retrospective analysis as a proof-of-concept.

Early administration and protocolization of massive hemorrhage protocols (MHP) has been associated with decreases in mortality, multiorgan system failure, and number of blood products used. Various prediction tools have been developed for the initiation of MHP, but no single tool has demonstrated strong prediction with early clinical data. We sought to develop a massive transfusion prediction model using machine learning and early clinical data. Using the National Trauma Data Bank from 2013 to 2018, we included severely injured trauma patients and extracted clinical features available from the pre-hospital and emergency department. We subsequently balanced our dataset and used the Boruta algorithm to determine feature selection. Massive transfusion was defined as five units at 4h and ten units at 24h. Six machine learning models were trained on the balanced dataset and tested on the original. A total of 326,758 patients met our inclusion with 18,871 (5.8%) requiring massive transfusion. Emergency department models demonstrated strong performance characteristics with mean areas under the receiver-operating characteristic curve of 0.83. Extreme gradient boost modeling slightly outperformed and demonstrated adequate predictive performance with pre-hospital data only, as well as 4-h transfusion thresholds. We demonstrate the use of machine learning in developing an accurate prediction model for massive transfusion in trauma patients using early clinical data. This research demonstrates the potential utility of artificial intelligence as a clinical decision support tool.

Platelet Transfusion and Death or Neurodevelopmental Impairment in Children Born Extremely Preterm

Infants born extremely preterm receive transfusions at higher platelet count thresholds than older children and adults due to concerns for intracranial hemorrhage. A recent randomized trial comparing 2 platelet transfusion thresholds showed the higher threshold was associated with increased risk of long-term adverse neurodevelopmental outcomes. To evaluate the association of platelet transfusion exposure with death and severe neurodevelopmental impairment (NDI) at 2 years' corrected age in a cohort of infants born extremely preterm. An observational cohort study and secondary analysis of the Preterm Erythropoietin Neuroprotection Trial, a randomized, placebo-controlled clinical trial of erythropoietin neuroprotection in neonates born extremely preterm, was conducted in 30 neonatal intensive care units in the US from December 1, 2013, to September 31, 2016. This analysis included 819 infants born extremely preterm at 24 to 27 completed weeks of gestation who had a documented outcome (death or neurodevelopmental assessment). Analysis was performed in April 2023. Any platelet transfusion during neonatal intensive care unit hospitalization. The primary composite outcome was death or severe NDI evaluated at 2 years' corrected age using the Bayley Scales of Infant Development-Third Edition (BSID-III) and the Gross Motor Function Classification System and was defined as the presence of severe cerebral palsy or a BSID-III composite motor or cognitive score 2 SDs below the mean. Confounding by indication for platelet transfusion was addressed with covariate adjustment and propensity score methods. Of the 819 infants included in the analysis (429 [52.4%] male; mean [SD] gestational age, 25.5 [1.1] weeks), 245 (30.0%) received at least 1 platelet transfusion during their initial hospitalization. The primary outcome occurred in 46.5% (114 of 245) of infants exposed to a platelet transfusion and 13.9% (80 of 574) of nonexposed infants with a corresponding odds ratio of 2.43 (95% CI, 1.24-4.76), adjusted for propensity score, gestational age at birth, and trial treatment group. The individual components of death and severe NDI were directionally consistent with the overall composite outcome. The findings of this study suggest that platelet transfusion in infants born extremely preterm may be associated with an increased risk of death or severe NDI at 2 years' corrected age, although the possibility of residual confounding by indication cannot be excluded.