Revisiting transfusion practices in critically ill patients

Transfusion practice in anemic, non-bleeding patients: Cross-sectional survey of physicians working in general internal medicine teaching hospitals in Switzerland

Background

Transfusion practice might significantly influence patient morbidity and mortality. Between European countries, transfusion practice of red blood cells (RBC) greatly differs. Only sparse data are available on transfusion practice of general internal medicine physicians in Switzerland.

Methods

In this cross-sectional survey, physicians working in general medicine teaching hospitals in Switzerland were investigated regarding their self-reported transfusion practice in anemic patients without acute bleeding. The definition of anemia, transfusion triggers, knowledge on RBC transfusion, and implementation of guidelines were assessed.

Results

560 physicians of 71 hospitals (64%) responded to the survey. Anemia was defined at very diverging hemoglobin values (by 38% at a hemoglobin <130 g/L for men and by 57% at <120 g/L in non-pregnant women). 62% and 43% respectively, did not define anemia in men and in women according to the World Health Organization. Fifty percent reported not to transfuse RBC according to international guidelines. Following factors were indicated to influence the decision to transfuse: educational background of the physicians, geographical region of employment, severity of anemia, and presence of known coronary artery disease. 60% indicated that their knowledge on Transfusion-related Acute Lung Injury (TRALI) did not influence transfusion practice. 50% of physicians stated that no local transfusion guidelines exist and 84% supported the development of national recommendations on transfusion in non-acutely bleeding, anemic patients.

Conclusion

This study highlights the lack of adherence to current transfusion guidelines in Switzerland. Identifying and subsequently correcting this deficit in knowledge translation may have a significant impact on patient care.

Smoking is Associated with Increased Blood Loss and Transfusion Use After Lumbar Spinal Surgery

BACKGROUND

Little is known about the association between smoking and intraoperative blood loss and perioperative transfusion use in patients undergoing spinal surgery. However, we found that although many of the common complications and deleterious effects of smoking on surgical patients had been well documented, the aspect of blood loss seemingly had been overlooked despite data reported in nonorthopaedic sources to suggest a possible connection.

QUESTIONS/PURPOSES

We asked: (1) Is smoking associated with increased estimated blood loss during surgery in patients undergoing lumbar spine surgery? (2) Is smoking associated with increased perioperative transfusion usage?

METHODS

Between 2005 and 2009, 581 lumbar decompression procedures (with or without fusion) were performed at one academic spine center. Of those, 559 (96%) had sufficient chart documentation to categorize patients by smoking status, necessary intra- and postoperative data to allow analysis with respect to bleeding and transfusion-related endpoints, and who did not meet exclusion criteria. Exclusion criteria included: patients whose smoking status did not fit in our two categories, patients with underlying coagulopathy, patients receiving anticoagulants (including aspirin and platelet inhibitors), history of hepatic disease, history of platelet disorder or other blood dyscrasias, and patient or family history of any other known bleeding disorder. Smoking history in packs per day was obtained for all subjects. We defined someone as a smoker if the patient reported smoking up until the day of their surgical procedure; nonsmokers were patients who quit smoking at least 6 weeks before surgery or had no history of smoking. We used a binomial grouping for whether patients did or did not receive a transfusion perioperatively. Age, sex, number of levels of discectomies, number of levels decompressed, number of levels fused, and use of instrumentation were recorded. The same approaches were used for transfusions in all patients regardless of smoking history; decisions were made in consultation between the surgeon and the anesthesia team. Absolute indications for transfusion postoperatively were: a hemoglobin less than 7 g/dL, continued symptoms of dizziness, tachycardia, decreased exertional tolerance, or hypotension that failed to respond to fluid resuscitation. Multiple linear regression analyses correcting for the above variables were performed to determine associations with intraoperative blood loss, while logistic regression was used to analyze perioperative transfusion use.

RESULTS

After controlling for potentially relevant confounding variables noted earlier, we found smokers had increased estimated blood loss compared with nonsmokers (mean, 328 mL more for each pack per day smoked; 95% CI, 249-407 mL; p < 0.001). We also found that again correcting for confounders, smokers had increased perioperative transfusion use compared with nonsmokers (odds ratio, 13.8; 95% CI, 4.59-42.52).

CONCLUSIONS

Smoking is associated with increased estimated surgical blood loss and transfusion use in patients undergoing lumbar spine surgery. Patients who smoke should be counseled regarding these risks and on smoking cessation before undergoing lumbar surgery.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The Effect of Patient-Specific Cerebral Oxygenation Monitoring on Postoperative Cognitive Function: A Multicenter Randomized Controlled Trial

BACKGROUND

Indices of global tissue oxygen delivery and utilization such as mixed venous oxygen saturation, serum lactate concentration, and arterial hematocrit are commonly used to determine the adequacy of tissue oxygenation during cardiopulmonary bypass (CPB). However, these global measures may not accurately reflect regional tissue oxygenation and ischemic organ injury remains a common and serious complication of CPB. Near-infrared spectroscopy (NIRS) is a noninvasive technology that measures regional tissue oxygenation. NIRS may be used alongside global measures to optimize regional perfusion and reduce organ injury. It may also be used as an indicator of the need for red blood cell transfusion in the presence of anemia and tissue hypoxia. However, the clinical benefits of using NIRS remain unclear and there is a lack of high-quality evidence demonstrating its efficacy and cost effectiveness.

OBJECTIVE

The aim of the patient-specific cerebral oxygenation monitoring as part of an algorithm to reduce transfusion during heart valve surgery (PASPORT) trial is to determine whether the addition of NIRS to CPB management algorithms can prevent cognitive decline, postoperative organ injury, unnecessary transfusion, and reduce health care costs.

METHODS

Adults aged 16 years or older undergoing valve or combined coronary artery bypass graft and valve surgery at one of three UK cardiac centers (Bristol, Hull, or Leicester) are randomly allocated in a 1:1 ratio to either a standard algorithm for optimizing tissue oxygenation during CPB that includes a fixed transfusion threshold, or a patient-specific algorithm that incorporates cerebral NIRS monitoring and a restrictive red blood cell transfusion threshold. Allocation concealment, Internet-based randomization stratified by operation type and recruiting center, and blinding of patients, ICU and ward care staff, and outcome assessors reduce the risk of bias. The primary outcomes are cognitive function 3 months after surgery and infectious complications during the first 3 months after surgery. Secondary outcomes include measures of inflammation, organ injury, and volumes of blood transfused. The cost effectiveness of the NIRS-based algorithm is described in terms of a cost-effectiveness acceptability curve. The trial tests the superiority of the patient-specific algorithm versus standard care. A sample size of 200 patients was chosen to detect a small to moderate target difference with 80% power and 5% significance (two tailed).

RESULTS

Over 4 years, 208 patients have been successfully randomized and have been followed up for a 3-month period. Results are to be reported in 2015.

CONCLUSIONS

This study provides high-quality evidence, both valid and widely applicable, to determine whether the use of NIRS monitoring as part of a patient-specific management algorithm improves clinical outcomes and is cost effective.

TRIAL REGISTRATION

International Standard Randomized Controlled Trial Number (ISRCTN): 23557269; http://www.isrctn.com/ISRCTN23557269 (Archived by Webcite at http://www.webcitation.org/6buyrbj64).

Relationship between hemoglobin concentration and extracorporeal blood flow as determinants of oxygen delivery during venovenous extracorporeal membrane oxygenation: a mathematical model

During veno-venous extracorporeal membrane oxygenation (VV-ECMO) support, optimization of oxygenation can be achieved by therapeutic interventions on both patient physiological variables and adjustment of ECMO settings. Based on the physiology of oxygen delivery during VV-ECMO support, we established the mathematical relationship between the variables which define the oxygenation state: hemoglobin (Hb), extracorporeal blood flow (ECBF), cardiac output (Q), and systemic oxygen consumption (VO2). Assuming constant values for Q and VO2, the model was applied to elucidate the interplay between Hb and ECBF in determining arterial oxygen saturation (SaO2), and the resultant systemic oxygen delivery (DO2) and native venous oxygen saturation (SvO2) in static conditions. At constant VO2 and Q, an inverse relationship exists between Hb and ECBF in determining SaO2 and SvO2. Despite the same value of SaO2, the DO2 resulting from the different combinations of Hb and ECBF progressively decreases with decreasing Hb. By demonstrating the quantitative relationship between Hb and ECBF as determinants of oxygenation during VV-ECMO support, this mathematical model could provide a theoretical basis for a rational approach to strategies to optimize oxygenation in patients on VV-ECMO.

Anemia and Transfusion in Critical Care

Objective:

The objective of this report is to review the physiology and management of anemia in critical care. Selected publications on physiology and transfusion related to anemia and critical care, including the modern randomized trials of conservative versus liberal transfusion policy, were used. Anemia is compensated and tolerated in most critically ill patients as long as oxygen delivery is at least twice oxygen consumption. There are risks to blood transfusion which can be minimized by blood banking practice. The availability of cultured red cells may allow correction of anemia without significant risk. The benefit of transfusion in anemia must be weighted against the risk in any specific patient.

Conclusion and Recommendation:

In a criticially ill patient, anemia should be managed to avoid oxygen supply dependency (oxygen delivery less than twice comsumption) and to maintain moderate oxygen delivery reserve (DO2/VO2 > 3).

Can old dogs learn new "transfusion requirements in critical care": a survey of packed red blood cell transfusion practices among members of The American Association for the Surgery of Trauma

BACKGROUND

The objective of this study was to characterize variations in packed red blood cell (PRBC) transfusion practices in critically ill patients and to identify which factors influence such practices. We hypothesized that significant variation in transfusion triggers exists among acute care surgeons.

METHODS

A survey of PRBC transfusion practices was administered to the American Association for the Surgery of Trauma members. The scenarios examined hemoglobin thresholds for which participants would transfuse PRBCs.

RESULTS

A hemoglobin threshold of less than or equal to 7 g/dL was adopted by 45% of respondents in gastrointestinal bleeding, 75% in penetrating trauma, 66% in sepsis, and 62% in blunt trauma. Acute care surgeons modified their transfusion trigger significantly in the majority of the modifications of these scenarios, often inappropriately so.

CONCLUSIONS

This study documents continued evidence-practice gaps and wide variations in the PRBC transfusion practices of acute care surgeons. Numerous clinical factors altered such patterns despite a lack of supporting evidence (for or against).

Monitoring compliance with transfusion guidelines in hospital departments by electronic data capture

BACKGROUND

The practice of transfusing red blood cells is still liberal in some centres suggesting a lack of compliance with guidelines recommending transfusion of red blood cells at haemoglobin levels of 6-8 g/dL in the non-bleeding patient. Few databases provide ongoing feedback of data on pre-transfusion haemoglobin levels at the departmental level. In a tertiary care hospital, no such data were produced before this study. Our aim was to establish a Patient Blood Management database based on electronic data capture in order to monitor compliance with transfusion guidelines at departmental and hospital levels.

MATERIALS AND METHODS

Hospital data on admissions, diagnoses and surgical procedures were used to define the populations of patients. Data on haemoglobin measurements and red blood cell transfusions were used to calculate pre-transfusion haemoglobin, percentage of transfused patients and transfusion volumes.

RESULTS

The model dataset include 33,587 admissions, of which 10% had received at least one unit of red blood cells. Haemoglobin measurements preceded 96.7% of the units transfused. The median pre-transfusion haemoglobin was 8.9 g/dL (interquartile range 8.2-9.7) at the hospital level. In only 6.5% of the cases, transfusion was initiated at 7.3 g/dL or lower as recommended by the Danish national transfusion guideline. In 27% of the cases, transfusion was initiated when the haemoglobin level was 9.3 g/dL or higher, which is not recommended. A median of two units was transfused per transfusion episode and per hospital admission. Transfusion practice was more liberal in surgical and intensive care units than in medical departments.

DISCUSSION

We described pre-transfusion haemoglobin levels, transfusion rates and volumes at hospital and departmental levels, and in surgical subpopulations. Initial data revealed an extensive liberal practice and low compliance with national transfusion guidelines, and identified wards in need of intervention.

Red blood cell transfusion practices in two surgical intensive care units: a mixed methods assessment of barriers to evidence-based practice

BACKGROUND

Despite evidence supporting restrictive red blood cell (RBC) transfusion thresholds and the associated clinical practice guidelines, clinical practice has been slow to change in the intensive care unit (ICU). Our aim was to identify barriers to conservative transfusion practice adherence.

STUDY DESIGN AND METHODS

A mixed-methods study involving observation of prescriber (i.e., physicians, physician assistants, nurse practitioners) and bedside nurse daily bedside rounds, provider survey, and medical record abstraction was conducted in one cardiac surgical ICU (CSICU) and one surgical ICU (SICU) in an academic hospital in Baltimore, Maryland.

RESULTS

Of 52 patient encounters observed during bedside rounds, 38 (73%) involved patients without evidence of active bleeding or cardiac ischemia. Surveys were completed by 52 (93%) of the 56 providers participating in rounds. Prescribers in the CSICU and SICU (87 and 90%, respectively) indicated the ideal pretransfusion hemoglobin (Hb) to be not more than 7 g/dL in nonbleeding and/or nonischemic patients compared to a minority of nurses (8% [p = 0.002] and 42% [p = 0.015], respectively). Prescribers and nurses in both ICUs overestimated the typical pretransfusion Hb in their units (CSICU, p < 0.001; SICU, p = 0.019). During rounds, providers infrequently explicitly discussed Hb monitoring or transfusion thresholds (33%) despite most (60%) reporting significant variation in transfusion thresholds between individual prescribers.

CONCLUSIONS

Our study identified several provider and system barriers to evidence-based transfusion practices including knowledge differences, overly optimistic estimates of current practice, and heterogeneous transfusion practice in each ICU. Further work is necessary to develop targeted interventions to improve evidence-based RBC transfusion practices.

Diagnosis and treatment of post-extubation dysphagia: results from a national survey

PURPOSE

This study sought to determine the utilization of speech-language pathologist (SLPs) for the diagnosis and treatment of post-extubation dysphagia in survivors of mechanical ventilation.

METHODS

We designed, validated, and mailed a survey to 1,966 inpatient SLPs who routinely evaluate patients for post-extubation dysphagia.

RESULTS

Most SLP diagnostic evaluations (60%; 95% CI, 59%-62%) were performed using clinical techniques with uncertain accuracy. Instrumental diagnostic tests (such as fluoroscopy and endoscopy) are more likely to be available at university than community hospitals. After adjusting for hospital size and academic affiliation, instrumental test use varied significantly by geographical region. Treatments for post-extubation dysphagia usually involved dietary adjustment (76%; 95% CI, 73-79%) and postural changes/compensatory maneuvers (86%; 95% CI, 84-88%), rather than on interventions aimed to improve swallowing function (24%; 95% CI, 21-27%).

CONCLUSIONS

SLPs frequently evaluate acute respiratory failure survivors. However, diagnostic evaluations rely mainly upon bedside techniques with uncertain accuracy. The use of instrumental tests varies by geographic location and university affiliation. Current diagnostic practices and feeding decisions for critically ill patients should be viewed with caution until further studies determine the accuracy of bedside detection methods.

The use of erythropoiesis-stimulating agents in the intensive care unit

Anemia is common in critically ill patients, but treatment with red blood cell transfusions can have unwanted effects. Limiting the occurrence and severity of anemia by using erythropoietic agents (iron and/or recombinant erythropoietin), therefore, remains an attractive option during the intensive care unit stay but also after hospital discharge. Moreover, these agents may have additional beneficial properties. In this article the authors review the rationale for the administration of iron and/or erythropoietin in critically ill patients.

A cross-country comparison of intensive care physicians' beliefs about their transfusion behaviour: a qualitative study using the Theoretical Domains Framework

BACKGROUND

Evidence of variations in red blood cell transfusion practices have been reported in a wide range of clinical settings. Parallel studies in Canada and the United Kingdom were designed to explore transfusion behaviour in intensive care physicians. The aim of this paper is three-fold: first, to explore beliefs that influence Canadian intensive care physicians' transfusion behaviour; second, to systematically select relevant theories and models using the Theoretical Domains Framework (TDF) to inform a future predictive study; and third, to compare its results with the UK study.

METHODS

Ten intensive care unit (ICU) physicians throughout Canada were interviewed. Physicians' responses were coded into theoretical domains, and specific beliefs were generated for each response. Theoretical domains relevant to behaviour change were identified, and specific constructs from the relevant domains were used to select psychological theories. The results from Canada and the United Kingdom were compared.

RESULTS

Seven theoretical domains populated by 31 specific beliefs were identified as relevant to the target behaviour. The domains Beliefs about capabilities (confident to not transfuse if patients' clinical condition is stable), Beliefs about consequences (positive beliefs of reducing infection and saving resources and negative beliefs about risking patients' clinical outcome and potentially more work), Social influences (transfusion decision is influenced by team members and patients' relatives), and Behavioural regulation (wide range of approaches to encourage restrictive transfusion) that were identified in the UK study were also relevant in the Canadian context. Three additional domains, Knowledge (it requires more evidence to support restrictive transfusion), Social/professional role and identity (conflicting beliefs about not adhering to guidelines, referring to evidence, believing restrictive transfusion as professional standard, and believing that guideline is important for other professionals), and Motivation and goals (opposing beliefs about the importance of restrictive transfusion and compatibility with other goals), were also identified in this study. Similar to the UK study, the Theory of Planned Behaviour, Social Cognitive Theory, Operant Learning Theory, Action Planning, and Knowledge-Attitude-Behaviour model were identified as potentially relevant theories and models for further study. Personal project analysis was added to the Canadian study to explore the Motivation and goals domain in further detail.

CONCLUSIONS

A wide range of beliefs was identified by the Canadian ICU physicians as likely to influence their transfusion behaviour. We were able to demonstrate similar though not identical results in a cross-country comparison. Designing targeted behaviour-change interventions based on unique beliefs identified by physicians from two countries are more likely to encourage restrictive transfusion in ICU physicians in respective countries. This needs to be tested in future prospective clinical trials.

Red blood cell transfusion in the critically ill patient

Red blood cell (RBC) transfusion is a common intervention in intensive care unit (ICU) patients. Anemia is frequent in this population and is associated with poor outcomes, especially in patients with ischemic heart disease. Although blood transfusions are generally given to improve tissue oxygenation, they do not systematically increase oxygen consumption and effects on oxygen delivery are not always very impressive. Blood transfusion may be lifesaving in some circumstances, but many studies have reported increased morbidity and mortality in transfused patients. This review focuses on some important aspects of RBC transfusion in the ICU, including physiologic considerations, a brief description of serious infectious and noninfectious hazards of transfusion, and the effects of RBC storage lesions. Emphasis is placed on the importance of personalizing blood transfusion according to physiological endpoints rather than arbitrary thresholds.

Red blood cell transfusions--are we narrowing the evidence-practice gap? An observational study in 5 Israeli intensive care units

PURPOSE

The aim of the study was to document transfusion practices in a cross section of general intensive care units (ICUs) in Israel and to determine whether current guidelines are being applied.

MATERIALS AND METHODS

This prospective study was performed in 5 general ICUs in Israel over a 3-month period. Red cell transfusion data collected on consecutive patients included the trigger, units transfused per transfusion event, and indications, categorized either to treat a specified condition for which transfusions may be beneficial (acute hemorrhage, acute myocardial ischemia, or severe sepsis) or to treat a low hemoglobin concentration.

RESULTS

Of the 238 patients studied, 50% received at least one red blood cell transfusion. The main indication for transfusion (43.7%, or 162/368 U transfused) was to treat a low hemoglobin concentration, in the absence of one of the specified conditions. Total red cell use was 3.0 ± 2.9 U per admission, and patients received a mean of 1.2 ± 0.4 U per transfusion event. The transfusion trigger for the whole group was 7.9 ± 1.1 g/dL. This did not differ significantly between the indications apart from a significantly higher trigger for patients with acute myocardial ischemia (8.8 ± 0.9 g/dL). In addition, patients with a history of heart disease had a higher trigger irrespective of the primary indication for transfusion and received significantly more units per transfusion event. Patients receiving a transfusion had significantly longer ICU stay and hospital mortality.

CONCLUSIONS

Our study showed that evidence-practice gaps continue to exist, and it appears that physician behavior is mainly driven by the absolute level of hemoglobin. Educational interventions focused on these factors are required to limit the widespread and often unnecessary use of this scarce and potentially harmful resource.

Risk of cardiac arrhythmias and conduction abnormalities in patients with acute myocardial infarction receiving packed red blood cell transfusions

PURPOSE

Although transfusion has been linked to the development of atrial fibrillation (AF) in cardiac surgical patients, this association has not been investigated in patients with acute myocardial infarction (AMI). Evidence supports an inflammatory mechanism in the development of AF, and red cell transfusions also elicit an inflammatory response. We therefore sought to evaluate whether packed red blood cell transfusion increases the risk of AF, ventricular tachycardia (VT), and other arrhythmias and conduction abnormalities in patients with AMI.

MATERIALS AND METHODS

This is a retrospective study on patients with AMI and no prior history of AF, admitted to a critical care area and entered in Project Impact database from 08/2003-12/2007. Primary outcome measures were new-onset cardiac arrhythmias or conduction disturbances.

RESULTS

Transfused patients had significantly higher incidences of AF (4.7% vs 1.3%, P = .008), cardiac arrest (9.5% vs 1.7%, P < .001) and heart block (3.4% vs 0.1%, P < .001), and a trend toward a higher incidence of VT (3.4% vs 1.3%, P = .058). Multivariate regression analysis confirmed transfusion as an independent risk factor for "non-lethal" cardiac events (AF/heart block; odds ratio [OR], 4.7 [1.9-11.9]; P = .001), "lethal" events (VT/cardiac arrest; OR, 2.4 [1.1-5]; P = .016), and all cardiac events (OR, 2.8 [1.5-65.1]; P = .001). Transfused patients had significantly longer length of stay (P < .0001) and significantly higher mortality rates than nontransfused patients (OR, 3 [1.7-5.5]; P < .001).

CONCLUSIONS

Packed red blood cell transfusion is independently associated with an increased risk of new-onset cardiac arrhythmias and conduction abnormalities in the setting of AMI, even after controlling for traditional risk factors.

Anemia causes hypoglycemia in intensive care unit patients due to error in single-channel glucometers: methods of reducing patient risk

OBJECTIVE

Intensive insulin therapy in the critically ill reduces mortality but carries the risk of increased hypoglycemia. Point-of-care blood glucose analysis is standard; however, anemia causes falsely high values and potentially masks hypoglycemia. Permissive anemia is practiced routinely in most intensive care units. We hypothesized that point-of-care glucometer error due to anemia is prevalent, can be corrected mathematically, and correction uncovers occult hypoglycemia during intensive insulin therapy.

DESIGN

The study has both retrospective and prospective phases. We reviewed data to verify the presence of systematic error, determine the source of error, and establish the prevalence of anemia. We confirmed our findings by reproducing the error in an in vitro model. Prospective data were used to develop a correction formula validated by the Monte Carlo method. Correction was implemented in a burn intensive care unit and results were evaluated after 9 mos.

SETTING

Burn and trauma intensive care units at a single research institution.

PATIENTS/SUBJECTS

Samples for in vitro studies were taken from healthy volunteers. Samples for formula development were from critically ill patients who received intensive insulin therapy.

INTERVENTIONS

Insulin doses were calculated based on predicted serum glucose values from corrected point-of-care glucometer measurements.

MEASUREMENTS AND MAIN RESULTS

Time-matched point-of-care glucose, laboratory glucose, and hematocrit values. We previously found that anemia (hematocrit <34%) produces systematic error in glucometer measurements. The error was correctible with a mathematical formula developed and validated, using prospectively collected data. Error of uncorrected point-of-care glucose ranged from 19% to 29% (p < .001), improving to < or = 5% after mathematical correction of prospective data. Comparison of data pairs before and after correction formula implementation demonstrated a 78% decrease in the prevalence of hypoglycemia in critically ill and anemic patients treated with insulin and tight glucose control (p < .001).

CONCLUSIONS

A mathematical formula that corrects erroneous point-of-care glucose values due to anemia in intensive care unit patients reduces the prevalence of hypoglycemia during intensive insulin therapy.

Forging a critical alliance: Addressing the research needs of the United States critical illness and injury community

OBJECTIVE

Discuss the research needs of the critical illness and injury communities in the United States.

DATA SOURCES

Workshop session held during the 5 National Institutes of Health Symposium on the Functional Genomics of Critical Illness and Injury (November 15, 2007).

STUDY SELECTION

The current clinical research infrastructure misses opportunities for synergy and does not address many important needs. In addition, it remains challenging to rapidly and properly implement system-wide changes based upon reproducible evidence from clinical research.

DATA EXTRACTION

Author presentations, panel discussion, attendee feedback.

DATA SYNTHESIS

The critical illness and injury research communities seek better communication and interaction, both of which will improve the breadth and quality of acute care research. Success in meeting these needs should come from cooperative and strategic actions that favor collaboration, standardization of protocols, and strong leadership. An alliance framed on common goals will foster collaboration among experts to better promote clinical trials within the critically ill or injured patient population.

CONCLUSIONS

The U.S. Critical Illness and Injury Trials Group was funded to create a clinical research framework that can reduce the barriers to investigation using an investigator-initiated, evidence-driven, inclusive approach that has proven successful elsewhere. This alliance will provide an annual venue for systematic review and strategic planning that will include framing the research agenda, raising awareness for the value of acute care research, gathering and promoting best practices, and bolstering the critical care workforce.

Anemia and blood transfusion practices in the critically ill: a prospective cohort review

BACKGROUND

Nearly 75% of critically ill patients develop anemia in the intensive care unit (ICU). Anemia can be treated with red blood cell (RBC) transfusions, although evidence suggests that lower hemoglobin levels are tolerated in the critically ill. Despite such recommendations, variation exists in clinical practice.

METHODS

A prospective cohort was assessed for anemia and RBC transfusion practices in 100 consecutive adults admitted to our General Systems ICU.

RESULTS

The prevalence of anemia in this cohort was 98%. Mean blood loss via phlebotomy was 25+/-10.3 mL per patient per day. The RBC transfusion rate for the ICU stay was 40%, increasing to 70% in patients whose ICU stay was >7 days. The mean pretransfusion level of hemoglobin was 7.35+/-0.47 mg/dL for the total cohort, and 8.2+/-0.65 mg/dL for those with a history of cardiovascular disease.

CONCLUSION

Anemia was common in this critically ill cohort, with hemoglobin levels continuing to drop with ICU stay. Pretransfusion hemoglobin levels were lower than reported by others, yet the RBC transfusion rate was comparable. There was no association between anemia and phlebotomy practices in our ICU.

Determinants of transfusion decisions in a mixed medical-surgical intensive care unit: a prospective cohort study

BACKGROUND

For reasons unknown, a restrictive transfusion policy of red blood cells (RBC) is only gradually being implemented by Intensive Care Unit (ICU) physicians, resulting in a large variation in transfusion practice. Insight into physicians' transfusion decisions may aid efforts to restrict transfusion practice.

STUDY DESIGN AND METHODS

In a prospective cohort study, transfusion triggers were determined in patients consecutively admitted to an ICU during a 10-week period. Using a questionnaire, the reasons why ICU physicians transfused RBC were evaluated.

RESULTS

Among 310 admissions, 90 patients (29%) received a RBC transfusion. Eighty-one of these 90 patients were included in this analysis. RBC were transfused at a mean haemoglobin (Hb) level of 7.4+/-1.1 g/dL. Residents transfused RBC at a higher Hb level compared to senior staff (7.7+/-1.0 versus 6.9+/-1.3, respectively; p<0.05). The most important reason for physicians to transfuse RBC was the suspicion of bleeding. Age and coronary ischaemia were the predominant reasons for transfusing RBC in 4% and 12% of cases, respectively. The average order for RBC transfusion was four units. Of each order, 38% of the units were not administered.

CONCLUSION

RBC transfusion decisions are predominantly based on Hb levels rather than on patients' characteristics. Residents transfuse at a higher Hb level compared to more experienced physicians. The major determinant for physicians to transfuse RBC is bleeding. However, the majority of patients were transfused in the absence of bleeding, and many of these patients received multiple units. The need for RBC may be overestimated, resulting in wasted orders.

Scientific and logistical challenges in designing the CONTROL trial: recombinant factor VIIa in severe trauma patients with refractory bleeding

BACKGROUND

Clinical research in trauma patients poses multiple challenges in study design. These reflect the heterogeneity of injury and treatment, the paucity of acceptable study endpoints aside from mortality, and the difficulties inherent in obtaining informed consent in acutely ill populations. A current example of this problem is the study of recombinant factor VIIa (rFVIIa), which has attracted considerable interest as a systemic procoagulant agent for use in trauma patients with exsanguinating hemorrhage.

PURPOSE

To report on the implementation of an international trial - CONTROL - intended to assess the efficacy and safety of rFVIIa in trauma, and discuss trauma research study design in light of this experience.

METHODS

The CONTROL trial international steering committee confronted a number of barriers in the design of the CONTROL trial. They addressed methodologies for (1) standardizing entry criteria for trauma patients suffering inherently heterogeneous injuries, (2) obtaining informed consent in an acutely injured population with altered levels of consciousness, (3) avoiding futile care, while recruiting subjects with incompletely diagnosed injuries, (4) standardizing trauma intensive care across different investigating sites and countries, and (5) establishing study endpoints that were both clinically relevant and convincing to regulatory authorities. The resulting study methodology is reported.

RESULTS

The CONTROL trial began active recruitment in October 2005, and was halted on June 11, 2008 because the observed mortality in the 576 enrolled patients was so far below expectations that the study would lack sufficient statistical power at the planned number of subjects to demonstrate a benefit. The utility of the endpoints selected for study will not be known until completion of data analysis.

LIMITATIONS

Any clinical trial in trauma patients must cope with the urgency of care required, issues of patient heterogeneity, standardization of care across multiple centers, and the difficulties of obtaining informed consent.

CONCLUSION

Research in acutely hemorrhaging trauma patients presents numerous scientific and ethical challenges. The methodology of the CONTROL study is presented as an example of how some of these challenges can be approached and managed, and of the pitfalls that may arise.

Early massive transfusion in trauma patients: Canadian single-centre retrospective cohort study

PURPOSE

To determine associations between red blood cell (RBC) transfusion and early and late clinical outcomes in massively transfused adult trauma patients.

METHODS

A retrospective cohort study (1992-2001) including 260 patients receiving >or=10 RBC units <or=24 hr after admission to a university-affiliated trauma centre. We extracted demographic and clinical data and used multivariable regression to determine independent effects of RBC transfusion on clinical outcomes.

RESULTS

Patients had a high (mean [standard deviation]) injury severity score (ISS) (42.5 [15.1]), a high admission sequential organ failure assessment (SOFA) score (8.4 [3.8]), and a high hospital mortality (58.5%). They received 38 (25-64) (median [interquartile range]) blood components within 48 hr, including 19 (14-28) RBC units. For 143 patients surviving >or=48 hr, the maximum SOFA score was associated with RBC units transfused before 48 hr (linear regression beta coefficient 0.075, P < 0.0001), lower nadir hemoglobin before 48 hr (0.034, P = 0.03), age (0.032, P = 0.015), and admission SOFA (0.59, P < 0.0001). The RBC units transfused by 48 hr were not associated with either hospital mortality (n = 35) among patients surviving >or=48 hr (independent predictors, age [logistic regression odds ratio (OR) 1.06, 95% confidence interval 1.03-1.10], ISS [OR 1.07, 1.02-1.13], and maximum SOFA score [OR 1.56, 1.27-1.93]) or 48-hr mortality (n = 117) (independent predictors, admission SOFA [1.65, 1.45-1.88] and later year of hospital admission [OR 1.15, 1.02-1.29]).

CONCLUSIONS

Hospital mortality is high among massively transfused trauma patients. Among early survivors, 48-hr RBC transfusion volume is associated with increased organ dysfunction, but not hospital mortality. Also, it is not associated with 48-hr mortality. Future research should continue to explore methods to improve hemostasis and minimize the need for RBC transfusion.

Red blood cell transfusion practices in acute lung injury: what do patient factors contribute?

OBJECTIVE

To describe red blood cell (RBC) transfusion practices and evaluate the association between patient-related factors and pretransfusion hemoglobin concentration in acute lung injury (ALI).

DESIGN

Secondary analysis of prospectively collected data.

SETTING

Nine intensive care units (ICUs) in three teaching hospitals in Baltimore, MD.

PATIENTS

Two hundred forty-nine consecutive patients with ALI requiring mechanical ventilation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Simple and multiple linear regression analyses were used to evaluate the association between the nadir hemoglobin concentration on the day of initial RBC transfusion and 20 patient-level demographic, clinical and ICU treatment factors as well as ICU type. Of 249 patients with ALI, 47% received an RBC transfusion in the ICU without evidence of active hemorrhage or acute cardiac ischemia. The mean (sd) nadir hemoglobin on the day of first transfusion was 7.7 (1.1) g/dL with 67%, 36%, 15%, and 5% of patients transfused at >7, >8, >9, and >10 g/dL, respectively. Transfused patients received a mean (sd) of 5 (6) RBC units from ALI diagnosis to ICU discharge. Prehospital use of iron or erythropoietin and platelet transfusion in the ICU were independently associated with lower pretransfusion hemoglobin concentrations. No patient factors were associated with higher hemoglobin concentrations. Admission to a surgical (vs. medical) ICU was independently associated with a 0.6 g/dL (95% confidence interval 0.1-1.1 g/dL) higher pretransfusion hemoglobin.

CONCLUSIONS

Patients with ALI commonly receive RBC transfusions in the ICU. The pretransfusion hemoglobin observed in our study was lower than earlier studies, but a restrictive strategy was not universally adopted. Patient factors do not explain the gap between clinical trial evidence and routine transfusion practices. Future studies should further explore ICU- and physician-related factors as a source of variability in transfusion practice.

Transfusion practices for acute traumatic brain injury: a survey of physicians at US trauma centers

PURPOSE

To determine whether physician specialty influences transfusion threshold in patients with acute severe traumatic brain injury (TBI).

METHODS

We surveyed transfusion preferences of chiefs of trauma surgery, chairs of neurosurgery, and surgical and neurosurgical ICU directors at all 187 US Level I trauma centers using a scenario-based, multiple-choice instrument administered by mail. We evaluated the hemoglobin value used as a transfusion threshold for patients with severe acute TBI in several scenarios as well as opinions regarding the rationale for transfusion.

RESULTS

The response rate was 58% (312/534). Mean time in practice was 17 +/- 8 years and 65% were board certified in critical care. Neurosurgeons (NS) used a greater mean hemoglobin threshold for transfusion of TBI patients than trauma surgeons (TS) and non-surgeon intensivists (CC) whether the intracranial pressure was normal (8.3 +/- 1.2, 7.5 +/- 1.0, and 7.5 +/- 0.8 g/dL; NS, TS, and CC, respectively, P < 0.001) or elevated (8.9 +/- 1.1, 8.0 +/- 1.1, and 8.4 +/- 1.1 g/dL; NS, TS, and CC, respectively, P < 0.001). All three groups commonly believed that secondary ischemic injury is an important problem following TBI (74, 66, and 63%, P = 0.32), but fewer NS believed that transfusions have important immunodulatory effects (25, 91, and 83%, P < 0.001).

CONCLUSIONS

Neurosurgeons prefer more liberal transfusion of TBI patients than TS and CC, suggesting that actual practice may depend largely on which specialist is primarily managing care. The observed clinical equipoise would justify a randomized trial of liberal versus restrictive transfusion strategies in patients with TBI.

Blood Transfusions in Trauma: Six-Year Analysis of the Transfusion Practices at a Level I Trauma Center

The objective of this study was to analyze the transfusion practices in trauma patients in one institution. A retrospective analysis of the Trauma Registry linked with the Blood Bank Database of a Level 1 trauma center was conducted. Over 6 years, 17 per cent of the 25,599 trauma patients received blood transfusions. The overall mortality in transfused patients was 20 per cent and remained the same during the study period. There was no change in the proportion of patients receiving transfusions throughout the years, however there was a significant 23.5 per cent reduction in the mean number of packed red blood cells (PRBC) units transfused (P < 0.001 for trend). This reduction in PRBC used remained true and even more evident in the group of more severely injured patients (Injury Severity Score ≥ 16), with a 27.9 per cent decrease in mean units of PRBC (P < 0.001 for trend). The highest reduction in PRBC transfusion was seen in blunt trauma patients (34.6%, P < 0.001). During the study period there was a concurrent increase in mean units of fresh frozen plasma used (60.7%, P < 0.001) and no change in the use of platelets and cryoprecipitate. In conclusion, transfusions of PRBC were significantly reduced over time in trauma patients without any evident negative impact on mortality.

A survey of Canadian intensivists' resuscitation practices in early septic shock

Introduction

Recent evidence suggests that early, aggressive resuscitation in patients with septic shock reduces mortality. The objective of this survey was to characterize reported resuscitation practices of Canadian physicians caring for adult critically ill patients with early septic shock.

Methods

A scenario-based self-administered national survey was sent out to Canadian critical care physicians. One hypothetical scenario was developed to obtain information on several aspects of resuscitation in early septic shock, including monitoring and resuscitation end-points, fluid administration, red blood cell transfusion triggers, and use of inotropes. The sampling frame was physician members of Canadian national and provincial critical care societies.

Results

The survey response rate was 232 out of 355 (65.3%). Medicine was the most common primary specialty (60.0%), most respondents had practiced for 6 to 10 years (30.0%), and 82.0% were male. The following monitoring devices/parameters were reported as used/measured 'often' or 'always' by at least 89% of respondents: oxygen saturation (100%), Foley catheters (100%), arterial blood pressure lines (96.6%), telemetry (94.3%), and central venous pressure (89.2%). Continuous monitoring of central venous oxygen saturation was employed 'often' or 'always' by 9.8% of respondents. The two most commonly cited resuscitation end-points were urine output (96.5%) and blood pressure (91.8%). Over half of respondents used normal saline (84.5%), Ringers lactate (52.2%), and pentastarch (51.3%) 'often' or 'always' for early fluid resuscitation. In contrast, 5% and 25% albumin solutions were cited as used 'often' or 'always' by 3.9% and 1.3% of respondents, respectively. Compared with internists, surgeons and anesthesiologists (odds ratio (95% confidence interval): 9.8 (2.9 to 32.7) and 3.8 (1.7 to 8.7), respectively) reported greater use of Ringers lactate. In the setting of a low central venous oxygen saturation, 52.5% of respondents reported use of inotropic support 'often' or 'always'. Only 7.6% of physicians stated they would use a red blood cell transfusion trigger of 100 g/l to optimize oxygen delivery further.

Conclusion

Our survey results suggest that there is substantial practice variation in the resuscitation of adult patients with early septic shock. More randomized trials are needed to determine the optimal approach.

[Changes in transfusion practice for surgery]

The context of transfusion has changed in recent years. Some data could lead to an increased demand: the risk of viral transmission has significantly decreased; a national survey has revealed that the mortality related to an insufficient or delayed transfusion was higher to the side effects of the transfusion itself. Some other data could decrease the demand: the preoperative use of EPO is now easier; the intraoperative use of antifibrinolytic has been shown to be efficient. The number of allogenic red blood cells units (RBCs) transfused each year in France regularly increases, while the transfusion of predeposited autologous blood is in sharp decline. However, in hospitals still using but reducing this technique, the consumption of allogenic RBCs does not increase and the transfusion of any blood (allogenic and/or autologous) decreases. The strategy is based on preoperative evaluation of usual blood loss and tolerable blood loss by accepting a reasonable risk of allogenic blood transfusion. Advances in public health seem to be found above all in the analysis of system failures.

Evolution of adverse changes in stored RBCs

Recent studies have underscored questions about the balance of risk and benefit of RBC transfusion. A better understanding of the nature and timing of molecular and functional changes in stored RBCs may provide strategies to improve the balance of benefit and risk of RBC transfusion. We analyzed changes occurring during RBC storage focusing on RBC deformability, RBC-dependent vasoregulatory function, and S-nitrosohemoglobin (SNO-Hb), through which hemoglobin (Hb) O(2) desaturation is coupled to regional increases in blood flow in vivo (hypoxic vasodilation). Five hundred ml of blood from each of 15 healthy volunteers was processed into leukofiltered, additive solution 3-exposed RBCs and stored at 1-6 degrees C according to AABB standards. Blood was subjected to 26 assays at 0, 3, 8, 24 and 96 h, and at 1, 2, 3, 4, and 6 weeks. RBC SNO-Hb decreased rapidly (1.2 x 10(-4) at 3 h vs. 6.5 x 10(-4) (fresh) mol S-nitrosothiol (SNO)/mol Hb tetramer (P = 0.032, mercuric-displaced photolysis-chemiluminescence assay), and remained low over the 42-day period. The decline was corroborated by using the carbon monoxide-saturated copper-cysteine assay [3.0 x 10(-5) at 3 h vs. 9.0 x 10(-5) (fresh) mol SNO/mol Hb]. In parallel, vasodilation by stored RBCs was significantly depressed. RBC deformability assayed at a physiological shear stress decreased gradually over the 42-day period (P < 0.001). Time courses vary for several storage-induced defects that might account for recent observations linking blood transfusion with adverse outcomes. Of clinical concern is that SNO levels, and their physiological correlate, RBC-dependent vasodilation, become depressed soon after collection, suggesting that even "fresh" blood may have developed adverse biological characteristics.

Blood transfusions in children: a multi-institutional analysis of practices and complications

BACKGROUND

Blood product transfusions are a valuable health-care resource. Guidelines for transfusion exist, but variability in their application, particularly in children, remains. The risk factors that threaten transfusion safety are well established, but because their occurrence in children is rare, single-institution studies have limited utility in determining the rates of occurrence. An epidemiologic approach that investigates blood transfusions in hospitalized children may help improve our understanding of transfused blood products in this vulnerable population.

STUDY DESIGN AND METHODS

This was a nonconcurrent cohort study of pediatric patients not more than 18 years of age hospitalized from 2001 to 2003 at 35 academic children's hospitals that are members of the Pediatric Health Information System (PHIS).

RESULTS

A total of 51,720 (4.8%) pediatric patients received blood product transfusions during the study period. Red blood cells (n = 44,632) and platelets (n = 14,274) were the two most frequently transfused products. The rate of transfusions was highest among children with neutropenia, agranulocytosis, and sickle cell crisis. Asian and American Indian patients had important differences in the rate of blood transfusions and their complications. Resource use in terms of length of stay and costs were higher in patients who received transfusion. Of those patients who received transfusions, 492 (0.95%) experienced a complication from the administered blood product. This accounted for a rate of complications of 10.7 per 1,000 units transfused.

CONCLUSIONS

The administration of blood products to children is a common practice in academic children's hospitals. Complications associated with these transfused products are rare.

Microvascular response to red blood cell transfusion in patients with severe sepsis

OBJECTIVES

Microvascular alterations may play a role in the development of multiple organ failure in severe sepsis. The effects of red blood cell transfusions on microvascular perfusion are not well defined. We investigated the effects of red blood cell transfusion on sublingual microvascular perfusion in patients with sepsis.

DESIGN

Prospective, observational study.

SETTING

A 31-bed, medical-surgical intensive care unit of a university hospital.

PATIENTS

Thirty-five patients with severe sepsis requiring red blood cell transfusions.

INTERVENTIONS

Transfusion of one to two units of leukocyte-reduced red blood cells.

MEASUREMENTS AND MAIN RESULTS

The sublingual microcirculation was assessed with an Orthogonal Polarization Spectral device before and 1 hr after red blood cell transfusion. Red blood cell transfusions increased hemoglobin concentration from 7.1 (25th-75th percentile, 6.7-7.6) to 8.1 (7.5-8.6) g/dL (p < .01), mean arterial pressure from 75 (69-89) to 82 (75-90) mm Hg (p < .01), and oxygen delivery from 349 (278-392) to 391 (273-473) mL/min.M (p < .001). Microvascular perfusion was not significantly altered by transfusion, but there was considerable interindividual variation. The change in capillary perfusion after transfusion correlated with baseline capillary perfusion (Spearman-rho = -.49; p = .003). Capillary perfusion was significantly lower at baseline in patients who increased their capillary perfusion by >8% compared with those who did not (57 [52-64] vs. 75 [70-79]; p < .01), while hemodynamic and global oxygen transport variables were similar in the two groups. Red blood cell storage time had no influence on the microvascular response to red blood cell transfusion.

CONCLUSIONS

The sublingual microcirculation is globally unaltered by red blood cell transfusion in septic patients; however, it can improve in patients with altered capillary perfusion at baseline.

Comparison of darbepoetin alfa and epoetin alfa in the management of anemia of critical illness

STUDY OBJECTIVE

To compare the effectiveness of darbepoetin alfa with epoetin alfa (recombinant human erythropoietin [rHuEPO]) for achieving transfusion independence and increasing hemoglobin concentrations in critically ill patients.

DESIGN

Retrospective, descriptive study.

SETTING

Level I trauma center intensive care units.

PATIENTS

Seventy-two patients who spent at least 3 days in the cardio-thoracic, medical, or surgery-trauma intensive care units and received at least one weekly dose of rHuEPO 40,000 units (33 patients) or darbepoetin alfa 100 microg (39 patients).

MEASUREMENTS AND MAIN RESULTS

Number of rHuEPO and darbepoetin alfa doses, hemoglobin concentrations, and cumulative number of transfusions were recorded for up to 28 days after the first dose was given, and the data were statistically analyzed. Beginning a median of 10 days after the patients were admitted to the intensive care unit, they received a median of 3.5 doses of darbepoetin alfa or 4 doses of rHuEPO. Mean hemoglobin concentrations at which treatment with darbepoetin alfa and rHuEPO were started were 8 and 8.2 g/dl, respectively (p=0.41). Transfusion independence was achieved in 44% of patients in the darbepoetin alfa group compared with 36% of patients in the rHuEPO group (p=0.63). Patients in both groups received a mean of 2.7 units of packed red blood cells during the 28-day study period. The mean change in hemoglobin levels from baseline over time did not significantly differ between groups (p=0.75).

CONCLUSIONS

Patients receiving darbepoetin alfa 100 microg/week and those receiving rHuEPO 40,000 units/week for anemia of critical illness achieved similar rates of transfusion independence and increases in hemoglobin concentrations from baseline at 28 days. Compared with previously published studies, erythropoietic agents were administered late in the course of critical illness in response to low hemoglobin concentrations.

Controversies in RBC Transfusion in the Critically Ill

Transfusion practice has been under great scrutiny over the last 2 decades. The examination of transfusion risks and benefits have been particularly important in the critically ill patient population. This review will examine some of the important controversies still surrounding the use of RBC transfusion in the critically ill patient.

Attitudes to blood transfusion post arthroplasty surgery in the United Kingdom: a national survey

Five hundred orthopaedic surgeons and 336 anaesthetists were surveyed to assess current UK attitudes towards transfusion practice following arthroplasty surgery. Seventy-two percent of surgeons and 73% of anaesthetists responded to the survey. In an uncomplicated patient following total hip arthroplasty, 53.2% of surgeons and 63.1% of anaesthetists would transfuse at or below a haemoglobin (Hb) level of 8 g/dL. Surgeons tended to be more aggressive in their attitudes, with a mean transfusion threshold of 8.3 g/dL compared to 7.9 g/dL for anaesthetists (p<0.01), and with 97% of surgeons transfusing two or more units compared to 78% of anaesthetists (p<0.01). This threshold Hb increased if the patient was symptomatic (surgeons 9.3 g/dL, anaesthetists 8.8 g/dL, p<0.05) or was known to have pre-existing ischaemic heart disease (surgeons 9.0 g/dL, anaesthetists 9.2 g/dL, p<0.05). A wide variability in attitudes and practices is demonstrated, and the development and adoption of consensus guidelines needs to be encouraged if efforts to reduce the use of blood products are to succeed.

Assessment of education and computerized decision support interventions for improving transfusion practice

BACKGROUND

Overuse of blood products is common, but prior efforts to improve transfusion decisions have met with limited success.

STUDY DESIGN AND METHODS

This study examines transfusion practices before and after a conventional educational intervention followed by a randomized controlled trial of a decision support (DS) intervention with computerized physician order entry (CPOE) for red blood cell, platelet, and fresh-frozen plasma orders. The study was conducted in an academic medical center between April 2003 and June 2004. Orders originating from units not using CPOE with DS (e.g., the emergency department) were excluded. Junior housestaff were randomly assigned into a control group and an intervention group who received DS for transfusion orders. Transfusion orders were initially classified according to guideline rules as DS-agree or DS-disagree. Chart reviews assessed inappropriateness for all DS-disagree orders and a sample of DS-agree orders. The total of inappropriate transfusion orders included chart review confirmed DS-disagree orders and DS-agree orders reclassified as inappropriate.

RESULTS

The percentages of inappropriate nonemergent transfusion orders during the baseline phase for the entire staff and randomly assigned junior housestaff were 72.6 percent (2154/2967) and 71.9 percent (1259/1752) and improved after conventional education to 63.8 percent (1699/2663; p < 0.0001) and 63.3 percent (1263/1996; p < 0.0001), respectively. The percentage of inappropriate orders in the DS intervention group continued to improve (59.6%, 804/1350; p < 0.0001). Physicians accepted 14 percent (133/939) of new DS-recommended orders, especially recommendations to increase transfusion doses (73%).

CONCLUSIONS

Education and computerized DS both decreased the percentage of inappropriate transfusions, although the residual amount of inappropriate transfusions remained high.

Can we safely restrict transfusion in trauma patients?

PURPOSE OF REVIEW

Transfusion of red blood cells in the trauma patient can be lifesaving. The question is how much and when? It is important to weigh the risks and benefits of red blood cell transfusions, as well alternatives to transfusion as these products are not benign.

RECENT FINDINGS

We explore the evidence, and provide the rationale for current and future red blood cell transfusion strategies within a framework of prehospital and hospital care of the trauma patient. We also describe how red blood cell transfusion trends are changing in trauma, discuss alternatives to red blood cell transfusion and present evidence from randomized controlled trials that support a lower transfusion trigger.

SUMMARY

Optimal transfusion practice and use of alternatives in trauma is a rapidly expanding and important area of research. Strong clinical evidence derived by future randomized controlled trials in the area of transfusion triggers as well as transfusion alternatives is required to determine their roles in clinical practice.

Red blood cell transfusion practices amongst Canadian anesthesiologists: a survey

PURPOSE

To assess red blood cell transfusion practices among Canadian anesthesiologists.

METHODS

A survey depicting three realistic clinical scenarios of elective surgical procedures with different risks of bleeding was administered to all Canadian practicing members (n = 2,100) of the Canadian Anesthesiologists' Society. Respondents were requested to choose hemoglobin thresholds for which they would transfuse red blood cells under various conditions within each scenario.

RESULTS

We obtained a response rate of 47% (719/1,512). Transfusion thresholds differed significantly between baseline scenarios. A threshold above 70 g x L(-1) was chosen by 48% of respondents in the general surgery scenario compared to 56% in the orthopedic surgery scenario and 79% in the vascular surgery scenario (P < 0.001). A history of coronary artery disease was associated with a transfusion threshold >or= 100 g x L(-1) in a significant proportion of respondents ranging from 20% in the orthopedic surgery scenario to 31% in the general surgery scenario and to 49% in the vascular surgery scenario (P < 0.001). Conversely, changing the patient's age from 60 to 20 yr resulted in the adoption of a transfusion threshold <or= 60 g x L(-1) by > 30% of respondents in two scenarios (P < 0.001). The year of respondent graduation was strongly associated with these findings.

CONCLUSION

There was significant variation in transfusion practices among Canadian anesthesiologists. The type of surgical procedure, patient's age and a history of coronary artery disease influenced reported transfusion threshold. Practice variation in specific subgroups would support the need for further research to identify optimal transfusion thresholds.

Transfusion in the intensive care unit

OBJECTIVE

To summarize the incidences of anemia and blood transfusions in critically ill patients, assess their comparative risks and benefits, and briefly speculate on the possible effects of leukoreduction and blood storage on the need to reevaluate transfusion triggers.

DESIGN

A review of the current literature was performed.

RESULTS

Anemia is common in intensive care unit patients and is associated with increased mortality. Some 20-53% of intensive care unit patients will receive a blood transfusion during their stay, and these have also been associated with worse outcomes. Leukoreduction may limit some of the infectious and immunomodulatory risks associated with blood transfusion.

CONCLUSIONS

Data on the risks and benefits of blood transfusion are conflicting, and with recent changes in blood transfusion practice, including the widespread introduction of leukoreduction, it is time to reevaluate our transfusion triggers.