How low is too low? Cardiac risks with anemia

Current Status of Measurement Accuracy for Total Hemoglobin Concentration in the Clinical Context

OBJECTIVE

The main objective of this investigation is to provide data about the accuracy of total hemoglobin concentration measurements with respect to clinical settings, and to devices within the categories of point-of-care and reference systems. In particular, tolerance of hemoglobin concentrations below 9 g/dL that have become common in clinical practice today determines the need to demonstrate the limits of measurement accuracy in patient care.

METHODS

Samples extracted from six units of heparinized human blood with total hemoglobin concentrations ranging from 3 to 18 g/dL were assigned to the test devices in a random order. The pool of test devices comprised blood gas analyzers, an automatic hematology analyzer, a laboratory reference method, and the point-of-care system HemoCue. To reduce the pre-analytic error, each sample was measured three times. Due to the characteristics of the tested devices and methods, we selected the mean values of the data from all these devices, measured at the corresponding total hemoglobin concentrations, as the reference.

MAIN RESULTS

The measurement results of the test devices overlap within strict limits (R² = 0.999). Only the detailed analysis provides information about minor but systematic deviations. In the group of clinically relevant devices, which are involved in patient blood management decisions, the relative differences were within the limit of +/- 5 % for values down to 3 g/dL.

CONCLUSIONS

A clinically relevant change of +/- 0.5 g/dL of total hemoglobin concentration can be detected with all selected devices and methods. Compliance with more stringent definitions-these are the relative differences of 5 % in relation to the corresponding reference values and the clinically adapted thresholds in the format of a tolerance level analysis-was achieved by the clinical devices assessed here.

Impact of liberal intraoperative allogeneic blood transfusion on postoperative morbidity and mortality in major thoracic and lumbar posterior spine instrumentation surgeries

PURPOSE

To investigate the impact of intraoperative blood transfusion on outcomes in patients who had major thoracic and lumber posterior spine instrumentation surgery.

METHODS

Retrospective study included patients who underwent major spine surgery between 2013 and 2017. Patients' demographics, surgical charts, anesthesia charts, discharge charts and follow-up outpatient charts were reviewed. Data collection included: age, gender, BMI, Charlson Co-morbidity Index (CCI) scores, American Society of Anesthesiologists (ASA) scores, amount of estimated blood loss [% estimated blood volume (%EBV)], amount of blood transfused during surgery and post-surgery before discharge, number of fusion levels, pre- and postoperative hemoglobin (Hb) levels, and length of hospital stay. Also collected in-hospital postoperative complications (cardiovascular, pulmonary, infections and deaths). Patients' postoperative intubation status data documented. Reviewed follow-up charts to document any complications.

RESULTS

Sample size = 289; No transfusion = 92; transfusion = 197. Transfused patients were significantly older, p < 0.001, higher average BMIs (p < 0.001); ASA scores (p < 0.001); CCI scores (p < 0.001), mean postoperative Hb level (p = 0.004), average intraoperative %EBV loss (p < 0.001), longer hospital stays (p = 0.003). Non-transfusion cohort had significantly higher proportion of patients (p < 0.001) extubated immediately after surgery. Seventeen patients had at least one in-hospital complication, p = 0.05. Complications were not significant among groups.

CONCLUSION

Intraoperative blood transfusions and high volume intraoperative allogeneic blood transfusions did not increase risk for in-hospital complications or surgical site infections. Delayed extubations noticed in patients who received higher volumes of intraoperative allogeneic blood transfusions. High-volume intraoperative blood transfusions increased length of hospital stays. High post-hospital surgical infections associated with high volume intraoperative blood transfusions. Results should be interpreted cautiously due to small sample size.

The influence of the optical properties on the determination of capillary diameters

Various clinically applicable scores and indices are available to help identify the state of a microcirculatory disorder in a patient. Several of these methods, however, leave room for interpretation and only provide clues for diagnosis. Thus, a measurement method that allows a reliable detection of impending or manifest circulatory malfunctions would be of great value. In this context, the optical and non-invasive method of shifted position-diffuse reflectance imaging (SP-DRI) was developed. It allows to determine the capillary diameter and thus to assess the state of the microcirculation. The aim of the present study is to investigate how the quantification of capillary diameters by SP-DRI behaves in different individuals, i.e. for a wide range of optical properties. For this, within Monte-Carlo simulations all optical properties (seven skin layers, hemoglobin) were randomly varied following a Gaussian distribution. An important finding from the present investigation is that SP-DRI works when the optical properties are chosen randomly. Furthermore, it is shown that appropriate data analysis allows calibration-free absolute quantification of the capillary diameter across individuals using SP-DRI. This underpins the potential of SP-DRI to serve as an early alert system for the onset of microcirculatory associated diseases.

Use of hyperbaric oxygenation as an adjunctive treatment for severe pernicious anaemia in a bloodless medicine patient

Severe anaemia in patients who cannot receive blood transfusion is an indication for the use of hyperbaric oxygen therapy (HBO). Most reports of the use of HBO for anaemia involve patients with acute blood loss. This report details a case of HBO used for a patient with severe pernicious anaemia. A 35-year-old Jehovah's Witnesses believer presented to a hospital with fatigue, dyspnoea and haemoglobin of 26 g/L. She was diagnosed with pernicious anaemia. As she could not receive blood transfusion due to her religious beliefs, vitamin B₁₂ supplementation and HBO were administered and resulted in significant improvement in her condition. The mechanisms of action of HBO, including increased systemic plasma oxygenation, can alleviate signs and symptoms of anaemia regardless of its aetiology. HBO administration can greatly enhance the plasma arterial oxygen content, leading to clinical improvement in patients with anaemia who cannot receive blood transfusion.

Combined Intravenous and Intraarticular Tranexamic Acid Does Not Offer Additional Benefit Compared with Intraarticular Use Alone in Bilateral TKA: A Randomized Controlled Trial

BACKGROUND

Tranexamic acid (TXA) is efficacious for reducing blood loss and transfusion use in patients who undergo bilateral TKA, and it is administered intravenously alone, intraarticularly alone, or as a combination of these. However, it is unclear whether combined intravenous (IV) and intraarticular TXA offers any additional benefit over intraarticular use alone in patients undergoing bilateral TKA.

QUESTIONS/PURPOSES

The purposes of our study was to determine (1) whether combined IV and intraarticular TXA reduces blood loss and blood transfusion use compared with intraarticular use alone and (2) whether the frequency of adverse events is different between these routes of administration in patients who undergo simultaneous or staged bilateral TKA.

METHODS

Between April 2015 and May 2017, one surgeon performed 316 same-day bilateral TKAs and 314 staged bilateral TKAs. Of those, 98% of patients in each same-day TKA (310) and staged bilateral TKA (309) groups were eligible for this randomized trial and all of those patients agreed to participate and were randomized. The study included four groups: simultaneous TKA with intraarticular TXA only (n = 157), simultaneous TKA with IV and intraarticular TXA (n = 153), staged TKA with intraarticular TXA only (n = 156), and staged TKA with IV and intraarticular TXA (n = 155). There were no differences in demographic data among the intraarticular alone and IV plus intraarticular TXA groups of patients who underwent simultaneous or staged bilateral TKA in terms of age, proportion of female patients, BMI, or preoperative hematologic values. The primary outcome variables were total blood loss calculated based on patient blood volume and a drop in the hemoglobin level and administration of blood transfusion. The secondary outcomes of this study were a decrease in the postoperative hemoglobin level; the proportion of patients with a hemoglobin level lower than 7.0, 8.0, or 9.0 g/dL; and the frequencies of symptomatic deep vein thrombosis, symptomatic pulmonary embolism, wound complications, and periprosthetic joint infection.

RESULTS

Total blood loss with intraarticular TXA alone in patients undergoing simultaneous bilateral TKA and those undergoing staged procedures was not different from the total blood loss with the combined IV plus intraarticular TXA regimen (1063 mL ± 303 mL versus 1004 mL ± 287 mL, mean difference 59 mL [95% CI -7 to 125]; p = 0.08 and 909 ml ± 283 ml versus 845 ml ± 278 ml; mean difference 64 mL [95% CI 1 to 127]; p = 0.046, respectively). The use of blood transfusions between intraarticular alone and combined IV and intraarticular TXA was also not different among patients undergoing simultaneous (0% [0 of 152] versus 1%; p = 0.149) and staged TKA (1% [1 of 155] versus 0% [0 of 153]; p = 0.98). Furthermore, the frequency of symptomatic thromboembolic events, wound complications, and periprosthetic joint infections was low, without any differences among the groups with the numbers available.

CONCLUSION

Because there was no difference between intraarticular alone and combined intraarticular plus IV regimen of TXA administration, we recommend that IV and intraarticular TXA should not be used in combination. Moreover, other studies have found no differences between intraarticular and IV TXA used alone, and hence to avoid potential complications associated with systemic administration, we recommend that intraarticular alone is sufficient for routine TKA.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Low relative muscle volume: Correlation with prevalence of venous thromboembolism following total knee arthroplasty

Background

There have been many efforts to find modifiable risk factors for venous thromboembolism (VTE) in the perioperative period of total knee arthroplasty (TKA), while no study has investigated the relationship between the muscle mass and deep vein thrombosis (DVT) or pulmonary embolism frequency following TKA. This study aimed to evaluate the relationship between muscle volume and the prevalence of symptomatic and radiologically confirmed venous thromboembolism (VTE) after total knee arthroplasty (TKA).

Methods

A total of 261 consecutive patients who underwent primary TKA between 2013 and 2015 were enrolled. Computed tomographic venography with pulmonary angiography (CTVPA) was performed between the 5th and 7th postoperative days to assess the presence of VTE. Four parameters of muscle volume at three levels were evaluated on CTVPA: (i) the cross-sectional area of all skeletal muscles (skeletal muscle index) and total psoas area at the level of the third lumbar vertebrae; (ii) the vastus lateralis muscle at the thigh level; and (iii) the posterior crural muscle at the lower leg level. The relationship between the muscle volume at each level and the prevalence of VTE after TKA was evaluated with multivariate adjusted logistic regression models.

Results

The CTVPA scan showed no proximal DVT, and all thrombi were located in muscular, peroneal, and posterior tibial veins. In unilateral TKA, patients with lower muscle volume of the vastus lateralis at the thigh level in the nonoperated limb had significantly higher prevalence of distal DVT in the operated limb (adjusted OR: 2.97 at subclinical DVT revealed by CTVPA and adjusted OR: 2.68 at symptomatic DVT). This finding was also discovered in patients who underwent simultaneous bilateral TKA (adjusted OR: 1.73–2.97 at subclinical DVT and adjusted OR:1.76–1.86 at symptomatic DVT).

Conclusions

The relative muscle volume of the vastus lateralis at the thigh level was negatively associated with the prevalence of symptomatic and radiologically confirmed DVT, suggesting that low thigh muscle mass is an independent risk factor for VTE in the postoperative period of TKA.

Emergency Medicine Evaluation and Management of Anemia

Anemia is a common condition and is diagnosed on laboratory assessment. It is defined by abnormally low hemoglobin concentration or decreased red blood cells. Several classification systems exist. Laboratory markers provide important information. Acute anemia presents with symptoms owing to acute blood loss; chronic anemia may present with worsening fatigue, dyspnea, lightheadedness, or chest pain. Specific treatments depend on the underlying anemia and etiology. Iron is an alternative treatment for patients with microcytic anemia owing to iron deficiency. Hyperbaric oxygen is an option for alternative rescue therapy. Most patients with chronic anemia may be discharged with follow-up if hemodynamically stable.

Different Kinetics of Perioperative CRP after Hip Arthroplasty for Elderly Femoral Neck Fracture with Elevated Preoperative CRP

This study aimed to determine the kinetics of four inflammatory markers and to identify the variables that affect the natural kinetics of inflammatory markers in aged patients having hip fractures with and without elevated preoperative CRP. 240 elderly patients who have been operated on for femoral neck fracture with no infectious complications were divided into two groups on elevated preoperative CRP level (>10 mg/L). The temporal values of four inflammatory markers of WBC, neutrophil count (N) (%), ESR, and CRP were assessed eight times every other day until the 14th postoperative day. At 48–60 h postoperatively, mean CRP was markedly higher in patients with preoperatively elevated CRP than in those with nonelevated CRP (122.1 ± 65.9 and 73.7 ± 35.5, p < 0.001). However, the abrupt elevation of CRP in the elevated group was conversely decreased on the 4th-5th postoperative day, demonstrating similar kinetic curves with no significant differences between both groups. For WBC, N (%), and ESR, both groups showed similar patterns of temporal values 14 days after surgery regardless of preoperative CRP level. Our findings could be used as guidelines for patient discharge and during the follow-up period after surgery.

What is the Ideal Route of Administration of Tranexamic Acid in TKA? A Randomized Controlled Trial

BACKGROUND

TKA commonly involves substantial blood loss and tranexamic acid has been used to reduce blood loss after TKA. Numerous clinical trials have documented the efficacy and safety of intravenous (IV) or intraarticular (IA) use of tranexamic acid. Combined administration of tranexamic acid also has been suggested; however, there is no consensus regarding the ideal route of tranexamic acid administration.

QUESTIONS/PURPOSES

(1) To compare the efficacy of tranexamic acid in terms of total blood loss and the allogeneic transfusion rate among three routes of administration: IV alone, IA alone, and combined IV and IA. (2) To compare these regimens in terms of venous thromboembolism (VTE) and the frequency of wound complications.

METHODS

In total, 376 patients undergoing TKA between March 2014 and March 2015 were randomized to four groups by the route of tranexamic acid administration: IV only, IA only, low-dose combined (IV + IA injection of 1 g), and high-dose combined (IV + IA injection of 2 g). The calculated total blood loss, allogeneic transfusion rate, decrease in hemoglobin, the frequency of symptomatic deep vein thrombosis and pulmonary embolism, wound complications, and periprosthetic joint infection were compared among the groups. Total blood loss was calculated using estimated total body blood volume and hemoglobin loss. The decision regarding when to transfuse was determined based on preset criteria.

RESULTS

The high- and low-dose combined groups and the IA-only group had lower total blood loss (564 ± 242 mL, 642 ± 242 mL, and 633 ± 205 mL, respectively) than the IV-only group (764 ± 217 mL; mean differences = 199 mL [95% CI, 116-283 mL], p < 0.001; 121 mL [95% CI, 38-205 mL], p = 0.001; 131 mL [95% CI, 47-214 mL], p < 0.001); no differences were found among the other three groups. No patients in any study group received an allogeneic transfusion. One patient in the IV-only group had a symptomatic pulmonary embolism develop, but no other symptomatic VTE events occurred in any group. In addition, no differences were observed in wound complications, such as superficial wound necrosis (one patient in the IV-only and the high-dose combined group, respectively) and oozing (IV-only, IA-only, low-dose combined, high-dose combined = 3%, 4%, 4%, and 7%; p = 0.572) between the groups. No patients had a periprosthetic joint infection.

CONCLUSION

IA tranexamic acid administration further reduces blood loss after TKA in comparison to IV use alone; no additional effect in further reducing blood loss was found in combination with IV tranexamic acid. Appropriately powered studies are needed to confirm the safety of this route of administration as the preferred route of administration in TKA.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Hemoglobin Level and Hospital Mortality Among ICU Patients With Cardiac Disease Who Received Transfusions

BACKGROUND

There is a paucity of randomized clinical trial data on the use of red blood cell (RBC) transfusion in critically ill patients, specifically in the setting of cardiac disease.

OBJECTIVES

This study examined how hemoglobin (Hgb) level and cardiac disease modify the relationship of RBC transfusion with hospital mortality. The aim was to estimate the Hgb level threshold below which transfusion would be associated with reduced hospital mortality.

METHODS

We performed secondary data analyses of Veterans Affairs intensive care unit (ICU) episodes across 5 years. Logistic regression quantified the effect of transfusion on hospital mortality while adjusting for nadir Hgb level, demographic characteristics, admission information, comorbid conditions, and ICU admission diagnoses.

RESULTS

Among 258,826 ICU episodes, 12.4% involved transfusions. Hospital death occurred in 11.6%. Without comorbid heart disease, transfusion was associated with decreased adjusted hospital mortality when Hgb was approximately <7.7 g/dl, but transfusion increased mortality above this Hgb level. Corresponding Hgb level thresholds were approximately 8.7 g/dl when comorbid heart disease was present and approximately 10 g/dl when the ICU admission diagnosis was acute myocardial infarction (AMI). Sensitivity analysis using additional adjustment for selected blood tests in a subgroup of 182,792 ICU episodes lowered these thresholds by approximately 1 g/dl.

CONCLUSIONS

Transfusion of critically ill patients was associated with reduced hospital mortality when Hgb level was <8 to 9 g/dl in the presence of comorbid heart disease. This Hgb level threshold for transfusion was 9 to 10 g/dl when AMI was the ICU admission diagnosis.

Is Total Knee Arthroplasty a Viable Treatment Option in Octogenarians with Advanced Osteoarthritis?

Purpose

This study directly compared clinical assessment scores and short-term systemic complications after total knee arthroplasty (TKA) between a group of patients aged 80 or older (141 patients) and another group of patients aged between 65 and 70 years (616 patients) with advanced osteoarthritis.

Materials and Methods

We retrospectively investigated 757 osteoarthritic patients who underwent primary TKA from January 2007 to January 2011 with a follow-up of 1 year. The surgery was performed using an extramedullary alignment guide instrument without invasion of the intramedullary canal to decrease embolic load and blood loss.

Results

At 1 year after surgery, the mean Knee Society knee score was improved in both groups (from 63.6 to 83.2 in octogenarians and from 68.3 to 89.0 in the younger group) and the level of satisfaction was excellent in both groups (8 in octogenarians and 8.3 in the younger group), even though there was no notable change in function score in the octogenarians (from 61.0 to 61.9 in the octogenarians and from 62.3 to 73.6 in the younger group). The total incidence of systemic complications (3.4% vs. 1.2%, p=0.400) and surgical complications (2.1% vs. 0.5%, p=0.229) showed no significant difference between groups.

Conclusions

TKA yielded favorable clinical outcomes with a comparatively low postoperative complication rate in octogenarians despite the negligible functional improvement.

Clinical value of tranexamic acid in unilateral and simultaneous bilateral TKAs under a contemporary blood-saving protocol: a randomized controlled trial

PURPOSE

Despite the documented blood-saving effects of tranexamic acid (TNA) in total knee arthroplasty (TKA), the question whether clinical values of TNA are identical in unilateral and bilateral TKAs remains unclear. This study was undertaken to determine the clinical values of TNA in unilateral and simultaneous bilateral TKAs under a contemporary blood-saving protocol in terms of efficacy (total blood loss and transfusion rate) and safety (the incidences of symptomatic deep vein thrombosis and pulmonary embolism).

METHODS

One hundred and eighty unilateral and 146 bilateral TKA patients were randomized into TNA group or control group. In unilateral TKA patients, TNA (10 mg/kg) was administered intravenously 20 min before tourniquet deflation and repeated 3 h after surgery. In bilateral TKA patients, one more dose (10 mg/kg) was given before tourniquet deflation in the second TKA. A contemporary blood-saving protocol was applied to all patients. The TNA and control groups were compared separately in unilateral and bilateral TKA patients for the efficacy and safety variables.

RESULTS

In unilateral TKA patients, the TNA group had less total blood loss (905 vs. 1,018 mL, p = 0.018) than the control group, but there was no difference in the allogenic transfusion rate (1 vs. 7 %, n.s.). In bilateral TKA patients, the TNA group showed no differences in total blood loss (1,282 vs. 1,379 mL, n.s.), but a significant reduction in the allogenic transfusion rate (7 vs. 27 %, p = 0.002). No symptomatic deep vein thrombosis or pulmonary embolism was found in all patients.

CONCLUSION

This study demonstrates that the use of TNA reduces total blood loss, but the effects on the transfusion rate can differ depending on the type of TKAs (unilateral vs. bilateral) and the blood-saving protocols.

The association between perioperative allogeneic transfusion volume and postoperative infection in patients following lumbar spine surgery

BACKGROUND

Perioperative allogeneic red blood cell transfusion is a risk factor for surgical site infection. The purpose of this study was to determine if the volume of perioperative allogeneic red blood cell transfusion influences the risk of surgical site infection following lumbar spine procedures.

METHODS

A retrospective matched case control study was performed by reviewing all patients who had undergone lumbar spine surgery at our institution from 2005 to 2009. Surgical site infections (spinal or iliac crest) were identified, all within thirty days of the procedure. Controls were matched to the infection cohort according to age, sex, body mass index, diabetic status, smoking status, Charlson Comorbidity Index, length of surgery, and procedure. A conditional logistic regression was performed to examine the association between transfusion volume and surgical site infection. The results were summarized by an odds ratio.

RESULTS

A total of 1799 lumbar procedures were identified with an infection rate of 3.1% (fifty-six cases). On the basis of the numbers, there was no significant difference in the matched variables between the infection cohort and the matched controls. The volume of transfusion was significantly associated with surgical site infection (odds ratio, 4.00 [95% confidence interval, 1.96 to 8.15]) after adjusting for both unmatched variables of preoperative hemoglobin level and volume of intraoperative blood loss.

CONCLUSIONS

In this retrospective matched case control study, the association between surgical site infection following lumbar spine surgery and volume of perioperative allogeneic red blood cell transfusion was supported.

Blood conservation in practice: an overview

Allogeneic blood transfusions are associated with risks and unfavourable outcomes. Blood conservation provides an alternative, with potential to improve patient care with limited or no blood transfusion. Many approaches are available, but the most essential ones are simple and cost free.

Anemia in critical care patients: incidence, etiology, impact, management, and use of treatment guidelines and protocols

PURPOSE

The incidence, etiology, impact, and management of anemia in critical care patients and the development of treatment guidelines and protocols for the management of anemia in this patient population are discussed.

SUMMARY

Most patients in intensive care units develop anemia as a result of blood losses, nutritional deficiencies, hemolysis, myelosuppression, renal insufficiency, inflammation, infection, or another disease process. Anemia can have an adverse impact on critically ill patients with severe ischemic heart disease or cerebrovascular disease and patients undergoing surgery. The use of blood conservation measures and restrictive blood transfusion strategies can circumvent problems associated with transfusion. Epoetin alfa increases hemoglobin concentrations and reduces the need for transfusion in critical care patients, including surgical patients with large anticipated blood losses. Epoetin alfa also appears to be effective for managing anemia in patients with multiple organ dysfunction syndrome. Iron supplementation is needed by most patients receiving erythropoietic therapy. Iron supplementation without erythropoietic therapy is inadequate to correct anemia unrelated to iron deficiency. Concerns have been raised about a possible increased risk for infection when parenteral iron therapy is used in critical care patients. Developing treatment guidelines or protocols for managing anemia in critical care patients can minimize the need for transfusions and improve prescribing of erythropoietic therapy.

CONCLUSION

Epoetin alfa can play an important role in managing anemia in critical care patients, thereby minimizing patient exposure to transfusion-related risks and optimizing the use of the limited blood supply. There is currently no data available for use of darbepoetin in this manner.

Use of blood bank services in a burn unit

Burn patients may need transfusions, especially during surgery. The purpose of the study was to determine blood bank services utilization at an urban burn center. This was a retrospective review (March 1999 to May 2004) of burn patient data on blood utilization. There were 1615 admissions; 800 (49.5%) of the patients had a type and screen (T and S); 180 of 1615 (11%) were transfused with 1691 red blood cell (RBC) units; 616 units of fresh- frozen plasma (FFP), 399 units of pooled platelets, and 38 units of apheresis platelets. Of the 180 transfused patients, 140 (79%) received RBCs, 11 (6%) received RBCs plus FFP, 23 (13%) received RBCs plus FFP plus platelets, and 3 (2%) each received RBCs plus platelets and FFP. Overall, 3393 red cell units were cross-matched, and 1691 units were transfused for a cross-match/transfused unit (C/T) ratio of 2.01. Seventy-three (5.7%) of 1282 of patients with 0% to 10% TBSA required transfusions; 42 (21%) of 193 with 11% to 20% TBSA; 24 (39%) of 61 with 21% to 30% TBSA; and 62% of patients with 31% or greater TBSA required transfusion (P = .001). As %TBSA increased, more of the cross-matched units were transfused: 37% in the 0% to 10% TBSA to 59% in the 30% or greater TBSA burn. The C/T ratio in the 0% to 10% TBSA was 2.69; only 18% of patients with a T&S received blood. Although most patients who underwent transfusion were in the less than 30% TBSA group, more of the red cell units were used in patients with a 30% or greater TBSA burn. Elimination of admission T&S and cross matches in burn patients with less than 20% TBSA may improve the C/T ratio in this cohort.

Allogeneic red blood cell transfusions: efficacy, risks, alternatives and indications

Careful assessment of risks and benefits has to precede each decision on allogeneic red blood cell (RBC) transfusion. Currently, a number of key issues in transfusion medicine are highly controversial, most importantly the influence of different transfusion thresholds on clinical outcome. The aim of this article is to review current evidence on blood transfusions, to highlight 'hot topics' with respect to efficacy, outcome and risks, and to provide the reader with transfusion guidelines. In addition, a brief synopsis of transfusion alternatives will be given. Based on up-to-date information of current evidence, together with clinical knowledge and experience, the physician will be able to make transfusion decisions that bear the lowest risk for the patient.