Blood transfusion and postoperative infection in orthopedic patients

Adverse effects of the transfusion of homologous blood on tumor recurrence and resistance to bacterial infection have been reported previously, but the findings are inconclusive. A retrospective review of patients undergoing orthopedic surgery was conducted, and the rate of the postoperative infectious complications was compared among those receiving homologous blood, autologous blood, both types, or no transfusion support. An overall postoperative infection rate of 6.1 percent was observed: 6.9 percent among persons receiving homologous blood, 5.0 percent among those receiving autologous blood, 11.9 percent among those receiving both homologous and autologous blood, and 4.9 percent among those not receiving transfusions (p = 0.37). Among patients receiving homologous blood, a subset of 15 patients received homologous whole blood and had an infection rate of 20 percent. Significant predictors of postoperative infection included increasing age, spinal surgery, high admission hematocrit, and greater time in surgery. Of factors relating to transfusion, only the use of homologous whole blood was a significant predictor of postoperative infection, which suggests a detrimental effect of homologous plasma. It can be concluded that, in this group of patients undergoing relatively nontraumatic surgery, several variables that are not related to transfusion, as well as the use of homologous whole blood, were significant predictors of postoperative infection.     

Autologous blood transfusion: The benefits to the patient undergoing abdominal aortic aneurysm repair

The clinical benefits of using intraoperative autologous blood transfusion during abdominal aortic aneurysm bypass surgery become increasingly apparent when use of autologous and homologous blood transfusions is compared. That homologous blood transfusions carry some risk is widely recognized. When autologous blood is used as a sole source of blood transfusion, the risk of transmission of infectious agents and potential immunologic side effects are avoided. A prospective randomized pilot study comparing autologous and homologous blood transfusion in patients undergoing elective infrarenal abdominal aortic aneurysm bypass surgery was undertaken. The purpose of this study was to determine whether autologous blood salvaged intraoperatively may serve as an alternative to homologous blood by comparing the rate of postoperative infection and duration of hospital stay for patients receiving autologous versus homologous blood transfusions. Fifty patients undergoing abdominal aortic aneurysm bypass surgery were prospectively randomly assigned to receive either a homologous or an autologous blood transfusion, with 27 receiving a homologous blood transfusion and 23 receiving an autologous blood transfusion. The data from this study show that the length of hospital stay of patients receiving an autologous blood transfusion intraoperatively was reduced by a mean of 3 days and the risk of postoperative complications, such as a systemic inflammatory response or sepsis, was reduced by more than 50%.     

Transfusion of buffy coat-depleted blood components and risk of postoperative infection in orthopedic patients

BACKGROUND: Allogeneic blood transfusions have been reported to increase susceptibility to postoperative infection, but the findings were inconclusive. This study was designed to investigate the effect of buffy coat-depleted allogeneic and autologous transfusion on postoperative infection in patients undergoing orthopedic surgery. STUDY DESIGN AND METHODS: Patients (n = 385) undergoing elective orthopedic surgery (primary and revision joint replacement, spinal, or pelvic surgery) were included in a prospective observational study of the incidence of postoperative infection between April and December 1996. Infection rates in patients who received allogeneic buffy coat-depleted blood transfusions were compared with those in patients who received no transfusion or only autologous (buffy coat-depleted) blood. RESULTS: Patients without exposure to allogeneic blood (no blood or only autologous blood) had an infection rate of 3.9 percent, as compared to a rate of 12.2 percent for those with exposure to allogeneic blood (allogeneic blood, autologous plus allogeneic blood) (odds ratio 3.442; 95% CI, 1.349-10.40; p = 0.006). Of the 385 study patients, 309 underwent primary hip or knee replacement surgery. In this homogeneous subgroup, the postoperative infection rate was 4.6 percent after no transfusion or autologous transfusion and 11.9 percent after allogeneic transfusion (odds ratio 2.827; 95% CI 1.059-8.799; p = 0.036). Multivariate regression analysis confirmed buffy coat-depleted allogeneic blood transfusion as an independent variable associated with high risk for postoperative infection. CONCLUSION: Buffy coat-depleted allogeneic blood transfusion increases the incidence of postoperative infection in patients undergoing uncontaminated orthopedic surgery.     

Should patients with human immunodeficiency virus infection or chronic hepatitis donate blood for autologous use?

BACKGROUND: The purpose of this project is to formally evaluate the benefits and the risks of allowing patients with human immunodeficiency virus (HIV) infection or hepatitis to donate blood for autologous use. STUDY DESIGN AND METHODS: With data on the incidence of transfusion- transmitted hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV; administrative error; and health-care worker exposure, decision analysis was used to quantitate the benefits and risks of autologous blood transfusions versus those of transfusions of blood from allogeneic donors. RESULTS: Assuming the highest documented probability of transfusion-related infection, the days of life saved by allowing the transfusion of autologous blood to a 30-year-old noninfected or HBV-, HCV-, or HIV-infected patient are 92.52, 70.60, 0.95, and 5.69, respectively. Assuming the lowest documented probability of transfusion- related infection, the days of life saved decrease to 2.96, 2.26, 0.15, and 0.18, respectively. Avoidance of HCV accounts for over 90 percent of the days gained. The days of life lost by other noninfected patients through administrative error average 0.11 in the case of HIV and those lost by health care workers average 0.04, 0.18, and 0.07 in the case of HBV, HCV, and HIV, respectively. CONCLUSION: The benefit of autologous transfusions in patients infected with HBV, HCV, and HIV is significantly less than that in noninfected patients. The risks of this infected blood to other noninfected patients are significant only in the case of HIV-infected blood transfusions; however, there is a measurable risk to health-care workers should all infected blood be allowed into the blood supply.     

Postoperative infections following autologous and homologous blood transfusions

Perioperative homologous blood transfusion has been linked to immune suppression and increased risk of postoperative infection. Autologous blood transfusion may not be associated with increased risk of infection because it presumably is not immunosuppressive. Fifty recipients of preoperatively donated autologous blood were matched to 50 recipients of homologous blood who underwent the same procedure, and the hospital course was reviewed for evidence of postoperative infection in both groups. Postoperative leukocytosis and febrile episodes were more common in homologous blood recipients (17 and 6 vs. 12 and 4, respectively). Sixteen percent of the 50 homologous blood recipients had positive cultures, as compared to 4 percent of the 50 autologous blood recipients (p less than 0.05). This study suggests that the association of blood transfusion with infection may be partially abrogated by the use of autologous blood.     

Accelerated erythropoiesis: the hidden benefit of autologous donation

The risks associated with the administration of blood products have increased efforts to avoid homologous transfusions. Preoperative autologous donation has received renewed interest as a method of decreasing homologous transfusion requirements. Autologous donations may also stimulate postoperative erythropoiesis. The purpose of this study is to evaluate the effect of an aggressive autologous donation program on postoperative erythropoiesis. Ten adult male baboons were divided into two groups. The autologous group (n = 5) donated an average of 2 units of blood per week for 5 weeks before operation. The control group (n = 5) had no preoperative treatment. All animals then underwent a laparotomy and exchange transfusion with hetastarch to a final hematocrit of 15 percent. The time required to recover to hematocrits of 20 percent (3.3 vs. 5.7 days, p less than 0.01), 25 percent (7.0 vs. 8.8 days, p less than 0.05), and 30 percent (11.1 vs. 17.7 days, p less than 0.01) was shorter in the autologous group. The autologous group had more intense reticulocytosis during the first 4 postoperative days (p less than 0.03). The data show that participation in an aggressive autologous donation program improves the erythropoietic response to anemia in the postoperative setting. This represents a hidden benefit of preoperative autologous donations and suggests that more aggressive donation schedules may be clinically beneficial. Recognition of that acceleration of erythropoiesis by autologous donation could further reduce the need for transfusion of homologous blood.     

A clinical and immunologic study of blood transfusion and postoperative bacterial infection in spinal surgery

Allogeneic blood transfusion has been implicated as an independent risk factor for postoperative bacterial infection in clinical and animal studies. The association among transfusion, quantitative immunologic factors, and infection was examined in 102 patients undergoing 109 spinal fusion procedures. In 60 procedures, patients received autologous blood only; in 24 procedures, they received at least 1 unit of allogeneic blood, and in 25 procedures, they received no transfusions. Twenty-two patients developed bacterial infections, in 8 cases while in hospital and in 14 cases after discharge. Univariate analysis revealed that patients who received any allogeneic blood and those who received no allogeneic blood differed significantly in the rate of hospital-acquired infection (20.8 vs. 3.5%), length of stay (12.3 vs. 9.7 days), days of fever greater than or equal to 38 degrees C (4.0 vs. 2.9), days on antibiotics (3.9 vs. 2.5), duration of surgery (309 vs. 231 min), blood loss (1343 vs. 887 mL), surgeon, and postoperative drop in natural killer (NK) cells (-174 vs. -42/microL). Multivariate logistic and linear regressions revealed that the number of allogeneic units transfused was the only significant predictor of in-hospital infection (p = 0.016) or days on antibiotics and length of stay. None of the clinical, surgical, or transfusion variables was significantly associated with posthospital infection, although a significantly greater drop in NK cells had occurred in patients who developed infection (p = 0.0035). These data strongly implicate allogeneic transfusion as a risk factor for in-hospital postoperative bacterial infection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cost-effectiveness of blood transfusion and white cell reduction in elective colorectal surgery

BACKGROUND: The use of white cell (WBC)-reduced blood in elective colorectal surgery appears to reduce the frequency of postoperative infection. The question to be addressed is whether the cost:benefit ratio justifies the recommendation that WBC-reduced blood should be used for all colorectal surgery. STUDY DESIGN AND METHODS: Patients admitted for elective colorectal surgery (n = 197) were randomly assigned to receive transfusion consisting of whole blood or WBC- reduced whole blood. Postoperative complications, postoperative stay, and hospital charges were compared. RESULTS: Forty-eight patients received WBC-reduced whole blood, 56 received unfiltered whole blood, and 93 received no transfusion. Postoperative infections were significantly higher (p < 0.001) in the group that received unfiltered whole blood. That group also had longer hospital stays: 17 days as compared to stays of 10 and 11 days for the group receiving no transfusion and the group receiving filtered whole blood transfusions, respectively (p < 0.01). The total hospital cost per patient receiving unfiltered whole blood was $12,347, as compared to $7,867 for those who received WBC-reduced whole blood and $7,030 for those who received no transfusion. CONCLUSION: The use of WBC-reduced whole blood transfusions in elective colorectal surgery significantly reduces the frequency of postoperative infection, the length of hospital stay, and the total hospital charges for patients needing blood transfusion.     

Faster engraftment but no reduction in infectious complications after peripheral blood stem cell transplantation compared to autologous bone marrow transplantation

Patients who receive transplants of autologous peripheral stem cells have a shorter duration of neutropenia than patients who receive autologous bone marrow transplants. There is conflicting evidence regarding the risk of infections. A retrospective analysis on 123 patients who received transplants of either auto- logous bone marrow or peripheral blood stem cells for multiple myeloma or breast cancer was performed to study whether this shorter duration of neutropenia can influence the risk of and the severity of infection. Patients who underwent peripheral blood stem cell transplantation (PBSCT) had faster engraftment than the group treated with autologous bone marrow transplantation (ABMT). Furthermore, the requirement for transfusions of red blood cells and platelets was a reduced. The number of days needed in hospital was significantly lower in PBSCT patients. No reduction in the frequency of infectious complications was found in PBSCT as compared with ABMT patients, but the numbers of days with fever and with antibiotic treatment were significantly lower in the PBSCT patients. Breast cancer patients had significantly faster engraftment but no fewer infectious complications than myeloma patients, regardless of the type of transplantation. Significantly lower numbers of clinically verified infections were found in the group of patients receiving colony-stimulating factors (CSF) after transplantation even though there was no difference in the duration of neutropenia. The need for antibiotic treatment was also significantly less in the group treated with CSF.     

Risk for postoperative infection after transfusion of white blood cell-filtered allogeneic or autologous blood components in orthopedic patients undergoing primary arthroplasty

BACKGROUND: This study was designed to obtain data on the incidence of postoperative infection in patients undergoing elective orthopedic surgery and receiving white blood cell (WBC)-filtered blood components prepared according to current standards. STUDY DESIGN AND METHODS: A total of 308 consecutive orthopedic patients who opted for preoperative autologous blood donation (PAD) for primary unilateral hip and knee replacement surgery were enrolled in a prospective observational study of the incidence of postoperative infection. Patients with contraindications for PAD or with any infectious disease were not included in the study. To identify probably confounding factors, differences between patient groups were analyzed first. Identified factors, which differed between groups, and variables describing blood supply were further tested in uni- and multivariate logistic regression analysis for their independent influence on development of postoperative infection. Infection rates were compared on the basis of actual transfusion groups. RESULTS: Of the 308 study patients, 101 were not transfused, 85 received their PAD, 100 received allogeneic WBC-filtered red blood cells (RBCs), and 22 were given autologous RBCs and additionally allogeneic WBC-filtered RBCs. Overall the infection rate was 6.82 percent (21/308). Infection rates varied significantly between transfusion groups (no transfusion, 6.9%; autologous RBCs, 1.2%; allogeneic WBC-filtered RBCs, 12.0%; both transfusion types, 4.6%; p = 0.03). Allogeneic recipients showed significantly more infections compared to autologous recipients (p = 0.0053). Multivariate regression analysis confirmed transfusion of allogeneic WBC-filtered RBCs as an independent variable predicting postoperative infection (odds ratio, 23.65; confidence interval, 1.3-422.1; p = 0.01). CONCLUSION: Differences in postoperative infection rates between allogeneic and autologous recipients are still observable, although universal WBC filtration has been introduced into clinical practice.     

Prostate cancer recurrence in radical surgery patients receiving autologous or homologous blood

An evaluation of the effects of blood transfusion on recurrence and survival after radical surgery for prostate cancer was performed. Between 1982 and 1986, 315 consecutive patients underwent radical retropubic prostatectomy by a single surgeon; of 309 patients for whom transfusion data were available, 94 received homologous blood (Group I) and 215 received autologous blood or no blood (Group II). At the time of surgery, there were no differences between Group I and Group II with respect to age, preoperative cancer stage, preoperative histologic grade (Gleason grade), prostatic acid phosphatase score, and preoperative potency. At discharge, the groups were similar in the status of neurovascular bundles, capsular involvement, seminal vesicle involvement, lymph node involvement, postoperative Gleason grade, and postoperative potency. No adjuvant hormone therapy or radiation therapy was administered until tumor recurrence. The patients were followed annually by physical examinations and measurements of prostate-specific antigen. Cancer recurrence was detected in 23 (24.5%) Group I patients and 49 (22.7%) Group II patients. These proportions were not significantly different in univariate or multivariate analysis, and the time to recurrence curves overlapped. It is concluded that homologous blood transfusions are not associated with more rapid tumor recurrence or death after radical surgery for prostate cancer than is seen with autologous transfusions. These results differ from previous reports, which suggested that transfusions may cause recurrence of cancer in patients with colorectal or prostate cancer because of the immunosuppressive effects of blood transfusions.     

Effects of the Sangvia blood collection system on patients undergoing elective hip surgery

We have conducted a randomized controlled study where 164 patients were randomized to receive autologous salvaged blood collected by Sangvia? Blood Salvage System or allogeneic red cell concentrates if transfusion was indicated by clinical judgement. The study was powered to detect if transfusion of autologous blood reduced the occurrence of postoperative infections. We found no statistical significant difference in postoperative infection rate between the groups, but this may be due to the fact that postoperative infections were diagnosed in only five patients. Increased C-reactive protein concentrations slightly above level of significance indicate that autologous blood transfusions stimulate the patient's immune system. However, there was no indication of increased transfusion reaction rate, including febrile reactions, in the autologous group. Transfusion of autologous blood did not reduce the use of allogeneic red cell concentrates. The mean use of allogeneic red cell concentrates was 0.93 units (both groups combined), indicating that the transfusion policy may have been too liberal. There was a highly significant inverse correlation between pre-operative haemoglobin concentration and transfusion of allogeneic blood. In a patient population with a low frequency of postoperative infection, a larger study is needed to clarify if autologous salvaged blood protects against postoperative infections.     

Banked and fresh autologous blood in cardiopulmonary bypass surgery

When 50 patients having autologous transfusions of two units of blood collected intraoperatively during coronary bypass surgery were compared with 50 patients receiving only homologous donor blood, it was found that a two-unit (20%) decrease in homologous blood usage per case occurred in the group receiving the autologous blood. No decrease occurred in total units of blood used per case. In 15 patients undergoing coronary bypass surgery, in addition to the two units of autolobous blood collected during surgery, two or four units of autologous blood were obtained preoperatively and administered intraoperatively. When four units were collected, the red blood cells were frozen until just prior to surgery. Total blood usage per case remained unchanged but a 4.6 unit (41%) decrease in homologous donor blood usage was noted. Patients phlebotomized preoperatively took 325 mgm of oral iron t.i.d. through the postoperative recovery period. These patients had an average decrease in hematocrit of 4.25 to 4.3 per cent following the final phlebotomy and just prior to surgery.     

Central venous catheter infections in patients with acute leukemia

BACKGROUND: Central venous catheters (CVCs) have become an essential tool for an appropriate management of patients with acute leukemia. Infectious complications are a major concern in patients treated for acute leukemia. Although CVC-related infections are considered to be a major source of infections during neutropenia (<500/microl), data regarding the incidence of CVC-related infections are rare in acute leukemia. PATIENTS AND METHODS: We analyzed nontunneled CVCs in 58 patients with acute leukemia (22 men/36 women) in 119 chemotherapy cycles from April 1996 to January 1998 in a prospective trial. Proven CVC-related infection was defined as the isolation of the same organism from peripheral blood and CVC tip. CVC infection was suspected or possible when exit site inflammation and positive blood culture or organisms typical for CVC infection were observed. RESULTS: Mean neutropenia/cycle was 16.3 days (SD 8.0). 178 CVCs with 2,576 CVC days (mean 14.5 days, SD 7.2 days) were used in 119 cycles. Fever occurred in 87 cycles (73%). Blood stream infection was proven in 31 out of 87 febrile episodes (26.1%) with 40 isolates (8 gram-negative, 31 gram-positive, 1 Candida spp.). Colonization of the CVC tip was observed in 24 CVC lines with 28 isolates (27 gram-positive, 1 gram-negative); however, proven CVC-related infections were observed in 5 episodes only, all with coagulase-negative staphylococci. In another 6 episodes, CVC-related infection was assumed (local inflammation and gram-positive blood culture). Six further episodes had typical blood isolates (4 coagulase-negative staphylococci, 1 Candida spp.) and were considered possible CVC-related infections. In none of the remaining afebrile 32 cycles was a CVC infection observed or suspected. CONCLUSION: Gram-positive organisms contributed to the majority of CVC-related infections (16 out 17 CVC infections); however, the overall incidence of CVC infections in acute leukemia patients was 6.5/1,000 CVC days only (1.9 proven/2.3 suspected/2.3 possible/1,000 CVC days).     

Association of transfusion with postoperative bacterial infection

Homologous blood transfusion has been implicated as a modulator of the host immune system in a number of clinical settings. Improved renal allograft survival is observed in patients receiving pretransplant transfusions. Decreased recurrence of active inflammatory bowel disease has been recently reported in transfused patients with Crohn's disease. Conversely, deleterious immunomodulatory effects of transfusion may explain the association between transfusion and increased susceptibility to cancer recurrence and bacterial and viral infection. Clinical studies regarding cancer recurrence and transfusion are retrospective and conflicting. There is epidemiologic evidence for more rapid progression of HIV-1 infection in heavily transfused patients. Studies on transfused surgical patients have shown transfusion to be associated with an increased frequency of postoperative bacterial infections. Some studies have come to different conclusions. These investigators have suggested that transfusion may represent a surrogate marker for other risk factors for infection. Animal models designed to control for confounding factors have supported an association between transfusion and bacterial infection severity in most, but not all, reports. Attempts to define the immunologic alterations associated with transfusion have revealed a generalized impairment of cellular immunity in both humans and animals. Although the preponderance of data supports an association between perioperative transfusion and increased susceptibility to postoperative bacterial infection, it is not certain to what extent this relationship constitutes cause and effect.     

The effects of intraoperative blood salvage and induced hypotension on transfusion requirements during spinal surgical procedures

Spinal surgical procedures, such as placement of Harrington rods for correction of scoliosis, are associated with considerable perioperative blood loss and, hence, with the risks associated with homologous blood transfusions. To test the hypothesis that intraoperative autologous blood transfusions could decrease the amount of homologous blood needed in such operations, we conducted a two-part study: (1) a retrospective review of 142 patients in whom blood salvage was not used and (2) a prospective review of 28 patients who received autologous transfusions. Intraoperative autologous transfusion reduced the amount of homologous blood required by more than 50% (5.1 versus 2.0 units; P less than 0.001). The total amount of homologous blood required during the hospital stay was also significantly reduced by intraoperative autologous transfusion (6.0 versus 3.4 units; P less than 0.001). Induced hypotension in 81 of the 142 patients who did not receive autologous transfusions did not decrease the homologous blood transfusion requirements from those needed by the normotensive patients. We conclude that intraoperative autologous transfusion significantly reduces the need for homologous blood products in patients who undergo spinal surgical procedures. Induced hypotension, which did not affect transfusion requirements in our study, should be further evaluated in a blinded, prospective study.     

Clinical efficacy of postoperative autologous transfusion of filtered shed blood in hip and knee arthroplasty

BACKGROUND: Total knee arthroplasty (TKA) or total hip arthroplasty (THA) regularly results in postoperative requirement of blood transfusion. Because of the disadvantages of allogeneic blood transfusion (ABT) such as the risk of transfusion-associated infections, incompatibility-related transfusion fatalities, or immunomodulatory effects, a continuing effort to reduce allogeneic blood transfusion is important. For this purpose, the effect of reinfusion of drain blood, via a postoperative wound drainage and reinfusion system, on the need for allogeneic blood transfusion was evaluated. STUDY DESIGN AND METHODS: Using a prospective observational quality assessment design, we compared 135 patients scheduled for TKA or THA with a historic group of 96 patients. In the study group the Bellovac ABT autotransfusion system was used. The shed blood was returned either when 500 mL were collected or at most 6 hours after surgery. Compared were the preoperative, postoperative, and discharge hemoglobin, as well as the number of allogeneic blood transfusions. RESULTS: There were no statistical differences between preoperative, postoperative, and discharge hemoglobin levels. Autologous transfusion reduced the number of patients receiving ABT overall from 35 percent (control) to 22 percent (study). The decrease of allogeneic transfusion requirement was most significant after TKA: from 18 percent to 6 percent (p < 0.001). CONCLUSION: We conclude that the Bellovac ABT device reduces allogeneic blood transfusions in TKA and THA.     

The effects of leukoreduced blood transfusion on infection risk following injury: a randomized controlled trial

Allogeneic blood transfusions in surgical patients have been associated with an increased risk of infectious complications and organ dysfunction. Residual leukocytes contaminating units of packed red blood cells have been incriminated through the induction of anergy and/or a potentiated inflammatory response, leading to the possibility that leukoreduced red blood cell transfusion might mitigate these effects. We set out to evaluate the effect of leukoreduced red cell transfusion on the risk of infections complications in patients requiring transfusion following injury. We conducted a single-center, double-blinded randomized controlled trial of leukoreduced versus standard, nonleukoreduced red blood cell transfusions in injured patients receiving transfusion within 24 hrs of injury. The primary endpoint was infectious complications within 28 days of randomization. Secondary end points were multiple organ failure, length of stay, febrile episodes, and mortality. Two hundred sixty eight subjects were eligible for analysis. Rates of infectious complications were similar in subjects receiving leukoreduced transfusions (30%) or standard transfusions (36%) ([RR], 0.84 [0.55-1.3]) and there was no statistically significant effect of leukoreduced blood transfusion on mortality [RR, 1.20 (0.74-1.9)], febrile episodes [RR, 1.01 (0.89-1.2)], or organ dysfunction scores (5.9 vs. 6.6; P=0.29). Thus, pre-storage leukoreduction of allogeneic red blood cells had a small, but non-significant effect on the rate of infectious complication in this high-risk population requiring transfusion. There was no effect on the rates of febrile episodes, mortality, length of stay, or severity of organ dysfunction.     

Postoperative complications associated with transfusion of platelets and plasma in cardiac surgery

BACKGROUND: Studies in cardiac surgery have reported increased postoperative morbidity and mortality after allogeneic red blood cell (RBC) transfusions. Whether platelet (PLT) and/or plasma transfusions are a marker for more concomitant RBC transfusions or are independently associated with complications after cardiac surgery is unknown. STUDY DESIGN AND METHODS: Data from two randomized controlled studies were combined to analyze the effects of PLT and/or plasma transfusions on postoperative infections, length of stay in the intensive care unit (ICU), all‐cause mortality, and mortality in the presence or absence of infections in the postoperative period. RESULTS: After adjusting for confounding factors, plasma units and not RBC transfusions were associated with all‐cause mortality. White blood cell (WBC)‐containing RBC transfusions and PLT transfusions were associated with mortality occurring in the presence of or after infections. The number of (WBC‐containing) RBC transfusions was also significantly associated with postoperative infections and with ICU stay for 4 or more days. CONCLUSION: Although it is difficult to separate the effects of blood components, we found that in cardiac surgery, perioperative plasma transfusions are independently associated with all‐cause mortality. WBC‐containing RBC transfusions and PLT transfusions are independently associated with mortality in the presence of infections in the postoperative period. Future transfusion studies in cardiac surgery should concomitantly consider the possible adverse effects of all the various transfused blood components.     

The intention-to-treat principle in clinical trials and meta-analyses of leukoreduced blood transfusions in surgical patients

BACKGROUND: The scientific method requires that only experiments actually and correctly performed be used to draw conclusions. The intention-to-treat principle requires that all patients, even those not or improperly treated, be included. In clinical trials and meta-analyses investigating leukoreduced blood transfusions to reduce postoperative infections, the intention-to-treat principle and the scientific method have been variably applied.
STUDY DESIGN AND METHODS: Clinical trials and meta-analyses were retrieved from the literature, and their scientific and statistical methods were assessed. A meta-analysis emphasizing the scientific method was created, restricted to patients who actually received transfusions, given that patients who did not receive transfusions cannot benefit from leukoreduction.
RESULTS: Nine clinical trials and 11 meta-analyses were identified. In 2 of the trials and all but 1 of the meta-analyses, conclusions were based on data that included many (>10%) patients who had been randomly assigned but not received a transfusion or data not derived from investigative results. Limiting the meta-analysis to patients who actually received transfusions (n = 3093), demonstrated that leukoreduced transfusions significantly reduced the odds of postoperative infection (summary odds ratio, 0.522; 95% confidence interval, 0.332-0.821; p = 0.005).
CONCLUSION: When data restricted to patients receiving transfusions are analyzed, and no data absent from the actual investigations are introduced, leukoreduced transfusions substantially and significantly reduce the odds of postoperative infection by approximately 50 percent. These results demonstrate the importance of including only scientifically valid data in clinical trials and meta-analyses. The intention-to-treat principle should never lead to inclusion of data not actually derived from experimental results.