Incidence and transfusion risk factors for transfusion‐associated circulatory overload among medical intensive care unit patients

BACKGROUND: Transfusion‐associated circulatory overload (TACO) is a frequent complication of blood transfusion. Investigations identifying risk factors for TACO in critically ill patients are lacking. STUDY DESIGN AND METHODS: We performed a 2‐year prospective cohort study of consecutive patients receiving blood product transfusion in the medical intensive care unit (ICU) of the tertiary care institution. Patients were followed for development of transfusion‐related complications. TACO was defined as acute hydrostatic pulmonary edema occurring within 6 hours of transfusion. In a nested case‐control design, transfusion characteristics were compared between cases (TACO) and controls after matching by age, sex, and ICU admission diagnostic category. In a secondary analysis, patient characteristics before transfusion were compared between cases (TACO) and randomly selected controls. RESULTS: Fifty‐one of 901 (6%) transfused patients developed TACO. Compared with matched controls, TACO cases had a more positive fluid balance (1.4 L vs. 0.8 L, p = 0.003), larger amount of plasma transfused (0.4 L vs. 0.07 L, p = 0.007), and faster rate of blood component transfusion (225 mL/hr vs. 168 mL/hr, p = 0.031). In a secondary analysis comparing TACO cases and random controls, left ventricular dysfunction before transfusion (odds ratio [OR], 8.23; 95% confidence interval [CI], 3.36‐21.97) and plasma ordered for the reversal of anticoagulant (OR, 4.31; 95% CI, 1.45‐14.30) were significantly related to the development of TACO. CONCLUSION: Volume of transfused plasma and the rate of transfusion were identified as transfusion‐specific risk factors for TACO. Left ventricular dysfunction and fresh‐frozen plasma ordered for the reversal of anticoagulant were strong predictors of TACO before the onset of transfusion.     

Effect of clopidogrel on bleeding after coronary artery bypass surgery.

OBJECTIVE: Platelet dysfunction is a common cause of bleeding after coronary artery bypass graft surgery. This study explores the effects of clopidogrel on bleeding complications after coronary artery bypass graft surgery. DESIGN: Prospective observational study of patients undergoing coronary artery bypass graft. SETTING: Tertiary care center. PATIENTS: A total of 247 patients undergoing coronary artery bypass graft surgery. INTERVENTIONS: None. MEASUREMENTS: Primary end point was need for reexploration secondary to bleeding. Secondary end points included need for transfusion of blood products and chest tube output. MAIN RESULTS: Eight (3.3%) of 247 patients required reexploration secondary to bleeding. Clopidogrel recipients had higher incidence of reexploration for bleeding (9.8 vs. 1.6, p =.01) with an odds ratio of 6.9 (95% confidence interval, 1.6-30). Clopidogrel also increased the percentage of patients receiving packed red blood cell transfusion (72.6 vs. 51.6%, p =.007), the number of packed red blood cell units (3 vs. 1.6, p =0.0004), and the number of cryoprecipitate units (2.4 vs. 1.2, p =.04) transfused after coronary artery bypass graft surgery. Among clopidogrel recipients, a trend for increased transfusion of platelet units (4.3 vs. 1.7, p =.05) and fresh frozen plasma units (1.1 vs. 0.6, p =.08) also was found. CONCLUSIONS: Preoperative use of clopidogrel in combination with aspirin is associated with increased need for surgical reexploration as well as risk of packed red blood cell and cryoprecipitate transfusions after coronary artery bypass graft surgery.     

Lack of effect of unrefrigerated young whole blood transfusion on patient outcomes after massive transfusion in a civilian setting

BACKGROUND: Warm fresh whole blood has been advocated for critical bleeding in the military setting. This study assessed whether unrefrigerated young whole blood transfusion, from donation to transfusion less than 24 hours, could reduce mortality of patients with critical bleeding in a civilian setting. STUDY DESIGN AND METHODS: A linked data cohort study was conducted on a total of 353 consecutive patients requiring massive transfusion, defined as 10 units or more of red blood cells or whole blood transfusion within 24 hours, in a quaternary health care center in Australia. RESULTS: Of the 353 patients with massive blood transfusion in the study, 77 received unrefrigerated young whole blood transfusion (mean, 4.0 units; interquartile range, 2‐6). The diagnosis, severity of acute illness, age, sex, and ABO blood group were not significantly different between the patients who received unrefrigerated young whole blood and those who did not. Unrefrigerated young whole blood transfusions were associated with a slightly improved coagulation profile (lowest fibrinogen concentrations 1.7 g/L vs. 1.4 g/L, p = 0.006; worst international normalization ratio, 2.4 vs. 2.8, p = 0.05) but did not reduce the total utilization of allogeneic blood products and subsequent use of recombinant Factor VIIa (27% vs. 22%, p = 0.358). Thirty‐day mortality and 8‐year survival after hospital discharge (hazard ratio, 1.05; 95% confidence interval, 0.41‐2.65; p = 0.93) were also not different after the use of unrefrigerated young whole blood transfusion. CONCLUSIONS: Unrefrigerated young whole blood transfusion was not associated with a reduced mortality of patients requiring massive transfusion in a civilian setting when other blood products were readily available.     

The effect of blood transfusion on pulmonary permeability in cardiac surgery patients: a prospective multicenter cohort study

BACKGROUND: There is an association between blood transfusion and pulmonary complications in cardiac surgery. Mediators of increased pulmonary vascular leakage after transfusion are unknown. We hypothesized that factors may include antibodies or bioactive lipids, which have been implicated in transfusion‐related acute lung injury. STUDY DESIGN AND METHODS: We performed a prospective cohort study in two university hospital intensive care units in the Netherlands. Pulmonary vascular permeability was measured in cardiac surgery patients after receiving no, restrictive (one or two transfusions), or multiple (five or more transfusions) transfusions (n = 20 per group). The pulmonary leak index (PLI), using ⁶⁷Ga‐labeled transferrin, was determined within 3 hours postoperatively. Blood products were screened for bioactive lipid accumulation and the presence of antibodies. RESULTS: The PLI was elevated in all groups after cardiac surgery. Transfused patients had a higher PLI compared to nontransfused patients (33 × 10^?3 ± 20 × 10^?3 vs. 23 × 10^?3 ± 11 × 10^?3/min, p < 0.01). The amount of red blood cell (RBC) products, but not of fresh‐frozen plasma or platelets, was associated with an increase in PLI (β, 1.6 [0.2‐3.0]). Concerning causative factors in the blood product, neither the level of bioactive lipids nor the presence of antibodies was associated with an increase in PLI. Patient factors such as surgery risk and time on cardiopulmonary bypass did not influence the risk of pulmonary leakage after blood transfusion. CONCLUSIONS: Transfusion in cardiothoracic surgery patients is associated with an increase in pulmonary capillary permeability, an effect that was dose dependent for RBC products. The level of bioactive lipids or the presence of HLA or HNA antibodies in the transfused products were not associated with increased pulmonary capillary permeability.     

Transfusion from male-only versus female donors in critically ill recipients of high plasma volume components

OBJECTIVE: To reduce the incidence of transfusion-related acute lung injury (ALI), the American Association of Blood Banks recently recommended rapid implementation of strategies to minimize transfusion of high plasma volume components, fresh frozen plasma and apheresis platelets, from potentially alloimmunized donors, especially females. The objective of this study was to evaluate the effect of transfusing components from male-only vs. female donors on development of ALI, gas exchange, and outcome in critically ill patients. DESIGN: In this retrospective case-control study, we identified patients who received high plasma volume components from male-only donors and compared them with patients matched by severity of illness, postoperative state, and number of transfusions but who received high plasma volume components from female donors. SETTING: Four intensive care units at a tertiary medical center. PATIENTS: Critically ill patients who received >2 units of fresh frozen plasma or apheresis platelets. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: From a database of 3,567 patients who received a total of 46,101 units of fresh frozen plasma and 6,251 units of apheresis platelets, we identified 112 patients who received three or more male-only donor components and 112 matched controls. Baseline characteristics, ALI risk factors, and development of ALI were similar between the two groups. Arterial oxygenation (PaO2/FIO2) worsened after the female (mean difference -52, 95% confidence interval -14 to -91, p = .008) but not after male-only donor product transfusion (mean difference 22, 95% confidence interval -23 to 67, p = .325). Male-only component recipients had more ventilator-free days (median 28 vs. 27, p = .006) and a trend toward lower hospital mortality rates (14% vs. 24%, p = .054). CONCLUSIONS: In critically ill recipients of high plasma volume components, gas exchange worsened significantly after transfusion of female but not male donor components. Prospective studies are needed to evaluate the effect of recommendations by the American Association of Blood Banks on outcome of transfused critically ill patients.     

Risk factors and outcome associated with hypomagnesemia in massive transfusion

BACKGROUND: Electrolyte disturbances are common in patients with critical bleeding requiring massive transfusion. The risk factors and outcome associated with the occurrence of hypomagnesemia in massive transfusion remain uncertain. STUDY DESIGN AND METHODS: A cohort of 353 consecutive patients who required massive transfusion, defined as 10 or more units of allogeneic red blood cells or whole blood transfusion within 24 hours, between 2002 and 2008 in a quaternary health care center in Western Australia was considered. Logistic regression was used to identify risk factors and outcome associated with hypomagnesemia during massive transfusion (<0.7 mmol/L or 1.7 mg/dL). RESULTS: Of the 353 patients requiring massive transfusion during the study period, 298 patients (84%) had serum magnesium concentrations available for analysis. Hypomagnesemia was common (172 patients, 58%), and the mean magnesium concentration was 0.68 mmol/L (1.65 mg/dL; standard deviation, 0.15 mmol/L) in these patients. The risk factors for hypomagnesemia were hypocalcemia (odds ratio [OR], 1.67 per 0.1 mmol/L decrement; 95% confidence interval [CI], 1.36‐2.01; p = 0.001) and hypofibrinogenemia (OR, 1.05 per 0.1 g/L decrement; 95% CI, 1.01‐1.09; p = 0.009). The lowest serum magnesium concentrations were associated with the lowest ionized calcium concentrations (Spearman correlation coefficient, 0.377; p = 0.001). Both magnesium concentrations (OR, 0.91 per 0.1 mmol/L increment; 95% CI 0.31‐2.69; p = 0.863) and the interaction term between magnesium and calcium concentrations were not associated with an increased risk of mortality after adjusting for other covariates. CONCLUSIONS: Hypomagnesemia was common and associated with hypocalcemia in massive transfusion, but serum magnesium concentrations had no independent effect or interactive effect with hypocalcemia on mortality of patients requiring massive transfusion.     

Transfusion of stored red blood cells adhere in the rat microvasculature

BACKGROUND: Ex vivo storage of red blood cells (RBCS) for transfusions is associated with a “storage lesion,” which decreases RBC deformability and increases RBC adhesiveness to vascular endothelium. This may impair microcirculatory flow with deleterious effects on oxygen delivery after transfusion. Previous studies have shown that human RBCs adhere to endothelial monolayers in vitro with prolonged storage and is reduced by prestorage leukoreduction (LR). The objective of this study was to determine whether duration of RBC storage and LR influence RBC adhesion in vivo in capillaries. STUDY DESIGN AND METHODS: Rat RBCs were collected and stored in CPDA‐1 under standard blood bank conditions. Three RBC products were compared: 1) fresh RBCs, less than 24 hours of storage (n = 6); 2) nonleukoreduced (NLR) RBCs stored for 7 days (n = 6); and 3) prestorage LR RBCs stored for 7 days (n = 6). RBCs were labeled with fluorescein isothiocyanate (FITC) 24 hours before transfusion and reinjected in an isovolemic manner into healthy rats. The FITC‐labeled RBCs were visualized in the extensor digitorum longus muscle using intravital video microscopy (20× magnification). The number of RBCs adherent in capillaries was counted 1 hour after transfusion in 10 random fields and the median values were compared with one‐way analysis of variance. RESULTS: Stored RBCs showed increased levels of adherence in capillaries compared to their fresh counterparts (p < 0.05). Prestorage LR decreased RBC adherence to levels equivalent to those of fresh RBCs (p < 0.05 for stored LR vs. stored NLR). CONCLUSION: Rat RBCs stored under conditions that closely mimicked clinical transfusion adhere in capillaries. The decreased RBC adherence with LR suggest a direct effect of white blood cells or their byproducts on RBC deformability and/or adhesiveness to microvascular endothelium. Further study will examine the mechanism of adherence and the impact it has on microcirculatory flow and oxygen delivery in the critically ill host.     

全氟化碳汽化吸入预处理对急性肺损伤实验兔早期炎症因子的影响

目的：探讨全氟化碳（PFC）汽化吸入预处理对油酸型兔急性肺损伤（ALI）早期炎症因子的干预作用。方法：实验兔12只随机分为对照组和PFC预处理组,每组6只。动物麻醉后气管插管行机械通气,对照组注油酸造ALI模型后行机械通气120min,预处理组在造模前先于经气管内汽化吸入PFC60min,再注油酸造AU模型后行机械通气120min。两组分别于麻醉通气30min（基础值）、ALI造模成功时、ALI后30、60、90、120min各时点检测氧合指数、PaO2、PaCO2。实验结束后留取静脉血离心取上清液,对左肺进行肺灌洗留取肺灌洗液,应用ELISA法检测血清及肺灌洗液中TNF-α、IL-1β的含量。结果：与对照组比较,PFC预处理组在各时点的氧合指数和PaO2均明显升高、PaO2明显下降（P均〈0．05）。PFC预处理组血清和肺灌洗液中TNF-α的含量分别为（211±1）ng／L、（326±9）ng／L,明显低于对照组（226±2）ng／L、（368±11）ng／L（P均〈0．05）;PFC预处理组血清和肺灌洗液中IL-1β的含量分别为（77±2）ng／L、（93±2）ng／L,也明显低于对照组（99±3）ng／L和（116±2）ng／L（P均〈0．05）。结论：经气道汽化吸入PFC预处理60min,可改善油酸型AU实验兔的氧合状况,减少早期炎症因子TNF-α、IL-1β的释放。     

Transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is characterized by the sudden development of noncardlogenic pulmonary edema (acute lung Injury) after transfusion of blood products. Poor awareness of TRALI outside of the blood transfusion medicine community has led to a serious underestimation of this condition, currently the most Important severe complication of blood transfusion. Concern for the transfer of donor antileukocyte antibodies has prompted major changes in the management of the blood supply in some countries; however, recent studies have suggested alternative pathophyslological mechanisms for TRALI related to the shelf life of cellular blood products. Although all blood products have been implicated, most reported cases were associated with fresh frozen plasma, red blood cell, and platelet transfusions. Because many patients have additional predisposing factors for acute lung injury, carefully designed prospective studies are needed to fully assess attributable risk related to transfusion. The treatment of TRALI is supportive, and the prognosis is generally better than for other causes of acute lung Injury. As many as one third of all patients who develop acute lung injury have been exposed to blood products. TRALI may be an important and potentially preventable cause of acute lung injury.     

Red blood cell transfusions and nosocomial infections in critically ill patients

OBJECTIVE: A previous retrospective evaluation of Project Impact data demonstrated an association between red blood cell transfusions, nosocomial infections, and poorer outcomes in critically ill patients, independent of survival probability or patient age. The objective of this study was to determine whether transfused patients, independent of survival probability based on Mortality Prediction Model scores, have higher nosocomial infection rates, longer intensive care unit and hospital lengths of stay, and higher mortality rates than nontransfused patients. DESIGN: Prospective, observational, cohort study. SETTING: A single-center, mixed medical/surgical, closed intensive care unit. PATIENTS:: Adults admitted to St. John's Mercy Medical Center between August 2001 and June 2003 (n = 2,085) were enrolled using Project Impact software. Both nonoperative and postoperative populations were represented, and transfusion decisions were made independently of patient study inclusion. Patients whose nosocomial infection was diagnosed before transfusion were counted as nontransfused. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS: Nosocomial infections, mortality rates, and intensive care unit and hospital length of stay were the main outcome measures. Of the 2,085 patients enrolled, 21.5% received red blood cell transfusions. The posttransfusion nosocomial infection rate was 14.3% in 428 evaluable patients, significantly higher than that observed in nontransfused patients (5.8%; p < .0001, chi-square). In a multivariate analysis controlling for patient age, maximum storage age of red blood cells, and number of red blood cell transfusions, only the number of transfusions was independently associated with nosocomial infection (odds ratio 1.097; 95% confidence interval 1.028-1.171; p = .005). When corrected for survival probability, the risk of nosocomial infection associated with red blood cell transfusions remained statistically significant (p < .0001). Leukoreduction tended to reduce the nosocomial infection rate but not significantly. Mortality and length of stay (intensive care unit and hospital) were significantly higher in transfused patients, even when corrected for illness severity. CONCLUSIONS: Red blood cell transfusions should be used sparingly, bearing in mind the potential risks of infection and poor outcomes in critically ill patients.     

Developments in component therapy: novel components and new uses for familiar preparations.

Over the years, the significant role of blood components in treating certain diseases or conditions has been recognized. The use of these components has expanded as patients undergo chemotherapy for bone marrow ablation and require short-term component support. On the other hand, these transfusions can cause reactions ranging from mild to severe. Despite advances in serological testing for infectious disease agents, the risk of infectious complications from transfusion still remains. In addition, newly identified agents that may be transmitted via transfusion are constantly identified. The cellular components most people are familiar with include packed red blood cells (PRBC), washed PRBC, leukoreduced PRBC, and pooled or apheresis platelets. Plasma products such as fresh frozen plasma (FFP) or crytoprecipitated anti-hemophiliac factor (CRYO), on the other hand, may not be as familiar. As our understanding of how the immune system functions and as technology has progressed, specialized components or manufactured products such as blood substitutes have been advanced as remedies to some of the complications with component transfusion or to meet the ever-increasing need for these products. In this article we will focus on some of the new uses of common components and uncommonly used or newly developing components. We will discuss their origins, composition, and the conditions or diseases they are used to treat. These components include: donor leukocyte infusions, dendritic cell vaccines, blood substitutes, novel platelet products and substitutes, intravenous immunoglobulin (IVIG), fresh frozen plasma and cryosupernatant in therapeutic plasma exchange. The variety of products and conditions reflect the ever-expanding role of immunohematology in the treatment of disease.     

Red blood cell storage is associated with length of stay and renal complications after cardiac surgery

BACKGROUND: The association of red blood cell (RBC) storage on morbidity outcome after cardiac surgery is debated. We sought to clarify the association of the age of transfused blood on outcome in patients undergoing cardiac surgery. STUDY DESIGN AND METHODS: Data were drawn from a prospective, observational cohort study of morbidity outcome in patients undergoing cardiac surgery. Blood transfusion data were obtained retrospectively via the Trust blood bank electronic records. Old blood was defined as more than 14 days old. The primary outcome measure was postoperative length of stay (PLOS). Secondary outcome measures included renal failure and morbidity as defined within the postoperative morbidity survey. RESULTS: A total of 176 (39.6%) of 444 participants received a blood transfusion. Patients transfused with new blood had a reduced PLOS compared with patients receiving exclusively old or any old blood (old blood ± new blood; 7 days vs. 8 days, p = 0.04 and vs. 10 days, p = 0.002, respectively). In patients who only had 1 unit transfused, PLOS was longer in those receiving only old blood compared with those receiving only new blood (8 days vs. 6 days, p = 0.02) with a 3.8‐fold risk of longer stay. Compared with patients receiving exclusively new blood, patients receiving any old blood had a higher incidence of new renal complications (65.7% vs. 43.9%, p = 0.008). Each 1‐day increase in storage was associated with a 7% increase in risk of new renal complications. CONCLUSION: Our data support previous suggestions of an association between transfusion of older RBCs and poorer outcome in cardiac surgery patients. Randomized controlled trials are required to determine the true causal nature of any such association.     

Transfusion medicine during the summer of 2006: lessons learned in northern Israel

In July 2006 a Hizballah attack erupted at the Lebanon-Israel border. Reported here is the experience of the Rambam Health Care Campus--a level I trauma center--during 33 days of warfare. Two hundred ninety-five soldiers and 209 civilians were admitted to the emergency department (ED). Forty-eight wounded soldiers (16%) and 12 civilians (6%) had transfusion. Twenty soldiers and 1 civilian had massive transfusions. The ratio between packed red blood cells and fresh frozen plasma (FFP) used for patients who had massive transfusion was 3:2. In these patients, the median prothrombin time international normalized ratio and partial thromboplastin time increased during the first 2 hours after admission from 1.29 to 1.51 and from 33.6 to 39 seconds, respectively. Twenty patients who had massive transfusion survived. Patients with an injury severity score of at least 16 had a higher need for blood products than others, with a lower severity score, with a mean packed red blood cells unit transfusion of 7 vs 4 (P = .03) and FFP transfusion of 13 vs 1.5 (P = .002), respectively. In conclusion, we observed that early transfusion of FFP to casualties with penetrating wounds requiring massive transfusion is needed to overcome the coagulopathy present. The presence of a transfusion service representative on-site in the ED is recommended to ensure proper identification and labeling of blood samples. Real-time consultations provided by a transfusion medicine physician in the operation theater was also found to be essential.     

Transfusion-related acute lung injury: reports to the French Hemovigilance Network 2007 through 2008

BACKGROUND: Transfusion‐related acute lung injury (TRALI) is a major cause of transfusion‐related mortality and morbidity. Epidemiologic studies using data from national transfusion schemes can help achieve a better understanding of TRALI incidence. STUDY DESIGN AND METHODS: A multidisciplinary working group analyzed TRALI cases extracted from the French Hemovigilance Network Database (2007‐2008). All notified cases were reviewed for diagnosis. Those meeting the Canadian Consensus Conference criteria for TRALI were classified according to imputability to transfusion and clinical severity. Patient data (clinical characteristics, number and types of products transfused, and serology results) were obtained. RESULTS: There were 62 TRALI cases and 23 possible TRALI cases during the 2‐year period. An immune‐mediated mechanism was identified in 30 of 50 TRALI cases with complete serology. TRALI was considered to be the cause of death in 7.1% of patients and might have contributed to death in an additional 9.4% of TRALI or possible TRALI patients. Occurrence ranked high in obstetrics (15%), after surgery (34%), and in hematologic malignancies (21%). Single‐donor high‐plasma‐volume components were involved in half of the cases where the implicated blood product could be determined and carried the highest risk per component (1:31,000 for single‐donor fresh‐frozen plasma units and apheresis platelet [PLT] concentrates, and 1:173,000 for red blood cells). No incident could be definitively related to the transfusion of solvent/detergent‐treated pooled plasma (>200,000 units transfused), nor to pooled PLT concentrates. CONCLUSION: The proportion of TRALI cases related to plasma‐rich components was lower than previously described.     

Ventilator-associated lung injury in patients without acute lung injury at the onset of mechanical ventilation

OBJECTIVE: Although ventilation with small tidal volumes is recommended in patients with established acute lung injury, most others receive highly variable tidal volume aimed in part at normalizing arterial blood gas values. We tested the hypothesis that acute lung injury, which develops after the initiation of mechanical ventilation, is associated with known risk factors for ventilator-induced lung injury such as ventilation with large tidal volume. DESIGN: Retrospective cohort study. SETTING: Four intensive care units in a tertiary referral center. PATIENTS: Patients who received invasive mechanical ventilation for > or = 48 hrs between January and December 2001. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The main outcome of interest, acute lung injury, was assessed by independent review of daily digital chest radiographs and arterial blood gases. Ventilator settings, hemodynamics, and acute lung injury risk factors were extracted from the Acute Physiology and Chronic Health Evaluation III database and the patients' medical records. Of 332 patients who did not have acute lung injury from the outset, 80 patients (24%) developed acute lung injury within the first 5 days of mechanical ventilation. When expressed per predicted body weight, women were ventilated with larger tidal volume than men (mean 11.4 vs. 10.4 mL/kg predicted body weight, p <.001) and tended to develop acute lung injury more often (29% vs. 20%, p =.068). In a multivariate analysis, the main risk factors associated with the development of acute lung injury were the use of large tidal volume (odds ratio 1.3 for each mL above 6 mL/kg predicted body weight, p <.001), transfusion of blood products (odds ratio, 3.0; p < 0.001), acidemia (pH < 7.35; odds ratio, 2.0; p =.032) and a history of restrictive lung disease (odds ratio, 3.6; p =.044). CONCLUSIONS: The association between the initial tidal volume and the development of acute lung injury suggests that ventilator-associated lung injury may be an important cause of this syndrome. Height and gender should be considered when setting up the ventilator. Strong consideration should be given to limiting large tidal volume, not only in patients with established acute lung injury but also in patients at risk for acute lung injury.     

The association of blood transfusion with mortality after cardiac surgery: cause or confounding? (CME)

BACKGROUND: Bleeding into the chest is a life‐threatening complication of cardiac surgery. Blood transfusion has been implicated as an important cause of harm associated with bleeding, based largely on studies demonstrating an independent association between transfusion and mortality. These studies did not, however, consider the possibility that bleeding may in itself be harmful, inasmuch as drains are inefficient at clearing blood from the chest and retained blood may compromise cardiac and lung function. STUDY DESIGN AND METHODS: We undertook a multivariate logistic regression analysis of the risk factors associated with mortality in 2599 consecutive patients undergoing cardiac surgery. Unlike previous studies the risk factors examined included the volume of chest tube drainage at 24 hours. A stratified analysis was also undertaken that compared the adjusted risk of death for patients exposed or not exposed to a postoperative blood transfusion. RESULTS: Blood transfusion was not an independent predictor of mortality (p = 0.4). Chest tube drainage was the strongest independent predictor of mortality (p < 0.001). In the stratified analysis, chest tube drainage remained an independent predictor of mortality for patients not exposed to a blood transfusion (p < 0.01). Furthermore, the risk of death of these patients was no different from patients exposed to a blood transfusion (p = 0.7 for interaction). CONCLUSIONS: Our results argue that for patients undergoing cardiac surgery bleeding contributes to mortality through mechanisms unrelated to blood transfusion.     

Implementation of a pediatric trauma massive transfusion protocol: one institution's experience

BACKGROUND: Massive transfusion protocols (MTPs) with fixed ratios of blood products may improve outcomes in coagulopathic adult trauma patients. However, there is a paucity of data on transfusion support protocols for pediatric trauma patients, whose mechanisms of injury may differ from those seen in adults. We hypothesized that an MTP would improve outcomes in children, through a balanced blood product resuscitation. STUDY DESIGN AND METHODS: A pediatric trauma MTP, with a fixed ratio of red blood cells (RBCs) : fresh‐frozen plasma (FFP) : platelets : cryoprecipitate in quantities based on the patient's weight, was initiated at a pediatric hospital. Data on clinical status, resuscitation volumes, and hospital course were collected and compared to data from pre‐MTP trauma patients requiring transfusion. RESULTS: Fifty‐three patients were enrolled over a 15‐month period and compared to 49 pre‐MTP patients. Seventy‐two percent of MTP patients had at least one coagulation value outside of the normal range upon emergency department (ED) arrival, and the median time to FFP transfusion decreased fourfold after MTP implementation (p < 0.0001). A total of 49% of MTP patients received greater than 70 mL/kg blood products, and the 24‐hour median FFP : RBC transfusion ratio was twofold higher in these patients than the pre‐MTP cohort (median, 1:1.8 vs. 1:3.6; p = 0.002). No improvement in mortality was observed after MTP implementation, taking into consideration injury severity, prothrombin time, and partial thromboplastin time. CONCLUSIONS: A pediatric trauma MTP is feasible and allows for rapid provision of balanced blood products for transfusion to coagulopathic children. Larger studies are warranted to determine whether such protocols will improve outcomes for pediatric trauma patients.     

After major ABO-mismatched allogeneic hematopoietic progenitor cell transplantation, erythroid engraftment occurs later in patients with donor blood group A than donor blood group B

BACKGROUND: Isohemagglutinins directed against the donor blood group frequently delay erythroid engraftment after major ABO-mismatched allogeneic hematopoietic progenitor cell transplantation (HPCT). Graft-versus-host reactions are capable of accelerating the clearance of isohemagglutinins. Whether immunogenicity of the A- and B-antigen is important in this process is unknown. PATIENTS AND METHODS: Data of 807 patients from three centers were screened for patients with major or bidirectionally ABO-mismatched donors. Clinical data and red blood cell (RBC) transfusion support were analyzed retrospectively. RESULTS: A total of 158 patients with major or bidirectionally mismatched donors were identified. After major mismatched HPCT, patients with anti-A directed against the donor blood group required RBC transfusion support for a median of 109 days (range, 0-324 days) compared to 21 days (range, 2-98 days) for patients with anti-B directed against donor blood group (log-rank test, p = 0.0001). Other risk factors associated with prolonged RBC transfusion support in univariate analysis were age (p = 0.024), cytomegalovirus infection (p = 0.016), hemolytic anemia (p = 0.027), and chronic bleeding disorders (p = 0.038). The independent influence of donor blood group and recipient age were confirmed in a multivariate analysis. CONCLUSION: These results indicate that the immunogenicity of the ABO antigen plays an important role for the kinetics of erythroid engraftment after ABO-mismatched HPCT.     

Toward the prevention of acute lung injury: protocol-guided limitation of large tidal volume ventilation and inappropriate transfusion

OBJECTIVE: We evaluated the effect of two quality improvement interventions (low tidal volume ventilation and restrictive transfusion) on the development of acute lung injury in mechanically ventilated patients. DESIGN: Observational cohort study. SETTING: Three intensive care units in a tertiary academic center. PATIENTS: We included patients who were mechanically ventilated for > or =48 hrs excluding those who refused research authorization or had preexisting acute lung injury or pneumonectomy. INTERVENTIONS: Multifaceted interdisciplinary intervention consisting of Web-based teaching, respiratory therapy protocol, and decision support within computerized order entry. MEASUREMENTS AND MAIN RESULTS: Of 375 patients who met the inclusion and exclusion criteria, 212 were ventilated before and 163 after the interventions. Baseline characteristics were similar between the two groups except for a lower frequency of sepsis (27% vs. 17%, p = .030), trend toward lower median glucose level (140 mg/dL, interquartile range 118-168 vs. 132 mg/dL, interquartile range 113-156, p = .096), and lower frequency of pneumonia (27% vs. 20%, p = .130) during the second period. We observed a large decrease in tidal volume (10.6-7.7 mL/kg predicted body weight, p < .001), in peak airway pressure (31-25 cm H2O, p < .001), and in the percentage of transfused patients (63% to 38%, p < .001) after the intervention. The frequency of acute lung injury decreased from 28% to 10% (p < .001). The duration of mechanical ventilation decreased from a median of 5 (interquartile range 4-9) to 4 (interquartile range 4-8) days (p = .030). When adjusted for baseline characteristics in a multivariate logistic regression analysis, protocol intervention was associated with a reduction in the frequency of new acute lung injury (odds ratio 0.21, 95% confidence interval 0.10-0.40). CONCLUSIONS: Interdisciplinary intervention effectively decreased large tidal volumes and unnecessary transfusion in mechanically ventilated patients and was associated with a decreased frequency of new acute lung injury.