Interrelationship of preoperative anemia, intraoperative anemia, and red blood cell transfusion as potentially modifiable risk factors for acute kidney injury in cardiac surgery: a historical multicentre cohort study.

PURPOSE: Acute kidney injury (AKI) is a potentially serious complication of cardiac surgery. Anemia and red blood cell (RBC) transfusion have individually been identified as potentially modifiable risk factors, but their interrelationship with AKI has not been clearly defined. The purpose of this study was to explore the interrelationship of preoperative anemia, intraoperative anemia, and RBC transfusion on the day of surgery with AKI in cardiac surgery. METHODS: This historical cohort study included 16 hospitals, each contributing data on approximately 100 consecutive patients who underwent cardiac surgery with cardiopulmonary bypass. Acute kidney injury was defined as a > 50% increase in creatinine levels during the first postoperative week. Multivariable regression was used to identify the interrelationship between preoperative anemia (hemoglobin < 130 g·L(-1) in males and < 120 g·L(-1) in females), intraoperative anemia (hemoglobin < 80 g·L(-1) during cardiopulmonary bypass), RBC transfusion on the day of surgery, and their interaction terms, after adjusting for site and baseline AKI risk. RESULTS: Of the 1,444 patients included in the study, 541 (37%) had preoperative anemia, 501 (35%) developed intraoperative anemia, 619 (43%) received RBC transfusions, and 238 (16%) developed AKI. After risk-adjustment, an individual with the combination of these three risk factors had a 2.6-fold (95% confidence interval 2.0 to 3.3) increase in the relative risk of AKI over an individual with none of these risk factors. CONCLUSIONS: Preoperative anemia, intraoperative anemia, and RBC transfusion on the day of surgery are interrelated risk factors for AKI after cardiac surgery. Targeting these risk factors may reduce the burden of AKI.

Off-label use of recombinant activated factor VII in surgical and non-surgical patients at 16 Canadian hospitals from 2007 to 2010 (Canadian Registry Report).

PURPOSE: Recombinant activated factor VII (rFVIIa) is a pro-hemostatic drug that is approved for treatment of bleeding in hemophilia patients, but it is frequently used off-label in non-hemophiliacs. The purpose of this study was to determine if the off-label use of rFVIIa is expanding and whether this poses a net harm to patients. METHODS: For this historical cohort study, data were collected on all non-hemophilia patients who received rFVIIa from 2007 to 2010 at 16 Canadian centres, and the pattern of use was examined. Logistic regression was used to determine the prognostic importance of severity of bleeding and the presence of an rFVIIa dose-effect relationship with major adverse events. RESULTS: One thousand three hundred seventy-eight patients received rFVIIa off-label, and 987 (72%) of these patients underwent cardiac surgery. The median [interquartile range] dose was 57 [36-85] µg·kg(-1). Usage increased from 2007 to 2008 (n = 341 and 380, respectively) but decreased in 2009 and 2010 (n = 350 and 307, respectively). Dose of rFVIIa and bleeding severity were associated with measured adverse events (P < 0.05). After adjusting for bleeding severity, dose was not associated with any of the adverse events. CONCLUSIONS: The off-label use of rFVIIa in Canada remains stable. Since severity of bleeding is prognostically important, the benefits of rapidly gaining control of bleeding that is non-responsive to conventional therapies may at times warrant the use of potent hemostatic drugs with established risk profiles, such as rFVIIa.

Should intraoperative cell-salvaged blood be used in patients with suspected or known malignancy?

PURPOSE: Intraoperative cell salvage (ICS) is used as an alternative to allogeneic blood transfusion in an attempt to avoid or minimize the risks associated with allogeneic blood. Intraoperative cell salvage is generally avoided in surgeries where malignancy is confirmed or suspected due to concern for potential metastasis or cancer recurrence. The application of post-processing methods for ICS is hypothesized to eliminate this potential risk. The purpose of this narrative review is to examine the in vitro experimental evidence as it pertains to the removal of tumour cells from ICS blood and to review the clinical studies where ICS blood has been used in patients with malignancy. SOURCE: A search of the English literature for relevant articles published from 1973 to 2012 was undertaken using MEDLINE and Cochrane databases. Bibliographies were cross-referenced to locate further studies. PRINCIPAL FINDINGS: Leukoreduction filters are an effective method for removal of malignant cells from ICS blood. Small non-randomized clinical studies to date do not show evidence of an increased rate of metastasis or cancer recurrence. Although a theoretical risk of disease recurrence persists, the decision to use autologous ICS blood must be weighed against the known risks of allogeneic blood transfusion. CONCLUSION: Transfusion of autologous blood harvested via ICS should be considered a viable option for reduction or avoidance of allogeneic product during many oncologic surgeries and may be a lifesaving option for those patients who refuse allogeneic blood products.

Tranexamic acid reduces allogenic transfusion in revision hip arthroplasty.

BACKGROUND: Revision THA is associated with high blood loss and a high probability of blood transfusion in the perioperative period. In November 2003, government legislation established the Blood Utilization Program at our center to reduce the rate and risks associated with allogenic transfusion. QUESTIONS/PURPOSES: The purposes of this study were to (1) determine whether the allogenic transfusion rate in patients undergoing revision THA decreased in those who were reviewed preoperatively by the Blood Utilization Program versus those who were not; (2) determine whether tranexamic acid reduced the rate of transfusion; and (3) identify potential perioperative clinical parameters that are associated with an increased risk of blood transfusion. METHODS: We included all 159 patients who underwent revision THA from January 2006 to October 2008 having either a socket and/or femoral stem revision except those having only a liner exchange. One hundred and one patients attended the Blood Utilization Program preoperatively and 58 patients did not (ie, they required urgent/emergency surgery). RESULTS: The Blood Utilization Program referral made no difference in transfusion rate or transfusion amount; however, the transfusion rates and amount were decreased by 8% and one unit, respectively. In patients referred to the Blood Utilization Program, the intraoperative use of tranexamic acid (an antifibrinolytic) was associated with reduced transfusions, regardless of dosage; preoperative erythropoietin tended to reduce transfusions while preoperative oral iron supplements did not. CONCLUSIONS: To further increase the relevance of the blood utilization program, the guidelines for patients undergoing revision hip arthroplasty need to be redefined. LEVEL OF EVIDENCE: Level III, therapeutic study. See the guidelines online for a complete description of level of evidence.

Comprehensive Canadian review of the off-label use of recombinant activated factor VII in cardiac surgery.

BACKGROUND: This observational study sought to identify the off-label use pattern of recombinant activated factor VII (rFVIIa) in cardiac surgery and to identify predictors of its effectiveness and risk. METHODS AND RESULTS: At 18 Canadian centers, 522 nonhemophiliac cardiac surgical patients received rFVIIa during the period 2003 through 2006; data were available, and retrospectively collected, on 503 patients. The median (quartile 1, quartile 3) units of red blood cells transfused from surgery to therapy and in the 24 hours after therapy were 8 (5, 12) and 2 (1, 5), respectively (P<0.0001). Mortality rate was 32%, and mortality or major morbidity rate was 44%. These rates were within expected ranges (mortality, 27% to 35%; mortality or morbidity, 39% to 48%), which were calculated with a separate cohort of cardiac surgical patients who did not receive rFVIIa used as reference. Independent predictors of complications included instability before therapy (multiple inotropes or intra-aortic balloon pump) and increasing red blood cell units transfused before and after therapy. Variables independently associated with nonresponse included abnormal coagulation parameters and >15 red blood cell units transfused before therapy. CONCLUSIONS: In Canada, rFVIIa is used primarily when standard interventions have failed to control bleeding. In this setting, rFVIIa is associated with reduced blood product transfusions and, after risk adjustment, does not appear to be associated with increased or decreased complication rates. The effectiveness of the drug may be enhanced if it is given early in the course of refractory blood loss in the setting of adequate amounts of circulating coagulation factors.