Perioperative Red Blood Cell Transfusion and Outcome in Stable Patients after Elective Major Vascular Surgery

Association of red blood cell transfusion and in-hospital mortality in patients admitted to the intensive care unit: a systematic review and meta-analysis

INTRODUCTION

Previous research has debated whether red blood cell (RBC) transfusion is associated with decreased or increased mortality in patients admitted to the intensive care unit (ICU). We conducted a systematic review and meta-analysis to assess the relationship of RBC transfusion with in-hospital mortality in ICU patients.

METHODS

We carried out a literature search on Medline (1950 through May 2013), Web of Science (1986 through May 2013) and Embase (1980 through May 2013). We included all prospective and retrospective studies on the association between RBC transfusion and in-hospital mortality in ICU patients. The relative risk for the overall pooled effects was estimated by random effects model. Sensitivity analyses were conducted to assess potential bias.

RESULTS

The meta-analysis included 28,797 participants from 18 studies. The pooled relative risk for transfused versus nontransfused ICU patients was 1.431 (95% CI, 1.105 to 1.854). In sensitivity analyses, the pooled relative risk was 1.211 (95% CI, 0.975 to 1.505) if excluding studies without adjustment for confounders, 1.178 (95% CI, 0.937 to 1.481) if excluding studies with relative high risk of bias, and 0.901 (95% CI, 0.622 to 1.305) if excluding studies without reporting hazard ratio (HR) or relative risk (RR) as an effect size measure. Subgroup analyses revealed increased risks in studies enrolling patients from all ICU admissions (RR 1.513, 95%CI 1.123 to 2.039), studies without reporting information on leukoreduction (RR 1.851, 95%CI 1.229 to 2.786), studies reporting unadjusted effect estimates (RR 3.933, 95%CI 2.107 to 7.343), and studies using odds ratio as an effect measure (RR 1.465, 95%CI 1.049 to 2.045). Meta-regression analyses showed that RBC transfusion could decrease risk of mortality in older patients (slope coefficient -0.0417, 95%CI -0.0680 to -0.0154).

CONCLUSIONS

There is lack of strong evidence to support the notion that ICU patients who receive RBC transfusion have an increased risk of in-hospital death. In studies adjusted for confounders, we found that RBC transfusion does not increase the risk of in-hospital mortality in ICU patients. Type of patient, information on leukoreduction, statistical method, mean age of patient enrolled and publication year of the article may account for the disagreement between previous studies.

Blood transfusion practice in a referral cardiovascular center in tehran, iran: a critical point of view

BACKGROUND

Unnecessary perioperative transfusions are likely to be related to increased morbidity and additional costs in cardiac surgery.

OBJECTIVES

The aim of this study was to evaluate the blood transfusion practice during and after adult cardiac surgery in a referral university hospital in Iran.

PATIENTS AND METHODS

In a descriptive study, we collected data from 153 adult patients underwent cardiac surgery at Rajaie Cardiovascular Medical and Research Center, Tehran, Iran from January to March 2013. The variables were patients' demographic, operative and post-operative data and the numbers of transfused packed red blood cell (PC) units and fresh frozen plasma (FFP) during and after cardiac surgery. Then we evaluated patients' and physicians' related causes of relatively increased transfusion rate in our patients and compared them with literature.

RESULTS

Of 153 patients, 96.8% received PC and 54.9% transfused FFP during or after surgery. Most of the transfusions were done after operation in intensive care unit (ICU). Also, 20% and 17% of the patients underwent transfusion of more than 6 units of PC and FFP, respectively. The mean left ventricular ejection fraction of the patients was 42.5 ± 10.9%. A significant number of patients had anemia (especially women) or received anticoagulants or antiplatelet agents preoperatively. Thirteen percent of the patients underwent emergency operations and 12.3% had re-exploration.

CONCLUSIONS

The results of this study demonstrate that the cardiac surgery patients receive a relatively greater number of PC or FFP units during and after the operation in our center. This finding may be explained to some extent by the fact that the sicker and more co-morbid patients referred to our center and such patients are more anemic and undergoing more emergent and complex procedures. Moreover, Transfusion strategy or protocol should be updated, especially after the operation in ICU.

Postoperative ICU management of vascular surgery patients

Critical care management of vascular surgical patients poses significant challenges owing to patients' comorbidities and the magnitude of the surgical procedures. The primary goals of the anesthesiologist and intensivist are reestablishing preoperative homeostasis, optimizing hemodynamics until return of normal organ function, and managing postoperative complications promptly and effectively. Postoperative critical care management demands a detailed knowledge of the various vascular surgical procedures and the potential postoperative complications. In this review, the authors describe the postoperative complications related to the major specific vascular surgical procedures and their perioperative management.

Preoperative anemia is an independent predictor of postoperative mortality and adverse cardiac events in elderly patients undergoing elective vascular operations

OBJECTIVE

The objective of this study was to assess the impact of preoperative anemia (hematocrit <39%) on postoperative 30-day mortality and adverse cardiac events in patients 65 years or older undergoing elective vascular procedures.

BACKGROUND

Preoperative anemia is associated with adverse outcomes after cardiac surgery, but its association with postoperative outcomes after open and endovascular procedures is not well established. Elderly patients have a decreased tolerance to anemia and are at high risk for complications after vascular procedures.

METHODS

Patients (N = 31,857) were identified from the American College of Surgeons' 2007-2009 National Surgical Quality Improvement Program-a prospective, multicenter (>250) database maintained across the United States. The primary and secondary outcomes of interest were 30-day mortality and a composite end point of death or cardiac event (cardiac arrest or myocardial infarction), respectively.

RESULTS

Forty-seven percent of the study population was anemic. Anemic patients had a postoperative mortality and cardiac event rate of 2.4% and 2.3% in contrast to the 1.2% and 1.2%, respectively, in patients with hematocrit within the normal range (P < 0.0001). On multivariate analysis, we found a 4.2% (95% confidence interval, 1.9-6.5) increase in the adjusted risk of 30-day postoperative mortality for every percentage point of hematocrit decrease from the normal range.

CONCLUSIONS

The presence and degree of preoperative anemia are independently associated with 30-day death and adverse cardiac events in patients 65 years or older undergoing elective open and endovascular procedures. Identification and treatment of anemia should be important components of preoperative care for patients undergoing vascular operations.

What evidence is there for intraoperative predictors of perioperative cardiac outcomes? A systematic review

Background

Patients undergo cardiac preoperative evaluation to identify those at risk of adverse perioperative cardiac events. The Revised Cardiac Risk index is commonly used for this task, although it is unable to accurately risk stratify in all patients. This may be partly a result of intraoperative events which significantly modify preoperative risk.

Methods

We conducted a systematic review to identify independent intraoperative predictors of adverse cardiac events in patients undergoing non-cardiac surgery. Four databases (Ovid Healthstar 1966 to Jan 2012, Ovid Medline 1946 to 6 March 2012, EMBASE 1974 to March 05 2012 and The Cochrane Library to March 06 2012) were searched.

Results

Fourteen eligible studies were identified. The need for intraoperative blood transfusion (odds ratio (OR), 2.3; 95% confidence interval (CI), 1.4-3.3), vascular surgery (OR, 2.3; 95% CI, 1.2-3.4) and emergent/urgent surgery (OR, 2.3; 95% CI, 1.1-3.5) were the only independent intraoperative risk predictors identified in more than study. Other independent intraoperative factors identified included a >20 mmHg fall in mean arterial blood pressure for > 60 min (OR, 3.0; 95% CI, 1.8-4.9), >30% increase in baseline systolic pressure (OR, 8.0; 95% CI, 1.3-50), tachycardia in the recovery room (>30 beats per min (bpm) from baseline for >5 min) (OR, 7; 95% CI, 1.9-26), new onset atrial fibrillation (OR, 6.6; 95% CI, 2.5-20), hypothermia (OR, 2.2; 95% CI, 1.1-5) and remote ischemic preconditioning (OR, 0.22; 95% CI, 0.07-0.67). Other markers of surgical complexity were not independently associated with postoperative adverse cardiac outcomes. None of these studies controlled for blood transfusion.

Conclusions

Intraoperative events significantly increase the risk for postoperative cardiac complications, although only intraoperative blood transfusion has strong evidence supporting this finding. It is possible that modification of these intraoperative risk factors by anesthetists and surgeons may reduce postoperative cardiac events and improve outcome. The Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) Study will add important information to understanding intraoperative risk factors for adverse cardiac events.

Low Hemoglobin Concentration Is Associated With Poor Outcome After Peripheral Arterial Surgery

Objective:

To assess the influence of low hemoglobin (Hb) concentration on major adverse cardiac events (MACE) and mortality in patients undergoing peripheral arterial surgery.

Methods:

This was a retrospective cohort study of patients undergoing peripheral arterial reconstructive surgery at a tertiary vascular center. Preoperative factors linked with the occurrence of MACE and death on univariate analysis ( P ≤ .1) were included in a multivariate model to confirm the independent association with the outcome variables.

Results:

A total of 360 consecutive patients (238 men) with a mean (standard deviation) age of 69 (10.7) years and Hb of 13.0 (2.12) g/dL treated under the care of a single specialist between January 2004 and December 2011 were included in the analysis. Of these, 193 (53.6%) were anemic. In all, 26 (7%) had a postoperative MACE and 18 (5%) died. On multivariate analysis, age > 80 years (odds ratio [OR] = 3; 95% confidence interval [CI] [1.2-7.5]; P = .025), renal impairment (OR = 3.2; 95% CI [.99-10.2]; P = .053), coronary disease (OR = 3.6; 95% CI [1.5-8.7]; P = .005), and low Hb (OR for each 1 g/dL drop below the mean = 1.4 [1.13-1.7]; P = .002) were independent risk factors for MACE. Unplanned surgery (OR = 4.5; 95% CI [1.2-16.9]; P = .025) and low Hb (OR for each 1 g/dL drop below the mean = 1.5; 95% CI [1.14-1.86]; P = .002) were independent risk factors for death.

Conclusion:

In peripheral arterial surgery, preoperative low Hb is associated with MACE and death. Further investigation is necessary to elucidate whether this relationship is causal. Meanwhile, consideration should be given to treating preoperative anemia as a significant risk factor for adverse outcome in this setting.

Anaemia in the older surgical patient: a review of prevalence, causes, implications and management

This review provides the clinician with a summary of the causes, implications and potential treatments for the management of anaemia in the older surgical patient. The prevalence of anaemia increases with age and is frequently identified in older surgical patients. Anaemia is associated with increased postoperative morbidity and mortality. Allogenic blood transfusion is commonly used to treat anaemia but involves inherent risks and may worsen outcomes. Various strategies for the correction of pre- and postoperative anaemia have evolved. These include correction of nutritional deficiencies and the use of intravenous iron and erythropoesis stimulating therapy. Clear differences exist between the elective and emergency surgical populations and the translation of research findings into these individual clinical settings requires more work. This should lead to a standardized approach to the management of this frequently encountered clinical scenario.

Post-operative auto-transfusion in total hip or knee arthroplasty: a meta-analysis of randomized controlled trials

BACKGROUND

Total hip or knee arthroplasty is an elective procedure that is usually accompanied by substantial blood loss, which may lead to acute anemia. As a result, almost half of total joint arthroplasty patients receive allogeneic blood transfusions (ABT). Many studies have shown that post-operative auto-transfusion (PAT) significantly reduces the need for ABT, but other studies have questioned the efficacy of this method.

METHODS

The protocol for this trial and supporting CONSORT checklist are available as supporting information; see Checklist S1. To evaluate the efficacy of PAT, we conducted a Cochrane systematic review that combined all available data from randomized controlled trials. Data from the six included trials were pooled for analysis. We then calculated relative risks with 95% confidence intervals (CIs) for dichotomous outcomes and mean differences with 95% CIs for continuous outcomes.

FINDINGS AND CONCLUSION

To our knowledge, this is the first meta-analysis to compare the clinical results between PAT and a control in joint replacement patients. This meta-analysis has proven that the use of a PAT reinfusion system reduced significantly the demand for ABT, the number of patients who require ABT and the cost of hospitalization after total knee and hip arthroplasty. This study, together with other previously published data, suggests that PAT drains are beneficial. Larger, sufficiently powered studies are necessary to evaluate the presumed reduction in the incidence of infection as well as DVT after joint arthroplasty with the use of PAT.

Transfusion in the critically ill: does it affect outcome?

Anemia and red blood cell (RBC) transfusions are common in critically ill and injured, trauma, and surgical patients. Tolerance of anemia is highly variable, depending on the presence of cardiovascular and other comorbid diseases that may diminish the hemodynamic response to a lower hemoglobin (Hb) level. The quest to define a minimum threshold Hb concentration at which patients achieve significant benefit to improve outcome has not yet been identified. Complications related to RBC transfusion are related to RBC storage and intrinsic properties of donor allogeneic RBCs, including bacterial contamination, transfusion-related acute lung injury, and transfusion-related immunomodulation. The best evidence related to transfusion-related outcome involves titrating transfusion requirements to parameters of severity of illness rather than arbitrarily defined Hb levels.