Dose-dependent effects of red blood cell transfusion and case mix index on venous thromboembolic events in spine surgery.

BACKGROUND AND OBJECTIVES: Venous thromboembolic (VTE) events represent a major source of morbidity and mortality in spine surgery. Our goal was to assess whether a dose-response relationship exists between red blood cell (RBC) transfusion and postoperative VTE events among spine surgery patients. MATERIALS AND METHODS: A total of 786 spine surgery patients at a single institution who received at least 1 RBC unit perioperatively were included (2016-2019). Patients were stratified based on RBC transfusion volume: 1-2 units (39.3%), 3-4 units (29.4%), 5-6 units (15.9%) and ≥7 units (15.4%). Subgroup analyses were performed after stratification by case mix index, a standardized surrogate for patients' disease severity and comorbidities. Multivariable regression was used to assess risk factors for the development of postoperative VTE events. RESULTS: The overall VTE event rate was 2.4% (n = 19). A dose-response relationship was seen between RBC transfusion volume and VTE events (1-2 units: 0.97%, 3-4 units: 1.30%, 5-6 units: 3.20%, ≥7 units: 7.44%; p < 0.01). Similar dose-response relationships were seen between case mix index and VTE events (1.00-3.99: 0.52%, 4.00-6.99: 2.68%, ≥7.00: 9.00%; p < 0.01). On multivariable regression, larger RBC transfusion volumes (adjusted odds ratio [OR] 1.18 per RBC unit, 95% confidence interval [CI] 1.07-1.29; p < 0.01) and higher case mix index scores (adjusted OR 1.39 per unit increase, 95% CI 1.14-1.69; p < 0.01) were associated with an increased risk of thrombosis. CONCLUSION: Larger RBC transfusion volumes and higher case mix index scores were associated with an increased risk of VTE events. Physicians should be aware of how these dose-response relationships can influence a patient's risk of developing thrombotic complications postoperatively.

Patient Blood Management in Vascular Surgery.

Patient blood management (PBM) is an evidence-based, multidisciplinary approach aimed at appropriately allocating blood products to patients requiring transfusion while simultaneously minimizing inappropriate transfusions. The 3 pillars of patient blood management are optimizing erythropoiesis, minimizing blood loss, and optimizing physiological reserve of anemia. Benefits seen from PBM include limiting hospital costs and mitigating harm from numerous risks of transfusion.

Retrograde Autologous Priming in Cardiac Surgery: Results From a Systematic Review and Meta-analysis.

BACKGROUND: Retrograde autologous priming (RAP) before cardiopulmonary bypass (CPB) may minimize allogeneic red cell transfusion. We conducted a systematic review of the literature to examine the impact of RAP on perioperative allogeneic red cell transfusions in cardiac surgical patients. METHODS: This study involved a systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies evaluating the use of RAP in cardiac surgery involving CPB. The primary outcome was intraoperative allogeneic red cell transfusion. Secondary outcomes included whole hospital allogeneic transfusions and adverse events such as acute kidney injury (AKI) and stroke. RESULTS: A total of 11 RCTs (n = 1337 patients) were included, comparing RAP patients (n = 674) to control (n = 663). In addition, 10 observational studies (n = 2327) were included, comparing RAP patients (n = 1257) to control (n = 1070). Overall, RAP was associated with a significantly reduced incidence of intraoperative red cell transfusion (n = 18 studies; odds ratio [OR] = 0.34; 95% confidence interval [CI], 0.22-0.55, P < .001) compared to controls. This effect was seen among RCTs (n = 10 studies; OR = 0.19; 95% CI, 0.08-0.45, P < .001) and observational studies (n = 8 studies; OR = 0.66; 95% CI, 0.50-0.87, P = .004) in isolation. RAP was also associated with a significantly reduced incidence of whole hospital red cell transfusion (n = 5 studies; OR = 0.28; 95% CI, 0.19-0.41, P < .001). Among the studies that reported AKI and stroke outcomes, there was no statistically significant increased odds of AKI or stroke in either RAP or control patients. CONCLUSIONS: Based on the pooled results of the available literature, RAP is associated with a significant reduction in intraoperative and whole hospital allogeneic red cell transfusion. Use of RAP may prevent hemodilution of cardiac surgical patients and thus, lessen transfusions. Additional high-quality prospective studies are necessary to determine the ideal priming volume necessary to confer the greatest benefit without incurring organ injury.