Red blood cell transfusion thresholds: can we go even lower?

The correlation of post-operative acute kidney injury and perioperative anaemia in patients undergoing cardiac surgery with cardiopulmonary bypass

Background and objective

Acute kidney injury (AKI) following cardiac surgery with cardiopulmonary bypass (CPB) is polyethiological clinical syndrome. During CPB haemodilution develops, which is useful in reducing the risk of thrombosis; however, haemodilutional anaemia decreases oxygen transfer and provokes tissue hypoxia, which can lead to acute organ damage. The aim of the study was to find out the impact of perioperative anaemia on AKI after cardiac surgery with CPB.

Materials and methods

This prospective study included 58 adult patients undergoing elective cardiac surgery with CPB, without any preoperative chronic renal disease or any systemic autoimmune disease. Serum concentrations of NGAL had been tested before the surgery, 2 hours, 6 hours, and one day after the surgery. Perioperative anaemia was assessed according to the Ht value before the surgery, the Ht value during CPB, and immediately after the surgery.

Results

The rate of haemodilutional anaemia is 77.59% in this study. The average of serum NGAL concentration before CPB was 63.95 ± 33.25 ng/mL and it was significantly lower than the average concentration 2 hours after the surgery, 6 hours after the surgery and one day after the surgery (respectively 148.51 ± 62.39, 119.44 ± 55, 128.70 ± 59.04 ng/mL, p < 0.05). AKI developed in 46.55% of the patients. A significant positive reasonable correlation between the development of perioperative anaemia and AKI was determined (r = 0.50, p < 0.05).

Conclusions

Post-operative AKI after cardiac surgery with CPB has a moderate positive correlation with perioperative haemodilutional anaemia. A longer CPB time and aortic cross-clamping time were found to be the risk factors for the development of AKI.

Recommendations on RBC Transfusion in General Critically Ill Children Based on Hemoglobin and/or Physiologic Thresholds From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the consensus recommendations and supporting literature for RBC transfusions in general critically ill children from the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

The panel of 38 experts developed evidence-based and, when evidence was lacking, expert-based recommendations and research priorities regarding RBC transfusions in critically ill children. The subgroup on RBC transfusion in general critically ill children included six experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 30, 2017, using a combination of keywords to define concepts of RBC transfusion and critically ill children. Recommendation consensus was obtained using the Research and Development/UCLA Appropriateness Method. The results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

Three adjudicators reviewed 4,399 abstracts; 71 papers were read, and 17 were retained. Three papers were added manually. The general Transfusion and Anemia Expertise Initiative subgroup developed, and all Transfusion and Anemia Expertise Initiative members voted on two good practice statements, six recommendations, and 11 research questions; in all instances, agreement was reached (> 80%). The good practice statements suggest a framework for RBC transfusion in PICU patients. The good practice statements and recommendations focus on hemoglobin as a threshold and/or target. The research questions focus on hemoglobin and physiologic thresholds for RBC transfusion, alternatives, and risk/benefit ratio of transfusion.

CONCLUSIONS

Transfusion and Anemia Expertise Initiative developed pediatric-specific good practice statements and recommendations regarding RBC transfusion management in the general PICU population, as well as recommendations to guide future research priorities. Clinical recommendations emphasized relevant hemoglobin thresholds, and research recommendations emphasized a need for further understanding of physiologic thresholds, alternatives to RBC transfusion, and hemoglobin thresholds in populations with limited pediatric literature.

Risk Factors for Reaching the Post-Operative Transfusion Trigger in a Community Primary Total Knee Arthroplasty Population

BACKGROUND

Little data exist to evaluate an individual's pre-operative risk of blood transfusion following total knee arthroplasty (TKA). Our aim is to identify the risk factors associated with reaching the transfusion trigger of Hb <8 g/dL (TT8) following surgery and how perioperative tranexamic acid (TXA) affects that outcome.

METHODS

Using a retrospective cohort study design, routine, unilateral TKAs performed between 2011 and 2013 in 19 hospitals were reviewed. Patients hospitalized ≤1 day or ≥4 days were excluded. Demographic data, clinical characteristics, and potential confounders were included in statistical models. Data were abstracted from electronic clinical and utilization databases. The main outcome was the risk of reaching the TT8. The primary exposure was use of single dose intravenous TXA. Logistic regression was used to model the adjusted association between TXA usage and post-operative risk of reaching TT8.

RESULTS

A total of 10,518 TKAs met criteria; 2566 (24.3%) received TXA (+TXA). The proportion that reached the TT8 was 2.1% for + TXA and 5.3% for -TXA (P < .0001). Pre-operative Hb levels were associated with increasing odds of reaching the TT8. Increasing age was weakly associated with this outcome. The odds of reaching the TT8 were lower for patients who had received TXA, had increasing body mass index, and surgical duration in the third quartile.

CONCLUSION

Not receiving TXA within 24 hours of TKA and pre-operative Hb levels <13 g/dL were independently associated with the odds of reaching the post-operative TT8 following a primary TKA.

Impact of Delta Hemoglobin on Provider Transfusion Practices and Post-operative Morbidity Among Patients Undergoing Liver and Pancreatic Surgery

BACKGROUND

Delta hemoglobin (ΔHb) is defined as the difference between the preoperative Hb and the lowest post-operative Hb level. We sought to define the impact of ΔHb relative to nadir Hb levels on the likelihood of transfusion, as well as characterize the impact of ΔHb and nadir Hb on morbidity among a large cohort of patients undergoing complex hepatopancreatobiliary (HPB) surgery.

METHODS

Patients who underwent pancreatic or hepatic resection between January 1, 2009 and June 30, 2015 at Johns Hopkins Hospital were identified. Data on the perioperative ΔHb, nadir Hb, as well as blood utilization were obtained and analyzed. Multivariable logistic regression models were used to identify the factors associated with ΔHb and the impact of ΔHb on perioperative morbidity. A Bayesian model was used to evaluate the correlation of ΔHb and nadir Hb with the likelihood of transfusion, as well as the impact on morbidity.

RESULTS

A total of 4363 patients who underwent hepatobiliary (n = 2200, 50.4 %) or pancreatic (n = 2163, 49.6 %) surgery were identified. More than one quarter of patients received at least one unit of packed red blood cells (PRBC) (n = 1187, 27.2 %). The median nadir Hb was 9.2 (IQR 7.9-10.5) g/dL resulting in an average ΔHb of 3.4 mg/dL (IQR 2.2-4.7) corresponding to 26.3 %. Both ΔHb and nadir Hb strongly influenced provider behavior with regards to use of transfusion. Among patients with the same nadir Hb, ΔHb was strongly associated with use of transfusion; among patients who had a nadir Hb ≤6 g/dL, the use of transfusion was only 17.9 % when the ΔHb = 10 % versus 49.1 and 80.9 % when the ΔHb was 30 or 50 %, respectively. Perioperative complications occurred in 584 patients (13.4 %) and were more common among patients with a higher value of ΔHb, as well as patients who received PRBC (both P < 0.001).

CONCLUSIONS

The combination of the Hb trigger with ΔHb was associated with transfusion practices among providers. Larger ΔHb values, as well as receipt of transfusion, were strongly associated with risk of perioperative complication following HPB surgery.

Pediatric Patient Blood Management Programs: Not Just Transfusing Little Adults

Red blood cell transfusions are a common life-saving intervention for neonates and children with anemia, but transfusion decisions, indications, and doses in neonates and children are different from those of adults. Patient blood management (PBM) programs are designed to assist clinicians with appropriately transfusing patients. Although PBM programs are well recognized and appreciated in the adult setting, they are quite far from standard of care in the pediatric patient population. Adult PBM standards cannot be uniformly applied to children, and there currently is significant variation in transfusion practices. Because transfusing unnecessarily can expose children to increased risk without benefit, it is important to design PBM programs to standardize transfusion decisions. This article assesses the key elements necessary for a successful pediatric PBM program, systematically explores various possible pediatric specific blood conservation strategies and the current available literature supporting them, and outlines the gaps in the evidence suggesting need for further/improved research. Pediatric PBM programs are critically important initiatives that not only involve a cooperative effort between pediatric surgery, anesthesia, perfusion, critical care, and transfusion medicine services but also need operational support from administration, clinical leadership, finance, and the hospital information technology personnel. These programs also expand the scope for high-quality collaborative research. A key component of pediatric PBM programs is monitoring pediatric blood utilization and assessing adherence to transfusion guidelines. Data suggest that restrictive transfusion strategies should be used for neonates and children similar to adults, but further research is needed to assess the best oxygenation requirements, hemoglobin threshold, and transfusion strategy for patients with active bleeding, hemodynamic instability, unstable cardiac disease, and cyanotic cardiac disease. Perioperative blood management strategies include minimizing blood draws, restricting transfusions, intraoperative cell salvage, acute normovolemic hemodilution, antifibrinolytic agents, and using point-of-care tests to guide transfusion decisions. However, further research is needed for the use of intravenous iron, erythropoiesis-stimulating agents, and possible use of whole blood and pathogen inactivation. There are numerous areas where newly formed collaborations could be used to investigate pediatric transfusion, and these studies would provide critical data to support vital pediatric PBM programs to optimize neonatal and pediatric care.

Packed red blood cell transfusion after surgery: are we "overtranfusing" our patients?

BACKGROUND

Data on the hemoglobin (Hb) after transfusion, or the "target," which reflects the "dose" of blood given are not well studied. We sought to examine the incidence and causes of "over transfusion" of red blood cells after surgery.

METHODS

Data on blood utilization including Hb triggers and targets were obtained for patients undergoing colorectal, pancreas, or liver surgery between 2010 and 2013.

RESULTS

A total of 2,905 patients were identified, of which 895 (31%) were transfused (median age 64, interquartile range: 53 to 72; 51% men; median American Society of Anesthesiologists class 3, interquartile range: 3-3; 51% pancreatic, 14% hepatobiliary, 21% colorectal, and 14% other). Among these, 512 (57%) were overtransfused (final Hb target after transfusion ≥9.0 g/dL). Among patients who were overtransfused, 171 (33%) were transfused at too high an initial trigger (>8.0 g/dL), whereas 304 (59%) had an appropriate trigger but received ≥2 packed red blood cell (PRBC) units, suggesting an opportunity to have transfused fewer units. There was significant variation in overtransfusion among surgeons (range 0% to 80%, P = .003).

CONCLUSIONS

Excess use of blood transfusion is common and was due to PRBC utilization for too high a transfusion trigger, as well as too many units transfused.

Significant Variation in Blood Transfusion Practice Persists following Upper GI Cancer Resection

PURPOSE

Perioperative blood transfusions are costly and linked to adverse clinical outcomes. We investigated the factors associated with variation in blood transfusion utilization following upper gastrointestinal cancer resection and its association with infectious complications.

METHODS

The Statewide Planning and Research Cooperative System was queried for elective esophagectomy, gastrectomy, and pancreatectomy for malignancy in NY State from 2001 to 2013. Bivariate and hierarchical logistic regression analyses were performed to assess the factors associated with receiving a perioperative allogeneic red blood cell transfusion. Additional multivariable analysis examined the relationship between transfusion and infectious complications.

RESULTS

Among 14,875 patients who underwent upper GI cancer resection, 32 % of patients received a perioperative blood transfusion. After controlling for patient, surgeon, and hospital-level factors, significant variation in transfusion rates was present across both surgeons (p < 0.0001) and hospitals (p < 0.0001). Receipt of a blood transfusion was also independently associated with wound infection (OR = 1.68, 95% CI = 1.47 and 1.91), pneumonia (OR = 1.98, 95% CI = 1.74 and 2.26), and sepsis (OR = 2.49, 95% CI = 2.11 and 2.94).

CONCLUSION

Significant variation in perioperative blood transfusion utilization is present at both the surgeon and hospital level. These findings are unexplained by patient-level factors and other known hospital characteristics, suggesting that variation is due to provider preferences and/or lack of standardized transfusion protocols. Implementing institutional transfusion guidelines is necessary to limit unwarranted variation and reduce infectious complication rates.

Red blood cell transfusion decision making in critically ill children

PURPOSE OF REVIEW

To discuss the tradeoff between permissive anemia and administering red blood cell transfusion to children in pediatric ICUs.

RECENT FINDINGS

Postsurgical mortality in adults increases abruptly if their nadir hemoglobin level falls below 5 g/dl. Patients with sepsis, even those in septic shock, and patients with upper gastrointestinal bleeding do not require red blood cell (RBC) transfusion if their hemoglobin level is above 7 g/dl.

SUMMARY

Anemia is common in critically ill children and is well tolerated most of the time. RBC transfusion is required in cases of hemorrhagic shock and in children with a hemoglobin level below 5 g/dl. Children with sepsis, including septic shock, those with a severe upper gastrointestinal bleeding and all stable critically ill children, including noncyanotic cardiac children older than 28 days, do not require an RBC transfusion if their hemoglobin level is above 7 g/dl. Transfusion threshold in children with univentricular physiology and in critically ill children with a hemoglobin level between 5 and 7 g/dl remains to be determined.