Anemia and red blood cell transfusion in critically ill cardiac patients

Impact of Hemoglobin Level in Ex Vivo Heart Perfusion on Donation After Circulatory Death Hearts: A Juvenile Porcine Experimental Model

BACKGROUND

Ex vivo heart perfusion (EVHP) of donation after circulatory death (DCD) hearts has become an effective strategy in adults; however, the small circulating volume in pediatrics poses the challenge of a low-hemoglobin (Hb) perfusate. We aimed to determine the impact of perfusate Hb levels during EVHP on DCD hearts using a juvenile porcine model.

METHODS

Sixteen DCD piglet hearts (11-14 kg) were reperfused for 4 h in unloaded mode followed by working mode. Metabolism, cardiac function, and cell damage were compared between the low-Hb (Hb, 5.0-5.9 g/dL; n = 8) and control (Hb, 7.5-8.4 g/dL; n = 8) groups. Between-group differences were evaluated using 2-sample t -tests or Fisher's Exact tests.

RESULTS

During unloaded mode, the low-Hb group showed lower myocardial oxygen consumption ( P  < 0.001), a higher arterial lactate level ( P  = 0.001), and worse systolic ventricular function ( P  < 0.001). During working mode, the low-Hb group had a lower cardiac output (mean, 71% versus 106% of normal cardiac output, P  = 0.010) and a higher arterial lactate level ( P  = 0.031). Adjusted cardiac troponin-I ( P  = 0.112) did not differ between the groups. Morphological myocyte injury in the left ventricle was more severe in the low-Hb group ( P  = 0.028).

CONCLUSIONS

Low-Hb perfusate with inadequate oxygen delivery induced anaerobic metabolism, resulting in suboptimal DCD heart recovery and declined cardiac function. Arranging an optimal perfusate is crucial to organ protection, and further endeavors to refine the priming volume of EVHP or the transfusion strategy are required.

Impact of anemia requiring transfusion or erythropoiesis-stimulating agents on new-onset cardiovascular events and mortality after continuous renal replacement therapy

Anemia is common in critically ill patients undergoing continuous renal replacement therapy (CRRT). We investigated the impact of anemia requiring red blood cell (RBC) transfusion or erythropoiesis-stimulating agents (ESAs) on patient outcomes after hospital discharge in critically ill patients with acute kidney injury (AKI) requiring CRRT. In this retrospective cohort study using the Health Insurance Review and Assessment database of South Korea, 10,923 adult patients who received CRRT for 3 days or more between 2010 and 2019 and discharged alive were included. Anemia was defined as the need for RBC transfusion or ESAs. Outcomes included cardiovascular events (CVEs) and all-cause mortality after discharge. The anemia group showed a tendency to be older with more females and had more comorbidities compared to the control group. Anemia was not associated with an increased risk of CVEs (adjusted hazard ratio [aHR]: 1.05; 95% confidence interval [CI]: 0.85-1.29), but was associated with an increased risk of all-cause mortality (aHR: 1.41; 95% CI 1.30-1.53). For critically ill patients with AKI requiring CRRT, anemia, defined as requirement for RBC transfusion or ESAs, may increase the long-term risk of all-cause mortality.

Predictors of mortality in heart failure patients with reduced or mildly reduced Ejection Fraction: The CASABLANCA HF Study

BACKGROUND

Heart failure (HF) poses a significant public health challenge throughout the world and Morocco. Our objective was to delineate the epidemiological characteristics of Moroccan patients living with chronic heart failure and to identify prognostic factors correlated with CHF mortality.

RESULTS

A total of 1344 patients participated in this study, with survival rates at 3, 6, and 10 years recorded at 75.2%, 60%, and 34%, respectively. During the follow-up, 886 patients succumbed, representing a mortality rate of 65.9%. A Cox regression model, utilizing baseline candidate variables, was developed to predict cardiovascular (CV) mortality. Predictors all of which had a P value less than 0.05 included age, left ventricular ejection fraction (EF) at commencement (< 35%), hypertension, male sex, anemia, creatinine levels, and the number of hospitalizations due to HF decompensation. Notably, the frequency of hospitalizations emerged as the most potent predictor of mortality, with an HR of 2.5 (95% CI [2-2.9]). Almost 90% of patients with three or more readmissions for HF decompensation experienced mortality by the follow-up's conclusion.

CONCLUSIONS

This study offers valuable insights into risk factors and clinical outcomes in HF patients in Morocco. Factors such as male gender, advanced age, a history of hypertension, lower systolic blood pressure, rehospitalizations for HF decompensation, low left ventricular ejection fraction, anemia, and elevated creatinine levels were associated with increased mortality. Medical and health services managers should be aware of the substantial burden and future challenges posed by HF in Morocco, prompting the adoption of multidisciplinary strategies for its management and care.

Prognostic Implication of Preoperative Anemia in Redo Cardiac Surgery: A Single-Center Propensity-Matched Analysis

Preoperative anemia has been associated with increased morbidity and mortality after cardiac surgery, but little is known about its prognostic value in the setting of redo procedure. A retrospective, observational cohort study of prospectively collected data was undertaken on 409 consecutive patients referred for redo cardiac procedures between January 2011 and December 2020. The EuroSCORE II calculated an average mortality risk of 25.7 ± 15.4%. Selection bias was assessed with the propensity-adjustment method. The prevalence of preoperative anemia was 41%. In unmatched analysis, significant differences between the anemic and nonanemic groups emerged in the risk for postoperative stroke (0.6% vs. 4.4%, p = 0.023), postoperative renal dysfunction (29.7% vs. 15.6%, p = 0.001), a need for prolonged ventilation (18.1% vs. 7.2%, p = 0.002), and high-dosage inotropes (53.1% vs. 32.9%, p < 0.001) along with both length of ICU and hospital stay (8.2 ± 15.9 vs. 4.3 ± 5.4 days, p = 0.003 and 18.8 ± 17.4 vs. 14.9 ± 11.1, p = 0.012). After propensity matching (145 pairs), preoperative anemia was still significantly associated with postoperative renal dysfunction, stroke, and the need for high-dosage inotrope cardiac morbidity. Preoperative anemia is significantly associated with acute kidney injury, stroke, and the need for high-dosage inotropes in patients referred for redo procedures.

Anaemia in the first week may be associated with long-term mortality among critically ill patients: propensity score-based analyses

BACKGROUND

Anaemia is highly prevalent in critically ill patients; however, the long-term effect on mortality remains unclear.

METHODS

We retrospectively included patients admitted to the medical intensive care units (ICUs) during 2015-2020 at the Taichung Veterans General Hospital. The primary outcome of interest was one-year mortality, and hazard ratios (HRs) with 95% confidence intervals (CIs) were determined to assess the association. We used propensity score matching (PSM) and propensity score matching methods, including inverse probability of treatment weighting (IPTW) as well as covariate balancing propensity score (CBPS), in the present study.

RESULTS

A total of 7,089 patients were eligible for analyses, and 45.0% (3,189/7,089) of them had anaemia, defined by mean levels of haemoglobin being less than 10 g/dL. The standardised difference of covariates in this study were lower than 0.20 after matching and weighting. The application of CBPS further reduced the imbalance among covariates. We demonstrated a similar association, and adjusted HRs in original, PSM, IPTW and CBPS populations were 1.345 (95% CI 1.227-1.474), 1.265 (95% CI 1.145-1.397), 1.276 (95% CI 1.142-1.427) and 1.260 (95% CI 1.125-1.411), respectively.

CONCLUSIONS

We used propensity score-based analyses to identify that anaemia within the first week was associated with increased one-year mortality in critically ill patients.

Blood transfusion demands in a tertiary otolaryngology, head and neck centre: A 5-year retrospective cohort study

OBJECTIVES

To retrospectively analyse and report the utilisation of red blood cell (RBC) transfusion in a tertiary otolaryngology, head and neck centre in the United Kingdom.

BACKGROUND

Twenty-seven per cent of RBC transfusions were for surgical indications in a 2014 England and North Wales survey. Currently, there is limited literature on RBC transfusions in Otolaryngology.

METHODS/MATERIALS

All inpatients admitted primarily under the care of the Otolaryngology, Head and Neck service between January 2015 and December 2019 were analysed. The primary outcomes of interest were number of units of RBC transfused over 5 years and distribution across clinical indications. Secondary outcome measure was cost of RBC transfusions over the same time period.

RESULTS

Most patients receiving transfusions are aged in their sixth and seventh decades. Epistaxis patients utilised 105 RBC units over the 5 years (56% of total RBC units) with emergency epistaxis accounting for 78% of use. Post-operative Head & Neck Cancer surgery with and without reconstruction required 47 RBC units over 5 years (25% of total RBC units). The mean cost incurred by the department over the 5-year period was £6171.49 (SD 1460.25). The cost has fallen by over £2000 over the 5-year period.

CONCLUSION

Blood transfusion use has fluctuated over the last 5 years. Epistaxis and post-operative Head and Neck cancer cases account for significant use compared with other patient groups. Prehabilitation strategies will add value towards mitigating future consumption of RBC.

Does a balanced colloid decrease perioperative blood loss in paediatric cardiac surgery: A double-blinded randomized controlled trial?

BACKGROUND

Unbalanced fluid solutions cause metabolic acidosis and could be associated with impaired coagulation and increased blood loss.

OBJECTIVE

To investigate whether the use of a balanced colloid compared with a saline colloid for peri-operative fluid therapy in children undergoing cardiac surgery is associated with decreased blood loss and exposure to blood products.

DESIGN

Double-blinded randomised controlled trial.

SETTING

Tertiary children's hospital from 2013 to 2016.

PATIENTS

Children older than 29 days and younger than 3 years admitted for cardiac surgery with cardiopulmonary bypass (CPB). Exclusion criteria were emergency cardiac surgery, moribund (American Society of Anesthesiologists 5), Jehovah's witnesses, coagulopathy, renal failure, liver injury, intracranial haemorrhage and electrolyte disturbances. From the 128 patients eligible, 88 were included in the study.

INTERVENTION

Random assignment of patients to either a saline colloid (6% hydroxyethyl starch 130/0.4 in 0.9% NaCl) or a balanced-electrolyte colloid (6% hydroxyethyl starch 130/0.4 in an isotonic solution) for CPB priming and intra- and postoperative fluid therapy during the first postoperative 48 h.

MAIN OUTCOME MEASURE

The primary outcome measure was calculated blood loss until the third postoperative day (POD3).

RESULTS

A total of 44 patients were included in each study arm. Calculated blood loss at POD3 was not significantly different between the groups (saline colloid 19.9 [IQR 13.8 to 26.1] ml kg-1 versus balanced colloid 15.9 [IQR 9.0 to 25.3 ml kg-1], P = 0.409). Secondary outcomes related to bleeding, exposure to blood products and coagulation were not different between groups. There was also no difference in length of mechanical ventilation, intensive care and hospital length of stay between groups.

CONCLUSION

The use of a balanced colloid for peri-operative fluid therapy compared with a saline one is not associated with decreased blood loss or exposure to blood products.

TRIAL REGISTRATION

EudraCT identifier: 2012-006034-17 and ClinicalTrial.gov identifier: NCT02584868.

Hematological Biomarkers, Mortality, Transfusion and Acute Heart Disease

BACKGROUND

Patients hospitalized with acute heart disease [acute myocardial infarction (MI); heart disease exacerbation] may require red blood cell (RBC) transfusion. These patients are at increased risk for morbidity and mortality. Hematological biomarkers may help to identify increased mortality risk. The aim of the study was to evaluate the association between hematological biomarkers and survival in these patients.

METHODS

A historical cohort study of all patients admitted to an internal medicine department, who were diagnosed with acute heart disease and requiring RBC transfusion, was carried out in a tertiary medical center between 2009-2014. The association between hematological biomarkers and 30-, 90-day and 5-year mortality was studied.

RESULTS

A total of 254 patients (median age 80 years, IQR 74-86.25; 40.9% females; acute MI 24.8%), were included. During the 5-year follow-up 212(83.5%) patients died. In a multivariate analysis the lower platelet to neutrophil ratio (PNR) was significantly associated with increased 30-, 90-day and 5-year mortality (p<0.001, 0.041, 0.003 respectively). A higher red cell distribution width (RDW) was significantly associated with 30- and 90-day mortality (p=0.003, 0.023 respectively), while higher neutrophil to lymphocyte ratio (NLR) was associated with increased 30-day and 5-year mortality (p= 0.036, 0.033 respectively).

CONCLUSIONS

Hematological biomarkers may help to identify increased mortality risk of acute heart disease patients, receiving RBC transfusions in an internal medicine department.

Using arterial-venous oxygen difference to guide red blood cell transfusion strategy

Background

Guidelines recommend a restrictive red blood cell transfusion strategy based on hemoglobin (Hb) concentrations in critically ill patients. We hypothesized that the arterial-venous oxygen difference (A-V O_2diff), a surrogate for the oxygen delivery to consumption ratio, could provide a more personalized approach to identify patients who may benefit from transfusion.

Methods

A prospective observational study including 177 non-bleeding adult patients with a Hb concentration of 7.0–10.0 g/dL within 72 h after ICU admission. The A-V O_2diff, central venous oxygen saturation (ScvO₂), and oxygen extraction ratio (O₂ER) were noted when a patient’s Hb was first within this range. Transfusion decisions were made by the treating physician according to institutional policy. We used the median A-V O_2diff value in the study cohort (3.7 mL) to classify the transfusion strategy in each patient as “appropriate” (patient transfused when the A-V O_2diff > 3.7 mL or not transfused when the A-V O_2diff ≤ 3.7 mL) or “inappropriate” (patient transfused when the A-V O_2diff ≤ 3.7 mL or not transfused when the A-V O_2diff > 3.7 mL). The primary outcome was 90-day mortality.

Results

Patients managed with an “appropriate” strategy had lower mortality rates (23/96 [24%] vs. 36/81 [44%]; p = 0.004), and an “appropriate” strategy was independently associated with reduced mortality (hazard ratio [HR] 0.51 [95% CI 0.30–0.89], p = 0.01). There was a trend to less acute kidney injury with the “appropriate” than with the “inappropriate” strategy (13% vs. 26%, p = 0.06), and the Sequential Organ Failure Assessment (SOFA) score decreased more rapidly (p = 0.01). The A-V O_2diff, but not the ScvO₂, predicted 90-day mortality in transfused (AUROC = 0.656) and non-transfused (AUROC = 0.630) patients with moderate accuracy. Using the ROC curve analysis, the best A-V O_2diff cutoffs for predicting mortality were 3.6 mL in transfused and 3.5 mL in non-transfused patients.

Conclusions

In anemic, non-bleeding critically ill patients, transfusion may be associated with lower 90-day mortality and morbidity in patients with higher A-V O_2diff.

Trial registration

ClinicalTrials.gov, NCT03767127. Retrospectively registered on 6 December 2018.

Patient Blood Management in Pediatric Cardiac Surgery: A Review

Efforts to reduce blood product transfusions and adopt blood conservation strategies for infants and children undergoing cardiac surgical procedures are ongoing. Children typically receive red blood cell and coagulant blood products perioperatively for many reasons, including developmental alterations of their hemostatic system, and hemodilution and hypothermia with cardiopulmonary bypass that incites inflammation and coagulopathy and requires systemic anticoagulation. The complexity of their surgical procedures, complex cardiopulmonary interactions, and risk for inadequate oxygen delivery and postoperative bleeding further contribute to blood product utilization in this vulnerable population. Despite these challenges, safe conservative blood management practices spanning the pre-, intra-, and postoperative periods are being developed and are associated with reduced blood product transfusions. This review summarizes the available evidence regarding anemia management and blood transfusion practices in the perioperative care of these critically ill children. The evidence suggests that adoption of a comprehensive blood management approach decreases blood transfusions, but the impact on clinical outcomes is less well studied and represents an area that deserves further investigation.

Red blood cell transfusion threshold after pediatric cardiac surgery: A systematic review and meta-analysis

BACKGROUND

Restrictive red blood cell transfusion strategy is implemented to minimize risk following allogeneic blood transfusion in adult cardiac surgery. However, it is still unclear if it can be applied to pediatric cardiac patients. The purpose of this systematic review and meta-analysis was to determine the effect of postoperative restrictive transfusion thresholds on clinical outcomes based on up-to-date results of randomized controlled trials (RCTs) and observational studies in pediatric cardiac surgery.

METHOD

We searched for RCTs and observational studies in the following databases: the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and ClinicalTrials.gov from their inception to October 26, 2017. We also searched reference lists of published guidelines, reviews, and relevant articles, as well as conference proceedings. No language restrictions were applied and no observational study met the inclusion criteria.

RESULTS

Four RCTs on cardiac surgery involving 454 patients were included. There were no differences in the pooled fixed effects of intensive care unit (ICU) stay between the liberal and restrictive transfusion thresholds (standardized mean difference SMD, 0.007; 95% confidence interval CI, -0.18-0.19; P = .94). There were also no differences in the length of hospital stay (SMD, -0.062; 95% CI, -0.28-0.15; P = .57), ventilation duration (SMD, -0.015; 95% CI, -0.25-0.22; P = .90), mean arterial lactate level (SMD, 0.071; 95% CI, -0.22-0.36; P = .63), and mortality (risk ratio, 0.49; 95% CI, 0.13-1.94; P = .31). There was no inter-trial heterogeneity for any pooled analysis. Publication bias was tested using Egger, Begg, or the trim-and-fill test, and the results indicated no significant publication bias.

CONCLUSION

Evidence from RCTs in pediatric cardiac surgery, though limited, showed non-inferiority of restrictive thresholds over liberal thresholds in length of ICU stay and other outcomes following red blood cell transfusion. Further high-quality RCTs are necessary to confirm the findings.

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.

Recommendations on RBC Transfusion in Infants and Children With Acquired and Congenital Heart Disease From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the recommendations and supporting literature for RBC transfusions in critically ill children with acquired and congenital heart disease developed by the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of 38 international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

Experts developed evidence-based and, when evidence was lacking, expert-based clinical recommendations and research priorities for RBC transfusions in critically ill children. The cardiac disease subgroup included three experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA appropriateness method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

Twenty-one recommendations were developed and reached agreement. For children with myocardial dysfunction and/or pulmonary hypertension, there is no evidence that transfusion greater than hemoglobin of 10 g/dL is beneficial. For children with uncorrected heart disease, we recommended maintaining hemoglobin greater than 7-9.0 g/dL depending upon their cardiopulmonary reserve. For stable children undergoing biventricular repairs, we recommend not transfusing if the hemoglobin is greater than 7.0 g/dL. For infants undergoing staged palliative procedures with stable hemodynamics, we recommend avoiding transfusions solely based upon hemoglobin, if hemoglobin is greater than 9.0 g/dL. We recommend intraoperative and postoperative blood conservation measures. There are insufficient data supporting shorter storage duration RBCs. The risks and benefits of RBC transfusions in children with cardiac disease requires further study.

CONCLUSIONS

We present RBC transfusion management recommendations for the critically ill child with cardiac disease. Clinical recommendations emphasize relevant hemoglobin thresholds, and research recommendations emphasize need for further understanding of physiologic and hemoglobin thresholds and alternatives to RBC transfusion in subpopulations lacking pediatric literature.

Bioelectrical Impedance Phase Angle-Predictor of Blood Transfusion in Cardiac Surgery

OBJECTIVE

To determine whether bioelectrical impedance-derived phase angle (PA) can be a predictor of red blood cell (RBC) transfusion in patients undergoing cardiac surgery.

DESIGN

An observational retrospective study of prospectively collected data.

SETTING

Single center, tertiary referral university hospital.

PARTICIPANTS

The study sample comprised 642 adult patients undergoing elective cardiac surgery.

INTERVENTIONS

Patient demographic and clinical variables were collected. The body composition of the patients was evaluated by bioelectrical impedance analysis (BIA) the day prior to surgery. The rates of postoperative RBC transfusion were recorded.

MEASUREMENTS AND MAIN RESULTS

Among the 642 patients (67.8% men, median age of 66 [range 59-73]) included in the present study, 210 (32.7%) received at least 1 RBC unit postoperatively. Hypertension, preoperative stroke, renal failure, preoperative hemoglobin and hematocrit values, BIA-derived PA, aortic crossclamp time, and cardiopulmonary bypass (CPB) time were associated with the risk of RBC transfusion in the univariate analysis, and were included in the final multivariate regression model. Preoperative stroke (odds ratio [OR] 0.394; 95% confidence interval [CI]: 0.183-0.848; p = 0.017), preoperative hemoglobin values (OR 0.943; 95% CI: 0.928-0.960; p < 0.001), PA <15th percentile (OR 2.326; 95% CI: 1.351-4.000; p = 0.002), and CPB time (OR 1.013; 95% CI: 1.008-1.018; p < 0.001) were identified as independent predictors of RBC transfusion.

CONCLUSION

Several factors were identified to be associated significantly with postoperative RBC transfusion in patients undergoing cardiac surgery. Among the conventional predictors, the value of the BIA-derived PA was indicated as a potent prognostic tool.

Anemia and acute coronary syndrome: current perspectives

Reference hemoglobin (Hb) values for the definition of anemia are still largely based on the 1968 WHO Scientific Group report, which established a cutoff value of <13 g/dL for adult men and <12 g/dL for adult nonpregnant women. Subsequent studies identified different normal values according to race and age. Estimated prevalence of anemia on admission in the setting of an acute coronary syndrome (ACS) is between 10% and 43% of the patients depending upon the specific population under investigation. Furthermore, up to 57% of ACS patients may develop hospital-acquired anemia (HAA). Both anemia on admission and HAA are associated with worse short- and long-term mortality, even if different mechanisms contribute to their prognostic impact. Baseline anemia can usually be traced back to preexisting disease that should be specifically investigated and corrected whenever possible. HAA is associated with clinical characteristics, medical therapy and interventional procedures, all eliciting cardiovascular adaptive response that can potentially worsen myocardial ischemia. The intrinsic fragility of anemic patients may limit aggressive medical and interventional therapy due to an increased risk of bleeding, and could independently contribute to worse outcome. However, primary angioplasty for ST elevation ACS should not be delayed because of preexisting (and often not diagnosed) anemia; delaying revascularization to allow fast-track anemia diagnosis is usually feasible and justified in non-ST-elevation ACS. Besides identification and treatment of the underlying causes of anemia, the only readily available means to reverse anemia is red blood cell transfusion. The adequate transfusion threshold is still being debated, although solid evidence suggests reserving red blood cell transfusions for patients with Hb level <8 g/dL and considering it in selected cases with Hb levels of between 8 and 10 g/dL. No evidence supports the use of iron supplements and erythropoiesis-stimulating agents in the setting of ACS.

Risk factors for inappropriate blood requisition among hospitals in Tanzania

BACKGROUND

Blood is a critical aspect of treatment in life saving situations, increasing demand. Blood requisition practices greatly effect sufficient supply in blood banks. This study aimed to determine the risk factors for inappropriate blood requisition in Tanzania.

METHODS

This was a cross sectional study using secondary data of 14,460 patients' blood requests from 42 transfusion hospitals. Primary data were obtained by using cluster-sampling design. Data were analysed using a two-level mixed-effects Poisson regression to determine fixed-effects of individual-level factors and hospital level factors associated with inappropriate blood requests. P-value <0.05 (2-tails) was considered statistically significant.

RESULTS

Inappropriate requisition was 28.8%. Factors significantly associated with inappropriate requisition were; reporting pulse rate and capillary refill decrease the risk (RR 0.74; 95% CI 0.64, 0.84) and (RR 0.73; 95% CI 0.63, 0.85) respectively and the following increased the risk; having surgery during hospital stay (RR 1.22; 95% CI 1.06, 1.4); being in general surgical ward (RR 3.3; 95% CI 2.7, 4.2), paediatric ward (RR 1.8; 95% CI 1.2, 2.7), obstetric ward (RR 2.5; 95% CI 2.0, 3.1), gynaecological ward (RR 2.1; 95% CI 1.5, 2.9), orthopaedics ward (RR 3.8; 95% CI 2.2, 6.7). Age of the patient, pallor and confirmation of pre-transfusion haemoglobin level were also significantly associated with inappropriate requisition. Majority of appropriate requisitions within the wards were marked in internal medicine (91.7%) and gynaecological wards (77.8%).

CONCLUSIONS

The proportion of inappropriate blood requests was high. Blood requisition was determined by clinical and laboratory findings and the ward patients were admitted to. Adherence to transfusion guidelines is recommended to assure the best use of limited blood supply.

Age and blood transfusion: relationship and prognostic implications in cardiac surgery

Background

Red blood cell (RBC) transfusion is a well-known predictor of acute kidney injury (AKI) and death after cardiac surgery. This study aimed to define the relationship between age and the need for RBC.

Methods

Study population included 1,765 consecutive patients undergoing on-pump procedures from 2013 to 2015. The relationship between RBC transfusion and both survival and AKI, and any interaction with age was estimated. A propensity score for the likelihood to receive RBC transfusion was calculated using multivariate logistic regression analysis to adjust for the effect of confounding factors. A logistic estimation curve was developed to investigate the interaction between this score and age.

Results

Patients receiving RBC transfusions had more comorbidities irrespective of age. Elderly patients underwent transfusion more often than younger patients with a 1.3-fold increase in the relative risk for transfusion. Age did not independently predict the need for RBC. AKI and mortality rates were significantly higher in transfused subsets irrespective of age.

Conclusions

Comorbidity profile and not age per se confers an increased risk of transfusion.

Strategies for blood conservation in pediatric cardiac surgery

Cardiac surgery accounts for the majority of blood transfusions in a hospital. Blood transfusion has been associated with complications and major adverse events after cardiac surgery. Compared to adults it is more difficult to avoid blood transfusion in children after cardiac surgery. This article takes into account the challenges and emphasizes on the various strategies that could be implemented, to conserve blood during pediatric cardiac surgery.

A retrospective study of transfusion practices in a Tertiary Care Institute

BACKGROUND AND AIMS

Excessive requests for cross matching blood which is more than the blood required for transfusion are usually based on worst case assumptions leading to overestimation of blood usage. We investigated the blood ordering pattern and transfusion practices so as to incorporate a blood ordering schedule for streamlining the use of blood in various hospital departments.

METHODS

The study was conducted over a period of 19 months in a 350 bedded tertiary teaching hospital. Source of data was blood bank requisition forms and blood bank registers of patients who underwent elective or emergency procedures in the hospital, for which blood was ordered. Data were entered in MS Excel and analysed using SPSS version 20.

RESULTS

The blood bank was requested to prepare 10,594 units of blood for 2556 patients. The blood utilised was 16.04% of total cross matched blood, leaving 83.9% of units cross matched but not transfused to patient for whom it was prepared, i.e., wasted. The surgery department had the highest number of units cross matched and transfused. The least number of units cross matched and wasted due to non-transfusion were from the Department of Oncology.

CONCLUSION

The current deficiency of explicit maximum blood order schedule in our hospital is the major factor responsible for high cross match: transfusion ratio. Therefore, a maximal surgical blood order schedule has been suggested to the hospital transfusion committee to implement maximum surgical blood order schedules for selected procedures.

Revisiting blood transfusion and predictors of outcome in cardiac surgery patients: a concise perspective

In the United States, cardiac surgery-related blood transfusion rates reached new highs in 2010, with 34% of patients receiving blood products. Patients undergoing both complex (coronary artery bypass grafting [CABG] plus valve repair or replacement) and non-complex (isolated CABG) cardiac surgeries are likely to have comorbidities such as anemia. Furthermore, the majority of patients undergoing isolated CABG have a history of myocardial infarction. These characteristics may increase the risk of complications and blood transfusion requirement. It becomes difficult to demonstrate the association between transfusions and mortality because of the fact that most patients undergoing cardiac surgery are also critically ill. Transfusion rates remain high despite the advances in perioperative blood conservation, such as the intraoperative use of cell saver in cardiac surgery. Some recent prospective studies have suggested that the use of blood products, even in low-risk patients, may adversely affect clinical outcomes. In light of this information, we reviewed the literature to assess the clinical outcomes in terms of 30-day and 1-year morbidity and mortality in transfused patients who underwent uncomplicated CABG surgery.

Pre-operative anaemia is associated with total morbidity burden on days 3 and 5 after cardiac surgery: a cohort study

BACKGROUND

Pre-operative anaemia is associated with mortality and red blood cell (RBC) transfusion requirement after cardiac surgery. However, the effect on post-operative total morbidity burden (TMB) is unknown. We explored the effect of pre-operative anaemia on post-operative TMB.

METHODS

Data were drawn from the Cardiac Post-Operative Morbidity Score (C-POMS) development study (n = 442). C-POMS describes and quantifies (0-13) TMB after cardiac surgery by noting the presence/absence of 13 morbidity domains on days 3 (D3), 5 (D5), 8 (D8) and 15 (D15). Anaemia was defined as a haemoglobin concentration below 130 g/l for men and 120 g/l for women.

RESULTS

Most patients were White British (86.1%) and male (79.2%) and underwent coronary artery bypass surgery (67.4%). Participants with pre-operative anaemia (n = 137, 31.5%) were over three times more likely to receive RBC transfusion (OR 3.08, 95%CI 1.88-5.06, p < 0.001), had greater D3 and D5 TMB (5 vs 3, p < 0.0001; 3 vs 2, p < 0.0001, respectively) and remained in hospital 2 days longer (8 vs 6 days, p < 0.0001) than non-anaemic patients. Transfused patients remained in hospital 5 days longer than non-transfused patients (p < 0.0001), had higher TMB on all days (all p < 0.001) and suffered greater pulmonary, renal, GI, neurological, endocrine and ambulation morbidities (p 0.026 to <0.001). Pre-operative anaemia and RBC transfusion were independently associated with increased C-POMS score.

CONCLUSIONS

Pre-operative anaemia and RBC transfusion are independently associated with increased post-operative TMB. Understanding TMB may assist in post-operative patient management to reduce morbidity. We recommend the use of the C-POMS tool as a standard outcome tool in further studies.

Effects of blood transfusion on oxygen extraction ratio and central venous saturation in children after cardiac surgery

BACKGROUND

Red blood cell transfusion is common in critically ill children after cardiac surgery. Since the threshold for hemoglobin (Hb) transfusion need is not well defined, the threshold Hb level at which dependent critical oxygen uptake-to-delivery (VO2-DO2) status compensation is uncertain.

OBJECTIVES

To assess the effects of blood transfusion on the oxygen extraction ratio (O2ER) and central venous oxygen saturation (ScvO2) to identify a critical O2ER value that could help us determine the critical need for blood transfusion.

DESIGN

Prospective, observational cohort study.

SETTING

Cardiac Surgical Intensive Care Unit at Prince Sultan Cardiac Center in Qassim, Saudi Arabia.

PATIENTS AND METHODS

Between January 2013 and December 2015, we included all children with cardiac disease who underwent surgery and needed a blood transfusion. Demographic and laboratory data with physiological parameters before and 1 and 6 hours after transfusion were recorded and O2ER before and 6 hours after transfusion was computed. Cases were divided into two groups based on O2ER: Patients with increased O2ER (O2ER > 40%) and normal patients without increased O2ER (O2ER < =40%) before transfusion.

MAIN OUTCOME MEASURE(S)

Changes in O2ER and ScvO2 following blood transfusion.

RESULTS

Of 103 patients who had blood transfusion, 75 cases had normal O2ER before transfusion while 28 cases had increased O2ER before transfusion. Following blood transfusion, O2ER and ScvO2 improved in the group that had increased O2ER before transfusion, but not in the group that had normal O2ER before transfusion.

CONCLUSIONS

The clinical and hemodynamic indicators O2ER and ScvO2 may be considered as markers that can indicate a need for blood transfusion.

LIMITATIONS

The limitation of this study is the small number of patients that had increased O2ER before transfusion. There were few available variables to assess oxygen consumption.

Hematocrit Levels, Blood Testing, and Blood Transfusion in Infants After Heart Surgery

OBJECTIVE

To determine whether judicious blood testing impacts timing or amount of packed RBC transfusions in infants after heart surgery.

DESIGN

A retrospective study comparing before and after initiation of a quality improvement process.

SETTING

A university-affiliated cardiac ICU at a tertiary care children's hospital.

PATIENTS

Infants less than 1 year old with Risk Adjustment for Congenital Heart Surgery category 4, 5, 6, or d-transposition of great arteries (Risk Adjustment for Congenital Heart Surgery 3) consecutively treated during 2010 through 2013.

INTERVENTION

A quality improvement process implemented in 2011 to decrease routine laboratory testing after surgery.

MEASUREMENTS AND MAIN RESULTS

Fifty-two infants preintervention and 214 postintervention had similar age, weight, proportion of cyanotic lesions, and surgical complexity. Infants with single versus biventricular physiology were compared separately. The number of laboratory tests per patient adjusted for cardiac ICU length of stay (laboratory tests/patient/day) was significantly lower in postintervention populations for single and biventricular groups (9 vs 15 and 10 vs 15, respectively; p < 0.001). The proportion of single ventricle patients transfused post- and preintervention was not statistically different (72% vs 90%; p = 0.130). Transfusion in the biventricular groups was the same over time (65% vs 65%). Time to first transfusion was significantly longer in the postintervention single ventricle group (4 vs 1 d; p < 0.001), and was not statistically different in the biventricular patients (4 vs 7 d; p = 0.058). The median hematocrit level at first transfusion was significantly lower (37% vs 40%; p = 0.004) postintervention in the cyanotic population, but did not differ in the biventricular group (31% vs 31%; p = 0.840).

CONCLUSION

In infants after heart surgery, blood testing targeted to individual needs significantly decreased the number of blood tests, but did not significantly decrease postoperative blood transfusion.

Determinants of red blood cell transfusion in pediatric trauma patients admitted to the intensive care unit

BACKGROUND

There are no well-designed prospective studies evaluating transfusion practices in pediatric trauma. We sought to describe red blood cell (RBC) transfusion practices in trauma patients who were admitted to a pediatric intensive care unit (PICU).

STUDY DESIGN AND METHODS

This study is a post-hoc analysis of a prospective, 6-month observational study in 30 PICUs. We studied a total of 580 patients aged less than 18 years who had been admitted to a PICU for more than 48 hours, including 95 who were trauma patients.

RESULTS

Trauma patients more frequently received transfusion before PICU admission (p < 0.001), were older (p < 0.0001), and more frequently were mechanically ventilated (p = 0.05). In the PICU, trauma patients received more transfusions (55% vs. 37%; p < 0.001), although admission hemoglobin levels were similar in both groups (p = 0.86). The mean (± standard deviation) pretransfusion hemoglobin level in the PICU was 9.0 ± 2.4 g/dL for trauma patients compared with 8.3 ± 2.4 g/dL for nontrauma patients (p = 0.09). Among the trauma patients, transfusion was associated with younger age, higher Pediatric Logistic Organ Regression scores, mechanical ventilation, bleeding, and transfusion before PICU admission. Multivariate regression demonstrated that receiving an RBC transfusion before admission was strongly associated with receiving a blood transfusion in the PICU (p = 0.008).

CONCLUSION

Trauma patients are at high risk for receiving an RBC transfusion both before and during their PICU stay, despite a similar transfusion threshold compared with nontrauma patients. Transfusion before PICU admission is a strong determinant, suggesting ongoing bleeding that will require re-transfusion. Further studies are needed to evaluate whether a restrictive transfusion strategy can safely be considered in these patients.

Red Blood Cell Transfusion in the Postoperative Care of Pediatric Cardiac Surgery: Survey on Stated Practice

The optimal red blood cell transfusion threshold for postoperative pediatric cardiac surgery patients is unknown. This study describes the stated red blood cell transfusion practice of physicians who treat postoperative pediatric cardiac surgery patients in intensive care units. A scenario-based survey was sent to physicians involved in postoperative intensive care of pediatric cardiac surgery patients in all Canadian centers that perform such surgery. Respondents reported their red blood cell transfusion practice in four postoperative scenarios: acyanotic or cyanotic cardiac lesion, in a neonate or an infant. In part A of each scenario, the patient was critically ill, but stabilized; in part B, the patient became unstable. Response rate was 58 % (71 of 123), with 45 respondents indicating direct involvement in postoperative intensive care. There was a wide variability in stated transfusion threshold, ranging from <7.0-14.0 g/dL for stabilized cases. There was no significant difference between neonates and infants in stated transfusion threshold. The mean hemoglobin level below which respondents would transfuse a stabilized patient was 9 g/dL for acyanotic and 11.2 g/dL for cyanotic patients, a statistically significant difference (2.2 ± 0.9 g/dL, p < 0.001). All clinical determinants of instability significantly increased transfusion threshold. Hemodynamic instability increased transfusion threshold by 2.3 ± 1.3 g/dL in acyanotic patients and by 1.3 ± 1.1 g/dL in cyanotic patients. Cyanotic lesion and clinical instability, but not patient age, increased stated red blood cell transfusion threshold. Significant variation in reported red blood cell transfusion practice exists among physicians treating pediatric patients in intensive care following cardiac surgery.

Hemoglobin Level and Hospital Mortality Among ICU Patients With Cardiac Disease Who Received Transfusions

BACKGROUND

There is a paucity of randomized clinical trial data on the use of red blood cell (RBC) transfusion in critically ill patients, specifically in the setting of cardiac disease.

OBJECTIVES

This study examined how hemoglobin (Hgb) level and cardiac disease modify the relationship of RBC transfusion with hospital mortality. The aim was to estimate the Hgb level threshold below which transfusion would be associated with reduced hospital mortality.

METHODS

We performed secondary data analyses of Veterans Affairs intensive care unit (ICU) episodes across 5 years. Logistic regression quantified the effect of transfusion on hospital mortality while adjusting for nadir Hgb level, demographic characteristics, admission information, comorbid conditions, and ICU admission diagnoses.

RESULTS

Among 258,826 ICU episodes, 12.4% involved transfusions. Hospital death occurred in 11.6%. Without comorbid heart disease, transfusion was associated with decreased adjusted hospital mortality when Hgb was approximately <7.7 g/dl, but transfusion increased mortality above this Hgb level. Corresponding Hgb level thresholds were approximately 8.7 g/dl when comorbid heart disease was present and approximately 10 g/dl when the ICU admission diagnosis was acute myocardial infarction (AMI). Sensitivity analysis using additional adjustment for selected blood tests in a subgroup of 182,792 ICU episodes lowered these thresholds by approximately 1 g/dl.

CONCLUSIONS

Transfusion of critically ill patients was associated with reduced hospital mortality when Hgb level was <8 to 9 g/dl in the presence of comorbid heart disease. This Hgb level threshold for transfusion was 9 to 10 g/dl when AMI was the ICU admission diagnosis.

'Blood doping' from Armstrong to prehabilitation: manipulation of blood to improve performance in athletes and physiological reserve in patients

Haemoglobin is the blood’s oxygen carrying pigment and is encapsulated in red blood corpuscles. The concentration of haemoglobin in blood is dependent on both its total mass in the circulation (tHb-mass) and the total plasma volume in which it is suspended. Aerobic capacity is defined as the maximum amount of oxygen that can be consumed by the body per unit time and is one measure of physical fitness. Observations in athletes who have undergone blood doping or manipulation have revealed a closer relationship between physical fitness (aerobic capacity) and total haemoglobin mass (tHb-mass) than with haemoglobin concentration ([Hb]). Anaemia is defined by the World Health Organisation (WHO) as a haemoglobin concentration of <130 g/L for men and <120 g/L for women. Perioperative anaemia is a common problem and is associated with increased mortality and morbidity following surgery. Aerobic capacity is also associated with outcome following major surgery, with less fit patients having a higher incidence of mortality and morbidity after surgery. Taken together, these observations suggest that targeted preoperative elevation of tHb-mass may raise aerobic capacity both directly and indirectly (by augmenting preoperative exercise initiatives- ‘prehabilitation’) and thus improve postoperative outcome. This notion in turn raises a number of questions. Which measure ([Hb] or tHb-mass) has the most value for the description of oxygen carrying capacity? Which measure has the most utility for targeting therapies to manipulate haemoglobin levels? Do the newer agents being used for blood manipulation (to increase tHb-mass) in elite sport have utility in the clinical environment? This review explores the literature relating to blood manipulation in elite sport as well as the relationship between perioperative anaemia, physical fitness and outcome following surgery, and suggests some avenues for exploring this area further.

Blood Transfusions After Pediatric Cardiac Operations: A North American Multicenter Prospective Study

BACKGROUND

Red blood cell transfusion is an important supportive measure after pediatric cardiac operations. However, no clear hemoglobin threshold has been established. This study characterized anemia development and red blood cell transfusions in the pediatric intensive care unit (PICU) after cardiac operations.

METHODS

A prospective, multicenter, 6-month cohort study on the management of anemia in critically ill pediatric patients was conducted in 30 North American PICUs. This observational study enrolled 977 consecutive children (aged <18 years) who stayed in the PICU for 48 hours or more. We analyzed a subgroup of postcardiac surgical patients from this study.

RESULTS

Included were 175 cardiac patients, 56% of whom had cyanotic heart disease. The mean Pediatric Risk of Mortality (PRISM III) score was 6.4 ± 5.4. Fifty-four percent of children were anemic in the PICU (20% on admission, 34% during PICU stay). Most patients (79%) received at least one red blood cell transfusion in the PICU. Patients who received a transfusion had a significantly longer PICU stay (9.3 ± 6.3 vs 6.1 ± 5.4 days, p = 0.01). Pretransfusion hemoglobin was different in acyanotic and cyanotic patients (mean ± standard deviation: 11.1 ± 2.2 g/dL and 11.8 ± 2.1 g/dL, respectively). According to the attending physician, a low hemoglobin level was the primary indication for transfusion in only 17% of cases.

CONCLUSIONS

Pediatric cardiac surgical patients are at high risk of receiving red blood cell transfusions. This study, which showed great variability in transfusion practices across North American PICUs, highlights the need for clearer transfusion guidelines in this specific population.

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.

Bleeding risk with systemic thrombolytic therapy for pulmonary embolism: scope of the problem

Acute pulmonary embolism represents a major complication of venous thromboembolism that is associated with high morbidity and mortality. Guidelines recommend the rapid initiation of anticoagulation and consideration of thrombolytic therapy in select patients, including those with hypotension or at high risk of developing hypotension. Evaluation for thrombolytic therapy should only be considered after assessment of contraindications and risk for major bleeding. The objective of this perspective article is to evaluate the bleeding risk associated with systemic thrombolytic therapy in the management of acute pulmonary embolism and discuss strategies to minimize this risk. Risk stratification of acute pulmonary embolism will be discussed to identify patient populations that warrant specific consideration of risk for major bleeding with thrombolytic therapy. In addition, the incidence, patient-specific risk factors, and pharmacologic characteristics, including concurrent anticoagulation and thrombolytic therapy, will be evaluated in the context of risk for major hemorrhage. Finally, supporting evidence for strategies to minimize risk of hemorrhage, including evaluation of contraindications, weight adjusted dosing, infusion strategy and catheter-directed thrombolytic administration will be evaluated. Despite published guidelines and review articles, select aspects to thrombolytic therapy for the management of pulmonary embolism remain controversial and under recognized, including risk of major hemorrhage. When making decisions about the role of thrombolytic therapy in pulmonary embolism, clinicians must be knowledgeable about the associated risks of thrombolytic therapy and individually evaluate patient risk factors prior to determining appropriate candidacy for thrombolytic therapy. For patients considered to be at high risk of major bleeding, strategies to minimize risk should be considered, including weight-adjusted doses and catheter directed therapy. Additional research is needed specific to the acute pulmonary embolism setting to validate risk factors and strategies to minimize major hemorrhage.

Anesthetic considerations in organ procurement surgery: a narrative review

PURPOSE

While a few publications specify the anesthetic implications of either brain or cardiac death, they lack detail on how to provide anesthesia during organ donation surgery. We provide a thorough description of important anesthetic considerations during organ donation surgery in patients with either brain or cardiac death.

SOURCE

A thorough literature review was undertaken to locate all relevant articles that describe systemic effects of brain and cardiac death and their anesthetic implications. We searched PubMed, Pubget, and EMBASE™ for relevant articles using the following search terms: anesthesia, management, donation cardiac death, donation brain death. In addition, we reviewed the relevant protocols at our own institution.

PRINCIPAL FINDINGS

Highly specific intraoperative management by an anesthesiologist is required during organ procurement after brain death. To manage the heart-beating brain-dead donor, the anesthesiologist must incorporate knowledge of the effects of brain death on each organ system as well as the effects of the preoperative measures that the donor required in the intensive care unit. It is also important to know which organs are going to be procured in order to establish specific goals and implement strategies (e.g., lung-protective ventilation or intraoperative glycemic control) to optimize donor outcome. During organ procurement after cardiac death, an anesthesiologist's direct involvement is particularly important for lung donors.

CONCLUSION

Anesthesiologist-guided physiological optimization of the brain-dead donor may be a factor in determining the outcome of the organ recipient. Additionally, anesthesiologists have an important role in helping to ensure that the highest quality and most appropriate care are rendered to non-heart-beating donors. This is achieved through establishing protocols in their hospitals for donation after cardiac death that maximize the number of available organs with the best chance for long-term graft viability.