Phlebotomy Blood Research Articles

Comparison of a Blood Self-Collection System with Routine Phlebotomy for SARS-CoV-2 Antibody Testing.

The Coronavirus Disease 2019 (COVID-19) pandemic forced researchers to reconsider in-person assessments due to transmission risk. We conducted a pilot study to evaluate the feasibility of using the Tasso-SST (Tasso, Inc, Seattle, Washington) device for blood self-collection for use in SARS-CoV-2 antibody testing in an ongoing COVID-19 prevalence and immunity research study. 100 participants were recruited between January and March 2021 from a previously identified sub-cohort of the Cabarrus County COVID-19 Prevalence and Immunity (C3PI) Study who were under-going bimonthly COVID-19 antibody testing. Participants were given a Tasso-SST kit and asked to self-collect blood during a scheduled visit where trained laboratory personnel performed routine phlebotomy. All participants completed an after-visit survey about their experience. Overall, 70.0% of participants were able to collect an adequate sample for testing using the device. Among those with an adequate sample, there was a high concordance in results between the Tasso-SST and phlebotomy blood collection methods (Cohen’s kappa coefficient = 0.88, Interclass correlation coefficient 0.98 [0.97, 0.99], p < 0.0001). The device received a high-level (90.0%) of acceptance among all participants. Overall, the Tasso-SST could prove to be a valuable tool for seroprevalence testing. However, future studies in larger, diverse populations over longer periods may provide a better understanding of device usability and acceptance among older participants and those with comorbidities in various use scenarios.

Reducing neonatal phlebotomy blood losses through the accurate calculation of minimum test volume requirements

Repeated phlebotomy for laboratory diagnostic testing is a known cause of iatrogenic anaemia and in critically ill neonates often leads to blood transfusion being required. This study has developed a spreadsheet clinical decision support tool to allow neonatal staff to determine the true minimum blood volume required to analyse groups of blood tests and modelled its potential benefit compared with the existing system in use. The tool calculates the minimum blood volume accounting for novel factors including the current patient haematocrit for plasma/serum samples, instrument minimum test and dead volumes (including those where shared) and sharing of samples within/between laboratory departments. A year of neonatal unit laboratory requests were examined comparing the volumes and containers of blood recommended by the hospital information system with both the amount actually collected by staff and that recommended by the tool. A total of 463 patients had 8481 blood draws for 23,899 tests or test profiles over the year. The hospital information system recommended collecting 11,222 mL of blood into 18,509 containers, while 17,734 containers were actually received (10,717 mL if fully filled). The tool recommended collecting 4915 mL of blood into 15,549 containers. This tool allows neonatal intensive care unit staff to objectively determine the minimum blood volume required for a combination of tests and is generalizable between laboratory instruments. Compared with the hospital information system, use of the minimum blood volume clinical decision support tool could maximally reduce the volume of blood collected from this neonatal unit by more than a half. Neonatal intensive care unit staff had apparently already gone some way to determining their own minimum volumes required.

Correlation between Phlebotomy Blood Loss and Hospital- Acquired Anemia among Acute Coronary Syndrome Patients

Correlation between Phlebotomy Blood Loss and Hospital- Acquired Anemia among Acute Coronary Syndrome Patients

Neonatal Umbilical Arterial Catheter Removal Is Accompanied by a Marked Decline in Phlebotomy Blood Loss

Background: Umbilical arterial catheters (UACs) are frequently used in critically ill neonates. UAC are convenient, reliable, and allow for caregiver convenience in performing painless arterial blood sampling. We hypothesized that UAC removal in extremely low birth weight (ELBW) neonates will result in significantly less phlebotomy blood loss (PBL) after correcting for severity of illness. Study Design and Methods: PBL was measured at a single center in 99 ELBW infants who survived to day 28. Individual infant’s paired daily PBL for the two 24-h periods before and after UAC removal were compared using the paired t test. Daily PBL up to 7 days before and 7 days after UAC removal were compared using a logistic regression with mixed model analysis for repeated measures. Cumulative 28-day phlebotomy loss was evaluated by multiple linear regression analysis. Results: PBL 24 h before and after UAC removal were 1.7 mL (95% CI 1.5–1.9) and 0.9 mL (95% CI 0.8–1.0; p < 0.0001), respectively. Cumulative 28-day PBL increased by 2.2 mL (±0.7) per day that a UAC was present with or without correction for severity of illness (p < 0.001). Conclusion: UAC removal is independently associated with a marked decline in PBL. We speculate the ease and convenience of UAC blood sampling lead to more frequent blood testing and greater PBL.

Patterns of phlebotomy blood loss and transfusions in extremely low birth weight infants.

Characterize frequency and volume of blood draws and transfusions in extremely low birth weight infants in the first 10 weeks of life. We included infants with a birth weight <1000 g born 23 0/7-29 6/7 weeks gestational age (GA) and with a length of stay ≥10 weeks, admitted between 2014 and 2016 to a single neonatal intensive care unit. Of 54 infants, median (25th, 75th percentile) GA and birth weight were 25 weeks (24, 26) and 665 g (587, 822), respectively. Median number of blood draws per infant decreased from 57 (49, 65) in week 1 to 12 (8, 22) in week 10. Median volume of blood extracted was 83 mL (70, 97), and median number of blood transfusions was 8 (5, 10). This cohort experienced a high number and volume of blood draws. Draw frequency and transfusions decreased over the first 10 weeks of life.

P1.07: THE EFFECTS OF MINIMIZING PHLEBOTOMY BLOOD VOLUME ON ANEMIA IN PEDIATRIC HOME PARENTERAL NUTRITION PATIENTS

Background & Objectives: Anemia is a common morbidity in pediatric patients who require home parenteral nutrition (HPN). One factor that increases the risk for anemia in this patient population is frequent phlebotomy as part of routine monitoring. At Loma Linda University Children’s Hospital (LLUCH), the majority of pediatric patients on HPN have monthly labs drawn as part of the standard monitoring protocol. In June 2016, LLUCH began using micro-tubes for routine blood sampling. Traditional phlebotomy tubes require 15–20 mLof blood. Micro-tubes require less than 2mLfor the same tests. The purpose of this study is to understand the effects of phlebotomy blood volume minimization strategies in reducing anemia in our pediatric patients requiring HPN. Methods: This study was IRB-approved and retrospective in design. Since June 2016, the HPN program at LLUCH began using micro tubes for routine laboratory monitoring. Standard clinical data (age, gender, weight) and laboratory data (CBC, ALT, bilirubin, albumin) were collected prior to June 2016 and after September 2016. The primary outcome of this study was to compare the change in hemoglobin concentrations before and after the use of micro-tubes. The secondary outcome was to estimate the prevalence of anemia for age before and after use of micro-tubes for phlebotomy. Statistical analyses were performed including standard descriptive analysis, t-tests, and bivariate analysis. P-value of <0.05 was considered statistically significant. The sensitivity and specificity of red cell mean corpuscle volume (MCV) and red cell distribution width (RDW) in detecting anemia for ages were also calculated. Results: N = Thirty-eight subjects. Mean age = 6.1 years (SD +/- 4.2y). Prevalence of anemia for age before micro-tube implementation = 22% Prevalence of anemia for age after micro-tube implementation = 14% Mean difference in the hemoglobin of before and after implementation = +0.62g/dL(CI=0.21 to 1.02; p=0.004) Secondary bivariate analysis: No correlation between anemia for age and the following factors: age, gender, weight, ALT, and albumin level. Conclusions: Strategies such as micro-tubes to reduce the volume of routine blood draws in pediatric patients requiring chronic HPN may reduce the prevalence of anemia and improve hemoglobin levels. Age, weight, and liver enzyme levels were not found to be independent risk factors for the presence of anemia for age.

Persistent inflammation and anemia among critically ill septic patients.

Associations among inflammatory cytokines, erythropoietin (EPO), and anemia in critically ill septic patients remain unclear. This study tested the hypothesis that elevated inflammatory cytokines and decreased EPO would be associated with iron-restricted anemia while accounting for operative blood loss, phlebotomy blood loss, and red blood cell (RBC) transfusion volume. Prospective observational cohort study of 42 critically ill septic patients was conducted. Hemoglobin (Hb) at sepsis onset and hospital discharge were used to calculate ΔHb. Operative blood loss, phlebotomy blood loss, and RBC transfusion volume were used to calculate adjusted ΔHb (AdjΔHb) assuming that 300 mL RBC is equal to 1 g/dL Hb. Patients with AdjΔHb of greater than 0 (positive AdjΔHb, n = 18) were compared with patients with AdjΔHb of less than or equal to 0 (negative AdjΔHb, n = 24). Plasma tumor necrosis factor α, granulocyte colony-stimulating factor, interleukin (IL)-6, IL-8, EPO, erythrocyte mean corpuscular volume, and serum transferrin receptor were measured on days 0, 1, 4, 7, and 14. Patients with negative AdjΔHb had significantly higher day 14 levels of IL-6 (37.4 vs. 15.2 pg/mL, p < 0.05), IL-8 (39.1 vs. 18.2 pg/mL, p = 0.01), and granulocyte colony-stimulating factor (101.3 vs. 60.5 pg/mL, p = 0.01), but not EPO. On linear regression analysis, lower AdjΔHb was associated with higher day 14 levels of IL-6 (r = 0.22, p < 0.01), IL-8 (r = 0.10, p = 0.04), stromal cell-derived factor 1 (r = 0.14, p = 0.02), and tumor necrosis factor α (r = 0.13, p = 0.02), but not EPO. Patients with negative AdjΔHb had significantly lower mean corpuscular volume on days 4 (89.6 vs. 93.2 fL/cell, p = 0.04), 7 (92.3 vs. 94.9 fL/cell, p = 0.04), and 14 (92.1 vs. 96.0 fL/cell, p = 0.03) but similar serum transferrin receptor levels. Persistent elevation of inflammatory cytokines was associated with iron-restricted anemia among critically ill septic patients, occurring in the absence of systemic iron deficiency, independent of endogenous EPO. Prognostic study, level II.

Impact of Nursing Education on Phlebotomy Blood Loss and Hospital-Acquired Anemia: A Quality Improvement Project.

Phlebotomy blood loss resulting in hospital-acquired anemia remains a significant problem in the critically ill population. A quality improvement project focused on decreasing phlebotomy blood loss and increasing nursing knowledge regarding blood conservation strategies was undertaken in the intensive care unit of a community hospital. The project followed a quasi-experimental design. Data were gathered using electronic chart review and surveys before and after educational sessions. Intensive care unit nurses attended educational sessions focused on increasing knowledge regarding phlebotomy blood loss, hospital-acquired anemia, blood conservation strategies, and utilization of blood conservation devices. The study showed a statistically significant increase in nursing knowledge regarding hospital-acquired anemia, phlebotomy blood loss, and blood conservation device use (P < .001) and a statistically significant change in blood conservation device application practice in the posteducation period when compared with the preeducation period (P = .016). The findings of this project support the added value of dedicated blood conservation education to nurses to promote increased knowledge, increased blood conservation device utilization, and decreases in phlebotomy blood loss.

The effects of beta blockade and clonidine on persistent injury-associated anemia

BackgroundNonselective beta blockade (BB) and clonidine may abrogate catecholamine-mediated persistent injury-associated anemia. We hypothesized that critically ill trauma patients who received BB or clonidine would have favorable hemoglobin (Hb) trends when adjusting for operative blood loss (OBL), phlebotomy blood loss (PBL), and red blood cell (RBC) transfusion volumes, and that the effect would be greatest among the elderly, who have higher catecholamine levels. MethodsWe performed a 4-y retrospective cohort analysis of 280 consecutive trauma patients with ICU stay ≥48 h and moderate/severe anemia. Patients who received BB or clonidine for ≥25% of their hospital stay were grouped as the BB/clonidine cohort (n = 84); all other patients served as controls (n = 196). Admission and discharge Hb were used to calculate ΔHb. OBL, PBL, and RBC volume were used to calculate adjusted ΔHb assuming 300 mL RBC = 1 g/dL Hb. ResultsBB/clonidine and control patients had similar age, injury severity, comorbid illness, and admission Hb. BB/clonidine patients received fewer RBCs despite greater OBL, though neither association was statistically significant. BB/clonidine patients had higher discharge Hb (9.9 versus 9.5, P = 0.029) and adjusted ΔHb (+1.0 versus −0.8, P = 0.003). Hb curves separated after hospital day 10. The difference in adjusted ΔHb between groups increased with advanced age (all patients: 1.7, ≥50 y: 1.8, ≥60 y: 2.4, ≥70 y: 3.7). ConclusionsCritically ill trauma patients receiving BB or clonidine had favorable Hb trends when accounting for OBL, PBL, and RBC transfusions. These findings support the hypothesis that BB and clonidine alleviate persistent injury-associated anemia, with strongest effects among the elderly.

Anemia and blood transfusion in elderly trauma patients

BackgroundThe natural history of postinjury among elderly trauma patients has not been well described. We hypothesized that elderly trauma patients would have lower admission hemoglobin (Hb) levels, higher transfusion rates, and worse outcomes than young trauma patients. MethodsWe performed a propensity-matched retrospective cohort analysis comparing elderly (age ≥65 y) to young (age 18-64) trauma patients matched by sex, mechanism of injury, Injury Severity Score, base deficit, comorbidities, operative blood loss, and phlebotomy blood loss (n = 41/group). Outcomes included Hb trends, packed red blood cell (PRBC) transfusion, length of stay, and mortality. ResultsElderly patients had lower admission Hb (11.3 versus 10.2 g/dL, P = 0.012), received more PRBC transfusions within 24 h (3.6 versus 1.8 units, P = 0.046), and during admission (6.9 versus 4.3 units, P = 0.008). Despite receiving more PRBC transfusions and having similar operative and phlebotomy blood loss, elderly subjects had lower discharge Hb (9.0 versus 9.7 g/dL, P = 0.013). Elderly subjects had fewer ICU-free days (2.0 versus 6.0 d, P < 0.001) and higher in-hospital mortality (15% versus 0%, P = 0.026). ConclusionsElderly trauma patients had lower admission Hb, received more transfusions, and had persistently lower Hb on discharge when controlling for injury severity, comorbid conditions, and blood loss. Aging may have a negative impact on postinjury anemia.

Secondary erythrocytosis due to hypoxemia as prognosis in exacerbated chronic pulmonary diseases

Introduction: Even though exacerbations are the main cause of emergency consultation in patients suffering from lung diseases, erythrocyte parameters are not assessed in their prognosis. Thus, determining the implications of erythrocyte parameters might contribute to define the usefulness of phlebotomy or red blood cells transfusion in these patients.Objective: To establish a possible relationship between the different hematocrit levels with a 30-day prognosis in patients admitted with exacerbated chronic lung disease and hypoxemia.Materials and methods: A study based on a 30-day follow-up was conducted. Variables were described using an additional categorization by hematocrit levels and an adjustment in a multivariate model through logistic regression.Results: Follow-up was completed for 110 Patients. The frequency of anemia was 7.3% and of erythrocytosis, 14.5%. A significant association to the outcome using Anthonisen score (OR=10.45, 95%CI: 1.11-98.48, p=0.04), hypertension (OR=11.02, 95%CI: 1.32-91.75, p=0.026) and heart failure (OR=0.09, 95%CI: 0.01-0.82, p=0.032) was found.Conclusion: This research could not determine any relationship between erythrocyte parameters and prognosis of patients suffering from pulmonary diseases; nevertheless, extreme values of hematocrits tended to have adverse outcomes.

Polycythemia Vera Dental Management -Case Report

Polycythemia vera was first reported in the medical literature in The term ldquo myeloproliferative disorder rdquo MPD was first used to described polycythemia vera and related disorders in In the World Health Organization reclassified MPDs to ldquo myeloproliferative neoplasms rdquo MPNs to reflect the consensus that these diseases are blood cancers neoplasms Polycythemia vera is a rare chronic disorder involving the overproduction of blood cells in the bone marrow myeloproliferation The overproduction of red blood cells is most dramatic but the production of white blood cells and platelets are also elevated in most cases Since red blood cells are overproduced in the marrow this leads to abnormally high numbers of circulating red blood cells red blood mass within the blood Polycythemia Vera is diagnosed by performing appropriate history and physical examination of the individual and using the appropriate test like Blood test Testing for blood hematocrit hemoglobin test level of hormone erythropoietin is also measured As the condition cannot be cured according to western methodology treatment focuses on treating symptoms and reducing thrombotic complications by reducing the erythrocyte levels The treatment of Polycythemia Vera is focused on methods to reduce the thickness or viscosity of the blood and prevent possible formation of clots which can cause more serious medical issues During Phlebotomy blood normally one unit is removed at a time every week until the blood is thinned out In addition to this individual may be put on aspirin as it will decrease the chance of forming blood clots

Risk Factors of Transfusion in Anemia of Very Low Birth Weight Infants

PurposeAnemia of prematurity is frequent in preterm infants, for which red blood cell (RBC) transfusion remains the treatment of choice. In this study, we attempted to evaluate the characteristics and risk factors of anemia of prematurity, and suggest ways to reduce anemia and the need for multiple transfusions.Materials and MethodsPreterm infants weighing less than 1500 g (May 2008-May 2009) were divided into two groups depending on whether they received RBC transfusions (transfusion group and non transfusion group). Hemoglobin (Hb) concentration, phlebotomy blood loss, and the amount of RBC transfusion were analyzed. Risk factors of anemia and RBC transfusions were analyzed.ResultsFifty infants that survived were enrolled in the present study: 39 in the transfusion group and 11 in the non transfusion group. Hb concentrations gradually decreased by eight weeks. In the transfusion group, gestational age and birth weight were smaller, bronchopulmonary dysplasia and sepsis were more frequent, full feeding was delayed, parenteral nutrition and days spent in the hospital were prolonged, and phlebotomy blood loss was greater than that in the non transfusion group.ConclusionAnemia of prematurity was correlated with increased laboratory blood loss, decreased birth weight, prolonged parenteral nutrition, and delayed body weight gain. Accordingly, reducing laboratory phlebotomy loss and parenteral nutrition, as well as improving body weight gain, may be beneficial to infants with anemia of prematurity.

Anaemia of prematurity: Pathophysiology and treatment

Most infants with birth weight < 1.0 kg are given multiple red blood cell (RBC) transfusions within the first few weeks of life. The anaemia of prematurity is caused by untimely birth occurring before placental iron transport and fetal erythropoiesis are complete, by phlebotomy blood losses taken for laboratory testing, by low plasma levels of erythropoietin due to both diminished production and accelerated catabolism, by rapid body growth and need for commensurate increase in red cell volume/mass, and by disorders causing RBC losses due to bleeding and/or hemolysis. RBC transfusions are the mainstay of therapy with recombinant human erythropoietin largely unused because it fails to substantially diminish RBC transfusion needs — despite exerting substantial erythropoietic effects on neonatal marrow.

How I transfuse red blood cells and platelets to infants with the anemia and thrombocytopenia of prematurity

Many aspects of hematopoiesis are either incompletely developed in preterm infants or still functioning to serve the fetus (i.e., the intrauterine counterpart to a liveborn preterm neonate). This delayed development and/or slow adaptation to extrauterine life diminishes the capacity of the neonate to produce red blood cells (RBCs), platelets (PLTs), and neutrophils—particularly during the stress of life-threatening illnesses encountered after preterm birth such as sepsis, severe pulmonary dysfunction, necrotizing enterocolitis, and immune cytopenias. The serious medical and/or surgical problems of preterm birth can be further complicated by phlebotomy blood losses, bleeding, hemolysis, and consumptive coagulopathy. To illustrate, some preterm infants, especially those with birth weight less than 1.0 kg and respiratory distress, are given numerous RBC transfusions early in life owing to several interacting factors. Neonates delivered before 28 weeks of gestation (birth weight, <1.0 kg) are born before the bulk of iron transport has occurred from mother to fetus via the placenta and before the onset of marked erythropoietic activity of fetal marrow during the third trimester. Soon after preterm birth, severe respiratory disease can lead to repeated blood sampling for laboratory studies and, consequently, to replacement RBC transfusions. Additionally, preterm infants are unable to mount an effective erythropoietin (EPO) response to decreasing numbers of RBCs, and this factor contributes to the diminished ability to compensate for anemia—thus enhancing need for RBC transfusions. PATHOPHYSIOLOGY OF ANEMIA OF PREMATURITY During the first weeks of life, all infants experience a decline in the number of circulating RBCs. In healthy term infants, the nadir blood hemoglobin (Hb) value rarely decreases to less than 9 g per dL (mean, 11-12 g/dL) at an age of approximately 10 to 12 weeks. 1 Because this postnatal decrease in Hb level is universal and is well tolerated by term infants, it is commonly called the physiologic anemia of infancy. Among preterm infants, this decline occurs at an earlier age and is more pronounced in severity. Mean Hb concentration decreases to approximately 8 g per dL in infants of 1.0 to 1.5 kg birth weight and to 7 g per dL in infants weighing less than 1.0 kg. 2

Citrate Blood a Century of Artifact.

Sodium citrate has been used as an anticoagulant to prepare blood and fractions for over 100 years. Its use is sufficiently common that many investigators do not differentiate anticoagulated blood from blood per se. To evaluate the influence of citrate anticoagulation on the dynamics of the blood coagulation process, we compared the properties of blood, platelet rich plasma (PRP) and platelet poor plasma (PPP) prepared and stimulated using standard citrate/Ca++ reconstitution methodologies with matching samples in which transient anticoagulation without disruption of Ca++ homeostasis was achieved by blockade of the contact pathway (using corn trypsin inhibitor (CTI) or inhibitory antibodies to factor XIa). Phlebotomy blood was collected into citrate, CTI or CTI supplemented with citrate, the latter combination establishing conditions in which the effects of citrate anticoagulation in the absence of contact pathway contributions could be studied. Coagulation reactions in citrated milieus were initiated in typical fashion by Ca++ addition or following preincubation with Ca++ prior to tissue factor (Tf) addition in CTI citrate plasma; blood/products stabilized by CTI alone were initiated via Tf addition. Reaction dynamics were analysed using either calibrated automated thrombography (CAT) or thromboelastography (TEG). Platelet aggregation studies compared the reactivity of a panel of agonists. Significant differences were seen in the response of samples exposed to citrate. These results included:CTI plasma and blood displayed a more potent response to Tf when compared to their respective CTI citrate products. Specifically shorter lag phases (~120 s) and higher thrombin levels (1.5–2 fold higher maximum thrombin levels) are observed in CTI plasma with CAT and similarly shorter r (lag) times [(mean ± SD)CTI blood, r = 7.1 ± 0.9 min (n=21, 9 individuals) vs CTI citrate blood, r = 9.1 ± 1.5 min (n=10, 5 individuals)] with TEG.Reconstitution of prechelation Ca++ in CTI citrate plasma or blood prior to Tf addition only partially restored thrombin generation to that of its prechelation product. For example preincubation with Ca++ resulted in altered TEG profiles with prolonged “K” (rate) values (mean ± SD) for CTI citrate blood (7.5 ± 0.6 min (n=5)) compared to CTI blood (3.3 ± 0.5 min (n=5)) from the same individuals.Vitamin K dependent protein conformational transitions in response to chelation/Ca++ reconstitution were important contributors to the differences observed between CTI and citrated blood/plasmas, including the process of protein S polymerization and depolymerizationPlatelet function studies in citrate containing PRP showed significant enhancement in reactivity toward epinephrine and ristocetin with lesser effects with collagen; in 3 of 4 donors CTI PRP showed no sensitivity to epinephrine.The magnitude of alterations induced by citrate chelation were in the order epinephrine> ristocetin> ADP > collagen. Historically, the regimen of citrate chelation followed by Ca++ addition has proven useful in the interpretation of the integrity of the coagulation system and thereby in clinical diagnosis. However, our results suggest that the procedure of Ca++ chelation/recalcification results in artifactual representations of the dynamics and biology of the blood coagulation process.

Blood Management Strategies Effect on Hemoglobin Levels in Hospitalized Patients.

Phlebotomy for diagnostic testing is a notable source of blood loss, causing hospitalized patients to lose significant volumes of blood in a short period of time. Previous studies have documented correlations in phlebotomy blood loss, decline in hemoglobin and possible contributions to transfusion volume. One study reported average blood drawn for phlebotomy to be 12.4 mL/day for patients in medical wards, 33.5 mL/day in ICU patients, and 73.9 mL/day in patients with an arterial line (Smoller et al. NEJM. 1986; 314: 1233–1235). Another study concluded that an average hemoglobin decrease of .79 g/dL was due to a similar volume of phlebotomy blood loss (Thavendiranthan et al. J Gen Intern Med 2005; 20:520–524). Patients treated at the Center for Bloodless Medicine and Surgery (CBMS) at Pennsylvania Hospital decline blood products. Thus, to minimize iatrogenic blood loss, strategies were implemented including the use of pediatric tubes, reduced phlebotomy and the avoidance of central line wastage. In this study we attempt to analyze the adherence to and effectiveness of these strategies in preventing hemoglobin decline. We conducted a retrospective chart review of 46 out of 341 hospitalizations in the CBMS between October 2005 and July 2006, excluding ICU patients and those with blood loss such as surgical patients, patients with gastrointestinal bleeding, and dialysis patients. Erthropoietin (EPO) therapy was not given before or during the days evaluated. The analyzed population had a mean age of 58.7, an initial hemoglobin of 12.3 g/dL and a hospitalization period of 5.1 days. The absolute change between initial and final hemoglobin was on average .71 g/dL. Taking into account fluctuations during their stay, the average change from highest documented hemoglobin to lowest was 1.2 g/dL. In 30.4 percent of this population EPO therapy was subsequently initiated during their hospitalization. Therapy began at an average hemoglobin of 10.8 g/dL and was presumably the result of phlebotomy induced anemia. An average of 2.8 laboratory tests were ordered per day; 57 percent were chemistry panels or complete blood counts. These two tests were ordered almost daily. Thus, even at a CBMS where pediatric tubes are utilized and strict staff protocols are prescribed, the average iatrogenic blood loss is not appreciably different from a non-bloodless center without these regulations. Pediatric tubes can be costly and labor intensive and may not be the most important determinant of iatrogenic blood loss. Therefore, hospitals should work more diligently to eliminate daily and unnecessary phlebotomies by retraining house staff to keep patient blood loss at a minimum.

The Significance of Circulating Factor IXa in Blood

The presence of activation peptides (AP) of the vitamin K-dependent proteins in the phlebotomy blood of human subjects suggests that active serine proteases may circulate in blood as well. The goal of the current study was to evaluate the influence of trace amounts of key coagulation proteases on tissue factor-independent thrombin generation using three models of coagulation. With procoagulants and select coagulation inhibitors at mean physiological concentrations, concentrations of factor IXa, factor Xa, and thrombin were set either equal to those of their AP or to values that would result based upon the rates of AP/enzyme generation and steady state enzyme inhibition. In the latter case, numerical simulation predicts that sufficient thrombin to produce a solid clot would be generated in approximately 2 min. Empirical data from the synthetic plasma suggest clotting times of 3-5 min, which are similar to that observed in contact pathway-inhibited whole blood (4.3 min) initiated with the same concentrations of factors IXa and Xa and thrombin. Numerical simulations performed with the concentrations of two of the enzymes held constant and one varied suggest that the presence of any pair of enzymes is sufficient to yield rapid clot formation. Modeling of states (numerical simulation and whole blood) where only one circulating protease is present at steady state concentration shows significant thrombin generation only for factor IXa. The addition of factor Xa and thrombin has little effect (if any) on thrombin generation induced by factor IXa alone. These data indicate that 1) concentrations of active coagulation enzymes circulating in vivo are significantly lower than can be predicted from the concentrations of their AP, and 2) expected trace amounts of factor IXa can trigger thrombin generation in the absence of tissue factor.

Transfusion Approach to Neonatal Anemia

After completing this article, readers should be able to: 1. Describe the basis for guidelines for red blood cell (RBC) transfusions to infants. 2. Delineate the guidelines for storing and administering RBCs to preterm infants as a means of reducing donor exposure without causing hyperkalemia or acidosis. 3. Describe an alternative to selecting blood from cytomegalovirus antibody-negative donors to prevent transfusion-transmitted infection. 4. Delineate the procedure used to prevent graft-versus-host disease in preterm infants receiving RBC transfusions. Neonates are given RBC transfusions for several reasons, including hemolytic disease of the newborn due to maternal alloimmunization, congenital abnormalities of RBC enzymes and membranes, and anemia of prematurity due to multiple interacting factors, the most important of which are phlebotomy blood loss and low erythropoietin levels. Although great efforts have been made during the past few years to optimize the transfusion of RBCs to these tiny patients, several questions have not been answered definitively. Accordingly, transfusion practices vary among physicians caring for neonates. This lack of precise approach stems from incomplete knowledge of the cellular and molecular biology of hematopoiesis during the perinatal period as well as an incomplete understanding of the infant’s response to severe anemia. Generally, RBC transfusions are administered in small volumes (15 mL/kg per dose) to maintain a hematocrit (HCT) level that is believed to be most desirable in terms of oxygen delivery and tissue oxygenation for each neonate’s clinical status (Table 1⇓ ). It is widely recognized that this clinical approach is imprecise, and more physiologic indications for RBC transfusions, such as circulating RBC mass, available oxygen, and measurements of oxygen delivery and tissue extraction, have been suggested. However, the means by which these techniques can best be applied to daily clinical practice remain to be defined. Because clearly established indications for neonatal RBC transfusions based on controlled scientific studies …

Blood banking issues pertaining to neonatal red blood cell transfusions

Many preterm infants are given multiple red blood cell transfusions during the early weeks of life. Because firm standards for neonatal transfusions do not exist, it is important to consider the pathophysiology of the anemia of prematurity, the goals of transfusion therapy and blood banking practices that best provide safe and effective neonatal transfusions. There is increasing agreement that efforts continue to minimize phlebotomy blood losses, to transfuse per conservative indications and to limit donor exposure by transfusing stored red blood cells from a single unit reserved for an infant – rather than insisting on fresh blood.