A randomized clinical trial comparing immediate versus delayed clamping of the umbilical cord in preterm infants: short-term clinical and laboratory endpoints

BACKGROUND

Most neonates less than 1.0 kg birth weight need red blood cell (RBC) transfusions. Delayed clamping of the umbilical cord 1 minute after delivery transfuses the neonate with autologous placental blood to expand blood volume and provide 60 percent more RBCs than after immediate clamping. This study compared hematologic and clinical effects of delayed versus immediate cord clamping.

STUDY DESIGN AND METHODS

After parental consent, neonates not more than 36 weeks' gestation were randomly assigned to cord clamping immediately or at 1 minute after delivery. The primary endpoint was an increase in RBC volume/mass, per biotin labeling, after delayed clamping. Secondary endpoints were multiple clinical and laboratory comparisons over the first 28 days including Score for Neonatal Acute Physiology (SNAP).

RESULTS

Problems with delayed clamping techniques prevented study of neonates of less than 30 weeks' gestation, and 105 neonates 30 to 36 weeks are reported. Circulating RBC volume/mass increased (p = 0.04) and weekly hematocrit (Hct) values were higher (p < 0.005) after delayed clamping. Higher Hct values did not lead to fewer RBC transfusions (p > or = 0.70). Apgar scores after birth and daily SNAP scores were not significantly different (p > or = 0.22). Requirements for mechanical ventilation with oxygen were similar. More (p = 0.03) neonates needed phototherapy after delayed clamping, but initial bilirubin levels and extent of phototherapy did not differ.

CONCLUSIONS

Although a 1-minute delay in cord clamping significantly increased RBC volume/mass and Hct, clinical benefits were modest. Clinically significant adverse effects were not detected. Consider a 1-minute delay in cord clamping to increase RBC volume/mass and RBC iron, for neonates 30 to 36 weeks' gestation, who do not need immediate resuscitation.

Commentary: is it safe to limit allogeneic red blood cell transfusions to neonates?

Two randomized clinical trials, conducted independently, have reported results of neonates transfused with red blood cells (RBCs) given per either liberal (relatively high pretransfusion blood hematocrit levels) or restrictive (relatively low pretransfusion blood hematocrit levels) transfusion programs. Both found fewer RBC transfusions given per restrictive programs and comparable outcomes for several clinical endpoints. However, the Iowa trial found significantly more problems with apnea, intraparenchymal brain hemorrhage and periventricular leukomalacia in infants transfused per the restrictive program - findings not found by the Canadian trial. A critical analysis of both trials and possible reasons for the discrepant findings are discussed. Until definitive data are reported by additional studies, it seems prudent not to severely restrict/limit allogeneic RBC transfusions to neonates - except in approved investigational settings.

Comparative sensitivity of solid phase versus PEG enhancement assays for detection and identification of RBC antibodies

Blood banks require a sensitive, specific, and efficient method to detect clinically significant RBC antibodies. Solid phase antibody screening methods are popular due to high sensitivity and automation. However, the high degree of reactivity detects "false positive" antibodies of questionable clinical significance leading to additional testing. We studied positive rates of Capture-R vs. PEG methods and categorized RBC antibodies identified by initial test results of 33,564 consecutive samples by Capture-R method. Capture-R was positive in 1,084/33,564 (3.2%) of samples. Using PEG as our "gold standard", PEG confirmed true positivity (i.e., > or = 1 cell reacting) in 710 Capture-R positive samples (65.5%); 374 Capture-R positive samples (34.5%) did not react in PEG (i.e., false positives). Of the 710 samples with true positivity, only 510 showed clinically significant alloantibodies. Using PEG as our "gold standard", only 2/3 of reactions by Capture-R were considered true positives. Because of ease and automation, Capture-R is popular as a screening test, but a more specific method may be helpful in order to identify truly significant alloantibodies.

Elmer L. DeGowin, MD: Blood Transfusions in War and Peace

Elmer L. DeGowin, MD, like many of the pioneers of American blood banking and transfusion medicine, entered the discipline because of scientific curiosity and a desire to provide efficacious and safe allogeneic transfusions to patients. Much of the early impetus and financial support were fueled by the military needs of World War II. Dr. DeGowin and his colleagues provided important information pertaining to the preservation, storage, transportation, and transfusion of blood. After the war, many of these investigations continued and were applied to civilian practices. The legacy of Dr. DeGowin to provide exemplary service, teaching, and research has been sustained by the physicians and staff of the Elmer L. DeGowin Memorial Blood Center (University of Iowa Hospitals and Clinics, Iowa City, Ia).

Pathogen inactivation of platelets with a photochemical treatment with amotosalen HCl and ultraviolet light: process used in the SPRINT trial

BACKGROUND

A photochemical treatment (PCT) system has been developed to inactivate a broad spectrum of pathogens and white blood cells in platelet (PLT) products. The system comprises PLT additive solution (PAS III), amotosalen HCl, a compound adsorption device (CAD), a microprocessor-controlled ultraviolet A light source, and a commercially assembled system of interconnected plastic containers.

STUDY DESIGN AND METHODS

A clinical prototype of the PCT system was used in a large, randomized, controlled, double-blind, Phase III clinical trial (SPRINT) that compared the efficacy and safety of PCT apheresis PLTs to untreated apheresis PLTs. The ability of multiple users was assessed in a blood center setting to perform the PCT and meet target process specifications.

RESULTS

Each parameter was evaluated for 2237 to 2855 PCT PLT products. PCT requirements with respect to mean PLT dose, volume, and plasma content were met. Transfused PCT PLT products contained a mean of 3.6 x 10(11) +/- 0.7 x 10(11) PLTs. The clinical process, which included trial-specific samples, resulted in a mean PLT loss of 0.8 x 10(11) +/- 0.6 x 10(11) PLTs per product. CAD treatment effectively reduced the amotosalen concentration from a mean of 31.9 +/- 5.3 micromol per L after illumination to a mean of 0.41 +/- 0.56 micromol per L after CAD. In general, there was little variation between sites for any parameter.

CONCLUSIONS

The PCT process was successfully implemented by 12 blood centers in the United States to produce PCT PLTs used in a prospective, randomized trial where therapeutic efficacy of PCT PLTs was demonstrated. Process control was achieved under blood bank operating conditions.

Pretransfusion trigger platelet counts and dose for prophylactic platelet transfusions

PURPOSE OF REVIEW

To assess critically both the blood platelet counts that prompt a platelet transfusion (i.e. trigger) in various clinical settings in patients with thrombocytopenia caused by marrow failure and the dose of platelets infused (i.e. number per each transfusion) for optimal hemostasis, feasibility, and safety.

RECENT FINDINGS

Definitive studies (e.g. well-designed, prospective, randomized clinical trials) are not available either historically or at present to support evidence-based decisions. Instead, retrospective reviews and anecdotal reports provide observational data to assist in best guess clinical practices.

SUMMARY

Reasonable clinical practice, until more definitive data become available, is to transfuse enough platelets per each transfusion to maintain the blood platelet count >10 x 10/L in stable nonbleeding patients, >20 x 10(9)/L in unstable nonbleeding patients, and >50 x 10(9)/L in bleeding patients or in those undergoing invasive procedures.

Controversies in the Management of the Anemia of Prematurity Using Single-Donor Red Blood Cell Transfusions and/or Recombinant Human Erythropoietin

Many controversial questions regarding the practice of neonatal red blood cell (RBC) transfusions exist, so that practices and policies vary widely. This article will critically assess information pertaining to two of these controversies, namely, the transfusion of RBCs stored for up to 42 days after collection vs the transfusion of fresh RBCs stored 7 days or less after donation and the use of recombinant human erythropoietin (rHuEPO) in attempts to either diminish the severity of or to treat the anemia of prematurity. Based on both theoretical considerations and several published clinical trials, RBCs from one donor stored up to 42 days in extended storage preservative solutions can safely provide all RBCs needed by most infants for small-volume transfusions. Based on a large number of clinical trials and a meta-analysis of these trials, it is impossible to provide firm guidelines for the use of rHuEPO in the treatment of the anemia of prematurity. Clearly, rHuEPO has efficacy in stimulating erythropoiesis in preterm infants, but success in the elimination or marked reduction in the need for RBC transfusions has not been definitively demonstrated.

Clinical safety of platelets photochemically treated with amotosalen HCl and ultraviolet A light for pathogen inactivation: the SPRINT trial

BACKGROUND

A photochemical treatment (PCT) method utilizing a novel psoralen, amotosalen HCl, with ultraviolet A illumination has been developed to inactivate viruses, bacteria, protozoa, and white blood cells in platelet (PLT) concentrates. A randomized, controlled, double-blind, Phase III trial (SPRINT) evaluated hemostatic efficacy and safety of PCT apheresis PLTs compared to untreated conventional (control) apheresis PLTs in 645 thrombocytopenic oncology patients requiring PLT transfusion support. Hemostatic equivalency was demonstrated. The proportion of patients with Grade 2 bleeding was not inferior for PCT PLTs.

STUDY DESIGN AND METHODS

To further assess the safety of PCT PLTs, the adverse event (AE) profile of PCT PLTs transfused in the SPRINT trial is reported. Safety assessments included transfusion reactions, AEs, and deaths in patients treated with PCT or control PLTs in the SPRINT trial.

RESULTS

A total of 4719 study PLT transfusions were given (2678 PCT and 2041 control). Transfusion reactions were significantly fewer following transfusion of PCT than control PLTs (3.0% vs. 4.1%; p = 0.02). Overall AEs (99.7% PCT vs. 98.2% control), Grade 3 or 4 AEs (79% PCT vs. 79% control), thrombotic AEs (3.8% PCT vs. 3.7% control), and deaths (3.5% PCT vs. 5.2% control) were comparable between treatment groups. Minor hemorrhagic AEs (petechiae [39% PCT vs. 29% control; p < 0.01] and fecal occult blood [33% PCT vs. 25% control; p = 0.03]) and skin rashes (56% PCT vs. 42% control; p < 0.001) were significantly more frequent in the PCT group.

CONCLUSION

The overall safety profile of PCT PLTs was comparable to untreated PLTs.

Platelet dose consistency and its effect on the number of platelet transfusions for support of thrombocytopenia: an analysis of the SPRINT trial of platelets photochemically treated with amotosalen HCl and ultraviolet A light

BACKGROUND

The SPRINT trial examined efficacy and safety of photochemically treated (PCT) platelets (PLTs). PCT PLTs were equivalent to untreated (control) PLTs for prevention of bleeding. Transfused PLT dose and corrected count increments (CIs), however, were lower and transfusion intervals were shorter for PCT PLTs, resulting in more PCT than control transfusions. PLT dose was analyzed to determine the impact of the number of PLTs transfused on transfusion requirements.

STUDY DESIGN AND METHODS

Transfusion response was compared for patients with all doses of >or=3.0 x 10(11) and the complementary subset of patients with any dose of fewer than 3.0 x 10(11). Analyses included comparison of bleeding, number of PLT and red blood cell (RBC) transfusions, transfusion intervals, and CIs between PCT and control groups within each PLT dose subset.

RESULTS

Mean PLT dose per transfusion in the PCT group was lower than in the control group (3.7 x 10(11) vs. 4.0 x 10(11); p<0.001). More PCT patients received PLT doses of fewer than 3.0 x 10(11) (n=190) than control patients (n=118; p<0.01). Comparisons of patients receiving comparable PLT doses showed no significant differences between PCT and control groups for bleeding or number of PLT or RBC transfusions; however, transfusion intervals and CIs were significantly better for the control group.

CONCLUSIONS

When patients were supported with comparable doses of PCT or conventional PLTs, the mean number of PLT transfusions was similar. Lower CIs and shorter transfusion intervals for PCT PLTs suggest that some PLT injury may occur during PCT. This injury does not result in a detectable increase in bleeding, however.

Randomized trial of liberal versus restrictive guidelines for red blood cell transfusion in preterm infants

OBJECTIVE

Although many centers have introduced more restrictive transfusion policies for preterm infants in recent years, the benefits and adverse consequences of allowing lower hematocrit levels have not been systematically evaluated. The objective of this study was to determine if restrictive guidelines for red blood cell (RBC) transfusions for preterm infants can reduce the number of transfusions without adverse consequences.

DESIGN, SETTING, AND PATIENTS

We enrolled 100 hospitalized preterm infants with birth weights of 500 to 1300 g into a randomized clinical trial comparing 2 levels of hematocrit threshold for RBC transfusion.

INTERVENTION

The infants were assigned randomly to either the liberal- or the restrictive-transfusion group. For each group, transfusions were given only when the hematocrit level fell below the assigned value. In each group, the transfusion threshold levels decreased with improving clinical status.

MAIN OUTCOME MEASURES

We recorded the number of transfusions, the number of donor exposures, and various clinical and physiologic outcomes.

RESULTS

Infants in the liberal-transfusion group received more RBC transfusions (5.2 +/- 4.5 [mean +/- SD] vs 3.3 +/- 2.9 in the restrictive-transfusion group). However, the number of donors to whom the infants were exposed was not significantly different (2.8 +/- 2.5 vs 2.2 +/- 2.0). There was no difference between the groups in the percentage of infants who avoided transfusions altogether (12% in the liberal-transfusion group versus 10% in the restrictive-transfusion group). Infants in the restrictive-transfusion group were more likely to have intraparenchymal brain hemorrhage or periventricular leukomalacia, and they had more frequent episodes of apnea, including both mild and severe episodes.

CONCLUSIONS

Although both transfusion programs were well tolerated, our finding of more frequent major adverse neurologic events in the restrictive RBC-transfusion group suggests that the practice of restrictive transfusions may be harmful to preterm infants.

Therapeutic efficacy and safety of platelets treated with a photochemical process for pathogen inactivation: the SPRINT Trial

We report a transfusion trial of platelets photochemically treated for pathogen inactivation using the synthetic psoralen amotosalen HCl. Patients with thrombocytopenia were randomly assigned to receive either photochemically treated (PCT) or conventional (control) platelets for up to 28 days. The primary end point was the proportion of patients with World Health Organization (WHO) grade 2 bleeding during the period of platelet support. A total of 645 patients (318 PCT and 327 control) were evaluated. The primary end point, the incidence of grade 2 bleeding (58.5% PCT versus 57.5% control), and the secondary end point, the incidence of grade 3 or 4 bleeding (4.1% PCT versus 6.1% control), were equivalent between the 2 groups (P =.001 by noninferiority). The mean 1-hour posttransfusion platelet corrected count increment (CCI) (11.1 x 10(3) PCT versus 16.0 x 10(3) control), average number of days to next platelet transfusion (1.9 PCT versus 2.4 control), and number of platelet transfusions (8.4 PCT versus 6.2 control) were different (P <.001). Transfusion reactions were fewer following PCT platelets (3.0% PCT versus 4.4% control; P =.02). The incidence of grade 2 bleeding was equivalent for PCT and conventional platelets, although posttransfusion platelet count increments and days to next transfusion were decreased for PCT compared with conventional platelets.

Association of single nucleotide polymorphisms in the thrombopoietin-receptor gene, but not the thrombopoietin gene, with differences in platelet count

Little is known about the mechanisms explaining the wide variation in platelet counts (PLT) and other hematologic parameters in humans. We previously showed that the sex-based difference in hematocrit was associated with nucleotide variation in the erythropoietin receptor gene (EPOR). We sought to identify new polymorphisms of the human thrombopoietin (TPO) and thrombopoietin receptor (TPOR) genes to determine any associations with blood PLT counts. We screened TPO and TPOR for polymorphisms using single-strand conformation polymorphism (SSCP) and DNA sequencing. Association of polymorphisms was studied in 304 normal subjects with low or high PLT counts. Distribution of allelic frequency was analyzed by the Chi-square statistic. Single nucleotide polymorphisms (SNPs) with two alleles were found in TPO and TPOR. The TPO SNP was a G to A transition at nucleotide 5753, and the TPOR SNP was a C to A transversion at position 550 in the 5'-promoter area. The allelic frequencies were 0.54 for G and 0.46 for A of TPO, and 0.62 for C and 0.38 for A of TPOR in a Caucasian population. The frequency of the TPOR allele "C" was significantly higher in subjects with high PLT count (>258 k/mm3) versus low PLT count (<224 k/mm3) and in males with high PLT count (>258 k/mm3) versus males with low PLT count (<212 k/mm3). In contrast, the frequency of the TPO alleles was not related to blood PLT counts. An association of TPO and TPOR allele distribution to red and white blood cell parameters was seen. These new SNPs found for the human TPO and TPOR genes help explain variations in blood PLT counts and may be useful in patient studies related to the roles of TPO and/or TPOR in disease.

A red blood cell autoantibody with mimicking anti-E specificity

BACKGROUND

Uncommonly, antibodies that appear to exhibit antigenic specificity on red blood cell (RBC) panels fail to maintain specificity following alloadsorption (i.e., they mimic antigenic specificity). Understanding both the pitfalls and the proper pathways to establish the diagnosis and to interpret the clinical significance of these mimicking antibodies is important for patient management.

CASE REPORT

A 68-year-old woman was admitted with dyspnea, anemia, bilateral pulmonary emboli, and metastatic ovarian cancer. Blood bank evaluation identified anti-E reactivity in the patient's plasma sample and a positive direct antiglobulin test (DAT).

RESULTS

The DAT was positive for immunoglobulin G and negative for C3b. An eluate of the RBCs showed E-antigen specificity on a RBC antibody panel. Repeat serologic testing with RBC antibody panels with adsorbed patient plasma showed removal of apparent anti-E reactivity with either E-antigen-positive or E-antigen-negative RBC stroma.

CONCLUSION

A mimicking autoantibody with apparent E-antigen specificity was identified in the plasma sample of a woman with newly diagnosed ovarian cancer. Despite their relative low frequency, mimicking antibodies, whether auto- or alloantibodies, may interfere with the timely issuance of compatible blood products and may confuse laboratory and clinical staff. Determining the clinical significance of the antibody, by taking into account the RBC phenotype of the patient and the antigen prevalence in the general population, guides the extent of workup required to best utilize resources while assuring patient safety.

Posttransfusion 24-hour recovery and subsequent survival of allogeneic red blood cells in the bloodstream of newborn infants

BACKGROUND

The feasibility, efficacy, and safety of transfusing stored allogeneic RBCs has been demonstrated for small-volume transfusions given to infants. We measured the posttransfusion recovery and intravascular survival of allogeneic RBCs stored up to 42 days to further elucidate their efficacy.

STUDY DESIGN AND METHODS

Preterm infants were transfused with 1.0 mL of biotinylated RBCs plus 15 mL per kg of unlabeled allogeneic RBCs. Posttransfusion infant blood samples obtained at 10 minutes, and at 1, 2, 4, 7, 10, 14, and 21 days were used to determine the 24-hour posttransfusion recovery (PTR(24)), mean potential life span (MPL), and time to disappearance of 50 percent of biotinylated RBCs (T(50)).

RESULTS

No significant differences were found between allogeneic RBCs stored 1 to 21 days versus 22 to 42 days for PTR(24), MPL, or T(50), indicating comparable posttransfusion circulation, regardless of storage age. Although MPL and T(50) values in infants using biotinylated RBCs were short, compared to those expected using chromium-labeled RBCs in adults, they agreed with results reported by others using biotinylated RBCs.

CONCLUSIONS

Satisfactory posttransfusion RBC recovery and survival, measured with biotinylated RBCs, support earlier clinical trials that established the efficacy and safety of stored allogeneic RBCs for small-volume transfusions given to infants. The relatively short MPL and T(50) values in some infants may underestimate true survival due to ongoing erythropoiesis and infant growth with commensurate increase in blood volume during the time of RBC survival studies. Because values in infants differ from those expected using chromium-labeled RBCs in adults, and the number of posttransfusion determinations was few, additional studies are needed to define the mechanisms involved.

RBCs labeled at two biotin densities permit simultaneous and repeated measurements of circulating RBC volume

BACKGROUND

The extend potential applications of a nonradioactive method for measuring circulating RBC volume, we tested the hypothesis that RBC volume could be determined independently using two populations of RBCs labeled with low-density biotin (LDB1) and high-density biotin (HDB).

STUDY DESIGN AND METHODS

In 10 healthy adults, autologous RBCs were labeled with HDB, LDB, or 51Cr. The labeled RBCs were mixed and transfused. RBC volume was measured in postinfusion peripheral venous blood by quantitating dilution of each population of labeled RBCs.

RESULTS

RBC volume measured using either LDB or HDB cells agreed well with RBC volume measured using 51Cr. For the regression of RBC volume by LDB versus RBC volume by 51Cr, correlation = 0.994 and slope = 0.933. For HDB versus 51Cr, correlation = 0.982 and slope = 0.953. RBC volume measured a second time in four subjects with HDB agreed well; mean CV for the differences between HDB and 51Cr were less than 5 percent.

CONCLUSIONS

Using RBCs labeled with two different densities of biotin, RBC volume can be accurately measured simultaneously and repeatedly in the same subject without radiation exposure.

Safety of donating multiple products in a single apheresis collection: Are we expecting too much?

Modern blood separators rapidly process many liters of donor blood and efficiently collect vast quantities of blood components from donors, who may be stimulated with potent recombinant hematopoietic growth factors or cytokines. Accordingly, the potential risks of modern multiple product/unit apheresis donations and recombinant growth factors is analyzed in this report. As is true for all medical procedures, risks are associated with apheresis donations. Risks of a "standard" apheresis donation, in which one unit of PLTs or plasma is collected, are comparable to the risks of whole blood donation. Risks of multiple unit apheresis donations, in which either vast quantities of a single blood component or multiple units of various components are collected, are incompletely understood, particularly, when donors are stimulated with recombinant hematopoietic growth factors to increase component yields. To minimize donor risks and to increase knowledge of multiple component apheresis donations, both short-term problems (e.g., donor reactions accompanying apheresis procedures and pre- vs. post-procedure changes in results of donor laboratory studies) and long-term problems (e.g., medical diagnoses/problems and abnormalities of donor blood counts and laboratory test results) should be monitored, ideally, by a repeat donor registry. When recombinant hematopoietic growth factors are prescribed, donors should give informed consent, and blood center professionals must be aware of 1) the effects of these drugs given at pharmacologic, rather than physiologic, doses; 2) the differences between the molecular structure of recombinant vs. natural/endogenous growth factors; 3) the fact that recombinant growth factors have both narrow/focused and broad biological activities; and 4) the probability that results of studies in sick/immunosuppressed patients may not be applicable to healthy/immunocompetent donors.

A randomized comparison of plateletpheresis with the same donors using four blood separators at a single blood center

At one blood center, each of 20 donors underwent plateletpheresis on four blood cell separators in random order. We compared the CS3000+, Amicus V 2.41, MCS Plus, and Spectra LRS V 7 Turbo regarding platelet (PLT) yield, pre- and post-procedure PLT counts, percent fall in donor PLT count, process time, efficiency, PLT product and donor PLT volume (MPV). Using >or= 150 x 10(9) PLTs/L pre-donation counts, a goal was set of 4.5 x 10(11) PLTs unit in up to 100 minutes processing time. Results were (mean values) PLT yields of Amicus, Spectra, CS3000+, and MCS Plus: 4.3, 4.6, 4.3, 4.0 x 10(11) PLTS, respectively; percent donor PLT fall: 24, 32, 30, 29%, respectively; processing times: 50, 74, 87, 101 minutes, respectively; relative efficiency (RE): 2.2, 1.6, 1.2,1.0, respectively (based on the MCS Plus performance with RE of 1 = 4 x 10(9) PLTS/min); PLT product MPV: 6.7, 7.4, 6.8,7.1 fL, respectively; pre-procedure donor MPV: 7.7, 7.3, 7.6 and 7.6 fL, respectively; and percent donor MPV change: -5.2, 0, -6.6, and -10%, respectively. Significant changes in the donor MPV were noted (P < 0.05) but could not be related to product MPV. Spectra seemed to collect larger PLTs (higher MPV); the significance remains unknown for both donors and recipients. Importantly, all four separators gave acceptable and comparable PLT yields (P < 0.05) with Spectra trending higher. The short process time and high RE together indicate highly efficient collections particularly by Amicus and Spectra.

Circulating RBC volume, measured with biotinylated RBCs, is superior to the Hct to document the hematologic effects of delayed versus immediate umbilical cord clamping in preterm neonates

BACKGROUND

One problem assessing the hematologic physiology of preterm infants after delivery and/or the efficacy and toxicity of therapeutic interventions affecting RBC measurements is the inability of blood Hct values to accurately reflect circulating RBC volume-owing to changes in plasma volume that influence Hct (i.e., a fall in plasma volume concentrates RBCs to increase Hct; a rise in plasma volume dilutes RBCs to decrease Hct).

STUDY DESIGN AND METHODS

As part of a randomized, clinical trial testing the hypothesis that delayed clamping of the umbilical cord at delivery expands neonatal circulating RBC volume, blood Hct was compared to circulating RBC volume results measured directly with autologous, biotinylated RBCs or estimated mathematically with neonatal body weight and Hct values in neonates after immediate or delayed (60 sec) cord clamping.

RESULTS

Circulating RBC volume measured directly with biotinylated RBCs significantly increased (p=0.04) in neonates after delayed (42.1 +/- 7.8 mL/kg) versus immediate (36.8 +/- 6.3 mL/kg) cord clamping-a difference not detected indirectly by measuring Hct or estimating circulating RBC volume mathematically.

CONCLUSIONS

Because true hematologic effects of delayed versus immediate cord clamping may not be apparent or may be misinterpreted, when based on indirect measurements of Hct or calculations of circulating RBC volume, it is important to measure circulating RBC volume directly-as done with autologous, biotinylated RBCs-to document whether delayed cord clamping truly results in a transfer of significant quantities of RBCs from placenta to neonate. The clinical benefits and potential toxicities of increased RBC transfer to neonates require further studies.

Rationale for medical director acceptance or rejection of allogeneic plateletpheresis donors with underlying medical disorders

A survey was completed by 25 medical directors at different institutions performing plateletpheresis. The practices of these 25 physicians were analyzed regarding the acceptance/rejection of plateletpheresis donors with a history of cardiac disease/surgery, seizures/epilepsy, cancer, or autoimmune diseases. Although available medical literature documents little risk of these disorders either to donors (i.e., donation reactions) or to transfusion recipients (i.e., disease transmission), up to 24% of medical directors outright reject some of these potential donors while others accept patients/donors with these illnesses, providing they meet certain medical/health criteria. Acceptance/rejection of individuals with medical disorders has relevance for the availability of the blood supply and blood product shortages because several million Americans, diagnosed with these illnesses, represent a sizable pool of potential blood and platelet donors.