No abstract

Bioreactive substances in the plasma supernatant of the platelet product cause most febrile reactions associated with platelet transfusions. Removing the plasma supernatant before transfusion can minimize or prevent these reactions.

Numerous studies have examined the outcomes of infants born to mothers with idiopathic thrombocytopenic purpura (ITP). Fewer studies have discussed the morbidity of obstetric patients with ITP. We describe a retrospective study of 92 women with ITP during 119 pregnancies over an 11-year period. Most women had thrombocytopenia during pregnancy. At delivery, women in 98 pregnancies (89%) had platelet counts lower than 150 ؋ 10 9 /L; most had mild to moderate thrombocytopenia. For many, the pregnancy was uneventful; however, women had moderate to severe bleeding in 25 pregnancies (21.5%). Women in 37 pregnancies (31.1%) required treatment to increase platelet counts. During delivery, 44 women (37.3%) received epidural analgesia without complications, with most having a platelet count between 50 and 149 ؋ 10 9 /L. Most deliveries (82.4%) were vaginal. Bleeding was uncommon at delivery. Infant platelet counts at birth ranged from 12 to 436 ؋ 10 9 /L; 25.2% of infants had platelet counts lower than 150 ؋ 10 9 /L, and 9% had platelet counts lower than 50 ؋ 10 9 /L. Eighteen infants (14.6%) required treatment for hemostatic impairment. Two fetal deaths occurred. One was caused by hemorrhage. ITP in pregnancy carries a low risk, but mothers and infants may require therapy to raise their platelet counts. ( IntroductionIdiopathic thrombocytopenic purpura (ITP) frequently occurs in young women. Consequently, hematologists often treat pregnant women who have a diagnosis or a history of ITP. 1 It is now recognized that, in many patients, the disease is caused by platelet autoantibodies that can cross the placenta and produce thrombocytopenia in some infants. 2 In the past decade, our understanding of ITP in pregnancy has improved; however, in almost all studies, the focus has been on the infant. We now recognize that most of these infants do not have severe thrombocytopenia and that they can be safely delivered vaginally. 3 There has not been much information about ITP outcomes in obstetric patients, including their hemostatic risk at delivery and the likelihood of needing treatment during pregnancy. For this reason, we reviewed the outcomes of pregnant patients with ITP treated over a period of 11 years in the 2 obstetric units of Hamilton hospitals affiliated with McMaster University. We found that mothers with very low platelet counts can successfully deliver healthy infants and that though maternal and fetal bleeding can occur, such complications are uncommon. Patients, materials, and methodsA retrospective chart review was performed for all obstetric patients with ITP who were treated and delivered at the 2 hospitals with obstetric services in Hamilton, Ontario, from January 1, 1990, to December 31, 2000. Patients were eligible for the study if they met the inclusion criteria of pregnancy with a diagnosis of ITP or pregnancy with a previous history of ITP. They were considered to have ITP if they had a history of thrombocytopenia for which other causes were excluded. Other causes of thrombocytopenia included sepsis, pre...

VER THE PAST DECADE, SEVeral studies have suggested that blood transfusions depress immune function in recipients. 1,2 Evidence of transfusion-associated immune suppression emerged following observations that blood transfusions improved renal allograft survival 3 and accelerated 4 and increased postoperative infections. 5 A recent randomized controlled trial undertaken to examine infections in cardiovascular surgical patients found an approximately 4.2% absolute decrease in mortality but no decrease in

IMPORTANCE More than 100 million units of blood are collected worldwide each year, yet the indication for red blood cell (RBC) transfusion and the optimal length of RBC storage prior to transfusion are uncertain.OBJECTIVE To provide recommendations for the target hemoglobin level for RBC transfusion among hospitalized adult patients who are hemodynamically stable and the length of time RBCs should be stored prior to transfusion.EVIDENCE REVIEW Reference librarians conducted a literature search for randomized clinical trials (RCTs) evaluating hemoglobin thresholds for RBC transfusion (1950( -May 2016 and RBC storage duration (1948( -May 2016 without language restrictions. The results were summarized using the Grading of Recommendations Assessment, Development and Evaluation method. For RBC transfusion thresholds, 31 RCTs included 12 587 participants and compared restrictive thresholds (transfusion not indicated until the hemoglobin level is 7-8 g/dL) with liberal thresholds (transfusion not indicated until the hemoglobin level is 9-10 g/dL). The summary estimates across trials demonstrated that restrictive RBC transfusion thresholds were not associated with higher rates of adverse clinical outcomes, including 30-day mortality, myocardial infarction, cerebrovascular accident, rebleeding, pneumonia, or thromboembolism. For RBC storage duration, 13 RCTs included 5515 participants randomly allocated to receive fresher blood or standard-issue blood. These RCTs demonstrated that fresher blood did not improve clinical outcomes.FINDINGS It is good practice to consider the hemoglobin level, the overall clinical context, patient preferences, and alternative therapies when making transfusion decisions regarding an individual patient. Recommendation 1: a restrictive RBC transfusion threshold in which the transfusion is not indicated until the hemoglobin level is 7 g/dL is recommended for hospitalized adult patients who are hemodynamically stable, including critically ill patients, rather than when the hemoglobin level is 10 g/dL (strong recommendation, moderate quality evidence). A restrictive RBC transfusion threshold of 8 g/dL is recommended for patients undergoing orthopedic surgery, cardiac surgery, and those with preexisting cardiovascular disease (strong recommendation, moderate quality evidence). The restrictive transfusion threshold of 7 g/dL is likely comparable with 8 g/dL, but RCT evidence is not available for all patient categories. These recommendations do not apply to patients with acute coronary syndrome, severe thrombocytopenia (patients treated for hematological or oncological reasons who are at risk of bleeding), and chronic transfusion-dependent anemia (not recommended due to insufficient evidence). Recommendation 2: patients, including neonates, should receive RBC units selected at any point within their licensed dating period (standard issue) rather than limiting patients to transfusion of only fresh (storage length: <10 days) RBC units (strong recommendation, moderate quality evidence). CONCLUSIONS AND R...

The efficacy of convalescent plasma for coronavirus disease 2019 (COVID-19) is unclear. Although most randomized controlled trials have shown negative results, uncontrolled studies have suggested that the antibody content could influence patient outcomes. We conducted an open-label, randomized controlled trial of convalescent plasma for adults with COVID-19 receiving oxygen within 12 d of respiratory symptom onset (NCT04348656). Patients were allocated 2:1 to 500 ml of convalescent plasma or standard of care. The composite primary outcome was intubation or death by 30 d. Exploratory analyses of the effect of convalescent plasma antibodies on the primary outcome was assessed by logistic regression. The trial was terminated at 78% of planned enrollment after meeting stopping criteria for futility. In total, 940 patients were randomized, and 921 patients were included in the intention-to-treat analysis. Intubation or death occurred in 199/614 (32.4%) patients in the convalescent plasma arm and 86/307 (28.0%) patients in the standard of care arm—relative risk (RR) = 1.16 (95% confidence interval (CI) 0.94–1.43, P = 0.18). Patients in the convalescent plasma arm had more serious adverse events (33.4% versus 26.4%; RR = 1.27, 95% CI 1.02–1.57, P = 0.034). The antibody content significantly modulated the therapeutic effect of convalescent plasma. In multivariate analysis, each standardized log increase in neutralization or antibody-dependent cellular cytotoxicity independently reduced the potential harmful effect of plasma (odds ratio (OR) = 0.74, 95% CI 0.57–0.95 and OR = 0.66, 95% CI 0.50–0.87, respectively), whereas IgG against the full transmembrane spike protein increased it (OR = 1.53, 95% CI 1.14–2.05). Convalescent plasma did not reduce the risk of intubation or death at 30 d in hospitalized patients with COVID-19. Transfusion of convalescent plasma with unfavorable antibody profiles could be associated with worse clinical outcomes compared to standard care.

Among patients in a general hospital population, there was no significant difference in the rate of death among those who underwent transfusion with the freshest available blood and those who underwent transfusion according to the standard practice of transfusing the oldest available blood. (Funded by the Canadian Institutes of Health Research and others; INFORM Current Controlled Trials number, ISRCTN08118744 .).

Summary. Background: Light transmission aggregometry (LTA) is commonly performed to assess individuals for bleeding disorders. Objectives: The goal was to evaluate the incidence and spectrum of platelet function abnormalities in a prospective cohort of individuals referred for bleeding disorder assessments after exclusion of thrombocytopenia and von Willebrand disease. Patients/methods: Subjects were healthy controls and patients from a prospective cohort of individuals referred for bleeding disorder assessments after exclusion of thrombocytopenia and von Willebrand disease. LTA was performed by standardized methods using platelet-rich plasma adjusted to 250 · 10 9 platelets L )1. Maximal aggregation data were analyzed to determine the likelihood of detecting a platelet function disorder by LTA, and the sensitivity and specificity of LTA for platelet disorders. Results: The incidence of false positive LTA among subjects excluded of having bleeding disorders was similar to healthy controls. Abnormal LTA was more common in subjects with bleeding disorders and the likelihood of a bleeding disorder was significantly increased (odds ratio 32) when maximal aggregation was reduced with two or more agonists. Receiver operator curve analyses indicated that LTA had high specificity and moderate sensitivity for detecting inherited defects in platelet function and that the LTA agonists 1.25 lg mL )1 collagen, 6 lM epinephrine, 1.6 mM arachidonic acid and 1.0 lM thromboxane analogue U44619 detected most inherited disorders with abnormal LTA. Conclusions: LTA is valuable for detecting platelet function abnormalities among individuals referred for bleeding problems, particularly when the test indicates abnormal responses to multiple agonists.