The AABB cannot recommend for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous). (Grade: uncertain recommendation; very-low-quality evidence).

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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...

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.

BACKGROUND:Anemia may be an important factor contributing to an increased risk of bleeding, particularly in patients with thrombocytopenia. STUDY DESIGN AND METHODS:A multicenter, single-blinded pilot randomized controlled trial (RCT) was performed to evaluate the feasibility of conducting a larger RCT to determine the effect of the hemoglobin (Hb) concentration on bleeding risk. Patients with acute leukemia receiving induction chemotherapy or those undergoing stem cell transplantation were assigned to one of two treatment groups: standard transfusion strategy (transfusion of 2 units of red blood cells [RBCs] when their Hb level was less than 80 g/L) or an augmented transfusion strategy (transfusion of 2 units of RBCs when their Hb level was less than 120 g/L). RESULTS: Sixty patients were enrolled: 29 in the control group and 31 in the experimental group. The proportions of patients experiencing clinically significant bleeding and the time to first bleed were not significantly different between the control and experimental groups. The experimental group received more RBC transfusions (transfusions/patient-day) than the control group (0.233 vs. 0.151; relative risk, 1.56; 95% confidence interval, 1.16-2.10; p = 0.003). The proportion of patient-days with platelet (PLT) transfusions was not different between the experimental and control groups. The mean number of donor exposures (PLT and RBC transfusions) was not different between experimental and control groups. Bleeding symptoms were systematically documented. CONCLUSION: This pilot study thus indicated that it would be feasible to enroll the required number of patients to enable the performance of a large RCT to investigate the effect of Hb on bleeding risk in thrombocytopenic patients. P atients with acute leukemia undergoing induction chemotherapy or patients undergoing stem cell transplantation (SCT) often have prolonged thrombocytopenia both because of the cytotoxic therapies they receive and because of their underlying disorders. The relationship between bleeding and thrombocytopenia has been well described, and bleeding is a frequent complication occurring in this patient population.1-8 Despite the administration of prophylactic or therapeutic platelet (PLT) transfusions, these patients are still at risk of bleeding.Experimental evidence in animal models suggests that the hemoglobin (Hb) concentration may play a role in determining the bleeding risk in patients with thrombocytopenia. In contrast, other groups have suggested that ABBREVIATIONS: AML = acute myeloid leukemia; RCT(s) = randomized controlled trial(s); RR(s) = relative risk(s). acute hemodilution may increase coagulation. 9,10 With a thrombocytopenic rabbit model, Blajchman and coworkers 11 demonstrated the bleeding time to be inversely correlated with the hematocrit (Hct). This study showed that increasing the red blood cell (RBC) mass by RBC transfusion partially corrected the bleeding time in thrombocytopenic anemic rabbits. The reasons for this are not clearly understood, but several mec...

Writing Committee for the REMAP-CAP Investigators IMPORTANCE The evidence for benefit of convalescent plasma for critically ill patients with COVID-19 is inconclusive.OBJECTIVE To determine whether convalescent plasma would improve outcomes for critically ill adults with COVID-19. DESIGN, SETTING, AND PARTICIPANTSThe ongoing Randomized, Embedded, Multifactorial, Adaptive Platform Trial for Community-Acquired Pneumonia (REMAP-CAP) enrolled and randomized 4763 adults with suspected or confirmed COVID-19 between March 9, 2020, and January 18, 2021, within at least 1 domain; 2011 critically ill adults were randomized to open-label interventions in the immunoglobulin domain at 129 sites in 4 countries. Follow-up ended on April 19, 2021. INTERVENTIONSThe immunoglobulin domain randomized participants to receive 2 units of high-titer, ABO-compatible convalescent plasma (total volume of 550 mL ± 150 mL) within 48 hours of randomization (n = 1084) or no convalescent plasma (n = 916). MAIN OUTCOMES AND MEASURESThe primary ordinal end point was organ support-free days (days alive and free of intensive care unit-based organ support) up to day 21 (range, −1 to 21 days; patients who died were assigned -1 day). The primary analysis was an adjusted bayesian cumulative logistic model. Superiority was defined as the posterior probability of an odds ratio (OR) greater than 1 (threshold for trial conclusion of superiority >99%). Futility was defined as the posterior probability of an OR less than 1.2 (threshold for trial conclusion of futility >95%). An OR greater than 1 represented improved survival, more organ support-free days, or both. The prespecified secondary outcomes included in-hospital survival; 28-day survival; 90-day survival; respiratory support-free days; cardiovascular support-free days; progression to invasive mechanical ventilation, extracorporeal mechanical oxygenation, or death; intensive care unit length of stay; hospital length of stay; World Health Organization ordinal scale score at day 14; venous thromboembolic events at 90 days; and serious adverse events. RESULTS Among the 2011 participants who were randomized (median age, 61 [IQR, 52 to 70] years and 645/1998 [32.3%] women), 1990 (99%) completed the trial. The convalescent plasma intervention was stopped after the prespecified criterion for futility was met. The median number of organ support-free days was 0 (IQR, -1 to 16) in the convalescent plasma group and 3 (IQR, -1 to 16) in the no convalescent plasma group. The in-hospital mortality rate was 37.3% (401/1075) for the convalescent plasma group and 38.4% (347/904) for the no convalescent plasma group and the median number of days alive and free of organ support was 14 (IQR, 3 to 18) and 14 (IQR, 7 to 18), respectively. The median-adjusted OR was 0.97 (95% credible interval, 0.83 to 1.15) and the posterior probability of futility (OR <1.2) was 99.4% for the convalescent plasma group compared with the no convalescent plasma group. The treatment effects were consistent across the primary outcome and the 11...

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