Evelyn Lockhart

Postpartum hemorrhage: When uterotonics and sutures fail

Systemic bleeding at the time of postpartum hemorrhage (PPH) is usually the result of coagulopathy that has developed acutely as a result of massive hemorrhage after uterotonics and sutures have failed. Occasionally, the patient has a preexisting coagulopathy, but more often, coagulopathy arises acutely as the result of massive hemorrhage, which is usually related to obstetrical and less often surgical bleeding. Despite being able to identify risk factors for PPH in the antenatal and intrapartum period, the majority of women who ultimately develop PPH do not have any such factors and every pregnancy is at risk. The coagulopathy associated with massive PPH may be due to hemodilution, failure of liver synthetic function as occurs with acute liver failure of pregnancy, or disseminated intravascular coagulation (DIC). There are no data from clinical trials to help guide management of transfusion in PPH, although the management of blood component therapy in severe PPH is similar to that in other massive hemorrhage. Standard practice is to replace fibrinogen to maintain a level of ≥100 mg/dL, yet recent evidence suggests that the level of fibrinogen needed to prevent PPH is at least 400 mg/dL. Recombinant activated factor VIIa (rFVIIa) has been used in the management of severe PPH unresponsive to blood component therapy. Coagulation laboratory evaluation may be useful in guiding hemostatic management during massive PPH, but for the results to be useful, they must be rapidly available and provide information that would not be available from clinical assessment alone. The hematologist or hemostasis expert has the opportunity to make the difference between life and death for the patient experiencing massive PPH. Am. J. Hematol. 2012.

Intraoperative use of low-dose recombinant activated factor VII during thoracic aortic operations.

BACKGROUND Numerous studies have supported the effectiveness of recombinant activated factor VII (rFVIIa) for the control of bleeding after cardiac procedures; however safety concerns persist. Here we report the novel use of intraoperative low-dose rFVIIa in thoracic aortic operations, a strategy intended to improve safety by minimizing rFVIIa exposure. METHODS Between July 2005 and December 2010, 425 consecutive patients at a single referral center underwent thoracic aortic operations with cardiopulmonary bypass (CPB); 77 of these patients received intraoperative low-dose rFVIIa (≤60 μg/kg) for severe coagulopathy after CPB. Propensity matching produced a cohort of 88 patients (44 received intraoperative low-dose rFVIIa and 44 controls) for comparison. RESULTS Matched patients receiving intraoperative low-dose rFVIIa got an initial median dose of 32 μg/kg (interquartile range [IQR], 16-43 μg/kg) rFVIIa given 51 minutes (42-67 minutes) after separation from CPB. Patients receiving intraoperative low-dose rFVIIa demonstrated improved postoperative coagulation measurements (partial thromboplastin time 28.6 versus 31.5 seconds; p=0.05; international normalized ratio, 0.8 versus 1.2; p<0.0001) and received 50% fewer postoperative blood product transfusions (2.5 versus 5.0 units; p=0.05) compared with control patients. No patient receiving intraoperative low-dose rFVIIa required postoperative rFVIIa administration or reexploration for bleeding. Rates of stroke, thromboembolism, myocardial infarction, and other adverse events were equivalent between groups. CONCLUSIONS Intraoperative low-dose rFVIIa led to improved postoperative hemostasis with no apparent increase in adverse events. Intraoperative rFVIIa administration in appropriately selected patients may correct coagulopathy early in the course of refractory blood loss and lead to improved safety through the use of smaller rFVIIa doses. Appropriately powered randomized studies are necessary to confirm the safety and efficacy of this approach.

Storage age of transfused platelets and outcomes after cardiac surgery.

BACKGROUND: The relationship between duration of platelet (PLT) storage, currently limited to 5 days, and surgical outcomes has not been established. We tested the hypothesis that PLT storage age was associated with adverse outcomes.

Impact of transfusion of autologous 7- versus 42-day-old AS-3 red blood cells on tissue oxygenation and the microcirculation in healthy volunteers.

BACKGROUND: Stored red blood cells (RBCs) accumulate biochemical and biophysical changes. Maximum storage duration is based on acceptable in vitro characteristics and 24‐hour survival, but not RBC function. Relatively little is known about the impact of RBC storage duration on oxygenation and the microcirculation.

The use of autologous platelet-rich plasma in the orthopedic setting

Autologous platelet‐rich plasma (aPRP) is widely used with orthopedic patients to help treat injuries to tendons, cartilage, ligaments, and muscle. A comprehensive review of the literature was conducted to evaluate aPRPs efficacy and compare available methods. In addition, the production and administration of aPRP were explored.

Autologous platelet-rich plasma: evidence for clinical use.

Purpose of reviewAutologous platelet-rich plasma (aPRP) is growing in popularity as a therapy to augment wound healing, speed the recovery from muscle and joint injuries, and enhance recovery after surgical repair. High-profile athletes treated with aPRP have increased the demand from the general population. Yet, evidence to support the use of aPRP in most clinical settings is weak, because of poorly controlled clinical trials. Recent findingsPreparations of aPRP vary by platelet count, leukocyte content, and degree of platelet activation. Nonetheless, these heterogeneous preparations are used in trials to assess the efficacy of aPRP treatment. SummaryDespite weak evidence, the use of aPRP continues to grow. High-quality randomized controlled trials are needed to validate or repudiate the potential efficacy of aPRP. Standards for aPRP preparation and quality should be created.

Many, but not all, outcome studies support exclusion of female plasma from the blood supply.

Transfusion-related acute lung injury (TRALI) has been identified as the most common cause of transfusion-related death. Although extensive literature supports restrictions on female-donor plasma to reduce antibody-mediated TRALI, only a few outcome studies have assessed for effects of this change, and some, but not all, have endorsed the policy. A recent report even suggests poorer outcomes in cardiac surgery patients with a shift to male-donor-only plasma, raising concerns that TRALI alone, whether catastrophic or more survivable, is insufficient compared with broader measures, such as short-term mortality or long-term survival, as an end point to assess for overall improvements in patient care.

Postpartum hemorrhage: a continuing challenge

Obstetric hemorrhage remains a leading cause of maternal morbidity and mortality worldwide. Many postpartum hemorrhages (PPHs) do not have identifiable risk factors; maternity units should therefore have obstetric hemorrhageprotocols in place for all parturients as every pregnancy has the potential to be complicated by hemorrhage. This review will examine the epidemiology of PPH as well as current recommendations for key elements in obstetric hemorrhage protocols. Recent advances in hematologic management of PPH will be also be reviewed, including: (1) recognition of hypofibrinogenemia as a risk factor for severe PPH, (2) use of antifibrinolytic therapy, and (3) strategies for fibrinogen replacement therapy.

Carboxyhemoglobinemia in a pediatric cardiopulmonary bypass patient derived from a contaminated unit of allogenic blood

A 4.3 kg, three-month-old patient, diagnosed with a perimembranous ventricular septal defect, presented for cardiac surgery. Upon initiation of cardiopulmonary bypass (CPB), the patient developed carboxyhemoglobinemia (11.1%). Potential sources for the unexpected acquired carboxyhemoglobinemia were sought quickly. Testing of residual blood from the unit of packed red blood cells (PRBCs) used to prime the CPB circuit revealed a carboxyhemoglobin (COHb) of 15.1 %. A decrease in cerebral oximetry (rSO2) on CPB was initially felt to be a result of the elevated COHb levels. When ventilation of the oxygenator with 100% oxygen (O2) failed to decrease COHb levels, a partial exchange transfusion was performed with reduction in COHb to 7.1%. The operation was completed successfully and the patient’s COHb levels returned to normal within 75 minutes. Post case analysis of events and data collected during the case revealed a broader differential for explaining the compromised patient’s O2 delivery than the transient acquired carboxyhemoglobinemia. A partial obstruction of the superior vena cava could have triggered the drop in rSO2 on CPB. Follow-up of the donor blood confirmed the donor had previously undiagnosed carboxyhemoglobinemia as a result of chronic carbon monoxide exposure from a faulty vehicle exhaust system.

A randomized controlled pilot study of VO2 max testing: a potential model for measuring relative in vivo efficacy of different red blood cell products

Randomized trials, for example, RECESS, comparing “young” (median, 7‐day) versus “middle‐aged” (median, 28‐day) red blood cells (RBCs), showed no difference in outcome. These data are important; however, they do not inform us about the safety and effectiveness of the oldest RBCs, which some patients receive. It may not be feasible to conduct a clinical trial randomizing patients to receive the oldest blood. Therefore, we propose strenuous exercise (VO2 max testing) as a model to study the relative efficacy to increase oxygen delivery to tissue of different RBC products, for example, extremes of storage duration.