6 research outputs found
Causes and Outcomes of the Acute Chest Syndrome in Sickle Cell Disease
Background The acute chest syndrome is the leading cause of death among patients with sickle cell disease. Since its cause is largely unknown, therapy is supportive. Pilot studies with improved diagnostic techniques suggest that infection and fat embolism are underdiagnosed in patients with the syndrome. Methods In a 30-center study, we analyzed 671 episodes of the acute chest syndrome in 538 patients with sickle cell disease to determine the cause, outcome, and response to therapy. We evaluated a treatment protocol that included matched transfusions, bronchodilators, and bronchoscopy. Samples of blood and respiratory tract secretions were sent to central laboratories for antibody testing, culture, DNA testing, and histopathological analyses. Results Nearly half the patients were initially admitted for another reason, mainly pain. When the acute chest syndrome was diagnosed, patients had hypoxia, decreasing hemoglobin values, and progressive multilobar pneumonia. The mean length of hospitalization was 10.5 days. Thirteen percent of patients required mechanical ventilation, and 3 percent died. Patients who were 20 or more years of age had a more severe course than those who were younger. Neurologic events occurred in 11 percent of patients, among whom 46 percent had respiratory failure. Treatment with phenotypically matched transfusions improved oxygenation, with a 1 percent rate of alloimmunization. One fifth of the patients who were treated with bronchodilators had clinical improvement. Eighty-one percent of patients who required mechanical ventilation recovered. A specific cause of the acute chest syndrome was identified in 38 percent of all episodes and 70 percent of episodes with complete data. Among the specific causes were pulmonary fat embolism and 27 different infectious pathogens. Eighteen patients died, and the most common causes of death were pulmonary emboli and infectious bronchopneumonia. Infection was a contributing factor in 56 percent of the deaths. Conclusions Among patients with sickle cell disease, the acute chest syndrome is commonly precipitated by fat embolism and infection, especially community-acquired pneumonia. Among older patients and those with neurologic symptoms, the syndrome often progresses to respiratory failure. Treatment with transfusions and bronchodilators improves oxygenation, and with aggressive treatment, most patients who have respiratory failure recover
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Evaluation of Chronic Transfusion (Tx) Practices in Children with Sickle Cell Disease (SCD): A Survey of STOP II Investigators
The follow-up Stroke Prevention Trial (STOP II) attempts to optimize tx therapy for primary stroke prevention in children with SCD who are at increased risk due to an abnormal Doppler ultrasound. A survey of participating investigators (PIs) was performed in order to assess tx practices; 12 PIs out of 26 responded. To begin chronic tx, 42 % of the PIs preferred erythrocytapheresis (ECP), partial or total exchange to bring hemoglobin (Hb) S 30%. Most PIs had a post-tx target hematocrit (Hct) 35–36%, but a third of them did not have one. Pre-tx Hct and/or Hb S (but not post-tx values) were used to predict the timing of the next tx by 83% of the group. When performing ECP, the PIs participated in the decision of how much to exchange pts only 33% of the time; generally ECP was planned by a blood bank physician and/or by machine programming. Chelation began either after 12–30 months of tx (median 18 months), or after serum ferritin 1000–2500 ng/ml (median 2000). 67% of the PIs obtained liver biopsies in all or some of the STOP II pts. Indications for liver biopsies were cited as routine for transfused pts (5 PIs) or depending on ferritin values (6 PIs). Deferoxamine 25–50 mg/kg was infused subcutaneously over 8–10 hours 5–7 nights a week in all pts. Eight PIs reported the use of central venous lines (ports) in some pts to facilitate IV access. Barriers cited to effective chronic tx were: pt compliance with chelation (7 reported it as most important), IV access, pt compliance with tx schedule, hypersplenism, and alloimmunization. We conclude that hematologists :(1) Administer leucoreduced Rh and Kell compatible, S negative PRBC to keep pre-tx Hb S levels <30%, (2) use pre-tx Hb S and Hct to predict next tx, usually every 3–4 weeks, (3) monitor and treat iron overload, and (4) report that poor compliance with chelation is a key barrier to an effective tx program. Although liver biopsy to monitor iron stores and partial/total exchange to limit iron overload are accepted interventions, medical practice still varies
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Academic Community Standards for Chronic Transfusion Therapy in Children with Sickle Cell Anemia and Stroke
Abstract Children with sickle cell anemia have a 5–10% incidence of primary stroke, after which they have a 50–90% risk of stroke recurrence. Monthly transfusions with a goal of maintaining sickle hemoglobin (HbS) 7 days after the scheduled date) occurring once in 22% and twice or more in 12% of children. The average pre-transfusion Hb was 9.0 ± 0.7 gm/dL. The average pre-transfusion %HbS was 35 ± 11 %, with a median %HbS value of 34%. Potential "cutoff " %HbS values for SWiTCH included 34% (50th percentile of reported values), 43% (75th percentile), and 52% HbS (90th percentile). These data indicate that transfusions to prevent recurrent stroke vary among academic pediatric institutions and 30% HbS may not be a realistic goal for this study. Although the goal for transfusions in the SWiTCH standard treatment arm will remain 30% HbS, maintaining an average pre-transfusion HbS value of ≤ 45% will be required to reflect the academic community standard