Background-Atrial fibrillation/flutter (AF) is a frequent complication of coronary artery bypass graft surgery (CABG) that leads to increased costs and morbidity. We hypothesized that heart rate variability (HRV), an indicator of cardiac sympathovagal balance, is altered before the onset of postoperative AF. Because nonlinear methods of HRV analysis provide information about heart rate dynamics not evident from usual HRV measures, we also hypothesized that approximate entropy (ApEn), a nonlinear measure of HRV, might have predictive value. Methods and Results-Analysis of HRV was performed in 3 sequential 20-minute intervals preceding the onset of postoperative AF (24 episodes in 18 patients). These data were compared with corresponding intervals in 18 sex-and age-matched postoperative control subjects who did not develop AF. Patients had left ventricular ejection fractions Ͼ45% before surgery and were not receiving ␤-blockers during ambulatory ECG monitoring after surgery. Logistic regression demonstrated that on the basis of averaged values for the three 20-minute intervals, increased heart rate and decreased ApEn were independently associated with AF. Heart rate dynamics before AF was associated with either lower (nϭ19) or higher (nϭ5) RR interval variation by traditional measures of HRV or quantitative Poincaré analysis, suggesting the possibility of divergent autonomic conditions before AF onset. Conclusions-In the hour before AF after CABG surgery, higher heart rate and lower heart rate complexity compared with values in control patients were independent predictors of AF. Decreased ApEn occurs in patients with either increased or decreased HRV by traditional measures and may provide a useful tool for risk stratification or investigation of mechanisms. (Circulation. 1998;98:429-434.)

Recombinant FVIIa (rFVIIa) has been approved for treatment of bleeding in hemophilia patients with inhibitors. It has also been successfully used in nonhemophilia patients with acquired antibodies against FVIII (acquired hemophilia). Pharmacological doses of rFVIIa have been found to enhance the thrombin generation on already activated platelets and, therefore, may also likely be of benefit in providing hemostasis in other situations characterized by profuse bleeding and impaired thrombin generation, such as patients with thrombocytopenia and in those with functional platelet defects. Additionally, it has been used successfully in a variety of less well-characterized bleeding situations, as well as in patients with impaired liver function. To date, case reports, anecdotal experience, and limited clinical trials describe these uses; data from randomized clinical trials are limited. Because of the recent trends in rFVIIa usage in non-approved settings among physicians from various disciplines, significant concerns about its safety, efficacy, and costs have arisen. Additionally, dosing of rFVIIa for these potentially broad clinical applications is not standardized. Currently, the decision on when and where to use rFVIIa for patients with uncontrolled bleeding continues to be one that must be made by individual physicians, assisted by their hospital pharmacotherapeutics and transfusion committees.

No abstract

Introduction: We analyzed donor platelet counts and platelet product yields in 708 consecutive platelet aphereses in our program in order to define the importance of this relationship for emerging issues in platelet transfusion therapy. Methods: Aphereses performed on the Spectra 3.6 (COBE, Lakewood. Colo.) the CS–3000 Plus (Fenwall–Baxter, Deerfield, Ill.) were analyzed. Results: Mean platelet count was 237±49×10³/mm³ (mean ± SD), and mean yield was 4.24±1.09×10¹¹ platelets. Eigthy–five (12%) procedures generated less that 3×10¹¹ platelets. Only thirty–eight (5.4%) procedures yielded ≥6×10¹¹ platelets, so that 'split products' could be obtained. Platelet yields were primarily related to the biologic contribution (baseline platelet count) of the donor. Procedure parameters selected for harvest, and the efficiency of the device also had a significant, but less important role in determining the final platelet yield. An increase in mean donor platelet count achieved with Mpl ligand therapy from 240,000 to 320,000/mm³ would reduce the cost from USD 378 to 267 for each apheresis product, since the fraction of split products would exceed 50% of apheresis procedures. Conclusion: Increasing the donor platelet count would have a significant economic impact on platelet apheresis programs, as well as important clinical consequences for the role of platelet apheresis products in future transfusion strategies.