Two weeks of buspirone protects against posthypoxic ventilatory pauses in the C57BL/6J mouse strain.

The purpose was to determine if 2 weeks of buspirone suppressed post-hypoxic breathing instability and pauses in the C57BL/6J (B6) mouse. Study groups were vehicle (saline, n=8), low-dose (1.5 mg/kg, n=8), and high-dose buspirone (5.0 mg/kg, n=8). Frequency, measured by plethysmography, was the major metric, and a pause defined by breathing cessation >2.5 times the average frequency. Mice were tested after 16 days of ip injections of vehicle or drug. On day 17, 4 mice in each group were tested after buspirone and the 5-HT(1A) receptor antagonist, 4-iodo-N-{2-[4-(methoxyphenyl)-1-piperazinyl] ethyl}-N-2-pyridinyl-benzamide (p-MPPI, 5 mg/kg). A post-hypoxic pause was present in 6/8 animals given vehicle and 1/16 animals given buspirone at either dose, but always present (8/8) with p-MPPI, regardless of buspirone dose. Post-hypoxic frequency decline was blunted by buspirone (-10% vehicle vs. -5% at both doses) and restored by p-MPPI; ventilatory stability as described by the coefficient of variation which was reduced by buspirone (p<0.04) was increased by p-MPPI (0.01). In conclusion, buspirone administration after 2 weeks acts through the 5-HT(1A) receptor to reduce post-hypoxic ventilatory instability in the B6 strain.

Ceftazidime-induced hemolysis in a patient with drug-dependent antibodies reactive by immune complex and drug adsorption mechanisms.

A 35-year-old woman developed acute intravascular hemolysis within five days of beginning a course of ceftazidime. The direct antiglobulin test became strongly positive with both anti-IgG and anticomplement. The serum contained an antibody that, in the presence of ceftazidime, sensitized unmodified reagent cells with IgG and complement (immune-complex type). The serum also agglutinated ceftazidime-pretreated cells at room temperature and 37 degrees C (drug-adsorption type). Retrospective testing disclosed that the drug adsorption antibody, which had been present before the current course of antibiotics, was not demonstrable during the hemolysis. The reactivity of the immune complex antibody, which developed by the second day of ceftazidime, paralleled the degree of hemolysis and the strength of the direct antiglobulin test. The authors believe that this patient had two separate ceftazidime-dependent antibodies and that the antibody reactive by immune complex mechanism mediated an episode of acute intravascular hemolysis.

Febrile reactions after platelet transfusion: the effect of single versus multiple donors.

Febrile reactions to platelet transfusions are a common problem. The platelet transfusion records from a 30-month period were analyzed to determine 1) when reactions occur in a transfusion sequence; 2) how frequently they recur; and 3) whether the choice of multiple-donor (pooled concentrates) or single-donor components (unmatched apheresis and HLA-compatible apheresis platelets) affected the reaction rate. Overall, 18.7 percent of all patients receiving platelets experienced reactions. A subset of 85 patients, who began platelet support with unmodified components during the study interval, were analyzed in detail. This group received 1204 unmodified transfusions (mean, 14.2/patient), which were associated with 171 reactions (per-transfusion reaction rate, 14.2%). Despite a higher mean white cell content, the transfusion of 438 unmatched single-donor platelets (10.84 x 10(8) white cells, 8.4% reaction rate) resulted in reactions significantly less often than did that of 583 pooled concentrates (8.53 x 10(8) white cells, 21.4% reaction rate) (p less than 0.001). The rate of reaction to HLA-compatible platelets (9/183 transfusions, 4.9%) was not significantly different from that to unmatched single-donor platelets. The use of platelet components from one donor, as opposed to multiple donors, may provide an effective means of reducing the incidence of febrile reactions.

Autologous blood donations prior to elective cardiac surgery. Safety and effect on subsequent blood use.

Blood transfusions are frequently necessary for patients having open heart surgery. Although autologous blood is free of such risks as transfusion-transmitted diseases, the safety and effectiveness of autologous donations by cardiac patients are debated. We analyzed the records of 291 consecutive patients undergoing elective open heart surgery. One hundred seven (36.8%) donated between 1 and 6 U of autologous blood (mean, 3.0 +/- 1.5 U) before undergoing surgery. First-time elective coronary artery bypass surgery was the most common indication for autologous donation (90.6% of autologous donors). Problems following donations were infrequent (2 of 326 donations) and without long-term consequences. Among patients having coronary artery bypass surgery who donated autologous blood, 27% required homologous blood transfusions as compared with 82% of other patients undergoing the same procedure. We conclude that autologous blood donations are safe for patients with cardiac disease and effective in significantly reducing homologous blood needs in patients undergoing elective coronary artery bypass surgery.

Passive transfusion of human chorionic gonadotropin from plasma donated during pregnancy.

Although fresh frozen plasma (FFP) prepared from autologous blood donated during pregnancy has frequently been given to homologous recipients at our institution, one transfusion resulted in an unanticipated diagnostic dilemma. A 31-year-old woman with disseminated intravascular coagulation of unclear etiology was transfused with multiple units of FFP, including 2 from pregnant autologous donors. A serum human chorionic gonadotropin (HCG) assay, performed because of the possibility that the patient's illness was a complication of unrecognized pregnancy, was positive using a blood sample drawn 7 h after the transfusions. An extensive evaluation was completed before the possibility of passive transfer of hormone from blood products was considered. Retrospective testing of serum samples established that HCG appeared in the patient's serum only after the first FFP transfusion from a pregnant autologous donor. In 8 other recipients of 1 or 2 units of FFP from pregnant autologous donors, post-transfusion HCG levels ranged between 96 and 1,750 mIU/ml. Of 15 recipients of packed red blood cells from pregnant autologous donors, only patients with renal failure or recipients of multiple units developed positive HCGs, which were always less than or equal to 85 mIU/ml. The differential diagnosis of a positive pregnancy test in a recently transfused individual should include the possibility of passively acquired hormone.

Autologous versus homologous donors. Evaluation of markers for infectious disease.

Autologous blood donations may provide a new source of blood when components not used by the donors are deemed suitable for homologous use. However, the risk of transfusion-transmitted diseases form such donors has not been evaluated. We compared the prevalence of infectious markers and rate of abnormal responses to a confidential donor ballot in autologous donors from two blood collection programs, one blood center and one hospital-based, to corresponding homologous blood programs. The incidence of abnormal test results in autologous donors for HIV antibodies (either Western blot confirmed or repeatedly reactive, unconfirmed), HBsAg, ALT, and anti-HBc were not statistically different from homologous rates. The incidence of STS abnormalities in autologous donors was statistically significant, although all positive results were biologic false positives. The rate of abnormal responses to the confidential ballot was statistically significant only in autologous donors whose collections were already determined to be unsuitable for homologous use due to medical history problems. Although the data do not address infectious complications in transfusion recipients, this study offers no evidence that autologous blood components are less safe than their homologous equivalents.

Utilization and effectiveness of a hospital autologous preoperative blood donor program.

The utilization and effectiveness of a hospital preoperative autologous blood donation program were analyzed. Over 16 months, 180 donors, or 11.6 percent of eligible patients (those undergoing elective surgical procedures where blood was routinely crossmatched), were enrolled in the program. They donated an average of 2.2 units of red cells, or 59 percent of the mean order of 3.7 units. Donations were completed in 17.9 days, leaving 10.7 days between the last donation and hospitalization. Of all scheduled donations, 25.5 percent were cancelled due to deferrals; 47.8 percent of patients were deferred at least once. Most patients were able to donate a unit of blood weekly, with minimal drops in hematocrit (mean 3.2%). The reaction rate, 4.8 percent, was comparable to figures reported for homologous donors. Nearly two-thirds of participants used no homologous blood during their hospitalization: 28.6 percent used no blood whatsoever, and 36.9 percent used only autologous components. Including released autologous components subsequently administered to other recipients, transfused autologous red cells were 2.1 percent and fresh-frozen plasma (FFP) 7.2 percent of the hospital's blood supply. Although the high deferral rate complicated the administration of the program, this complication was offset by the demonstration of donor safety, reduction in the proportion of patients who used homologous blood, and the contribution of autologous blood components to the hospital's blood inventory.