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Biomedical subjects

J P Crowley

Publications and source records attributed to J P Crowley.

At least 19 recordsLinked to original sources
PubMed1998

The red cell transfusion trigger: has a sin of commission now become a sin of omission?

The benefits of a Hct range of 30 to 35 percent include improved oxygen delivery and enhanced hemostasis, which help minimize complications in patients at high risk for ischemia and perioperative nonsurgical bleeding. In these settings, the conservative transfusion practice of using a lower Hct range should be replaced with a more aggressive approach. The known risks of blood transfusion would appear to be sufficiently low and the benefits sufficiently high to justify maintaining a Hct of at least 30 percent. An even higher Hct, of 35 percent, may be desirable in patients who have overt cardiopulmonary disease or who are at high risk for myocardial ischemia. Many retrospective studies have been conducted to persuade us that a conservative transfusion trigger is a safe and prudent practice, but retrospective studies are not what we need. What we need is a series of well-designed, prospective, randomized trials to evaluate the impact of a more aggressive transfusion policy on perioperative mortality, morbidity, and nonsurgical bleeding in patients with known cardiopulmonary disease or who are at high risk for myocardial and cerebrovascular ischemia.

Anemia↗
PubMed1997

The volume of blood shed during the bleeding time correlates with the peripheral venous hematocrit.

The relation among the bleeding time, the peripheral venous hematocrit, and the amount of blood shed at the template bleeding time site has not been previously defined. We studied this relation in 227 persons: 26 were patients with idiopathic thrombocytopenic purpura (ITP), 137 were patients with a variety of other bleeding disorders, and 64 were healthy subjects. The bleeding time (mean +/- SD) for the healthy group was 7.1 +/- 1.2 minutes, and the amount of shed blood was 136.4 +/- 47.2 microL; in patients with ITP the bleeding time was 14.0 +/- 4.1 minutes and the shed blood was 508.1 +/- 387 microL; and in the group with other bleeding disorders, the mean bleeding time was 9.0 +/- 3.5 minutes, and the amount of shed blood was 224.7 +/- 184 microL. Bleeding times for all persons studied showed a significant correlation of 0.75 for the amount of shed blood on the filter paper and a significant correlation of 0.28 for the peripheral venous hematocrit. There was also a significant correlation between the bleeding time and the platelet count in patients with ITP. This study demonstrates that the volume of blood shed at the bleeding time site correlates with the peripheral venous hematocrit and emphasizes the contribution of the hematocrit to primary hemostasis in healthy subjects and patients with bleeding disorders.

Bleeding Time↗
PubMed1997

Laparoscopic accessory splenectomy for recurrent idiopathic thrombocytopenic purpura.

This report describes the use of laparoscopic accessory splenectomy in treating recurrent idiopathic thrombocytopenic purpura (ITP). The patient presented 36 months after initial splenectomy with a platelet count of 16,000 cells/microl and nontolerance of medical therapy. A technetium-99 labeled, heat-damaged red blood cell scan revealed two small foci in the upper left quadrant. This finding was confirmed by an abdominal computed tomography scan. After laparoscopic accessory splenectomy, the patient was discharged (23 h after surgery) and at 9 months showed a platelet count of 234,000 cells/microl with no medical therapy. A minimally invasive approach to accessory spleen removal can be beneficial to patients with recurrent ITP and documented accessory splenic tissue.

Adult↗
PubMed1996

Late recurrence of Hodgkin's disease after partial splenectomy.

The use of laparotomy and splenectomy for staging purposes in patients with Hodgkin's disease (HD) gained popularity in the early 1970s. Accurate staging and more effective treatment regimens, including combined chemotherapy and irradiation, have resulted in improved patient survival rates. Similarly, an increased number of late complications have been reported, including the development of thyroid disease, second malignancies, and septic complications related to splenectomy. Partial splenectomy has been proposed as one method of preventing overwhelming postsplenectomy sepsis. The authors present a case of recurrence of HD, which occurred in the splenic remnant 13 years after the initial treatment. This case demonstrates that the spleen is a potential for recurrent intraabdominal Hodgkin's disease after partial splenectomy; thus, the use of partial splenectomy for HD should be discouraged.

Chemotherapy, Adjuvant↗
PubMed1995

Immune responses to major histocompatibility complex homozygous lymphoid cells in murine F1 hybrid recipients: implications for transfusion-associated graft-versus-host disease.

Graft-versus-host disease (GVHD) is currently encountered after bone marrow transplantation and transfusion. GVHD associated with transfusion (TA-GVHD) in apparently immunocompetent recipients has been recently reported with increasing frequency. A consistent finding in many of these cases is that the recipient received blood from a donor homozygous for one of the recipient's HLA haplotypes. However, the observed frequency of TA-GVHD is much lower than the estimated probability of this donor/recipient combination. The potential role of recipient immune responses in controlling TA-GVHD was investigated using an analogous murine model in which GVHD is induced by the injection of parental lymphoid cells into unirradiated F1 hybrid recipients. The effect of various immune manipulations of the recipient of GVHD induction was assessed by determining the number of donor lymphoid cells required to induce GVHD responses. Whereas depletion of recipient CD4+ cells increased the number of donor cells needed to induce GVHD, depletion of recipient CD8+ and natural killer cells resulted in fewer donor cells being needed to induce a GVHD response. These studies suggest a central role for functioning recipient CD8 and natural killer cells in the down-regulation of TA-GVHD development in recipients.

Animals↗
PubMed1995

Thrombotic thrombocytopenic purpura and HIV infection.

We report on a man who was HIV-seropositive and who was initially admitted following multiple episodes of syncope. He gradually developed fulminant thrombotic thrombocytopenic purpura (TTP). Twenty-one patients with TTP who were HIV-positive have been reported previously. Of these 22 patients, all treated with plasmapheresis, 7 died from TTP and 3 suffered relapse but eventually recovered. Delay in initiating plasmapheresis may be fatal. We have correlated the laboratory data of these patients at time of admission with subsequent clinical outcome; only the platelet count correlated with outcome. Patients with lower platelet counts were less likely to relapse or die with therapy. Physicians caring for patients infected with HIV should always consider the possibility of TTP in those patients with thrombocytopenia of unknown etiology. Review of the peripheral blood smear, allowing the detection of microangiopathic hemolytic anemia, is an important clue, enabling one to consider the correct diagnosis.

Adult↗
PubMed1994

Therapeutic support of the patient with thrombocytopenia.

This article provides an update on the methods of collection, preservation, storage, and administration of platelet concentrates. The current indications for platelet transfusions are reviewed, and current knowledge concerning alloimmunization and its prevention is summarized. In addition, the ongoing controversies related to prophylactic administration of platelets versus therapeutic administration are reviewed.

Blood Platelets↗
PubMed1993

Easy bruisability, aspirin intolerance, and response to DDAVP.

Easy bruisability raises the issue of bleeding during otolaryngological surgery. Ten female patients with easy bruisability were evaluated by aspirin challenge; clinical history and screening coagulation studies in these patients had revealed no evidence of a bleeding disorder. The baseline Ivy bleeding time (BT) test (4.5 to 9.5 minutes) was found to be normal in 6 patients and prolonged in 4 patients. Following treatment with aspirin, the bleeding time prolonged significantly in the three groups evaluated: normal controls (6.0 +/- 1.5 minutes vs. 8.4 +/- 2.0 minutes), patients with easy bruisability and a normal baseline (7.8 +/- 1.3 minutes vs. 12.0 +/- 1.6 minutes), and patients with easy bruisability and an abnormal baseline (11.0 +/- 0.7 minutes vs. 14.5 +/- 0.9 minutes). Administration of DDAVP (desmopressin acetate) 0.3 microgram/kg normalized the prolonged bleeding times in all groups after 7 days of daily aspirin therapy. Performing bleeding times before aspirin challenge, after aspirin challenge, and after DDAVP therapy following aspirin challenge is both a useful way of confirming aspirin sensitivity in patients with easy bruisability as well as a useful way of documenting improved hemostasis after DDAVP administration.

Adult↗
PubMed1993

Perioperative paraplegia and multiorgan failure from heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia and thrombosis syndrome is a rare but devastating complication. We report a patient with heparin-induced thrombocytopenia in whom heparin-induced thrombocytopenia and thrombosis syndrome developed after a cardiac operation, complicated by acute thrombosis of the aorta followed by renal failure, paralysis, and ischemic necrosis of the lower extremities. The literature suggests aspirin, dipyridamole, and iloprost as effective prophylactic agents for perioperative heparin-induced thrombocytopenia and thrombosis syndrome. This unfortunate complication underscores the importance of close platelet count monitoring in all preoperative patients undergoing prolonged heparin therapy.

Aorta, Abdominal↗
PubMed1993

Infusion of stroma-free cross-linked hemoglobin during acute gram-negative bacteremia.

Twelve dogs were divided into two groups of six each, and were infused with bis-3,5-dibromosalicyl fumarate stroma-free hemoglobin (DBBF-Hb) or albumin. Their responses to an intravenous bolus of Escherichia coli were followed for 4 hr. Bacterial clearance from the blood stream was studied using standard colony counting methodology as well as blood counts, blood chemistries, and clotting factor analysis. There was a significant difference in mean arterial pressure (MAP) over time between DBBF-Hb-treated dogs and those treated with albumin (P < 0.02). While the DBBF-treated dogs had a higher MAP during the 10 min of bacteremia, after 1 hr, there were no longer any appreciable differences between septic dogs treated with DBBF-Hb vs. albumin. Consumption of clotting and natural anticoagulant factors was observed to be similar in both groups, as were endotoxin levels. Blood urea nitrogen (BUN) increased slightly in both groups, while white blood cell counts and clotting factor levels fell in both groups in a similar fashion. There was a more pronounced fall (P < 0.04) in platelet counts in the animals treated with DBBF-Hb. In the dogs treated with DBBF-Hb, there was also a late rise in pCO2 (P < 0.01), a more pronounced fall in pO2, and greater acidosis, which suggested that ventilation perfusion abnormalities may have been exacerbated by DBBF-Hb treatment. Since the exacerbation of respiratory abnormalities was not related to diminished bacterial or endotoxin clearance, the possibility is raised that DBBF-Hb interferes with compensatory respiratory changes during sepsis.

Acute Disease↗
PubMed1992

Comparing the transfusion medicine content of the NBME's examinations in 1984-1985 and 1989-1990.

Recognition of the seriousness of transfusion-transmitted diseases has been demonstrated by U.S. medical schools through the integration of transfusion medicine (TM) content into their curricula. To evaluate the degree to which these changes in curricula have been reflected in the National Board of Medical Examiners' (NBME) examinations, a study conducted in 1991 evaluated the proportions of TM-related items on Parts I and II of the NBME examinations for 1984-1985 versus 1989-1990. Both Part I (basic sciences) and Part II (clinical sciences) demonstrated significant gains in TM items between the comparison periods (p less than .001), with Part II having the higher gain. An analysis of students' knowledge revealed that students in 1989-1990 tended to perform better on TM items than on examination items generally. The increases in TM content and student performance on TM items on the 1989-1990 examinations suggest that the national effort to expand and improve teaching of TM in U.S. medical schools has been effective.

Blood Transfusion↗
PubMed1992

The effect of viable and nonviable autologous red blood cell transfusions on experimental bacteremia.

Nonviable red blood cells are rapidly cleared from the peripheral blood by the reticuloendothelial system. Since bacteria present in the blood stream are also cleared by the reticuloendothelial system, the possibility that nonviable red blood cells would interfere with the clearance of bacteria has been raised. Groups of dogs were studied in whom an experimental bacteremia was produced by the injection of E. coli (1 x 10(10)/kg). Bacterial clearance, endotoxin clearance, changes in mean arterial pressure, changes in oncotic pressure, and coagulation responses were monitored before and following autologous transfusion of approximately 10 cc/kg of packed red blood cells (PRBC) preserved with acid citrate dextrose or heparinized PRBC stored without preservative. In the latter blood product the majority of the red blood cells were nonviable. Clearance of E. coli over a 4-hr period was similar in the two transfused groups and in a control group without blood transfusion. Mean arterial pressure and blood pH fell significantly in all groups, but was again not significantly different among the groups studied. Endotoxin clearance, changes in oncotic pressure, blood oncotic proteins, and parameters of the blood coagulation system were also similar in all three groups. The results of this study indicate that in normal dogs made acutely bacteremic with E. coli, there were no significant differences over a 4-hr period in their hemodynamic or hematologic responses following transfusion of viable or nonviable autologous red blood cells.

Animals↗
PubMed1992

Blood histamine levels following graded cold challenge in atypical acquired cold urticaria.

Acquired cold urticaria with a negative cold stimulation test has been described in seven patients in whom the standard ice cube test did not induce localized urticaria. Subsequent total body cold exposure induced a generalized urticaria. A patient with this syndrome is presented where blood histamine levels rose from 9 to 60 micrograms/dL after a negative local cold stimulation test and from 60 to 90 micrograms/dL after total body cold exposure. Urticaria occurred only after generalized cold exposure. Blood histamine levels following the ice cube test may represent a sensitive method to diagnose this form of atypical acquired cold urticaria, without subjecting the patient to the risk of anaphylaxis reported following total body cold exposure.

Adult↗