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Byline: S.Y. DeLeon (1), C. Thomas (1), P.T. Roughneen (1), N. King (1), R. Lehne (1), A.M. DeLeon (1), J. Walenga (1), R. Pifarre (1) Keywords: Key words: Cerebral injury -- Hypothermia -- Cardiopulmonary bypass Abstract: Choreoathetosis, seizures, and impaired mental development continue to occur in children undergoing cardiopulmonary bypass (CPB) and profound hypothermia with or without circulatory arrest. Although there is some evidence that the hypothermia itself may be causing these neurologic problems, skepticism remains because of lack of evidence from experimental studies simulating the clinical setting. In this experimental study, we examined the effect of profound and moderate hypothermia on the brain while maintaining normal flow rates during CPB. Ten adult mongrel dogs equally divided into two groups were anesthetized and subjected to CPB and varying levels of hypothermia (group 1, a$?15degC group 2, a$?32degC). Both groups were kept at the desired temperature for 1 hour prior to rewarming and discontinuation of CPB. The dogs were euthanized 4--6 weeks later and neuropathologic studies were performed. The mean CPB flow rates during cooling and at the desired rectal temperature were comparable in both groups: group 1, 108 +- 10 ml/kg/min versus 106 +- 7 ml/kg/min in group 2 (p= NS) and 95 +- 12 ml/kg/min in group 1 versus 101 +- 5 ml/kg/min in group 2 (p= NS). Because of the difference in temperature between the two groups, the mean cooling time (onset of CPB to desired rectal temperature) was longer in group 1 (70 +- 14 minutes) than in group 2 (28 +- 11 minutes, p= 0.007). Hence, the total mean CPB time was also longer in group 1 (198 +- 25 minutes) than in group 2 (143 +- 13 minutes, p= 0.002). The lowest mean blood and rectal temperature achieved in group 1 were 11 +- .9degC and 12 +- 1degC versus 29 +- .4degC (p &lt 0.001) and 30 +- .6degC (p= 0.001), respectively, in group 2 (p= 0.001). Neuronal loss and degeneration was noted in all dogs in group 1 ranging from 2 to 8 cells per 1000 cells counted compared to none in group 2 (p= 0.05). These lesions occurred in both the basal ganglia and the cortex, although they were more marked in the caudate when compared to the cortex and cerebellum. Both in the cortex and in the caudate, neuronal loss was more marked around the capillaries. We conclude that the use of profound hypothermia of a$?15degC and maintenance of normal flow rates during cooling at this temperature for 1 hour produces neuronal loss and degeneration in the brain. These lesions being more marked around capillaries points to the vulnerability of the neurons, probably because of their high lipid content to injury from the cold perfusate. Author Affiliation: (1) Departments of Thoracic and Cardiovascular Surgery, Pathology, Loyola University Medical School, 2160 South First Avenue, Maywood, IL 60153, USA, US

STUDY OBJECTIVES: It has been suggested that diabetes mellitus is associated with an increased susceptibility to infection, the risk of using more aggressive therapeutic agents, and increased morbidity and mortality; however, current evidence supporting these events in the field of pneumonia is scarce. The aim of the present study was to provide information on clinical and microbiological characteristics and the outcome of community-acquired pneumonia in patients with diabetes mellitus. DESIGN: Prospective study of cases. SETTING: A university hospital in Lleida, Spain. PATIENTS: During a 5-year period, we prospectively studied the clinical and radiologic characteristics, the spectrum of causative agents and other microbiological data, and the outcomes of 660 consecutive episodes of community-acquired pneumonia. Data derived from 106 patients with diabetes mellitus were analyzed and compared with data obtained from the remaining population. MEASUREMENTS AND RESULTS: Patients with diabetes mellitus were significantly older (p = 0.001) and more frequently had other concomitant comorbid conditions (p = 0.018). Diabetes was also significantly associated with the development of pleural effusion (p = 0.015) and mortality (p = 0.002); for both events, diabetes remained as an independent predictive factor in multivariate analyses. By contrast, the incidence of the main etiologic agents, and the bacteremia or empyema rates did not show significant differences in relation to the remaining patients. In the subgroup of patients with diabetes, mortality was associated with the presence of multilobar infiltrates (p = 0.004), concomitant underlying diseases (p = 0.004), and some diabetes-related complications (nephropathy, p = 0.040; and vasculopathy, p = 0.002), although only multilobar infiltrates and comorbidities were selected as prognostic factors in the multivariate analysis. CONCLUSIONS: In patients with community-acquired pneumonia, diabetes mellitus is associated with a poor prognosis, increasing the rate of pleural effusion and mortality. Our results suggest that this adverse outcome is more attributable to the underlying circumstances of patients than to uncommon microbiological findings. [ABSTRACT FROM AUTHOR]

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Purpose: The complications of heparin-induced thrombocytopenia include thrombosis and death. The purpose of the study was to determine whether early heparin cessation can prevent these outcomes.Subjects and Methods: We performed a retrospective analysis of consecutive patients with heparin-induced thrombocytopenia diagnosed by platelet aggregometry. Demographic, clinical, and laboratory findings were compared in patients by whether heparin treatment was stopped early (< or = 48 hours) or late (>48 hours) after the onset of thrombocytopenia, as well as between patients with and without thrombosis. Thrombocytopenia was defined as a 50% decline in baseline platelet counts or an absolute platelet count < 100,000/mm3.Results: Of the 113 patients, 38% developed thrombosis and 27% died. One-half of patients had thrombosis diagnosed >24 hours after heparin cessation. No difference in thrombosis or mortality was found in the 40 patients with early heparin cessation [mean (+/-SD) time of cessation 0.7 +/- 0.6 days] compared with the 73 patients with late heparin cessation (5 +/- 3 days). Thrombosis >24 hours after heparin cessation occurred in 61% of the patients in the early group and in 40% of the late group (P = 0.17). In a multivariate analysis, only a lower nadir of the platelet count (percent of baseline) was associated with thrombosis. Neither thrombosis nor the time to heparin cessation were associated with mortality.Conclusions: Early heparin cessation was not effective in reducing morbid events in patients with heparin-induced thrombocytopenia. Treatment strategies other than heparin cessation alone should be considered in patients with this condition. [ABSTRACT FROM AUTHOR]

Study Objectives: Community-acquired pneumonia is a frequent event in the course of chronic obstructive pulmonary disease (COPD). The aim of the present study was to provide information on clinical and microbiological characteristics and outcome of community-acquired pneumonia in these patients, in a comparative study with the non-COPD population., Design: Prospective study of cases., Setting: A university hospital in Lleida, Spain., Patients: During a 6 year-period, we prospectively studied the clinical and radiological manifestations, microbiological data and outcome of all patients with community-acquired pneumonia. A comparative analysis of characteristics of pneumonia between 132 patients with a definitive diagnosis of COPD and 575 patients who did not have this underlying disease was performed., Measurements and Results: COPD was associated with an older and predominantly male population. These patients frequently had concomitant comorbidities such as diabetes mellitus or chronic heart failure. Clinical presentation was more severe, manifested by septic shock, tachypnea, lower values of pH, pO(2) and oxygen saturation, and greater values of pCO(2). Purulent expectoration was also more frequent in this subset of patients. Admission was usually required for patients with COPD, and length of hospitalization was significantly increased; however, difference in the mortality rate was not observed. Although the spectrum of responsible microorganisms was very similar, the incidence of Pseudomonas aeruginosa and other Gram-negative bacilli was increased in COPD, particularly among patients with advanced situation and/or oral corticosteroid treatment., Conclusions: Community-acquired pneumonia in patients with COPD was associated with epidemiological and clinical particularities mainly related to the underlying disease but showed only minor differences in outcome parameters. Gram-negative bacilli and P. aeruginosa are potential pathogens that need to be considered.

Heparin-induced thrombocytopenia is one of the most difficult problems facing clinicians today. Despite recent understanding of the pathophysiology of this disorder, there are many unresolved issues about diagnosis, prevention, and treatment. In this article, difficulties physicians encounter when faced with a suspected heparin-induced thrombocytopenia patient will be reviewed as well as our experience in 113 patients with heparin-induced thrombocytopenia which highlights the failure of current preventive strategies for heparin-induced thrombocytopenia. The experience of using warfarin in 51 patients with heparin-induced thrombocytopenia will also be reviewed.

Background: Aprotinin significantly decreases postoperative blood loss, yet its exact mechanism of action remains unproven., Methods: To study the cytoprotective effect on platelets, we collected blood samples from patients during cardiopulmonary bypass (CPB) operations performed with or without aprotinin. Analysis included whole-blood flow cytometry., Results: The highest percentages of activated platelets (positive for GMP-140 expression) were bound to leukocytes and erythrocytes in all CPB patients. Platelet-platelet activation did not reveal any marked differences between groups. However, in the platelet-cell bound region, increased ristocetin-stimulated platelet activation was observed from 30 minutes on CPB to 90 minutes after CPB with aprotinin (11.9% +/- 5.1% to 33.1% +/- 8.6%; p < 0.05), but not without aprotinin (17.5% +/- 0.1% to 17.9% +/- 2.3%). Platelet autoactivation increased more in the untreated group with time on CPB., Conclusions: This study demonstrates that in the presence of aprotinin, platelets remain unstimulated during CPB and the von Willebrand GPIb-mediated activatability of platelets is preserved, thus maintaining a viable platelet population. Most important, this study reveals that these mechanisms are more related to platelet-leukocyte than to platelet-platelet interactions.

Background: After reapproval by the Food and Drug Administration of the CardioWest total artificial heart for clinical investigation, an international study was started in January 1993 to ascertain the safety and efficacy of this device for bridging to heart transplantation. To date, 40 devices have been implanted in five centers., Methods: Retrospective data collection from participating centers provided enough material for analysis of patient selection, patient survival, adverse events, and comparison with contemporary devices used for bridge to transplantation., Results and Conclusions: Twelve patients (30%) died after implantation and before transplantation after an average of 10.6 +/- 10 days of support. The major cause of death in this group was multiorgan failure. Twenty-eight patients (70%) were supported 36 +/- 36 days before transplantation. There were two deaths after transplantation (1 rejection, 1 multiorgan failure) leaving 26 patients (65% of the total patients and 93% of those who were transplanted) who survived to discharge from the hospital. There was one late death from rejection at one month post discharge. The mean survival time of the 25 surviving patients is 12 months. These results compare favorably with those of other contemporary devices used for bridge to transplantation.