Biomedical subjects
Publications and source records attributed to E Bass.
Pharmaceutical companies like to test their drugs in patients who are less seriously ill, so that the drugs will look good. A recent FDA meeting focused attention on the need for more trials in advanced patients, the importance of long-term safety follow-up for all patients, and how the necessary trials and monitoring could be conducted.
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BACKGROUND: The purpose was to assess the current variation in complication rates and evaluate the association between specific types of complications and in-hospital mortality and total hospital charges for patients having abdominal aortic surgery. PATIENTS/METHODS: We studied 2987 patients for abdominal aortic surgery in Maryland from 1994 to 1996 and used discharge diagnoses and procedure codes to identify diagnoses that most likely represent major surgery complications. We evaluated how in-hospital mortality and total hospital charges related to specific complications, adjusting for patient demographics, severity of illness, comorbidity, and hospital and surgeon volumes. Discharge data was obtained from the hospital marketing departments. RESULTS: Complication rates varied widely among hospitals. Complications independently associated with increased risk of in-hospital death include cardiac arrest with an odds ratio (OR) of 90 and a 95% confidence interval (CI) of 32-251, septicemia (OR 6.1, CI 3.3-11.3), acute myocardial infarction (OR 5.7, CI 2.3-14.3), acute renal failure (OR 5.0, CI 2.3-11.0), surgical complications after a procedure (OR 3.1, CI 2.0-4.9), and reoperation for bleeding (OR 2.2, CI 1.1-4.8). The population-attributable risk for in-hospital mortality was 47% for cardiac arrest and 27% for acute renal failure. CONCLUSIONS: In abdominal aortic surgery on patients in Maryland, the rates of some complications vary widely and are independently associated with increased in-hospital mortality and hospital charges (charges differ from costs). Efforts to reduce these complications should help to decrease both levels.
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CONTEXT: Morbidity and mortality rates in intensive care units (ICUs) vary widely among institutions, but whether ICU structure and care processes affect these outcomes is unknown. OBJECTIVE: To determine whether organizational characteristics of ICUs are related to clinical and economic outcomes for abdominal aortic surgery patients who typically receive care in an ICU. DESIGN: Observational study, with patient data collected retrospectively and ICU data collected prospectively. SETTING: All Maryland hospitals that performed abdominal aortic surgery from 1994 to 1996. PATIENTS AND PARTICIPANTS: We analyzed hospital discharge data for patients in non-federal acute care hospitals in Maryland who had a principal procedure code for abdominal aortic surgery from January 1994 through December 1996 (n = 2987). We obtained information about ICU organizational characteristics by surveying ICU medical directors at the 46 Maryland hospitals that performed abdominal aortic surgery. Thirty-nine (85%) of the ICU directors completed this survey. MAIN OUTCOME MEASURES: In-hospital mortality and hospital and ICU length of stay. RESULTS: For patients undergoing abdominal aortic surgery, in-hospital mortality varied among hospitals from 0% to 66%. In multivariate analysis adjusted for patient demographics, comorbid disease, severity of illness, hospital and surgeon volume, and hospital characteristics, not having daily rounds by an ICU physician was associated with a 3-fold increase in in-hospital mortality (odds ratio [OR], 3.0; 95% confidence interval [CI], 1.9-4.9). Furthermore, not having daily rounds by an ICU physician was associated with an increased risk of cardiac arrest (OR, 2.9; 95% CI, 1.2-7.0), acute renal failure (OR, 2.2; 95% CI, 1.3-3.9), septicemia (OR, 1.8; 95% CI, 1.2-2.6), platelet transfusion (OR, 6.4; 95% CI, 3.2-12.4), and reintubation (OR, 2.0; 95% CI, 1.0-4.1). Not having daily rounds by an ICU physician, having an ICU nurse-patient ratio of less than 1:2, not having monthly review of morbidity and mortality, and extubating patients in the operating room were associated with increased resource use. CONCLUSIONS: Organizational characteristics of ICUs are related to differences among hospitals in outcomes of abdominal aortic surgery. Clinicians and hospital leaders should consider the potential impact of ICU organizational characteristics on outcomes of patients having high-risk operations.
BACKGROUND: There is increasing pressure to perform traditional inpatient surgical procedures in an outpatient setting. The aim of the current trial was to determine the safety and cost savings of performing laparoscopic cholecystectomy in an outpatient setting using a "mock" outpatient setting. METHODS: Patients who were scheduled for laparoscopic cholecystectomy by four attending surgeons and for whom operating time was available in the outpatient center were studied. All patients received a standardized anesthetic, including ondansetron, and were discharged from the outpatient postanesthesia care unit if appropriate. At discharge, all patients were admitted to a clinical research center where they were observed in a "mock home" setting and monitored for complications that would have necessitated readmission. A decision analysis was created assuming all patients underwent outpatient surgery with either direct admission or discharge to home and readmission if complications developed. RESULTS: Of 99 patients who were enrolled in this study, 96 patients would have met the discharge criteria for home. No major complications were observed in these 96 patients. Eleven patients experienced postoperative nausea and vomiting, 3 of whom required an additional 24 h of hospital observation. In the decision model, the optimal strategy would be to perform the procedure on an outpatient basis and readmit patients only for complications, with an average baseline cost savings of $742/patient. CONCLUSIONS: The results show that outpatient laparoscopic cholecystectomy is safe and cost-effective in selected patients, and that the mock home setting provides a means of studying the safety of transition of care.
The statistical and practical implications of including second eye surgeries were examined in a clinical trial designed to evaluate the impact of routine preoperative testing prior to cataract surgery on major medical events occurring within seven days following surgery. In order to detect a 0.8% difference in the rates of rare major medical events between the tested and untested groups, 20,000 surgeries must be randomized. About 30% of cataract operations were estimated to be done on second eyes of patients already included in the cohort. Different options for dealing with second eye surgeries were: (1) exclusion of all second eye surgeries, (2) inclusion of second eye surgeries only if the first eye is not enrolled, (3) inclusion of first and second eyes but randomization of patients rather than eyes, and (4) inclusion of first and second eyes but randomization of surgeries rather than patients. The final decision was to exclude second eye surgeries done within 28 days of first eye surgeries, but to rerandomize all other second eye surgeries. Differences in event rates between treatment groups can be estimated using Generalized Estimating Equations, and the association between outcomes of first and second eye operations estimated with pairwise odds ratios. An anticipated small positive correlation is likely to have minimal impact on statistical power and effective sample size.
The effects of base-in (BI) and base-out (BO) prism upon performance of four occupational-like tasks were measured on a group of 10 subjects who had normal binocular vision. Performance on tasks which required depth perception was significantly poorer when subjects wore prism glasses with 8 and 12 delta BI and BO, whereas 4 delta BI and BO did not significantly affect performance. The performance decrements with prism (3.0 to 6.7%) were considerably less than those induced by denial of binocularity (20 to 30%) as measured in a previous study. Thus, vergence-inducing prism does impair task performance but not as much as does the denial of binocularity. The reading and counting tasks did not require critical depth judgement and were much less affected by the prism than the needle-threading and pointers-and-straws tasks.
Functional advantages of binocularity were investigated by having 13 subjects perform a group of occupational-type tasks under monocular and binocular conditions. Significant binocular advantages ranging from 29.5% (pointers in straws) to 3.7% (reading speed) were measured. Tasks with many disparity cues showed the greatest binocular advantage. This shows that patients with normal binocular vision use binocular cues, most likely stereopsis, to enhance performance. In a second experiment, three subjects with normal binocular vision underwent monocular occlusion for 5 days to investigate whether monocular skills improved to compensate for the loss of binocular vision. During that period binocular performance was consistently better than monocular performance, and both monocular and binocular performance improved, even though the subjects were only gaining monocular experience. Although the 5 day occlusion period does not simulate the long-term denial of normal binocularity that strabismics or monocular patients experience, it shows that binocular superiority remains after short-term loss of binocularity.
Cardiopulmonary arrest is a test of the brain's tolerance to global ischemia. New insights into the pathophysiology of global ischemia have led to the potential use of early prophylactic anticonvulsants, hypothermia, barbiturate coma, glucose manipulations, calcium-blocking agents, and hemodilution. A wide spectrum of neurologic sequelae may follow global ischemia, ranging from brain death, vegetative states, and impairment of higher intellectual function to syndromes of amnesia and cortical blindness, post-anoxic myoclonus, delayed leukoencephalopathy, and spinal stroke. The distinctive features of these sequelae and their pathophysiologic aspects are discussed. Special attention is given to brain death and prognostication.
A variety of central nervous system (CNS) insults may be complicated by the acute development of pulmonary edema. This occurrence has been termed neurogenic pulmonary edema (NPE), and experimental models have clearly shown that CNS insults may cause pulmonary edema. Unfortunately, the pathophysiologic aspects of this response are not clearly understood. Basing an approach to the development of pulmonary edema on Starling's equation leads to the conclusion that NPE is caused by changes in pulmonary endothelial permeability and/or microvascular pressures. It was previously suggested (the "blast theory") that CNS insults caused acute systemic arterial and pulmonary venous spasm and increased venous return, which would result in a severe pulmonary vascular hydrostatic insult and a secondary permeability defect. Although such hydrostatic derangements may explain certain cases of NPE, recent clinical and experimental studies have indicated that CNS disorders may cause a permeability defect without a vascular insult. The mediating factor for a permeability defect is not clear. The implications of these findings are that NPE may be caused by either permeability abnormalities or hydrostatic insults, may present clinically in a variety of ways, and may require different approaches to treatment. Our understanding of the CNS sites that might mediate NPE is not sophisticated enough, at present, to define the neural mechanisms involved in the pathogenesis of NPE.
A case of presumed anticoagulant induced hemorrhage into infarction is presented along with a retrospective study of 110 cases of cerebral embolus. An accurate recommendation for the timing of anticoagulation following cerebral embolism hinges on balancing the risk of hemorrhage into infarction against the benefits of early treatment attributed to preventing recurrent embolism. It is felt that the present literature, concepts of pathogenesis and experimental data provide insufficient information to make absolute clinical decisions. The available evidence implies that the risk of further embolic events is three to four times that of hemorrhage into infarction, yet additional randomized prospective studies and better experimental models are needed to establish a valid treatment plan. It may be possible to distinguish separate mechanisms underlying early diffuse hemorrhage into infarction from sudden delayed massive hematoma formation.
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The effectiveness of 400 and 800 mg. of ibuprofen was compared to that of 650 mg. of aspirin, 65 mg. of propoxyphene HCl, and placebo in 510 patients experiencing pain subsequent to oral surgical procedures. In double-blind study, patients were randomly assigned to one of five experimental groups and instructed to report the intensity of pain (complete, partial, or none) over a 3-hour period of evaluation. Ibuprofen, at both doses, was shown to be more effective for both degree and duration of relief from pain.
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A randomized controlled trial was conducted to examine the effects of interdisciplinary team care on acute hospitalized stroke patients. After obtaining baseline information on 42 stroke victims receiving conventional care in a general hospital, 130 stroke patients were stratified and randomly assigned either to Traditional or Team care. Assessments by independent evaluators permitted comparisons between Team and Traditional groups with reference to patient survival, motor performance and functional abilities. Data obtained prospectively from charts and treatment logs allowed the care process across groups to be compared. Results demonstrated that Team and Traditional patients fared similarly in survival. However there was an unexpected difference in survival depending upon sex. For motor performance, male survivors performed better with Team care and female survivors with the Traditional method. In terms of functional abilities, male patients receiving Team care again performed better than their Traditional counterparts, whereas in women there was no difference between the treatment groups.