Heterogeneous accretion and the moderately volatile element budget of Earth.

Several models exist to describe the growth and evolution of Earth; however, variables such as the type of precursor materials, extent of mixing, and material loss during accretion are poorly constrained. High-precision palladium-silver isotope data show that Earth's mantle is similar in 107Ag/109Ag to primitive, volatile-rich chondrites, suggesting that Earth accreted a considerable amount of material with high contents of moderately volatile elements. Contradictory evidence from terrestrial chromium and strontium isotope data are reconciled by heterogeneous accretion, which includes a transition from dominantly volatile-depleted to volatile-rich materials with possibly high water contents. The Moon-forming giant impact probably involved the collision with a Mars-like protoplanet that had an oxidized mantle, enriched in moderately volatile elements.

NCCN Practice Guidelines for Breast Cancer.

The therapeutic options for patients with noninvasive or invasive breast cancer are complex and varied. In many situations, the patient and physician have the responsibility to jointly explore and ultimately select the most appropriate option from among the available alternatives. With rare exception, the evaluation, treatment, and follow-up recommendations contained within these guidelines were based largely on the results of past and present clinical trials. However, there is not a single clinical situation in which the treatment of breast cancer has been optimized with respect to either maximizing cure or minimizing toxicity and disfigurement. Therefore, patient and physician participation in prospective clinical trials allows patients not only to receive state-of-the-art cancer treatment but also to contribute to the improvement of treatment of future patients.

Does a full-time, 24-hour intensivist improve care and efficiency?

This article reviews the hypothesis that staffing with full-time intensive care physicians leads to improvements in the management of ICUs and in the outcome for ICU patients. Variations in the professional organization of critical care units in the United States are discussed. The advantages and disadvantages of open, closed, and transitional (comanagement) ICU organizational structures are presented.

Trade-offs between survival and breast preservation for three initial treatments of ductal carcinoma-in-situ of the breast.

PURPOSE: To assess the trade-offs between survival and breast preservation of currently accepted approaches for ductal carcinoma-in-situ (DCIS) of the breast. PATIENTS AND METHODS: Decision analysis was performed using the Markov model of hypothetical cohorts of 55-year-old white women with nonpalpable mammographic abnormalities found to be DCIS. Strategies were breast-conserving surgery (BCS), BCS with 50-Gy radiation (RT) or initial mastectomy. Recurrence rates were derived from the published literature. Main outcomes were overall, breast cancer-free, and event-free survival plus years of both breasts preserved. RESULTS: Using the conditions defined in this model, the actuarial survival rates at 10 and 20 years were 91.7% and 74.1% for the initial mastectomy strategy, 91.0% and 72.1% for BCS plus RT, and 89.6% and 68.2% for BCS alone. At 20 years, the initial mastectomy strategy also had a greater breast cancer-free survival rate of 74.5%, compared with 63.3% for BCS plus RT, or 46.8% for BCS alone. However, BCS alone had the highest survival rate with both breasts preserved (64.2%) compared with BCS plus RT (56.0%) or initial mastectomy (0%). Of the breast-conserving strategies at 20 years, the breast event-free survival rate (no invasive cancer or DCIS) was greater for BCS plus RT (47.2%) compared with BCS alone (28.4%). Using just survival as the primary end point, mastectomy is the optimal strategy by a small margin. However, if quality-adjusted survival is at issue, mastectomy is the choice only if the yearly reduction in quality of life due to mastectomy is less than 1%. CONCLUSION: BCS with or without radiation compared with mastectomy as initial management of DCIS of the breast trades a slight decrease in survival rates for the value of breast preservation. This model should aid clinicians in matching treatments to their patients' preferences.

Impact of critical care physician staffing on patients with septic shock in a university hospital medical intensive care unit.

To evaluate the effects of reorganizing physician resources in a medical intensive care unit (MICU), we studied the impact of these changes in patients with septic shock. Patients were compared during two consecutive 12-month periods: (1) an interval in which faculty without critical care medicine (CCM) training supervised the MICU (before CCM, n = 100) and (2) following staffing with physicians formally trained in CCM (after CCM, n = 112). Acute Physiology and Chronic Health Evaluation scores were utilized to compare severity of illness and were similar for each group (29 +/- 11 before CCM vs 28 +/- 10 after CCM). However, mortality was significantly lower during the post-CCM interval (74% vs 57%, respectively). There was no significant difference in the frequency of use of mechanical ventilation (83% vs 87%), although pulmonary artery catheters (48% vs 64%) and arterial catheters (24% vs 73%) were employed more frequently after CCM. The number of subspecialty consultations and MICU and hospital length of stay were similar for both intervals. We conclude that the implementation of dedicated staffing by CCM physicians in a university hospital MICU was associated with a favorable impact on patients with septic shock.

Comparison of clinical assessment with APACHE II for predicting mortality risk in patients admitted to a medical intensive care unit.

The APACHE II (Acute Physiology and Chronic Health Evaluation) system has been widely used as an objective means of predicting outcome in critically ill patients. We prospectively evaluated patients consecutively admitted to the medical intensive care unit to compare the predictive accuracy of APACHE II with clinical assessment by critical care personnel. At the time of admission to the intensive care unit, the house staff and nurse responsible for each patient were asked to estimate the patient's hospital mortality risk. The patient's APACHE II score was calculated and a prediction of the patient's hospital mortality risk was then computed on the basis of this score. A total of 366 patients were studied. Mortality predictions were obtained from 57 physicians and 33 critical care nurses. We were unable to demonstrate a significant difference in the accuracy of APACHE II predictions compared with either physicians' or nurses' predictions. Clinical assessment and APACHE II were both highly predictive of outcome.

Development of a comprehensive supportive care team for the hopelessly ill on a university hospital medical service.

We developed a supportive care service for a university hospital medical service that serves a socially and medically disadvantaged urban population. The team includes a faculty physician and a clinical nurse specialist who provide primary medical care, family support, and in-service guidance to hospital staff about ethical issues. A multidisciplinary approach incorporates nursing, pastoral care, social work, and other hospital services. We report our experience from November 1985 through May 1987, during which time 222 patients were referred to the team; 212 patients were accepted. The goals and operation of the service are described. The most common (n = 62, 29%) diagnosis on referral was global central nervous system anoxia following cardiopulmonary arrest. Other severe neurological conditions accounted for an additional 79 patients (37%). Comparison of patients on the service with a similar group revealed no difference in survival rate, although hospital length of stay and charges were progressively reduced after implementation of the service. This approach to the care of hopelessly ill patients may serve as an alternative method of treatment in similar hospital settings.

KIE: The authors document the first 19 months of a service dedicated to the care of hopelessly ill patients in a teaching hospital. A comprehensive supportive care team (CSCT) was established to ensure a humane, uniform, and consistent approach to the care of patients for whom aggressive care is no longer warranted. The goals and operation of the CSCT are described, including the components of patient evaluation and development of treatment plans. Results of a study of 212 patients accepted by the CSCT are reported. The authors conclude that the service successfully provided conservative but comprehensive care for the hopelessly ill, and that it increased awareness of ethical issues among hospital personnel, patients, and families.

The stat laboratory: facilitating blood gas and biochemical measurements for the critically ill and injured.

The stat laboratory has evolved to fulfill the need for rapidly available laboratory data in support of clinical decision-making af the bedside of the critically ill or injured patient. The operation of a stat laboratory, which was first organized more than 12 years ago, is described. Methods of organization, instrumentation, technics and sequencing of analyses, and costs for a standard panel of stat laboratory measurements on arterial or mixed venous blood are described. In addition to blood gases, measurements include hematocrit, hemoglobin, oxygen saturation, methemoglobin, carboxyhemoglobin, blood lactate, plasma electrolytes, plasma osmolality, plasma colloid osmotic pressure, and estimated plasma protein content. The panel of tests is completed and reported within 11 min after a 5-ml sample of arterial or mixed venous blood is delivered to the laboratory.