Table of Contents

The authors measured the nighttime highway driving performance of 12 young men immediately after coffee (containing 200 mg of caffeine), placebo (decaffeinated coffee containing 15 mg of caffeine), or a 30-minute nap. When daytime highway driving was used as a reference point for nighttime driving, 75% drove as well after coffee and 66% drove as well after a nap, but only 13% drove as well after placebo. Drinking coffee or napping significantly reduced nighttime highway driving impairment.

During a 1-month inpatient rotation, interns followed a nap schedule for 2 weeks and a standard call schedule for 2 weeks. The nap schedule provided on-duty interns with coverage from midnight to 7:00 a.m. to finish their work and take a nap. While on the nap schedule, interns slept 41 minutes longer than on the standard call schedule. Despite the brevity of the naps, interns reported less overall fatigue than with the standard schedule. Coverage to allow a nap during an extended shift can increase sleep and decrease fatigue.

The authors surveyed emergency preparedness linkages among hospitals, public health officials, and first responders. Although most hospitals reported substantial integration, the results suggest that these linkages require strengthening to allow optimum communication during a crisis.

In patients with a low clinical probability of pulmonary embolism who also have negative d-dimer test results, withholding additional diagnostic testing does not increase the frequency of venous thromboembolism during follow-up. Low clinical probability and negative d-dimer test results occur in 50% of outpatients and in 20% of inpatients who have suspected pulmonary embolism.

The authors examined the association between psychosocial factors and subclinical coronary atherosclerosis in a multiethnic, community-based sample of adults. The prevalence and extent of coronary calcification were essentially the same across the full range of anxiety and depressive symptom scores and chronic stress burden in both men and women. Depressive symptoms, anger, anxiety, and chronic stress burden were not associated with coronary calcification in asymptomatic adults.

The decision to adopt a new diagnostic test depends on whether it improves patient outcomes more than the test it might replace. When do sensitivity and specificity provide enough information to infer the new test's clinical value? The authors provide an approach to deciding whether to adopt a new diagnostic test on the basis of its test performance alone or wait for randomized trials of using the test in clinical practice.

Studies of its test performance show that at commonly used cutoff thresholds, calcaneal quantitative ultrasound does not definitively exclude or confirm osteoporosis as diagnosed by a gold standard test (dual-energy x-ray absorptiometry). Additional research is needed before recommending calcaneal quantitative ultrasound for evidence-based screening programs for osteoporosis.

Neurofibromatoses are inherited disorders, designated as neurofibromatosis type 1 (NF1), neurofibromatosis type 2, and schwannomatosis, that tend to result in benign tumors of the nerve sheath. Much has been learned about the pathophysiology of NF1, the most common of these disorders, since the NF1 gene (which produces the NF1 phenotype) was identified in 1990. This review discusses the NF1 phenotype, the current understanding of basic mechanisms, and the status of translation of this knowledge into clinical application.

The United States is progressing toward a 24-hour society, and sleep deprivation is a growing problem in the workplace. What can hospital staff do about sleepiness? What are possible countermeasures, and how effective are they? In this issue, Philip and colleagues and Arora and coworkers evaluate the effects of naps on performance in real-life tasks.

In this issue, Diez Roux and colleagues examined the relationship between psychological factors (depressive symptoms, anxiety, anger, and chronic burden) and coronary artery calcium and found no association. Given the substantial evidence supporting an association between psychological factors and coronary heart disease events, are these negative findings surprising? Do they contradict more than a century of epidemiologic observations? How do they improve our understanding of the link between psychological factors and coronary heart disease events?