Internet Medline providers.

Each database in this review has features that will appeal to some users. Each provides a credible interface to information available within the Medline database. The major differences are pricing and interface design. In this context, features that cost more and might seem trivial to the occasional searcher may actually save time and money when used by the professional. Internet Grateful Med is free, but Ms. Coady and I agree the availability of only three ANDable search fields is a major functional limitation. PubMed is also free but much more powerful. The command line interface that permits very sophisticated searches requires a commitment that casual users will find intimidating. Ms. Coady did not believe the feedback currently provided during a search was sufficient for sustained professional use. Paper Chase and Knowledge Finder are mature, modestly priced Medline search services. Paper Chase provides a menu-driven interface that is very easy to use, yet permits the user to search virtually all of Medline's data fields. Knowledge Finder emphasizes the use of natural language queries but fully supports more traditional search strategies. The impact of the tradeoff between fuzzy and Boolean strategies offered by Knowledge Finder is unclear and beyond the scope of this review. Additional software must be downloaded to use all of Knowledge Finders' features. Other providers required no software beyond the basic Internet browser, and this requirement prevented Ms. Coady from evaluating Knowledge Finder. Ovid and Silver Platter offer well-designed interfaces that simplify the construction of complex queries. These are clearly services designed for professional users. While pricing eliminates these for casual use, it should be emphasized that Medline citation access is only a portion of the service provided by these high-end vendors. Finally, we should comment that each of the vendors and government-sponsored services provided prompt and useful feedback to e-mail questions about usage. In conclusion, we would suggest you try the various services, determine which interface suits your style and budget, then perform simple searches until you learn the strengths and weaknesses of the service you select.

Recent developments in the diagnosis, treatment, and prevention of pulmonary embolism.

The diagnosis of pulmonary embolism remains enigmatic. Points to look for are: (1) Ninety percent or more of patients with pulmonary embolism have known predisposing factors. (2) Eighty percent or more complain of dyspnea and exhibit hyperpnea (eg, respiratory rate > 20 breaths per minute). (3) Chest roentgenogram abnormalities occur in more than 80% of patients. (4) Seventy percent to 90% of patients complain of chest pain. (5) Either the pCO2 is low or the alveolar-arterial oxygen gradient is high in more than 95% of cases. (6) Twenty percent of patients have normal pO2. (7) Anxiety is present more often than not, and, if present, is no reason to dismiss the cause as "hyperventilation syndrome." Pulmonary arteriography is the "gold standard" for diagnosis, although the combination of ventilation/perfusion scan and noninvasive leg vein studies may decrease its use. An experimental test, the immunosorbent plasma D-dimer assay, seems a promising future screening tool if its reportedly high sensitivity is confirmed. Transthoracic or esophageal echocardiology, if immediately available, may have a place in assessing patients who present with cardiovascular collapse. Early and adequate heparinization coupled with the use of intravenous heparin protocols should lower future mortality rates. Food and Drug Administration approval of low-molecular-weight heparin and heparinoids may revolutionize the management of routine thromboembolism, as these substances are easier to use and less hazardous. A recent British study showed no advantage to anticoagulation beyond 4 weeks for patients with perioperative thrombophlebitis and no other risk factors. In selected cases, thrombolytic therapy, vena caval filters, and invasive embolectomy have been shown to decrease both short- and long-term mortality.