Annals of internal medicine
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The decision to use bedside pulmonary artery catheterization for managing patients must involve a careful assessment of the risks compared to the benefits. Complications can be minimized by following specific guidelines for catheter insertion and maintenance. Pulmonary artery catheterization has been shown to be more accurate than clinical assessment alone in critically ill patients for determining the cause of shock (hypovolemic, cardiogenic, or septic) or for assessing the cause of severe pulmonary edema (cardiogenic or noncardiogenic). ⋯ Similarly, although clinical management of hemodynamic instability in septic shock is facilitated by pulmonary artery catheterization, the mortality remains very high because of the lack of specific therapy to reverse the sepsis syndrome. Adequate volume resuscitation and improved tissue oxygenation are universally accepted goals, but specific hemodynamic endpoints are controversial and direct measurements of tissue oxygenation are not possible. Prospective studies to define the clinical value of pulmonary artery catheterization are needed, but must be designed very carefully in order to identify unequivocally the effect of pulmonary artery catheterization on outcome in critically ill patients.
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Evaluation of demonstrated clinical efficacy of magnetic resonance (MR) imaging in the central nervous system. ⋯ Use of standards for quality of evidence leads to more conservative conclusions than those of reports describing the clinical potential of MR imaging. Some applications of MR imaging were confirmed by rigorous studies, whereas others were not well supported by reports free of methodologic biases. If the diagnostic alternative is invasive (for example, myelography and cisternography), MR imaging is preferred, but adequate diagnosis for many conditions (head trauma, simple stroke, and dementia) may not require the detail of an MR imaging study. In general, more rigorous clinical research studies are needed for new technologies such as MR imaging. Because the field of MR imaging is changing, review of its clinical efficacy will need to be revised frequently.
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Hepatocellular carcinoma is the most frequent cancer worldwide, responsible for approximately 1,000,000 deaths annually, most of them in the Far East and in sub-Saharan Africa. It usually presents at an advanced stage and has a poor prognosis. There is evidence of an etiologic role for hepatitis B virus infection in the etiology of hepatocellular carcinoma. ⋯ Programs have been established to detect hepatocellular carcinoma at an early stage; persons at high risk are regularly screened by measurement of serum alpha-fetoprotein levels and ultrasound examination of the liver. Surgical resection offers the only hope of cure at present, as chemotherapy, radiotherapy, and immunotherapy have not shown promise. Ideally, surgery should be done on small asymptomatic tumors.
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Meta-analysis is the process of combining study results that can be used to draw conclusions about therapeutic effectiveness or to plan new studies. We review important design and statistical issues of this process. The design issues include protocol development, objectives, literature search, publication bias, measures of study outcomes, and quality of the data. ⋯ Guidelines are provided to assess the quality of meta-analyses based on our discussion of the design and statistical issues. Limitations and areas for further development of this approach are discussed; researchers should come to a general agreement on how to conduct meta-analysis. As an explicit strategy for summarizing results, meta-analysis may help clinicians and researchers better understand the findings of clinical studies.