Occult cardiac tamponade detected by transesophageal echocardiography.

Transesophageal echocardiography is a safe, minimally invasive procedure that should be considered when the diagnosis of cardiac tamponade is a possibility and when conventional methods fail to provide conclusive diagnostic information. In this report, we describe a 74-year-old man in the intensive-care unit whose condition was unstable postoperatively because of an occult loculated pericardial effusion and cardiac tamponade. Routine noninvasive and invasive monitoring, including hemodynamic monitoring and transthoracic echocardiography, failed to confirm definitively the suspected diagnosis of cardiac tamponade. In addition, because of the hemodynamic instability of the patient, transporting him for definitive tests (such as fast computed tomographic scanning of the mediastinum, which could not be performed at the bedside) for assessment of cardiac tamponade was relatively contraindicated. In our patient, the diagnostic information obtained by transesophageal echocardiography may have been lifesaving.     

Acute pain management services have progressed, albeit insufficiently in Canadian academic hospitals

PURPOSE: Acute pain management services (APMS) evolved in response to the desire for improved management of postoperative pain. The management of postoperative pain received formal support from international organizations over the past decade and by 1993 half of the Canadian university-affiliated teaching hospitals had implemented an APMS. The purpose of this survey was to describe APMSs in Canadian academic institutions, with specific emphasis on postoperative analgesics, new analgesic methods, training and research. METHODS: Between June 2000 and January 2001, 62 Canadian hospitals affiliated with the 16 Canadian university anesthesiology departments were sent a postal questionnaire. RESULTS: Fifty of the 62 respondents returned a completed questionnaire representing a response rate of 81%. Eighty percent of the hospitals surveyed had at least 200 beds, 90% (45) had implemented an APMS. Anesthesiology was primarily responsible in all 45 hospitals with an APMS. The results presented are based on the 45 centres with an APMS. CONCLUSION: Since the early 1990s the percent of Canadian academic hospitals with an APMS has increased from 53% to 92%. These figures are comparable to the United States. Greater collaboration from nursing and pharmacy, mandatory training for medical and nursing students and residents, and a standardized approach to continuous quality improvement remain necessary.     

Multicoil Dixon chemical species separation with an iterative least-squares estimation method.

This work describes a new approach to multipoint Dixon fat-water separation that is amenable to pulse sequences that require short echo time (TE) increments, such as steady-state free precession (SSFP) and fast spin-echo (FSE) imaging. Using an iterative linear least-squares method that decomposes water and fat images from source images acquired at short TE increments, images with a high signal-to-noise ratio (SNR) and uniform separation of water and fat are obtained. This algorithm extends to multicoil reconstruction with minimal additional complexity. Examples of single- and multicoil fat-water decompositions are shown from source images acquired at both 1.5T and 3.0T. Examples in the knee, ankle, pelvis, abdomen, and heart are shown, using FSE, SSFP, and spoiled gradient-echo (SPGR) pulse sequences. The algorithm was applied to systems with multiple chemical species, and an example of water-fat-silicone separation is shown. An analysis of the noise performance of this method is described, and methods to improve noise performance through multicoil acquisition and field map smoothing are discussed.     

Effect of body positions and splints in bioelectrical impedance analysis.

The objective of this study was to evaluate body composition as measured by bioelectric impedance analysis using splints and body positions differing from the standard supine position. Forty-three patients, randomized into two groups of different body positions, and 101 healthy volunteers were prospectively studied. Resistance and reactance of body tissues were measured by bioelectric impedance analysis. Body composition is described by a three-compartment model composed of body fat, body cell mass, and extra cellular mass. The patients were measured in the standard supine position and then randomized into two groups. They were then remeasured with the appropriate splinting device or position change. Volunteers were measured in the standard supine position and all four alternative positions. There was a statistically significant difference demonstrated in whole body resistance, whole body reactance, body cell mass, and the ratio of extracellular mass to body cell mass in some body positions. The percentage of change with different body positions and splints, when compared with the standard supine position, was generally below 2%, a clinically insignificant difference. We conclude that the reliability of resistance and reactance as measured by bioelectric impedance analysis is clinically valid using any of the tested body positions and/or splints. The three-compartment model may be a useful concept to measure body composition changes in both healthy and sick persons.     

Performance characteristics and image fidelity of gray-scale monitors.

Gray-scale monitors are an essential element of electronic radiology, and their ability to provide images that are perceived to be identical to those available on conventional or laser-printed film is crucial to success of electronic radiology. Image fidelity is measured in physical characteristics (luminance, dynamic range, distortion, resolution, and noise) and with psychophysical techniques, including receiver operator characteristics analysis with clinical images and testing with contrast-detail patterns to determine threshold contrast. Currently, laser-printed images facilitate greater information transfer than does a gray-scale monitor because of their higher absolute luminance (500 ft-L vs 60 ft-L), greater perceived dynamic range, and better spatial resolution. In the near future, the developments of gray-scale monitors with 150-200 ft-L luminance, a display standard based on just noticeable differences, and algorithms to improve similarities between gray-scale display images and laser-printed images will help increase the acceptability of monitors as a means to make primary diagnoses.     

Check samples for laboratory self-assessment in DNA flow cytometry. The National Cancer Institute's Flow Cytometry Network experience

The National Cancer Institute's Flow Cytometry Network (NCI-FCN) is attempting to facilitate the transfer of flow cytometry (FCM) of exfoliated bladder cells from the research laboratory to the clinical laboratory. Demonstrating interinstitutional consistency in FCM analysis of replicate specimens simulating clinical barbotage specimens, fixed to allow easy transportation and storage at room temperature was one specific objective. Simulated barbotage specimens were prepared by mixing cultured aneuploid bladder carcinoma cells with normal or mitogen-stimulated peripheral blood mononuclear cells in different ratios. The samples were fixed in 10% formalin for 30 minutes, stored in buffer, and enucleated with pepsin, pH 1.5, before staining with propidium iodide for FCM DNA analysis. Preservation in ethanol or other common DNA cytochemical reagents was found to be unsatisfactory. In contrast, the formalin-fixed samples showed excellent preservation of quantitative DNA fluorescence and coefficient of variation of histogram peaks for over 2 weeks. Exchange of eight fixed specimens among five network laboratories that analyzed them as "unknowns" showed good overall agreement on histogram data and interpretation, although some noteworthy interlaboratory differences were found. This technique could be used for self-assessment surveys of clinical laboratory performance in DNA FCM of bladder barbotage specimens.     

Analysis of orthologous gene expression between human pulmonary adenocarcinoma and a carcinogen-induced murine model

Human adenocarcinoma (AC) is the most frequently diagnosed human lung cancer, and its absolute incidence is increasing dramatically. Compared to human lung AC, the A/J mouse-urethane model exhibits similar histological appearance and molecular changes. We examined the gene expression profiles of human and murine lung tissues (normal or AC) and compared the two species' datasets after aligning approximately 7500 orthologous genes. A list of 409 gene classifiers (P value <0.0001), common to both species (joint classifiers), showed significant, positive correlation in expression levels between the two species. A number of previously reported expression changes were recapitulated in both species, such as changes in glycolytic enzymes and cell-cycle proteins. Unexpectedly, joint classifiers in angiogenesis were uniformly down-regulated in tumor tissues. The eicosanoid pathway enzymes prostacyclin synthase (PGIS) and inducible prostaglandin E(2) synthase (PGES) were joint classifiers that showed opposite effects in lung AC (PGIS down-regulated; PGES up-regulated). Finally, tissue microarrays identified the same protein expression pattern for PGIS and PGES in 108 different non-small cell lung cancer biopsies, and the detection of PGIS had statistically significant prognostic value in patient survival. Thus, the A/J mouse-urethane model reflects significant molecular details of human lung AC, and comparison of changes in orthologous gene expression may provide novel insights into lung carcinogenesis.