PubMed Health⌕ Search

Biomedical subjects

R Englander

Publications and source records attributed to R Englander.

6 recordsLinked to original sources
PubMed2001

Localizing acute stroke-related EEG changes: assessing the effects of spatial undersampling.

Because of its sensitivity to metabolic and ionic disturbances related to ischemia, the EEG can be a potentially useful tool for acute stroke detection and for monitoring affected tissue. However, the clinical use of the EEG in detecting stroke is determined in part by how accurately the spatial information is characterized. The purpose of the current study was to determine the effects of spatial undersampling on the distribution and interpretation of the stroke-related topographic EEG. Using a 128-channel sensor montage, EEG was recorded from six stroke patients acutely (between 8 and 36 hours) after symptom onset. The EEG was submitted to a spectral analysis and was compared with patient symptoms and MRI and computed tomographic findings. To determine loss of spatial and clinical information resulting from spatial undersampling, the average-referenced data from the original 128-channel recording montage were subsampled into 64-, 32-, and 19-channel arrays. Furthermore, the analytical findings were compared with a board-certified electroencephalographer's review of the raw EEG using a conventional clinical montage. As predicted, the results showed that accurate description of stroke-related topographic EEG changes is dependent on adequate spatial sampling density. Accurate description of the spatial distribution of the stroke-related EEG was achieved only with the 64- and 128-channel EEG. As the recording density decreases to 32 channels, the distribution of the scalp EEG spectra is distorted, potentially resulting in mislocalization of the affected region. Results of the clinical review by an expert electroencephalographer corroborated the quantitative analyses, and the results also demonstrated the shortcomings of the conventional 10-20 recording density for capturing focal EEG abnormalities in several cases. The EEG provides useful information about the localization of acute cerebral ischemia, but recording densities of 64 channels or higher are required for accurate spatial characterization of focal stroke-related EEG changes.

Adult↗
PubMed2001

Predictors of ventriculoperitoneal shunt pathology.

BACKGROUND: Diagnosis of ventriculoperitoneal (VP) shunt pathology remains a dilemma in patients with nonspecific constitutional signs and symptoms. Eosinophilia has been described in association with shunt infection and malfunction. Our purpose was to further define the relationship of eosinophilia and shunt pathology and to determine other predictors of VP shunt infection and malfunction. METHODS: Records of all patients admitted with a suspected VP shunt infection or malfunction were reviewed. The following data were abstracted: age; reason for and age at initial shunt placement; number of revisions; date of last revision; history of fever or vomiting; ventricular fluid cell count; differential and culture; complete blood count and differential; need for shunt revision or replacement; and use of antibiotics. After exclusion of patients admitted for initial shunt placement, the remainder were divided into three groups: those with shunt infection; those with shunt malfunction; and those without documented infection or malfunction. RESULTS: Of 12 patients with shunt infection and 69 with shunt malfunction, 2 and 11, respectively, had eosinophilia defined as > or =5%. The presence of eosinophilia had a 96% positive predictive value for shunt pathology and raised the pretest probability of pathology from 84% to a post test probability of 96%. The combination of fever history and ventricular fluid neutrophils >10% had a 99% specificity for shunt infection, had a 93 and 95% positive and negative predictive value, respectively, and raised the pretest probability of infection from 12% to a posttest probability of 92%. CONCLUSIONS: In patients suspected of having a VP shunt malfunction, the presence of > or =5% eosinophils in the ventricular fluid indicates shunt pathology. The combination of fever and ventricular fluid neutrophils > 10% is predictive of shunt infection.

Adolescent↗
PubMed2000

The objective structured clinical examination: a step in the direction of competency-based evaluation.

BACKGROUND: The Accreditation Council for Graduate Medical Education is embarking on the major task of a paradigm shift in graduate education in the direction of competency-based medical education and evaluation of outcomes. The Objective Structured Clinical Examination (OSCE), a measure of clinical competence that focuses on outcomes via observable behaviors, is gaining national recognition. OBJECTIVE: To review the pediatric literature relevant to the OSCE. METHOD: A MEDLINE search from the date of the original report of the OSCE (1975) to the present was performed. All English-language studies regarding the use of the OSCE in pediatric education published in the United States and Great Britain were reviewed. MAIN OUTCOME MEASURES: Reliability and validity of the OSCE were examined. Use of standardized pediatric patients was discussed. RESULTS: A greater number of stations and similarity between tasks at different stations increased the reliability of the OSCE. A greater number of stations increased sampling of material and content validity. Correlation between the OSCE and precertification examinations ranged between 0.59 and 0.71, with P< or =.01. Correlation between the OSCE and monthly clinical evaluations was much lower (0.39-0.57), but still statistically significant at P< or =.05. Gaps between expected and actual performance were documented. Overall, the experience of being a standardized patient was viewed as positive by children and their parents. CONCLUSIONS: With appropriate attention to design, acceptable reliability and validity can be achieved for the OSCE. Significant correlations between the OSCE and precertification examinations as well as monthly clinical evaluations were found, the former being stronger than the latter. We conclude that the combination of the OSCE, standardized board examinations, and direct observation in the clinical setting has the potential to become the "gold standard" for measuring physician competence.

Accreditation↗
PubMed1995

Efficacy of leukocyte filters in the bypass circuit for infants undergoing cardiac operations.

BACKGROUND: Leukocyte filters have been used in cardiopulmonary bypass circuits to decrease potentially deleterious consequences of white blood cell product release in adults undergoing cardiac operations. Studies in animal models have also demonstrated benefits of white blood cell depletion during cardiopulmonary bypass. We sought to examine the efficacy of a leukocyte filter placed in the bypass circuit of infants undergoing operation for correction of congenital heart disease. METHODS: We conducted a retrospective study of infants undergoing correction of congenital heart defects (all had left-to-right shunts) between July 1993 and May 1994. Six infants (group I) had a Leukoguard-3 leukocyte filter (Pall Biomedical Products) placed in the arterial limb of the bypass circuit, and 6 infants (group II) had no filter. We analyzed for differences between groups in intraoperative variables (total pump time, aortic cross-clamp time, deep hypothermic cardiac arrest time, and time for rewarming), postoperative clinical variables (fever in the first 24 hours, days of mechanical ventilation, length of intensive care unit stay, and total hospital stay) and laboratory variables (change in white blood cell and platelet counts preoperatively to postoperatively, and arterial oxygen tension/inspired oxygen fraction ratio). RESULTS: Comparisons between groups were made using Student's t test or chi 2 where appropriate, and results were considered significant at p less than 0.05. No differences between groups were seen in the demographic data or in any of the intraoperative variables. Fever was the only parameter (clinical or laboratory) showing statistical significance between the groups, affecting 1/6 patients in group I and 5/6 patients in group II (chi 2 = 5.33; p < 0.05). CONCLUSIONS: Although these data suggest that the leukocyte filter offers little clinical benefit, a prospective, randomized study should be undertaken to further elucidate the efficacy of leukocyte depletion for infants undergoing cardiopulmonary bypass for correction of congenital heart disease.

Cardiopulmonary Bypass↗