Biomedical subjects
T Hall
Publications and source records attributed to T Hall.
Nursing challenge: caring for a patient with complex, multiple complications.
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Exposure of miners to diesel exhaust particulates in underground nonmetal mines.
A study was initiated to examine worker exposures in seven underground nonmetal mines and to examine the precision of the National Institute for Occupational Safety and Health (NIOSH) 5040 sampling and analytical method for diesel exhaust that has recently been adopted for compliance monitoring by the Mine Safety and Health Administration (MSHA). Approximately 1000 air samples using cyclones were taken on workers and in areas throughout the mines. Results indicated that worker exposures were consistently above the MSHA final limit of 160 micrograms/m3 (time-weighted average; TWA) for total carbon as determined by the NIOSH 5040 method and greater than the proposed American Conference of Governmental Industrial Hygienists TLV limit of 20 micrograms/m3 (TWA) for elemental carbon. A number of difficulties were documented when sampling for diesel exhaust using organic carbon: high and variable blank values from filters, a high variability (+/- 20%) from duplicate punches from the same sampling filter, a consistent positive interference (+26%) when open-faced monitors were sampled side-by-side with cyclones, poor correlation (r 2 = 0.38) to elemental carbon levels, and an interference from limestone that could not be adequately corrected by acid-washing of filters. The sampling and analytical precision (relative standard deviation) was approximately 11% for elemental carbon, 17% for organic carbon, and 11% for total carbon. An hypothesis is presented and supported with data that gaseous organic carbon constituents of diesel exhaust adsorb onto not only the submicron elemental carbon particles found in diesel exhaust, but also mining ore dusts. Such mining dusts are mostly nonrespirable and should not be considered equivalent to submicron diesel particulates in their potential for adverse pulmonary effects. It is recommended that size-selective sampling be employed, rather than open-faced monitoring, when using the NIOSH 5040 method.
MR-guided procedures using contemporaneous imaging frameless stereotaxis in an open-configuration system.
Frameless MR-guided procedures have had limited application using conventional closed magnets, due largely to the technical difficulties involved. As a result of in-room MR image-monitoring capabilities, new open-design magnets now allow frameless stereotaxis using contemporaneous imaging to guide more invasive procedures. We evaluate our clinical experience with this new technique. An open-design 0.2 T magnet (Siemens OPEN) combined with an in-room monitor was used for 33 frameless MR-guided procedures (aspiration cytology, biopsy, and/or treatment) in a variety of locations in the head, neck, spine, brain, pelvis, and abdomen. Success of the procedure was based on the ability to accurately position the instrument in the target region to allow biopsy and/or treatment. The open-design magnet allowed the physician to directly access the patient for frameless stereotaxis as the procedure was performed. The in-room monitor provided contemporaneous imaging feedback during the procedure for successful placement of the instrument in the target region. Twenty-eight biopsy and five treatment procedures were performed. In all cases the technique resulted in successful placement of the instrument within the target tissue to complete the procedure. MR-guided procedures using contemporaneous imaging frameless stereotaxis are possible in an open-design magnet with in-room image monitoring and offer exciting possibilities for further development.
Clinical use of pulse rates to determine daily energy expenditures in trauma and surgical patients.
This study was conducted to establish practical application by using pulse rates to determine resting energy expenditures in trauma and surgical patients. A continuous flow gas analyzer measured energy expenditures and a cardiotachometer/recorder determined pulse rates simultaneously. The study consisted of 18 normal subjects as controls, seven surgical patients (totaling 36 samples), a combination of the seven surgical and three trauma patients (totaling 23 samples). The group of seven surgical patients had a correlation coefficient of 0.531 when comparing pulse rate/min with kcal/m2/hr, and this was the best correlation among the group population studied. An attempt to establish a single regression line from individual patients showed no significant correlation, with the exception of two surgical patients. Of the total number of patient samples, we found no significant correlation between pulse rate and energy expenditures. Independently, Andrews (Am J Clin Nutr 24:1139-1147, 1971) and Payne (Am J Clin Nutr 24:1164-1170, 1971) suggested that there are multiple variables such as stroke volume, state of physical training, etc., that affect the outcome of such data. In this study, our variables were more extensive with respect to the severity of injuries and varying degrees of surgical procedures. The study concluded that there is no practical clinical use of pulse rates in determining daily resting energy expenditures of surgical or trauma patients.
Treatment of renal carcinoma: a phase III randomized trial of oral medroxyprogesterone (Provera), hydroxyurea, and nafoxidine.
Seventy patients with metastatic renal carcinoma were randomized to receive hydroxyurea, nafoxidine, or medroxyprogesterone (Provera) orally. Sixty patients were considered evaluable, with a response rate of 5% for medroxyprogesterone (one complete remission) and hydroxyurea (one partial remission) and a response rate of 16% for nafoxidine (two complete remissions and one partial remission). Differences in response rates and duration of survival were not statistically significant. The major toxicity observed with hydroxyurea was hematologic, and the major toxic effect of nafoxidine was an ichthyosis-like skin rash. Toxicity for medroxyprogesterone was minimal.