Restricted versus open ICUs.
A satisfaction study investigates whether a more liberal ICU visitation policy satisfactorily meets visitors' and nurses' needs and expectations.
Attitude of Health Personnel↗
Biomedical subjects
L L Glenn
Publications and source records attributed to L L Glenn.
Effect of ambient temperature and cardiac stability on two methods of cardiac output measurement.
The dependence of cardiac output measurement precision on ambient temperature and cardiac output stability was assessed by concurrent continuous and bolus thermodilution methods in postoperative cardiac surgery patients. The degree of agreement between the two methods was depended on room temperature (0.1 L/min for each degree below 25 degrees C). The agreement was also closer in trials where cardiac output was stable (< 10% variation). The continuous thermodilution method shows sufficient agreement with the bolus method for use in critical care; however, improved precision of cardiac output thermodilution measurements can be achieved by use of correction factors for cardiac instability and for ambient temperature.
Aged↗
Effect of hospital type, insurance type, and gender on the treatment of cardiovascular disease in middle-aged adults.
The cost and duration of cardiovascular care was studied for 4,804 episodes of hospitalization in patients between 45 and 64 years of age. Men were more likely than women to be treated in urban medical centers for shorter, more expensive hospital care; women were more likely to be treated in rural hospitals for longer, less expensive care. Cost of treatment per day was not dependent on the type of insurance, but Medicaid claims (which represent low income patients) were associated with greater lengths of stay.
Cardiovascular Diseases↗
Equal dependence of the high prevalence of health problems on age and family income in rural southern areas.
BACKGROUND: People who have periods of low family income are at risk for increased health problems in the future, even if they present a similar clinical picture before the reduction in family income. The association between low income and health status was studied in residents of an area with relatively low-average family income and with a historically unstable economy. METHODS: We surveyed a stratified, clustered sample of residents of Johnson County, Tennessee, using a structured interview. The responses were analyzed in conjunction with national and regional data (National Health Interview Survey). RESULTS: Residents of the geographic area under study had a markedly higher prevalence of self-reported health problems than either the national average or rural areas in the southeast United States. The higher prevalence was accounted for by the combination of age and family income, which had equal effects on health status, but not by age differences alone. CONCLUSIONS: Family income and economic development are critically important to improving community health. Sensible capitation rates in managed care arrangements can be obtained only if the income distribution of an insured population is considered along with their age, sex, and physical health status.
Adolescent↗
Risk-adjusted in-hospital death rates for peer hospitals in rural and urban regions.
The purpose of this research project was to compare inpatient mortality rates for rural hospitals with mortality rates of urban hospitals of given sizes and ranges of service. Statistical adjustments for risk were made in the probability of death during hospitalization for 43,000 patients across 166 hospitals by age, gender, principal diagnosis, principal surgical procedure, characteristics of the secondary diagnoses, and whether or not cancer was a secondary diagnosis. Eighty-three small hospitals that had a relatively unspecialized range of services constituted the study group. Patient characteristics of this study group were moderately representative of the national population. A standardized score was calculated for each hospital using a formula based on the actual hospital death rate and the death rate expected for a given hospital with patients of the same demographic and medical characteristics. Patients admitted to hospitals in nonmetropolitan areas had a mortality rate of 0.41 percent compared with a mortality rate of 0.66 percent in peer hospitals in metropolitan areas. After mortality rates were risk-adjusted and converted to z scores, nonmetropolitan areas had an average z of +0.16, and metropolitan areas had an average z of -0.25, where positive z scores reflect a lower-than-average adjusted mortality rate. The metropolitan-nonmetropolitan (urban-rural) difference was not statistically significant, but it is meaningful in that rural hospitals tended to have a lower adjusted mortality rate than urban hospitals of the same size and type, indicating that rural hospitals had the same or lower adjusted mortality rates. The possibility of urban hospitals having riskier patients was minimized but could not be definitively ruled out. Taken together with other studies, the data are consistent with the view that small rural hospitals generally make appropriate transfer decisions for severely ill patients and provide quality care for retained patients.
Adolescent↗
Client characteristics and practice patterns of nurse practitioners and physicians.
This study's purpose was to describe the practice patterns of nurse practitioners (NPs) in Tennessee--specifically, the demographic characteristics and health problems of their clients and the therapeutic services they provide. A random sample of NPs practicing 20 or more hours per week in primary care in Tennessee provided data on a total of 680 clients seen during one selected day of care. An instrument adapted from the National Ambulatory Medical Care Survey (NAMCS) allowed comparison of the NP findings with a national survey of office-based physicians in five areas: client demographics, client health status, diagnostic tests ordered, therapeutic interventions provided, and client disposition. Although many similarities were seen, differences included the tendency of NPs to care for more younger and female clients, to perform fewer office surgical procedures, and to provide more health teaching/counseling interventions.
Age Distribution↗
Effect of a transient, geographically localised economic recovery on community health and income studied with longitudinal household cohort interview method.
STUDY OBJECTIVE: The main purpose of the study was to determine whether the health or economic status of a cohort of residents in an economically troubled geographical area changed between 1990 and 1993. DESIGN: Longitudinal, single cohort, interview survey method with the key variables of health status and economic status. Quasi-experimental pre-post design with economic rebound as the intervention. SETTING: A relatively low income geographical area in a rural, mountainous region before and after an economic rebound. In 1990, the local economy and health care system collapsed because of the closure of a series of manufacturing plants; outward migration from the area peaked. Between 1990 and 1993, new industries opened, and state and private community assistance programmes intervened, resulting in an economic rebound, migration into the area, and marked growth of the health service sector. PARTICIPANTS: A 2% sample of residents of households, using a combination of random, stratified, and clustered sampling. Residents included in the study had lived within the area throughout the 1990-1993 period of the study. MAIN RESULTS: Stable, non-migrating residents had a statistically significant 7% reduction in health status between 1990 and 1993, as measured by a composite of subjective and objective measures. The non-migrating residents also had a significant decrease in average household income ($14,700 in 1990 and $12,400 in 1993 in constant 1990 dollars) during the strong economic expansion, and therefore did not participate in or receive direct economic benefit from the expansion. There was a rapid population increase during the expansion, attributable to inward migrants who were younger and healthier than existing residents. The decline in health for the non-migrating residents was tentatively attributed to either direct or indirect effects of the decline in family income. CONCLUSIONS: Local economic development accompanied by expanded health care services availability can leave existing area residents poorer and less healthy, and this problem may be masked by an abundance of healthier, wealthier inward migrants.
Adolescent↗
Horseradish peroxidase study of the spatial and electrotonic distribution of group Ia synapses on type-identified ankle extensor motoneurons in the cat.
Eight functionally identified group Ia muscle afferents from triceps surae or plantaris muscles were labeled intraaxonally with horseradish peroxidase (HRP) in seven adult cats. Subsequently, HRP was injected into two to six homonymous or heteronymous alpha-motoneurons per animal (total = 22), each identified by motor unit type and located near the site of afferent injection. The complete trajectories of labeled afferents were reconstructed, and putative synaptic contacts on HRP-labeled motoneurons were identified at high magnification. Dendritic paths from each contact were also mapped and measured. A total of 24 contact systems (the combination of a group Ia afferent and a postsynaptic motoneuron) were reconstructed, of which 17 were homonymous, and seven were heteronymous. Overall, homonymous contact systems had an average of 9.6 boutons, whereas heteronymous contact systems had an average of 5.9 boutons. The average number of boutons found on type S motoneurons in homonymous contact systems was smaller (6.4, range 3-17) than in systems involving types FF or FR motoneurons (FF: 10.4, range 4-18; FR: 11.3, range 4-32). Neither of these differences were statistically significant. In contrast to earlier reports, a majority (15/24) of contact systems included more than one collateral from the same Ia afferent. The complexity (number of branch points) in the arborization pathway leading to each contact (overall mean 8.4 +/- 3.3) was virtually identical in all contact systems, irrespective of the type of postsynaptic motoneuron. The three-dimensional distribution of group Ia contacts was not coextensive with the radially organized dendrites of motoneurons: Dendrites oriented in the ventromedial to dorsolateral axis had the fewest (8%) contacts, whereas rostrocaudal dendrites had the most (63%) contacts. Nevertheless, contacts were widely distributed on the motoneuron surface, with few on and near the soma (< or = 200 microns radial distance from the soma) or on the most distal parts of the tree (> or = 1,000 microns). The boutons in individual contact systems also showed wide spatial and estimated electrotonic distributions; only 3/24 systems had all contact located within a restricted spatial/electrotonic region. The relations between these anatomical results and existing electrophysiological data on group Ia synaptic potentials are discussed.
Animals↗
Nurses' compliance with universal precautions before and after implementation of OSHA regulations.
The principal objective of this study was to investigate whether or not nurses' compliance with universal precautions procedures improved after the mandatory Occupational Safety and Health Administration regulations were implemented in 1992. Two random samples of registered nurses and licensed practical nurses registered in Tennessee responded to survey questionnaires measuring universal precautions compliance and practice barriers to compliance in 1991 and 1993 (n = 306). The 1993 sample of nurses reported significantly greater compliance with universal precautions (p < 0.001) than the 1991 sample. The most noteworthy improvement between the 1991 and the 1993 groups was a significant increase in compliance for patients described as HIV/HBV-status unknown and HIV/HBV-negative (p < 0.001). Practice barriers hindering compliance with universal precautions decreased significantly (p < 0.001) in the 1991-1993 time frame. Problematic practice barriers identified in both groups were needle recapping, preference for isolation door signs, and concerns about offending patients and visitors.
Adult↗
Nurse practitioner research network: patterns of practice in Northeast Tennessee.
Explore the source record for details and available documents.
Databases, Factual↗
Nurses' body fluid exposure reporting, HIV testing, and hepatitis B vaccination rates: before and after implementing universal precautions regulations.
The purpose of this study was to investigate whether mandatory universal precautions changed nurses' body fluid exposure and reporting rates, hepatitis B vaccination rates, and human immunodeficiency virus (HIV) testing rates. Random cross-sectional surveys of nurses in Tennessee were conducted in 1991 and 1993 (n = 145 in 1991; n = 143 in 1993). The questionnaire in both surveys included frequency of body fluid exposures and reporting in the past year, and whether or not the respondent had received the hepatitis B vaccine or had been HIV tested. Findings indicated that self reported needlestick injuries decreased by 69%, and other sharps injuries decreased by 81%. Only 4.1% of all exposure incidents reported on this anonymous survey were reported to employee health officials, as required. Body fluid exposure incidents were the most common form of exposure (81%) and the most underreported. Hepatitis B vaccinations significantly increased (61.4% to 82.5%), with a nonsignificant increased in HIV testing (47.2% to 55.6%) from 1991 to 1993. Findings of this study suggest that the universal precautions regulatory mandate has been effective in increasing nurses' compliance to universal precautions. Body fluid contacts were significantly underreported and showed no decrease between 1991 and 1993.
AIDS Serodiagnosis↗
A linear method for the curve fitting of multiexponentials.
Two single-pass methods for fitting multiexponentials to experimental data are described. These methods rely on the construction of a matrix whose characteristic polynomial is used to determine the rates of decay. In the first method, which we call the multiple-delay method, the matrix is constructed using time delays of the experimental data. This method is fast and highly accurate even if the experimental signal contains exponential components with similar rates of decay. In the second method, which we call the successive-integral method, the matrix is constructed using integrals of the experimental data. This procedure yields good results for noisy signals and is a generalization of the method of Martin et al. ((1993) J. Neurosci. Methods, 51: 135-146). In addition, a particular instability of the multiexponential curve fitting problem is identified and a method for overcoming this instability is given.
Algorithms↗
Universal precautions compliance and exposure frequency to patient body fluids in nurses employed by urban and rural health care agencies.
Previous studies have suggested that health care workers may differ with respect to universal precautions knowledge, compliance, practice setting barriers, or exposure to patient body fluids in rural and urban areas. The purpose of this study was to determine whether or not there are rural/urban differences in the degree of precaution taken by health care workers to prevent the spread of blood borne pathogens, specifically human immunodeficiency virus (HIV) and hepatitis B virus (HBV). A random sample of rural and urban registered and licensed practical nurses in Tennessee was surveyed. The respondents completed two instruments that assessed self-reported universal precautions knowledge, precautions, and practice barriers. No measurable differences in universal precautions knowledge, compliance, or barrier scores between the two groups were found; yet rural nurses were 2.7 times as likely to be exposed to patient body fluids than urban nurses (P < 0.005). The conclusion was that rural nurses were as experienced and as knowledgeable about universal precaution techniques as their urban peers, but their knowledge was not translated into practice to the same degree. Two possible explanations offered are (1) rural nurses are more likely to be acquainted with, and thus trusting of, their patients, and (2) the lower seroprevalence of human immunodefiency virus and hepatitis B virus in rural areas may lead to complacency.
Acquired Immunodeficiency Syndrome↗
Patient-reported medical outcomes according to physician type and region.
The purpose of the present study was to determine whether patients with common foot disorders have different medical outcomes depending on whether podiatrists, orthopedic surgeons, or other physicians provided their medical care in rural or urban areas. A validated medical effectiveness score was formulated using indirect standardization of risk-adjusted morbidity, based on patient reports from a national random household interview survey of 3,270 subjects. Patients in rural and urban areas did not differ significantly in medical outcomes across provider types, but there was a trend for patients in rural areas to have poorer outcomes. The medical effectiveness score of podiatrists was 3.9 times higher (indicating more beneficial outcomes) than that of orthopedic surgeons or other physicians (p < 0.01). Patients that visited podiatrists for common foot problems reported significantly more beneficial outcomes than those who visited other types of health care providers.
Adolescent↗
Overestimation of the electrical length of neuron dendrites and synaptic electrotonic attenuation.
The electrical (also termed electrotonic) length of dendrites is a key factor in determining the magnitude of the decay of a postsynaptic potential as it propagates from the dendrites to the soma. The average electrotonic length of dendrites in spinal, hippocampal, and red nucleus neurons have been estimated at 1.2 (range of 0.9-1.5), based on single (equivalent) cylinder models. Synaptic potentials evoked at the terminals of dendrites that are 1.2 space constants in length have been estimated to decay 50% during propagation to the soma, the lost energy being dissipated as heat. The present analysis was conducted because a 50% propagation loss seemed unlikely for such a widespread neuron function as passive dendritic propagation. The explicit and implicit assumptions of the cylinder model were reconsidered. It was found that the simplifying assumption of uniform dendritic electrotonic length has led to a three-fold overestimate of dendritic electrotonic length by previous investigators. The conclusion is that dendrites have a typical electrotonic length of 0.4 rather than 1.2, therefore resulting in a propagation loss of only 7% rather than 50% for distal dendritic synapses.
Dendrites↗
Method for stable intracellular recordings of spinal alpha-motoneurons during treadmill walking in awake, intact cats.
A method is described for recording from spinal alpha-motoneurons, which are identified according to muscle innervated, with an intracellular microelectrode during treadmill walking in awake, normally respiring, intact, adult cats. The procedure involves the implantation of an orthopedic-style spinal unit, the training of the subject to locomote on the treadmill with the lumbar region restrained, and the micropipette recording of motoneurons through a small laminotomy.
Animals↗
Electrotonic parameters of cat spinal alpha-motoneurons evaluated with an equivalent cylinder model that incorporates non-uniform membrane resistivity.
The membrane voltage transients in response to constant intracellular current steps were analyzed in cat spinal alpha-motoneurons, using an equivalent cylinder model extended to include spatial non-uniformity in membrane resistivity. The main hypothesis was that the soma membrane resistivity did not differ significantly from the dendritic membrane resistivity. Evidence was found that the uniform-resistance cylinder model cannot be applied to motoneurons on the basis of inconsistencies in calculations of electrotonic length. Assuming a constant membrane capacitance, the membrane resistivity of the dendrites was found to be 500 times that of the soma. We conclude that there is a considerable difference in the membrane resistivity between the soma and dendrites of motoneurons, and that uniform-resistance models should not be applied to spinal alpha-motoneurons.
Animals↗
Membrane area and dendritic structure in type-identified triceps surae alpha motoneurons.
The size and branching structure of the dendritic tree were studied in nine type-identified triceps surae alpha-motoneurons that were labeled intracellularly with horseradish peroxidase and reconstructed from serial sections in the light microscope. The average total membrane area (AN) for motoneurons of type S (slow-twitch) motor units was about 22% smaller than AN for cells of type F units (including both FF and FR motor unit types in this category) (480.1 X 10(3) microns 2 vs. 617.7 X 10(3) microns 2, respectively). Systematic correlations were found between stem dendrite diameter and three measures of dendritic size: dendrite membrane area, combined dendritic length, and number of terminations. All of these correlations were significantly different for the dendrites of F and S motoneurons. Power-function relations between stem diameter and dendritic membrane area were used to estimate AN for a sample of 79 type-identified motoneurons. Mean estimated AN values were significantly different for the F and S motoneuron groups, despite a large overlap in AN values between these groups. The branching structure of dendrites of F and S motoneurons also showed clear differences. Type S motoneuron dendrites showed less-profuse branching and a more-even radial distribution of branch points than found in type F cells. Examination of two forms of the "3/2 power rule" for the relation between the diameters of parent and daughter dendritic branches at branch points showed that the dendrites of type S motoneurons conform less well with the anatomical constraints necessary to represent binary branching trees as equivalent cylinders than do dendrites of type F cells. There was no systematic difference between F and S motoneuron dendrites in the degree of asymmetry of first-order daughter trees. The results overall indicate that the dendrites of F and S motoneuron groups are structurally different, giving rise to a systematic difference in AN between these groups. Such structural differences suggest that the F and S groups of alpha-motoneurons can be viewed as intrinsically distinct cell types and not just large vs. small variants of the same cell species.
Animals↗