Emergency department injury surveillance systems: the best use of limited resources?
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Bias↗
Biomedical subjects
G S Smith
Publications and source records attributed to G S Smith.
Infant injury deaths with unknown intent: what else do we know?
OBJECTIVES: Strong evidence based on case record reviews indicates that the incidence of child homicide reported from death certificates is under ascertained. The characteristics of infant injury fatalities with undetermined, but suspicious, intent were compared for the probability that they should be considered homicides. METHODS: Using linked birth and death certificates for all birth cohorts in the US from 1983-91, 2345 injury fatalities reported as intentional, 7594 as unintentional, and 431 as undetermined intent were identified. Maternal and infant variables potentially predictive of injury fatalities were selected based on increased bivariate associations. Relative risks of injury death by intentional, unintentional, and undetermined intent were assessed for maternal and infant characteristics. RESULTS: Relative risks were consistently higher across all intent categories for infants of mothers with the least education, no prenatal care, young maternal age, and single marital status, as well as for infants who are second or later born, preterm, black, or American Indian. Fatalities with undetermined intent have larger relative risks in the highest risk categories than either intentional or unintentional injuries. Deaths with undetermined intent have risk profiles that more closely resemble profiles for intentional deaths than unintentional. CONCLUSIONS: Injury homicide rates would be almost 20% greater than official classifications indicate if deaths with undetermined intent were included. In analyses of infant homicide, excluding deaths of undetermined intent may lead to an underestimation of the magnitude of the public health problem of intentional injuries among infants. Other studies based on record reviews from multiple sources indicate that misclassification and under ascertainment of homicides may be even greater.
Adolescent↗
Cerebral glucose metabolic response to combined total sleep deprivation and antidepressant treatment in geriatric depression.
OBJECTIVE: The treatment of geriatric depression is complicated by a variable and delayed response to antidepressant treatment. The present study was undertaken to test the hypothesis that combined total sleep deprivation and paroxetine treatment would produce a persistent reduction in glucose metabolism in the anterior cingulate cortex similar to that reported after long-term antidepressant treatment. METHOD: Six elderly depressed patients who met the DSM-IV criteria for major depressive disorder and six age-matched comparison subjects underwent serial positron emission tomography (PET) studies at baseline, after total sleep deprivation, after recovery sleep (after the initial paroxetine dose), and after 2 weeks of paroxetine treatment (patients only). The PET data were analyzed by using statistical parametric mapping methods. RESULTS: The patients' scores on a 13-item version of the Hamilton Depression Rating Scale were decreased after total sleep deprivation, after recovery sleep, and after 2 weeks of treatment. The Hamilton depression scores of the comparison subjects were not significantly altered. In the patients, the greatest reductions in normalized, relative glucose metabolism after sleep deprivation were observed in the anterior cingulate cortex (Brodmann area 24), and they persisted after recovery sleep and antidepressant treatment. The comparison subjects demonstrated increased metabolism in these areas. CONCLUSIONS: Improvement in the patients' depressive symptoms was accompanied by reduced glucose metabolism in the right anterior cingulate cortex and right medial frontal cortex. These preliminary data indicate that in elderly depressed patients, total sleep deprivation may accelerate the clinical and glucose metabolic response to antidepressant treatment.
Age Factors↗
Back injury in municipal workers: a case-control study.
OBJECTIVES: The purpose of this study was to identify factors associated with acute low back injury among municipal employees of a large city. METHODS: For each of 200 injured case patients, 2 coworker controls were randomly selected, the first matched on gender, job, and department and the second matched on gender and job classification. In-person interviews were conducted to collect data on demographics, work history, work characteristics, work injuries, back pain, psychosocial and work organization, health behaviors, and anthropometric and ergonomic factors related to the job. Psychosocial work organization variables were examined with factor analysis techniques; an aggregate value for job strain was entered into the final model. Risk factors were examined via multivariate logistic regression techniques. RESULTS: High job strain was the most important factor affecting back injury (odds ratio [OR] = 2.12, 95% confidence interval [CI] = 1.28, 3.52), and it showed a significant dose-response effect. Body mass index (OR = 1.54, 95% CI = 1.08, 2.18) and a work movement index (twisting, extended reaching, and stooping) (OR = 1.42, 95% CI = 0.97, 2.08) were also significant factors. CONCLUSIONS: Results suggest that increasing workers' control over their jobs reduces levels of job strain. Ergonomic strategies and worksite health promotion may help reduce other risk factors.
Accidents, Occupational↗
Fatal nontraffic injuries involving alcohol: A metaanalysis.
STUDY OBJECTIVE: Estimates of alcohol involvement in fatal injuries vary widely. For injuries other than those involving motor vehicles, no national data exist and the quality of regional data is limited. This study synthesizes US medical examiner studies of nontraffic fatalities for the purpose of estimating alcohol involvement by injury mechanism and intent. METHODS: We reviewed 331 medical examiner studies published between 1975 and 1995 that reported nontraffic injury fatalities. These studies were identified from computerized bibliographic databases and by hand searching of reference lists from 26 review publications and the subject indices of 7 prominent journals. A final total of 65 articles (19.6%) met our inclusion criteria for analysis. National data on motor vehicle fatalities were used for comparison. RESULTS: A total of 7,459 unintentional injury deaths, 28,696 homicide cases, and 19,347 suicide cases were aggregated. The aggregate percentage tested for blood alcohol concentration (BAC) was highest among homicide cases (88.2%), followed by unintentional injury deaths (84.0%) and suicide cases (81.7%). The aggregate percentage determined to be intoxicated (BAC, >/=100 mg/dL) was highest among homicide cases (31.5%), followed by unintentional injury deaths (31.0%) and suicide cases (22.7%). Mean and median comparisons produced comparable findings. Fewer than one quarter of the 65 articles reported gender- and age-specific rates. Inconsistent reporting of gender and age-specific rates in fatal nontraffic injuries prevented their analysis by cause of death. Fatally injured motor vehicle drivers, however, demonstrated distinct variation in alcohol involvement by age and gender. CONCLUSION: This metaanalysis is the first systematic attempt to estimate alcohol involvement in fatal nontraffic injuries at the national level. It demonstrates that alcohol is an important factor in many fatal injuries and that its importance varies by cause of injury.
Accidents↗
Randomized trial to study the effect of fundic mobilization on long-term results of Nissen fundoplication.
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Fundoplication↗
A simplified method for studying hypoxia and reoxygenation injury under in vitro conditions.
A hypoxia chamber was constructed which allowed for the sequential sampling and blood gas analysis of buffer bathing cells in culture which were subjected to graded periods of hypoxia. Following hypoxia, the human fetal small intestinal cells (CCL-241) were placed into a normoxic environment for the remainder of a 24 h study period. A cytotoxicity assay revealed significant mortality in cells subjected to hypoxia and reoxygenation, but not in those subjected to hypoxia alone. Analysis of lactate dehydrogenase release into buffer samples also indicated a greater cellular injury among cells exposed to hypoxia and reoxygenation. Additionally, levels of lipid peroxidation products were found to be significantly elevated in cells exposed to periods of hypoxia followed by reoxygenation, but not hypoxia alone, as measured by a thiobarbituric acid fluorometric assay. This suggests that lipid peroxidation mediated by oxygen-derived free radical species is the mechanism of injury in these cells. This study demonstrates that such a chamber provides a more precise way to monitor hypoxia and is a useful tool for studying hypoxia and reoxygenation under in vitro conditions.
Cell Death↗
An inexpensive alternative approach to bone compression analyses.
A new method for testing the compression strength of vertebrae was developed and implemented using minimal resources and time expenditure. The device digitally measured and analyzed the torque and force necessary to load rat lumbar and thoracic vertebrae to failure. The system was calibrated using a series of known lead masses. Similar to other standardized force/compression and torque devices, this method has been shown to provide reliable and reproducible results. Furthermore, although vertebrae were the only specimens used to collect data in these initial studies, this measurement system could be altered quite easily to allow for a variety of test materials.
Animals↗
Hypoxia-reoxygenation potentiates zymosan activated plasma-induced endothelial injury.
The pathophysiology of ischemia-reperfusion injury and the role played by the interaction of plasma proteins, including complement, with reperfused endothelium remains incompletely understood. Venular endothelial changes due to hypoxia followed by reoxygenation (H-R) are vital because venules are the primary site of fluid accumulation and polymorphonuclear leukocyte deposition due to inflammation. This investigation focused on whether H-R potentiates the response to permeability inducing agents found in activated plasma. Activated complement was studied by using zymosan activated plasma (ZAP). Permeability changes were assessed by quantitating rate of clearance of albumin across the monolayers. H-R alone did not change permeability relative to the normoxic condition. ZAP at 2% in normoxic cells increased albumin clearance from 2 +/- 0.2 to 9 +/- 1. 0 microL/h, which increased significantly to 13.5 +/- 2.0 microL/h when given to hypoxia-reoxygenation challenged monolayers. The permeability response to ZAP was dose related and not present with heat inactivated ZAP. ZAP at 2% altered the structure of the cytoskeleton of the human umbilical vein endothelial cells (HUVEC). However, addition of monoclonal anti-complement antibodies or addition of soluble complement receptor-1 did not attenuate ZAP-induced HUVEC permeability. Addition of zymosan-activated serum did not alter the permeability and addition of heparin inhibited the ZAP-induced changes in permeability, suggesting that these changes were mediated via thrombin and not complement. The increase in monolayer permeability due to ZAP was prevented by increasing intracellular adenosine-3',5'-cyclic monophosphate. These findings suggest that HUVEC monolayers challenged with H-R are more susceptible to increases in permeability induced by activated plasma components.
Actins↗
Evaluation of narrative text for case finding: the need for accuracy measurement.
This article reviews the analysis of a narrative text electronic search technique being used in the insurance industry. We reviewed a previously published study of motor vehicle crashes in roadway construction workzones as well as additional data supplied by the authors with respect to the methods of keyword selection. The narrative text search technique was evaluated with decision statistics and was found to have a sensitivity of 92.3%, 95% confidence interval 67.5%-99.6%. This range of sensitivity, at its most extreme value, led to a 32.5% underestimation of claims prevalence. Furthermore, because the electronic search developed two classification categories from a limited text field (approximately 20 words), only half of the cases had at least one classification. Systematic error estimates were used to obtain true population proportions for crash characteristics, revealing significant underestimations in costs. This analysis highlights the need for investigators to apply decision statistics to narrative text searching techniques when they are used essentially as diagnostic test procedures on insurance claims datasets.
Accidents, Occupational↗
Acute traumatic injuries in automotive manufacturing.
Motor vehicle manufacturing, with its varied tasks, challenging work environment, and diverse worker populations, presents many hazards to employees. This study examined routinely collected surveillance data from a major motor vehicle manufacturer to identify injury types, high-risk workers, causes of injury, and factors associated with work loss. Injury and personnel data were used to calculate injury rates. Injury data were from the routinely collected medical and safety surveillance system on occupational injuries. The number of persons working in the plants was estimated using year-end personnel reports. Key word searches supplementing the analyses provided insight into the specific circumstances of injury. The most common injuries were sprains/strains (39% of the total), lacerations (22%), and contusions (15%). Forty-nine percent of the injuries resulted in one or more lost or restricted workdays; 25% resulted in 7 or more lost or restricted workdays. The injuries most likely to result in work loss were amputations, hernias and fractures. Sprains/strains accounted for 65% of all lost workdays. Injury rates ranged from 13.8 per 100 person-years at stamping plants to 28.7 at parts depots. Even within similar types of plants, injury rates varied widely, with a twofold difference among the individual assembly plants in overall injury rates. Injury surveillance systems with descriptive data on injury events shed light on the circumstances under which certain types of injuries occur and can provide the basis for preventive interventions. Sources of variation and potential biases are discussed, providing guidance for those interested in designing and using surveillance systems for occupational injuries.
Accidents, Occupational↗
Test-retest variability of serotonin 5-HT2A receptor binding measured with positron emission tomography and [18F]altanserin in the human brain.
The role of serotonin in CNS function and in many neuropsychiatric diseases (e.g., schizophrenia, affective disorders, degenerative dementias) support the development of a reliable measure of serotonin receptor binding in vivo in human subjects. To this end, the regional distribution and intrasubject test-retest variability of the binding of [18F]altanserin were measured as important steps in the further development of [18F]altanserin as a radiotracer for positron emission tomography (PET) studies of the serotonin 5-HT2A receptor. Two high specific activity [18F]altanserin PET studies were performed in normal control subjects (n = 8) on two separate days (2-16 days apart). Regional specific binding was assessed by distribution volume (DV), estimates that were derived using a conventional four compartment (4C) model, and the Logan graphical analysis method. For both analysis methods, levels of [18F]altanserin binding were highest in cortical areas, lower in the striatum and thalamus, and lowest in the cerebellum. Similar average differences of 13% or less were observed for the 4C model DV determined in regions with high receptor concentrations with greater variability in regions with low concentrations (16-20%). For all regions, the absolute value of the test-retest differences in the Logan DV values averaged 12% or less. The test-retest differences in the DV ratios (regional DV values normalized to the cerebellar DV) determined by both data analysis methods averaged less than 10%. The regional [18F]altanserin DV values using both of these methods were significantly correlated with literature-based values of the regional concentrations of 5-HT2A receptors determined by postmortem autoradiographic studies (r2 = 0.95, P < 0.001 for the 4C model and r2 = 0.96, P < 0.001 for the Logan method). Brain uptake studies in rats demonstrated that two different radiolabeled metabolites of [18F]altanserin (present at levels of 3-25% of the total radioactivity in human plasma 10-120 min postinjection) were able to penetrate the blood-brain barrier. However, neither of these radiolabeled metabolites bound specifically to the 5-HT2A receptor and did not interfere with the interpretation of regional [18F]altanserin-specific binding parameters obtained using either a conventional 4C model or the Logan graphical analysis method. In summary, these results demonstrate that the test-retest variability of [18F]altanserin-specific binding is comparable to that of other PET radiotracers and that the regional specific binding of [18F]altanserin in human brain was correlated with the known regional distribution of 5-HT2A receptors. These findings support the usefulness of [18F]altanserin as a radioligand for PET studies of 5-HT2A receptors.
Adult↗
Role of neutrophils in hepatotoxicity induced by oral acetaminophen administration in rats.
Acetaminophen (APAP) is a common analgesic and antipyretic compound which, when administered in high doses, has been associated with significant morbidity and mortality, secondary to hepatic toxicity. To date, the mechanism(s) whereby APAP induces liver injury remains to be delineated. This study investigated the potential role of neutrophils as contributors to liver injury in rats administered sublethal doses of APAP. Oral APAP administration (650 mg/kg) was associated with increases in serum alanine transaminase (ALT) levels indicating biochemical evidence of significant liver damage. Furthermore, histological analyses verified significant hepatocellular necrosis as well as enhanced myeloperoxidase staining in these liver specimens. However, if animals were pretreated with antineutrophil sera prior to APAP administration, neutrophil counts remained depressed, ALT levels were significantly decreased, and the degree of liver injury was attenuated on a histological level. Taken together these data suggest that neutrophils mediate, at least in part, the hepatotoxic effects of oral acetaminophen administration in rats.
Acetaminophen↗
A neutron reflectivity study of polymer-modified phospholipid monolayers at the solid-solution interface: polyethylene glycol-lipids on silane-modified substrates.
The structure of polymer-decorated phospholipid monolayers at the solid-solution interface was investigated using neutron reflectometry. The monolayers were composed of distearoylphosphatidylethanolamine (DSPE) matrixed with varying amounts of DSPE-PEG (DSPE with polyethylene glycol covalently grafted to its headgroup). Mixed lipid monolayers were Langmuir-Blodgett deposited onto hydrophobic quartz or silicon substrates, previously hydrophobized by chemically grafting a robust monolayer of octadecyltrichlorosilane (OTS). We show that this method results in homogeneous and continuous phospholipid monolayers on the silanated substrates and determine that the grafted PEG chains extend away from the monolayers into the solvent phase as a function of their density, as expected from scaling theories. In addition, ligands were coupled to the end of the PEG chains and selective binding was demonstrated using fluorescence microscopy. Our results demonstrate that these constructs are ideal for further characterization and studies with well-defined monomolecular films.
Adsorption↗
Structural studies of polymer-cushioned lipid bilayers.
The structure of softly supported polymer-cushioned lipid bilayers, prepared in two different ways at the quartz-solution interface, were determined using neutron reflectometry. The polymer cushion consisted of a thin layer of branched, cationic polyethyleneimine (PEI), and the bilayers were formed by adsorption of small unilamellar dimyristoylphosphatidylcholine (DMPC) vesicles. When vesicles were first allowed to adsorb to a bare quartz substrate, an almost perfect bilayer formed. When the polymer was then added to the aqueous solution, it appeared to diffuse beneath this bilayer, effectively lifting it from the substrate. In contrast, if the polymer layer is adsorbed first to the bare quartz substrate followed by addition of vesicles to the solution, there is very little interaction of the vesicles with the polymer layer, and the result is a complex structure most likely consisting of patchy multilayers or adsorbed vesicles.
Adsorption↗
Early hypotension worsens neurological outcome in pediatric patients with moderately severe head trauma.
PURPOSE: The objective of this study was to determine the morbidity associated with hypotension in the resuscitative phase of pediatric head trauma. METHODS: A retrospective review (1990 to 1995) was performed at a level-1 pediatric trauma facility. Inclusion criteria included a Glasgow coma score (GCS) of 6 to 8 and absence of penetrating trauma or bleeding disorders. The GCS was assigned using a postresuscitation examination by a neurosurgeon. Hypotension was defined as a blood pressure reading of less than the fifth percentile for age that lasted longer than 5 minutes. Episodes were monitored from the onset of injury through the first 24 hours of hospitalization. Glasgow outcome scale (GOS) was assigned based on a 3-month follow-up evaluation. Analysis of variance (ANOVA) and contingency table analysis were performed on all groups, and a P value of less than .05 was taken to represent statistical significance. RESULTS: Seventy-two patients met inclusion criteria. They had a mean GCS of 7.2 and a mean age of 6 years; 97% survived. Early hypotension was associated with worse neurological outcome (GOS) and prolonged hospitalization. There was no significant correlation between GOS and age, gender, injury mechanism, associated injuries, or transport time. CONCLUSIONS: These data suggest that maintaining adequate blood pressure during the early resuscitation of pediatric blunt head trauma patients may improve neurological outcome.
Child↗
Glutamate modulation of dopamine measured in vivo with positron emission tomography (PET) and 11C-raclopride in normal human subjects.
Subanesthetic doses of the noncompetitive N-methyl-D-aspartate (NMDA) antagonist ketamine exacerbate psychosis in schizophrenic patients, and ketamine has significant abuse liability. These observations indicate that a secondary effect of ketamine may be to increase dopamine concentrations. The present study was undertaken using positron emission tomography (PET) and the dopamine (D2) radiotracer 11C-raclopride to determine whether ketamine would decrease D2 receptor availability, indicative of an increase in dopamine concentrations. Two scans were performed in seven male control subjects before and after administration of ketamine (0.5 mg/kg, i.v. infused over 20 min). Ketamine significantly increased cortisol levels and decreased dopamine receptor availability in the striatum (specific binding), but not in the cerebellum (nonspecific binding). In addition, the cerebellar binding subtracted from the striatal binding (to account for changes in nonspecific binding) was significantly decreased after ketamine administration. These results provide in vivo evidence for the ability of ketamine to increase striatal dopamine concentrations, consistent with the role of the NMDA receptor in modulating dopamine function.
Adult↗
Adaptive cytoprotection against deoxycholate-induced injury in human gastric cells in vitro: is there a role for endogenous prostaglandins?
The majority of previous work investigating adaptive cytoprotection has involved in vivo studies, which have suggested that this protective response is in large part mediated by endogenous prostaglandins (PGs). The aim of this study was to investigate adaptive cytoprotection under in vitro conditions in human gastric cells and to better delineate the role of endogenous PGs in this protective response. AGS cells (a human gastric carcinoma cell line) were characterized morphologically and subsequently used for all experiments. Sodium deoxycholate was used as both the mild irritant and the damaging agent, and cell injury was quantified using both a commercial viability/cytotoxicity kit as well as transepithelial permeability studies. Finally, endogenous PG synthesis in response to varying concentrations of deoxycholate was determined. AGS cells were determined to be morphologically similar to gastric mucous cells. Pretreatment of cells with low-dose deoxycholate significantly attenuated injury upon subsequent exposure to damaging concentrations of deoxycholate, and this protection was determined to be dependent upon both concentration and duration of mild irritant exposure. Preincubation of AGS cells with indomethacin reversed protection induced by mild irritant pretreatment and also significantly increased cellular susceptibility to injury. Results of the permeability studies closely paralleled those assessing cell mortality. While deoxycholate exposure increased PG synthesis, the concentrations required were much higher than those needed to initiate protection. Adaptive cytoprotection exists in AGS cells under in vitro conditions independent of intact blood flow, neural innervation, or circulating humoral mediators. While this protection is reversed by indomethacin, it appears that this reversal results from increased cellular injury secondary to diminished basal PGs, rather than inhibition of endogenous PG synthesis.
Cell Membrane Permeability↗