A-constant and intraocular lenses.
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Biometry↗
Biomedical subjects
J Luck
Publications and source records attributed to J Luck.
Sensitivity and specificity of serology in determining recent acute Campylobacter infection.
BACKGROUND: The measurement of serum antibodies to Campylobacter spp. has been used to investigate links between prior Campylobacter infections and the development of Guillain-Barre syndrome and its variants. Little is known of the serum antibody response to acute infections in the short- or long-term. AIMS: The aims of the present study were to investigate the normal serum response to an acute Campylobacter infection and the sensitivity and specificity of anti-Campylobacter antibodies in determining recent Campylobacter infection. METHODS: An enzyme-linked immunosorbent assay (ELISA) method was used to measure serum anti-Campylobacter immunoglobulin G (IgG), IgA and IgM antibodies. Controls consisted of 420 blood donors without recent gastroenteritis, 25 patients with other gastrointestinal infections, 24 patients with neurological conditions not affecting the peripheral nerves and 19 patients with autoimmune disorders. Three patient groups were assessed: 99 patients with acute Campylobacter infections, all of whom were tested 3 weeks post-infection; 69 of these patients tested 3-6 months later; and 74 additional patients tested >20 months post-infection. Western blot analysis was performed on controls and patients with high titre anti-Campylobacter antibodies to assess for cross-reactivity and specificity. RESULTS: Following acute infections, all antibody classes rose in the majority of but not in all patients, followed by decreasing titres that did not return to baseline levels. Sixteen per cent of enteritis cases did not demonstrate a rise in titres and 9% of cases had significant levels of antibodies >20 months post-infection. The ELISA used was shown to be highly specific for the detection of Campylobacter antibodies. CONCLUSION: The use of Campylobacter-specific antibody levels as the sole marker of prior infection is an unreliable method of determining the association between Campylobacter infection and neurological disease.
Acute Disease↗
Malignant melanoma of the conjunctiva metastasising to the parotid gland.
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Aged↗
Primary iris pigment epithelial hyperplasia and glaucoma.
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Adolescent↗
The ethical problem of false positives: a prospective evaluation of physician reporting in the medical record.
OBJECTIVE: To determine if the medical record might overestimate the quality of care through false, and potentially unethical, documentation by physicians. DESIGN: Prospective trial comparing two methods for measuring the quality of care for four common outpatient conditions: (1) structured reports by standardised patients (SPs) who presented unannounced to the physicians' clinics, and (2) abstraction of the medical records generated during these visits. SETTING: The general medicine clinics of two veterans affairs medical centres. PARTICIPANTS: Twenty randomly selected physicians (10 at each site) from among eligible second and third year internal medicine residents and attending physicians. MAIN MEASUREMENTS: Explicit criteria were used to score the medical records of physicians and the reports of SPs generated during 160 visits (8 cases x 20 physicians). Individual scoring items were categorised into four domains of clinical performance: history, physical examination, treatment, and diagnosis. To determine the false positive rate, physician entries were classified as false positive (documented in the record but not reported by the SP), false negative, true positive, and true negative. RESULTS: False positives were identified in the medical record for 6.4% of measured items. The false positive rate was higher for physical examination (0.330) and diagnosis (0.304) than for history (0.166) and treatment (0.082). For individual physician subjects, the false positive rate ranged from 0.098 to 0.397. CONCLUSIONS: These data indicate that the medical record falsely overestimates the quality of important dimensions of care such as the physical examination. Though it is doubtful that most subjects in our study participated in regular, intentional falsification, we cannot exclude the possibility that false positives were in some instances intentional, and therefore fraudulent, misrepresentations. Further research is needed to explore the questions raised but incompletely answered by this research.
Benchmarking↗
Analysis of host responses of guinea pigs during Helicobacter pylori infection.
Host responses of guinea pigs infected with Helicobacter pylori were investigated. Passaged H. pylori colonised the stomach for up to 13 weeks after infection, but after 1 month the number of bacteria fell sharply. Specific antibodies, predominantly of the IgG2 subtype, were present from week 3 onwards. Antibodies to urease A and flagella were abundant. Severe inflammation of the gastric mucosa and damage to the stomach epithelium was seen. Infiltrates of mononuclear cells and eosinophils were found near the parietal glands. As infection progressed, inflammation and tissue damage became more localised and more variable between individual animals. These parameters can be used as markers for colonisation of the stomach by H. pylori.
Animals↗
How well does chart abstraction measure quality? A prospective comparison of standardized patients with the medical record.
PURPOSE: Despite widespread reliance on chart abstraction for quality measurement, concerns persist about its reliability and validity. We prospectively evaluated the validity of chart abstraction by directly comparing it with the gold standard of reports by standardized patients. SUBJECTS AND METHODS: Twenty randomly selected general internal medicine residents and attending faculty physicians at the primary care clinics of two Veterans Affairs Medical Centers blindly evaluated and treated actor-patients (standardized patients) who had one of four common diseases: diabetes, chronic obstructive pulmonary disease, coronary artery disease, or low back pain. Charts from the visits were abstracted using explicit quality criteria; standardized patients completed a checklist containing the same criteria. For each physician, quality was measured for two different cases of the four conditions (a total of 160 physician-patient encounters). We compared chart abstraction with standardized-patient reports for four aspects of the encounter: taking the history, examining the patient, making the diagnosis, and prescribing appropriate treatment. The sensitivity and specificity of chart abstraction were calculated. RESULTS: The mean (+/- SD) chart abstraction score was 54% +/- 9%, substantially less than the mean score on the standardized-patient checklist of 68% +/- 9% (P <0.001). This finding was similar for all four conditions and at both sites. "False positives"-chart-recorded necessary care actions not reported by the standardized patients-resulted in a specificity of only 81%. The overall sensitivity of chart abstraction for necessary care was only 70%. CONCLUSIONS: Chart abstraction underestimates the quality of care for common outpatient general medical conditions when compared with standardized-patient reports. The medical record is neither sensitive nor specific. Quality measurements derived from chart abstraction may have important shortcomings, particularly as the basis for drawing policy conclusions or making management decisions.
Ambulatory Care↗
Comparison of vignettes, standardized patients, and chart abstraction: a prospective validation study of 3 methods for measuring quality.
CONTEXT: Better health care quality is a universal goal, yet measuring quality has proven to be difficult and problematic. A central problem has been isolating physician practices from other effects of the health care system. OBJECTIVE: To validate clinical vignettes as a method for measuring the competence of physicians and the quality of their actual practice. DESIGN: Prospective trial conducted in 1997 comparing 3 methods for measuring the quality of care for 4 common outpatient conditions: (1) structured reports by standardized patients (SPs), trained actors who presented unannounced to physicians' clinics (the gold standard); (2) abstraction of medical records for those same visits; and (3) physicians' responses to clinical vignettes that exactly corresponded to the SPs' presentations. Setting Outpatient primary care clinics at 2 Veterans Affairs medical centers. PARTICIPANTS: Ninety-eight (97%) of 101 general internal medicine staff physicians, faculty, and second- and third-year residents consented to be randomized for the study. From this group, 10 physicians at each site were randomly selected for inclusion. MAIN OUTCOME MEASURES: A total of 160 quality scores (8 cases x 20 physicians) were generated for each method using identical explicit criteria based on national guidelines and local expert panels. Scores were defined as the percentage of process criteria correctly met and were compared among the 3 methods. RESULTS: The quality of care, as measured by all 3 methods, ranged from 76.2% (SPs) to 71.0% (vignettes) to 65.6% (chart abstraction). Measuring quality using vignettes consistently produced scores closer to the gold standard of SP scores than using chart abstraction. This pattern was robust when the scores were disaggregated by the 4 conditions (P<.001 to <.05), by case complexity (P<.001), by site (P<.001), and by level of physician training (P values from <.001 to <.05). The pattern persisted, although less dominantly, when we assessed the component domains of the clinical encounter--history, physical examination, diagnosis, and treatment. Vignettes were responsive to expected directions of variation in quality between sites and levels of training. The vignette responses did not appear to be sensitive to physicians' having seen an SP presenting with the same case. CONCLUSIONS: Our data indicate that quality of health care can be measured in an outpatient setting by using clinical vignettes. Vignettes appear to be a valid and comprehensive method that directly focuses on the process of care provided in actual clinical practice. Vignettes show promise as an inexpensive case-mix adjusted method for measuring the quality of care provided by a group of physicians.
Ambulatory Care↗
A randomized controlled trial of intracameral lidocaine during phacoemulsification under topical anesthesia.
OBJECTIVE: To test the hypothesis that adjunctive intracameral 1% lidocaine reduces intraoperative pain during phacoemulsification using topical anesthesia. DESIGN: Prospective, double-masked, randomized, controlled trial. PARTICIPANTS: A total of 200 patients undergoing routine phacoemulsification under topical 1% tetracaine were studied. INTERVENTION: Randomization to 0.5 ml intracameral, unpreserved, epinephrine-free 1% lidocaine or placebo was conducted. MAIN OUTCOME MEASURE: Intraoperative pain was quantified by the patients using a 0-10 visual analog pain scale. RESULTS: Intraoperative pain scores (+/- standard deviation) for the lidocaine and control groups were 1.29 +/-1.24 and 1.44 +/- 1.33, respectively (P > 0.35). CONCLUSIONS: In a rigorously double-masked, prospective, randomized, controlled trial there was no significant reduction in intraoperative pain when intracameral 1% lidocaine was used during phacoemulsification under topical anesthesia.
Adult↗
Using standardized patients to measure quality: evidence from the literature and a prospective study.
BACKGROUND: Use of standardized patients for evaluating the clinical skills of medical students and medical trainees is commonplace. This has encouraged the use of standardized patients to evaluate the quality of physician practice in outpatient settings. However, there may be substantive differences between observing student performance and evaluating whether the provision of care meets defined quality criteria. OBJECTIVES: This study had two primary objectives: (1) to review studies that use standardized patients to evaluate physician performance and (2) to ascertain directly whether standardized patients could be useful in assessing quality of outpatient care. METHODS: A comprehensive literature review of studies that used standardized patients to assess physician performance was conducted. A prospective study that included 20 physicians at two outpatient settings and 27 actor patients assessed quality of care using eight clinical cases divided into five clinical domains, each of which had explicit criteria checklists based on widely accepted guidelines. RESULTS: The literature review identified five important issues: developing scenarios, selecting explicit criteria, standardizing standardized patient training, creating subterfuges, and ensuring reliability and validity of measures. In the study, trained standardized patients were able to assess physician practice accurately for common medical conditions, using proven criteria linked to health outcomes. The detection rate was 3%. There was no performance variation between actors for seven of the eight cases. CONCLUSIONS: Using standardized patients to measure the quality of care is practical and feasible. The major methodological challenge is incorporating observable evidence-based criteria into realistic scripts and objective checklists. The major logistical challenge is obtaining and maintaining undetected entry into physicians' offices.
Clinical Competence↗
Measuring compliance with preventive care guidelines: standardized patients, clinical vignettes, and the medical record.
OBJECTIVE: To determine how accurately preventive care reported in the medical record reflects actual physician practice or competence. DESIGN: Scoring criteria based on national guidelines were developed for 7 separate items of preventive care. The preventive care provided by randomly selected physicians was measured prospectively for each of the 7 items. Three measurement methods were used for comparison: (1) the abstracted medical record from a standardized patient (SP) visit; (2) explicit reports of physician practice during those visits from the SPs, who were actors trained to present undetected as patients; and (3) physician responses to written case scenarios (vignettes) identical to the SP presentations. SETTING: The general medicine primary care clinics of two university-afflliated VA medical centers. PARTICIPANTS: Twenty randomly selected physicians (10 at each site) from among eligible second- and third-year general internal medicine residents and attending physicians. MEASUREMENTS AND MAIN RESULTS: Physicians saw 160 SPs (8 cases x 20 physicians). We calculated the percentage of visits in which each prevention item was recorded in the chart, determined the marginal percentage improvement of SP checklists and vignettes over chart abstraction alone, and compared the three methods using an analysis-of-variance model. We found that chart abstraction underestimated overall prevention compliance by 16% (P < .01) compared with SP checklists. Chart abstraction scores were lower than SP checklists for all seven items and lower than vignettes for four items. The marginal percentage improvement of SP checklists and vignettes to performance as measured by chart abstraction was significant for all seven prevention items and raised the overall prevention scores from 46% to 72% (P < .0001). CONCLUSIONS: These data indicate that physicians perform more preventive care than they report in the medical record. Thus, benchmarks of preventive care by individual physicians and institutions that rely solely on the medical record may be misleading, at best.
Adult↗
Improving the public sector: can reengineering identify how to boost efficiency and effectiveness at a VA medical center?
Reengineering is a widespread management technique, but few evaluations of its application in health care, especially in public sector organizations, have been reported. We conducted a reengineering analysis to determine if the method could identify how to improve the efficiency and effectiveness of a VA medical center's primary care delivery system. We found that the reengineering method appears applicable in the institutional context of a public sector teaching hospital.
Benchmarking↗
Interstitial hydraulic conductivity in a fibrosarcoma.
Convective transport of therapeutic agents in solid tumors can be improved through intratumoral infusion. To optimize the convection, we investigated the dependence of the hydraulic conductivity on tissue deformation induced by interstitial fluid pressure gradient during the infusion. Two experimental systems were used in the investigation: 1) one-dimensional perfusion through tumor slices and 2) intratumoral infusion using a needle. With these systems, we found that the apparent hydraulic conductivity (K(app)) could be altered by several orders of magnitude in fibrosarcomas through changes in perfusion conditions. When the perfusion pressure was less than a threshold level, fluid flow in tissues could not be detected. When the perfusion pressure was increased above the threshold level, K(app) depended on perfusion system and pressure. The maximum variation in K(app) in fibrosarcomas reached 80,260-fold in our experiments. The large variation in K(app) could be explained by perfusion pressure-induced tissue deformation. These experimental data suggest that the hydraulic conductivity is very sensitive to tissue deformation and imply that it is possible to improve intratumoral infusion of therapeutic agents through optimization of infusion conditions.
Animals↗
How far down the managed care road? A comparison of primary care outpatient services in a Veterans Affairs medical center and a capitated multispecialty group practice.
BACKGROUND: Under increasing pressure to provide more efficient, higher-quality care, the Department of Veterans Affairs (VA) is expanding primary care and implementing other managed care techniques. To assess the magnitude of performance improvement possible in the VA and to investigate potential barriers to implementation of new techniques, we compared a VA facility with similar managed care organizations on specific managed care performance benchmarks. METHODS AND DATA COLLECTION: Detailed case studies of a large VA medical center and a large capitated multispecialty group practice in the same region were carried out. Various qualitative and quantitative data were collected between October 1, 1994, and September 30, 1997. Unstructured and semistructured interviews, participant and direct observations, document review, electronic data abstractions, and patient surveys were used to collect the data. RESULTS: Patients in the VA medical center were poorer (average income, $13300 per year), older (36.5% aged 65 years and older), and more likely to be homeless (10.5%). The VA patients saw more specialists and made more emergency department visits than managed care patients. Although the VA had better electronic information flows, its providers saw fewer patients, had more unscheduled visits, and received fewer consultant reports, and its patients waited longer. Inpatient utilization was also higher (length of stay averaged 8 days) among VA primary care patients. CONCLUSIONS: On many dimensions the VA did not compare favorably with the efficiency or lower utilization of the capitated managed care practice. Part of the reason must be attributed to the VA's multiple missions, which include teaching and research; another reason is the VA's role to be a service provider to all eligible veterans regardless of sociodemographic or health characteristics. Whether these differences are also caused by different case mix, or differences in socioeconomic status of patients, surprisingly is not well understood. This hampers future efforts to use managed care techniques to improve the operation of the VA.
Age Factors↗
Early induced astigmatism following phacoemulsification and flexible lens implantation through an oblique corneal tunnel.
PURPOSE: To analyse the early surgically induced corneal astigmatism (SICA) with a 3.5 mm oblique clear corneal incision (CCI) for phacoemulsification and flexible silicone implant. METHODS: Sixty-four consecutive patients were included in this study. The keratometry readings were recorded on the day prior to surgery, the first day post-operatively and at 6 weeks. The SICA was evaluated according to four different methods: (i) simple subtraction, (ii) vector analysis, (iii) vector decomposition and (iv) Naeser polar values. RESULTS: At 6 weeks post-operatively the SICA was equally divided between with-the-rule (WTR) and against-the-rule (ATR) astigmatism, according to the vector analysis in combination with vector decomposition. Both the simple subtraction method and Naeser polar values were misleading. CONCLUSION: The oblique clear corneal section for phacoemulsification is a comfortable and safe incision with a predictable and acceptable degree of SICA that may be better tolerated than that induced by superior incision.
Adult↗
Analyzing the time and value of housestaff inpatient work.
OBJECTIVE: To determine time allocation and the perceived value to education and patient care of the weekday activities of internal medicine housestaff on inpatient rotations and to compare the work activities of interns and residents. DESIGN: An observational study. We classified activities along five dimensions (association, location, activity, time, and value), developed a computer-assisted self-interview survey, and demonstrated its face and content validity, internal consistency, and interrater reliability. Subjects were assigned survey computers for 5 consecutive weekdays over a 24-week period, into which they entered data when prompted several times a day. SETTING: The medical service of a university-affiliated Veterans Administration Medical Center. PARTICIPANTS: Sixty housestaff (36 interns, 24 residents) rotating on the inpatient wards. MEASUREMENTS AND MAIN RESULTS: We analyzed activities according to content (direct patient care, indirect patient care, education), association, and location. Likert-scale ratings of perceived value to education and patient care were also obtained. Housestaff provided complete responses to 3,812 (95%) of 3,992 prompts by a median of 11 seconds; 93% of responses were logically consistent across the measured dimensions. Housestaff spent more time in indirect patient care (56%) than in direct patient care (14%) or educational activities (45%). Formal educational activities had the highest educational value (66 on 0-100 scale), and direct care had the highest value to patient care (81). Over 30% of time was spent in administrative activities, which had low educational value(40). Compared with residents, interns allocated significantly less time to educational activities (38% vs 57%) and more time to lower-value activities such as documentation (19% vs 12%). CONCLUSIONS: Improved data collection methods demonstrate that housestaff in our program, particularly interns, spend much of their workday in activities that are low in educational and patient care value. Selective elimination or delegation of such activities would preserve higher-value experiences during reductions in overall inpatient training time. Planners can use automated random sampling to guide the rational redesign of housestaff work.
Confidence Intervals↗
Advances in the molecular genetic analysis of the flax-flax rust interaction.
The L6 and M rust-resistance genes, representing two of the five rust-resistance gene loci in flax (Linum usitatissimum), have been cloned. The molecular data are fully consistent with earlier genetic data: the L locus is a single gene with multiple alleles expressing different rust resistance specificities, and the M locus is complex, containing an array of about 15 similar genes. Thus, while L6 and M resistance genes have 86% nucleotide identity, their locus structure is very different. These genes encode products belonging to the nucleotide binding site-leucine-rich repeat class of disease-resistance proteins. Analysis of alleles from the L locus and chimeric genes is providing evidence suggesting that important specificity determinants occur in the C-terminal half of the proteins, the region containing the leucine-rich repeats. The isolation and characterization of the rust (Melampsora lini) avirulence genes that correspond to the cloned rust-resistance genes is one of the major challenges remaining to the understanding of this system.
Journal Article↗
Sensitivity and specificity of QTc dispersion for identification of risk of cardiac death in patients with peripheral vascular disease.
OBJECTIVE: To determine whether QTc dispersion, which is easily obtained from a standard electrocardiogram, can predict those patients with peripheral vascular disease who will subsequently suffer a cardiac death, despite having no cardiac symptoms or signs. DESIGN: Patients with peripheral vascular disease were followed up for five years after they had had coronary angiography, radionuclide ventriculography, and their QTc dispersion calculated from their 12 lead electrocardiogram. SUBJECTS: 49 such patients were then divided into three groups: survivors (34), cardiac death (12), and non-cardiac death (3). MAIN OUTCOME MEASURE: Survival. RESULTS: The mean (SD; range) ejection fractions were similar in all three groups: survivors 45.9 (11.0; 27.0-52.0), cardiac death 44.0 (7.90; 28.5-59.0), and non-cardiac death 45.3 (4.55; 39.0-50.0). QTc dispersion was significantly prolonged in the cardiac death group compared with in the survivors (86.3(23.9; 41.0-139) v 56.5 (25.4; 25.0-164); P = 0.002). A QTc dispersion > or = 60 ms had a 92% sensitivity and 81% specificity in predicting cardiac death, QTc dispersion in patients with diffuse coronary artery disease was significantly (P < 0.05) greater than in those with no disease or disease affecting one, two, or three vessels. CONCLUSIONS: There is a strong link between QTc dispersion and cardiac death in patients with peripheral vascular disease. QTc dispersion may therefore be a cheap and non-invasive way of assessing the risk of cardiac death in patients with peripheral vascular disease.
Aged↗