Near-patient test for C-reactive protein in general practice: assessment of clinical, organizational, and economic outcomes.
BACKGROUND: The benefits of near-patient, point-of-care tests have not been fully examined. We have assessed the clinical, organizational, and economic outcomes of implementing a near-patient test for C-reactive protein (CRP) in general practice. METHODS: In a randomized crossover trial during intervention periods, general practitioners (GPs) were allowed to measure CRP within 3 min, using NycoCard(R) CRP. During control periods, they had to mail blood samples for CRP measurements to the hospital laboratory and received test results 24-48 h later. Twenty-nine general practice clinics participated (64 GPs), and 1853 patients were included in the study. Results were evaluated at both the level of participating GPs and the level of included patients. RESULTS: For participating GPs, the overall use of erythrocyte sedimentation rates (ESRs) decreased by 8% (95% confidence interval, 1-14%) during intervention periods, and the number of blood samples mailed to the hospital laboratory decreased by 6% (1-10%). No reduction in the prescription of antibiotics was seen. The proportion of study patients having a follow-up telephone consultation was reduced from 63% to 53% (P = 0. 0001), and patients with CRP concentrations >50 mg/L had their antibiotic treatments started earlier when CRP was measured in general practices (P = 0.0161). CONCLUSION: The implementation of the near-patient CRP test was cost-effective mainly on the basis of a reduction in the use of services from the hospital laboratory by GPs. If the implementation is followed by education and clinical guidelines, opportunities exist for additional reduction in the use of ESR and for a more appropriate use of antibiotics. (+info
Duplex scanning may be used selectively in patients with primary varicose veins.
Reflux was assessed using hand-held Doppler (HHD) and duplex scanning in 72 patients with primary, previously untreated varicose veins (108 limbs). The aims of the study were (i) to compare the accuracy of HHD assessment with duplex scanning, (ii) to assess the benefit of tourniquet testing and (iii) to identify patients who would benefit from a policy of selective duplex scanning. HHD accurately assesses the saphenofemoral junction (SFJ) and long saphenous vein (LSV) reflux. HHD assessment of the saphenopopliteal junction (SPJ) reflux has a low positive predictive value. A high negative predictive value reflects absent SPJ reflux assessed using HHD accurately. Tourniquet testing is not helpful. Selective duplex scanning of limbs with suspected SPJ reflux, no identifiable site of reflux or posterior thigh perforator reflux on HDD (39% of limbs), would result in the appropriate surgical procedure being performed in 102 (94%) limbs, excessive surgery in 5 (5%) limbs and inadequate surgery in only 1 (1%) limb. The use of selective criteria for duplex scanning would reduce the workload of the vascular laboratory without compromising patient care. (+info
Seamless multiresolution display of portable wavelet-compressed images.
Image storage, display, and distribution have been difficult problems in radiology for many years. As improvements in technology have changed the nature of the storage and display media, demand for image portability, faster image acquisition, and flexible image distribution is driving the development of responsive systems. Technology, such as the wavelet-based multiresolution seamless image database (MrSID) portable image format (PIF), is enabling image management solutions that address the shifting "point-of-care." The MrSID PIF employs seamless, multiresolution technology, which allows the viewer to determine the size of the image to be viewed, as well as the position of the viewing area within the image dataset. In addition the MrSID PIF allows control of the compression ratio of decompressed images. This capability offers the advantage of very rapid image recall from storage devices and portability for rapid transmission and distribution using the internet or wide-area networks. For example, in teleradiology, the radiologist or other physician desiring to view images at a remote location has full flexibility in being able to choose a quick display of an overview image, a complete display of a full diagnostic quality image, or both without compromising communication bandwidth. The MrSID algorithm will satisfy Joint Photographic Experts Group (JPEG) 2000 standards, thereby being compatible with future versions of the Digital Imaging and Communications in Medicine (DICOM) standard for image data compression. (+info
Quantitative bedside assay for cardiac troponin T: a complementary method to centralized laboratory testing.
BACKGROUND: In the evaluation of chest pain patients, whole blood bedside assays of highly specific cardiac molecules may be an attractive alternative to centralized clinical chemistry testing. We now report on an optimized test strip device for cardiac troponin T (cTnT) that can be analyzed by a cardiac reader for quantitative assessment of the test result. METHODS AND RESULTS: The cTnT test strip reader measures, via a CCD camera, the reflectance of the signal line. For quantitative analysis, a calibration curve was constructed from 1030 samples of 252 consecutive patients with acute coronary syndromes. In a method comparison of 140 samples, the quantitative results of the cTnT test strip reader correlated closely with the results of the cTnT ELISA (r = 0.98; y = 0.85x + 0. 002). Within-run and day-to-day (n = 10) mean CVs were between 11% and 16%, respectively. The cross-reactivity with skeletal troponin T was <0.02%. In patients with myocardial infarction, 45% and 91% of all samples were positive on admission and at 4-8 h after the onset of symptoms, respectively. ROC curve analysis demonstrated a comparable efficiency of the cTnT test strip reader and the laboratory-based cTnT ELISA in patients with suspected myocardial infarction. CONCLUSIONS: It is now possible to quantitatively determine cTnT at the patient's bedside with a rapid and convenient test device. This will facilitate the diagnostic work up of patients with suspected myocardial cell necrosis. (+info
Risk stratification after acute myocardial infarction by Doppler stroke distance measurement.
OBJECTIVE: To establish the value of Doppler stroke distance measurement as a predictor of mortality risk following acute myocardial infarction. DESIGN: Follow up study. SETTING: Coronary care unit of a teaching and district general hospital. SUBJECTS: 378 patients (mean age 61 years) with acute myocardial infarction followed up for a mean of five years (range 2-7 years); 299 (79%) patients received thrombolysis. MAIN OUTCOME MEASURES: Stroke distance (the systolic velocity integral of blood flow in the aortic arch (percentage of age predicted normal value)); presence or absence of left ventricular failure on the admission chest radiograph; the codified admission ECG; death during follow up. RESULTS: Mean (SD) stroke distance was 81 (19)% and five year survival 76%. For patients with stroke distance > 100% (n = 60), 82-100% (n = 134), 63-81% (n = 122), and < 63% (n = 62), the one month mortality rates were 0%, 1.5%, 4%, and 18%, respectively; the corresponding estimates for mortality at five years were 17%, 19%, 24%, and 43%. Survival was independently related to age (p < 0.0001), stroke distance (p < 0.0001), and chest radiograph appearance (p = 0.002), but not to ECG codes (p = 0.31) or receipt of thrombolysis (p = 0.60). The areas under receiver operator characteristic plots for stroke distance measurements were 82%, 76%, 71%, and 65% for deaths within one month, six months, one year, and two years, respectively. CONCLUSIONS: The bedside measurement of stroke distance stratifies mortality risk after acute myocardial infarction. The predictive ability of this simple measure of left ventricular systolic function compares well with published accounts of the more complex measurement of ejection fraction. (+info
Computing for the next millennium.
Computer technology has changed our lives, even that of physicians. In a few years time, a physician can expect to have a new tool by the bedside: a hand-held computer small enough to put into a pocket and powerful enough for all everyday activities, including highly specialized and sophisticated activities such as prevention of adverse drug reactions. The Croatian Academic and Research Network (CARNet) was crucial in bringing the benefits of the information technology to the Croatian scientists. At the Split University School of Medicine, we started the Virtual Medical School project, which now also includes the Mostar University School of Medicine in neighboring Bosnia and Herzegovina. Virtual Medical School aims to promote free dissemination of medical knowledge by creating medical education network as a gateway to the Internet for health care professionals. (+info
Accuracy of the i-STAT bedside blood gas analyser.
The performance of the i-STAT portable clinical analyser for measuring blood gases and pH was evaluated with reference to a conventional blood gas analyser (ABL520 Radiometer). Ninety-two samples from the routine blood gas analysis laboratory were chosen according to a wide distribution of partial pressure of carbon dioxide (Pa,CO2), partial pressure oxygen (Pa,O2) and pH and then analysed. All measurements were performed in duplicate by trained technicians from the central hospital laboratory. Differences between duplicate measurements were computed for Pa,CO2: (1.2 versus 0.4%), Pa,O2 (1.7 versus 1.1%) and pH (0.06 versus 0.02%), for the i-STAT and ABL520, respectively. pH and Pa,CO2 values measured with the i-STAT were very close to those obtained with the ABL520, the difference (mean+/-SD) being 0.006+/-0.018 and -0.13+/-0.17 kPa, respectively. Statistical analysis showed that the differences between analysers did not depend on values of pH or Pa,CO2. The performance of the analysers depended on the level of PO2. Below 15 kPa (n=48), the two systems gave nearly identical values, the mean difference was 0.01+/-0.37 kPa. Between 16 and 55 kPa (n=44), there was a systematic but small (-0.69+/-0.67 kPa) underestimation of Pa,O2 measured with the i-STAT (p<10(-8)). In conclusion, this study shows that blood gas analysis using the i-STAT portable device is comparable with that performed by a conventional laboratory blood gas analyser. (+info
Systematic review of near patient test evaluations in primary care.
OBJECTIVE: To identify and qualitatively synthesise the findings from all studies that have examined the performance and effect of near patient tests in the primary care setting. DESIGN: Systematic review of published and unpublished research 1986-99. MAIN OUTCOME MEASURES: Test performance characteristics, measures of effect on clinical practice or patient outcome. RESULTS: 101 relevant publications were identified. The general quality of these papers was low, and consequently only 32 papers were assessed in detail. Although these papers gave some indication of the value of near patient testing in areas such as anticoagulation monitoring and group A beta haemolytic streptococcus testing, the research raised many more questions than it answered. Almost no reports were found of unbiased assessment of the effect of near patient tests in primary care on patient outcomes, organisational outcomes, or cost. CONCLUSIONS: Available research provides little evidence to guide the expansion of use of near patient testing in primary care. Further research is needed in areas of clinical practice where near patient tests might be most beneficial. (+info