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PubMed2006

Evaluation of diagnostic imaging technologies and therapeutics devices: better information for better decisions: proceedings of a multidisciplinary workshop.

We are entering an era in which the success of biomedical science and the increasing understanding of the value of evidence for practice are in a state of tension. This tension is especially notable in the device arena, in which the short life cycles and iterative nature of development are at odds with current design constructs of the types of clinical trials that provide evidence for medical decision making. The financial pressure arising from strained budgets and expanding costs from the aging of the population and the continued development of new technology heightens the need for a focus on new approaches. Given this background, a group of experts representing constituencies with different perspectives were convened for a day and a half to discuss key issues and their potential solutions. Because of the complex and heterogeneous nature of the environments in which devices are used, the meeting focused on 3 broad, general uses of devices: imaging, risk stratification, and therapeutics. The goal of the meeting was to develop a preliminary list of ideas that could be framed as researchable questions or constructs for consideration by policy makers that ultimately might lead to improvements in the current system. Across diagnostic imaging, risk stratification devices, and therapeutic devices, the crosscutting issues can be identified: We need better methods of collaborative funding and priority setting, improved and more flexible methods, and new approaches to the integration of federal agencies in overseeing the system.

Alzheimer Disease↗
PubMed2006

Update on bispectral index monitoring.

Since 1997, bispectral index (BIS; Aspect Medical Systems Inc., Natick, MA) has been in clinical practice and a wealth of experimental research has accumulated on its use. Originally, the device was approved only for monitoring hypnosis and has now received an indication for reducing the incidence of intraoperative awareness during anesthesia. Numerous studies have documented the ability of BIS to reduce intermediate outcomes such as hypnotic drug administration, extubation time, postoperative nausea and shortened recovery room discharge. Two recent large-scale outcome studies using BIS (one randomized controlled trial and one prospective, nonrandomized historical cohort study) identified an approximately 80% reduction in the incidence of recall after anesthesia. BIS provides clinicians with unique information that can be used to tailor hypnotic drug doses to individual patient requirements. BIS does not predict movement or hemodynamic response to stimulation, nor will it predict the exact moment consciousness returns. This review will also discuss other BIS applications including use in pediatrics, intensive care and for procedural sedation. Some limitations exist to the use of BIS and it is not useful for some individual hypnotic agents (ketamine, dexmedetomidine, nitrous oxide, xenon, opioids). BIS technology is moving out of the operating room and into diverse environments where conscious and deep sedation are provided. Anesthesiologists need to be actively involved in promoting patient safety and helping transition this technology into broader use.

Adult↗
PubMed2005

Quantitative analysis of delta9-tetrahydrocannabinol in preserved oral fluid by liquid chromatography-tandem mass spectrometry.

A rapid and sensitive method for the analysis of delta9-tetrahydrocannabinol (THC) in preserved oral fluid was developed and fully validated. Oral fluid was collected with the Intercept, a Food and Drug Administration (FDA) approved sampling device that is used on a large scale in the U.S. for workplace drug testing. The method comprised a simple liquid-liquid extraction with hexane, followed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis. Chromatographic separation was achieved using a XTerra MS C18 column, eluted isocratically with 1 mM ammonium formate-methanol (10:90, v/v). Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions. The use of the liquid-liquid extraction was demonstrated to be highly effective and led to significant decreases in the interferences present in the matrix. Validation of the method was performed using both 100 and 500 MicroL of oral fluid. The method was linear over the range investigated (0.5-100 ng/mL and 0. 1-10 ng/mL when 100 and 500 microL, respectively, of oral fluid were used) with an excellent intra-assay and inter-assay precision (relative standard deviations, RSD <6%) for quality control samples spiked at a concentration of 2.5 and 25 ng/mL and 0.5 and 2.5 ng/mL, respectively. Limits of quantification were 0.5 and 0.1 ng/mL when using 100 and 500 microL, respectively. In contrast to existing GC-MS methods, no extensive sample clean-up and time-consuming derivatisation steps were needed. The method was subsequently applied to Intercept samples collected at the roadside and collected during a controlled study with cannabis.

Body Fluids↗
PubMed2005

Quantitative analysis of multiple illicit drugs in preserved oral fluid by solid-phase extraction and liquid chromatography-tandem mass spectrometry.

We present a validated method for the simultaneous analysis of basic drugs which comprises a sample clean-up step, using mixed-mode solid-phase extraction (SPE), followed by LC-MS/MS analysis. Deuterated analogues for all of the analytes of interest were used for quantitation. The applied HPLC gradient ensured the elution of all the drugs examined within 14 min and produced chromatographic peaks of acceptable symmetry. Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions for the non-deuterated analogues. Oral fluid was collected with the Intercept, a FDA approved sampling device that is used on a large scale in the US for workplace drug testing. However, this collection system contains some ingredients (stabilizers and preservatives) that can cause substantial interferences, e.g. ion suppression or enhancement during LC-MS/MS analysis, in the absence of suitable sample pre-treatment. The use of the SPE was demonstrated to be highly effective and led to significant decreases in the interferences. Extraction was found to be both reproducible and efficient with recoveries >76% for all of the analytes. Furthermore, the processed samples were demonstrated to be stable for 48 h, except for cocaine and benzoylecgonine, where a slight negative trend was observed, but did not compromise the quantitation. In all cases the method was linear over the range investigated (2-200 microg/L) with an excellent intra-assay and inter-assay precision (coefficients of variation <10% in most cases) for QC samples spiked at a concentration of 4, 12 and 100 microg/L. Limits of quantitation were estimated to be at 2 microg/L with limits of detection ranging from 0.2 to 0.5 microg/L, which meets the requirements of SAMHSA for oral fluid testing in the workplace. The method was subsequently applied to the analysis of Intercept samples collected at the roadside by the police, and to determine MDMA and MDA levels in oral fluid samples from a controlled study.

Chromatography, Liquid↗
PubMed2006

Double-balloon endoscopy: from concept to reality.

The history of the double-balloon endoscope from conception to development and practical application has been described. The theory itself is quite simple, and there were opinions doubting its practicality at the early stage of development.Double-balloon endoscopes, however, are commercially available now. They have been used widely, and their usefulness has been recognized. When development of the double-balloon endoscope was progressing, development of capsule endoscopes also was progressing. The authors often heard opinions that, since capsule endoscopes were expected to become commercially available in the near future, it was out-of-date to devise a method to insert an enteroscope into the small intestine. The authors, however, believed that if the use of capsule endoscopes spread, the necessity of an enteroscope that can reach the entire area in the small intestine would not disappear, but become even bigger. If any abnormal finding is detected by a capsule endoscope, the necessity of enteroscopy for a detailed examination increases. This is being proven at present.

Catheterization↗
PubMed2004

Reasons patients recommend laser in situ keratomileusis.

PURPOSE: To evaluate the reasons patients who have had laser in situ keratomileusis (LASIK) recommend it to others and examine the disparity between high levels of satisfaction and patient reports of night-vision symptoms and/or dry eye after LASIK. SETTING: Northeastern Eye Institute, Scranton, and the University of Pittsburgh, Pittsburgh, Pennsylvania, and the University of California at Los Angeles, Los Angeles, California, USA. METHODS: Questionnaires assessing symptoms and satisfaction after LASIK were mailed to 2,100 patients. The questionnaires included items about night-vision symptoms and satisfaction and an open-ended question for patients to give their reasons for recommending LASIK to others. The open-ended responses were categorized and tabulated. RESULTS: Four hundred thirty-four patients provided reasons for recommending LASIK to others. Sixteen categories of reasons were identified. "No more spectacles/contact lenses" was listed by 180 patients (42%), followed by "better vision" (21%) and "convenience" (15%). Women were significantly more likely to cite "better comfort" (27 women versus 3 men; chi square = 8.99, P =.003) and "better quality of life" (41 women versus 9 men; chi square = 7.36, P =.007) as a reason for recommending LASIK. Of the 35 patients who reported dissatisfaction with post-LASIK vision, 20 (57%) would recommend LASIK to a friend because "LASIK helps others." CONCLUSIONS: Categories of reasons for recommending LASIK to others were similar to reasons given by patients for seeking LASIK. Some patients who reported dissatisfaction with their vision said they would recommend LASIK, suggesting that recommendation of LASIK to others is not necessarily a measurement of the quality of a patient's vision after LASIK.

Adult↗
PubMed2006

Clinical evaluation of the Crystalens AT-45 accommodating intraocular lens: results of the U.S. Food and Drug Administration clinical trial.

PURPOSE: To evaluate the 12-month U.S. phase II clinical trial results of the Crystalens AT-45 (eyeonics, Inc.) intraocular lens (IOL) used to provide uncorrected distance, intermediate, and near visual acuities in patients having cataract extraction and to compare in a substudy the contrast sensitivity and near visual acuity in patients with the Crystalens AT-45 IOL and those receiving a standard IOL. SETTING: Fourteen clinical sites throughout the U.S. for efficacy and 3 non-U.S. sites for safety and efficacy. METHODS: Patients 50 years or older had small-incision cataract extraction with implantation of the Crystalens AT-45 IOL. Unilateral implantation was followed by fellow-eye implantation. Postoperatively, uncorrected distance, near, and intermediate visual acuities were determined. Near and intermediate visual acuities were tested through a distance correction to eliminate potential pseudoaccommodative effects of residual myopia and corneal cylinder. A substudy tested contrast sensitivity under mesopic conditions with and without glare, as well as visual acuity in a subset of Crystalens AT-45 patients and a control group receiving a standard IOL. RESULTS: A total of 263 patients participated in the U.S. clinical trial and had 1 year of follow-up. Near visual acuities through the distance correction of 20/40 (J3) or better, monocularly and bilaterally, respectively, were seen in 90.1% and 100%; intermediate near visual acuities were seen in 99.6% and 100%. More than half the bilaterally implanted Crystalens AT-45 patients achieved uncorrected near acuity of 20/25 (J1) or better through the distance correction, and 84% achieved 20/32 (J2) or better. In the substudy, monocular near vision through the distance correction of 20/25 (J1) or better was seen in 50.4% with the Crystalens AT-45 IOL and in 4.7% with the standard IOLs. Mesopic contrast sensitivity results with and without glare for the Crystalens AT-45 were similar to those with standard monofocal IOLs. Nearly all patients (74 patients; 97.3%) who bilaterally were within 0.50 diopter of plano postoperatively achieved 20/32 (J2) or better uncorrected near, intermediate, and distance visual acuities. CONCLUSIONS: The Crystalens AT-45 accommodating IOL provided good uncorrected near, intermediate, and distance vision in pseudophakic patients. Contrast sensitivity with the Crystalens AT-45 was not diminished relative to standard monofocal IOLs, and near and intermediate visual performance was significantly better than with standard IOLs.

Accommodation, Ocular↗
PubMed2006

FDA marketing claims, and the practitioner.

The Food and Drug Administration (FDA) is the federal agency that is tasked with regulating market entry for medical devices. The laws that govern this process are codified in the Federal Food Drug and Cosmetic Act (the Act) and the regulations are based on this law. The medical device amendments to the Act were instituted in 1976, instituting the methods for classification of medical devices and the format for the premarket review of devices. Information for practitioners on how medical devices come to market, what data are required, how specific claims are cleared, and how the practitioner can give input to the system are critical for the further development of safe and effective medical devices.

Device Approval↗
PubMed2005

Use of standards in the review of medical devices.

In keeping with its mandate to provide the least burdensome means of product regulation, the US Food and Drug Administration's (FDA) Center for Devices and Radiological Health uses many different standards to facilitate the review of premarket submissions of medical devices. The benefits of using standards in this manner include providing a set of common requirements and test protocols to the device manufacturer, thus reducing the manufacturer's need to "reinvent the wheel" for each new bench test to ensure safety and effectiveness of the device. With the current trend toward international harmonization of standards, tests performed in accordance with an international standard may be acceptable to several countries. However, there are instances in which the FDA does not agree with certain provisions in a standard. This article aims to clarify the approaches taken by the FDA to balance or resolve issues that arise when there is disagreement regarding the acceptability of a particular standard. One approach begins with the recognition of only some provisions of a standard, or more commonly, excluding those parts of a standard that are unacceptable to the FDA for regulatory or scientific validity reasons. Other approaches include working with the standards development organizations to revise the standard to include language more agreeable to all parties involved. Specific examples will be presented on medical devices, such as electrocardiogram cables and connectors, and noninvasive blood pressure monitors.

Device Approval↗