Showing papers in "Journal of clinical engineering in 1991"

Health Conditions in the Americas

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The definition of a clinical engineer.

Abstract: The American College of Clinical Engineering formed a committee to develop a contemporary definition of a Clinical Engineer. The committee considered existing definitions including that currently used by the Clinical Engineering Board of Examiners of the International Certification Commission. Educators and other societies provided other definitions. Following substantial discussion and revisions, the definition was adopted by the Board of Directors of the ACCE on May 13, 1991.

Laboratory and hospital testing of new infrared tympanic thermometers.

Abstract: A patented approach to infrared thermometry based on the use of a standard pyrosensor has resulted in the development of two new infrared tympanic thermometers, one for professional use, the other for home use. Both were tested to evaluate accuracy in the laboratory and to evaluate equivalence to standards, correlation to standards, and precision in human subjects. Accuracy was found to be well within ASTM standards on both models. Mean ear temperatures were 0.2 degrees C below oral and 0.7 degrees C below bladder temperature. Correlations between ear and oral and ear and bladder temperatures were r = .77 to .84. Repeatability in the same ear was very high at r = .95 (left) and .97 (right). Reproducibility between left and right ear ranged from r = .89 to .92.

Noninvasive Functional Localization by Biomagnetic Methods Part II

Abstract: External biomagnetic measurements can be used to obtain functional information concerning the electrical activity of various organs, e.g. the human heart and brain. These methods are completely noninvasive, and they have turned out to be promising in localizing bioelectric sources in the body. During the last few years, the number of localization studies reported has increased rapidly. Although the methods are not yet clinically accepted, possible clinical applications are numerous; for example, the localization of various cortical sources and epileptic foci in the brain, as well as the localization of sources of life-threatening arrhythmias in the heart. The best localization accuracies reported in brain studies are of the order of a few millimeters, and in heart studies, about 1–2 centimeters. Part I of this paper describes the generation of biomagnetic fields in living tissue and presents the basic theory of source localization. The most popular models used in various localization studies are presented, and applications are presented. Part II will deal with realistic digital torso and head models, validation of the localization results, and instrumentation.

Clinical engineering in Brazil: current status.

Abstract: It is estimated that 20-40% of all existing healthcare equipment in Brazil is not working because of a lack of service, parts, or supplies, or because it has not been installed. Traditionally, equipment goes completely unattended until a complete failure occurs. Then, it sits idle, paralyzing those services provided by it, until its owner gathers enough money to afford the extravagant repairs provided by manufacturers and their representatives, with little continuing assurance of quality and efficacy. During the last 10 years, a few medical institutions have started to establish their own clinical engineering (CE) teams. Besides providing significant savings, these pioneers are contributing to the improvement of the process of managing the introduction of technology into healthcare. Now, about 10% of all hospitals with more than 150 beds have their own CE departments. Three years ago, the Brazilian Association of Hospital Engineering and Maintenance was created to promote the recognition of CE as a new profession. The main difficulties that inhibit the faster and wider adoption of the self-reliant approach are analyzed and some possible solutions are discussed.

Integrated monitoring can detect critical events and improve alarm accuracy.

Abstract: A computer-based, integrated monitor system was designed and utilized to collect and interactively manage physiologic data (13 variables and 3 waveforms) from six routinely used operating room monitors. Various approaches were developed to reduce false alarms, classify waveforms, and recognize events. False alarms: false alarms in ECG heart rate detection were reduced from 37.3% to 2.6% (p=0.005) of total alarms using multi-variable analysis and rate-of-change limits. Waveform classification: using artificial neural networks (AN), CO2 waveforms were classified into (a) spontaneous, (b) mechanical, and (c) mechanical/with spontaneous breathing attempts. The system properly classified 47 of 71 spontaneous, 65 of 67 mechanical, and 37 of 44 mechanical breaths/with spontaneous breathing attempts. Another ANN was used for detection of elevated and depressed ST segments in the ECG signal. All ST segment elevations and depressions of 0.1 mV were correctly identified. Event recognition: an algorithm developed to identify endotracheal intubation correctly recognized 13 of 17 intubations. This resulted in a 42% reduction in low end-tidal-CO2 false alarms.

The Medical device industry : science, technology, and regulation in a competitive environment

Abstract: "Introduction Focus on Patient Care Historic Overview/Legal Framework of the Regulatory Environment A History of Government Regulation of Adulteration and Misbranding of Medical Devices Medical Device Regulation: The Big Picture FDA's Regulatory Program for Medical Devices Overview of Current FDA Requirements for Product Approvals Responding as Organizations to the Regulatory Environment CDRH's Medical Device Laboratories The FDA's Role in Assisting Small Manufacturers Precautionary Checklist for Addressing the Issue of Medical Device User Error and Product Misuse FDA's Role in Medical Device User Education Industry's Role in Standards Development Role of NCCLS and ECCLS in the Voluntary Consensus Process Role of AAMI in the Voluntary Standards Process Role of ECRI Role of ASTM in the Voluntary Standards Process Role of USP Responding as Companies to the Regulatory Environment How to Submit a Successful 510(k) Compiling a Successful PMA Application Optimal Use of FDA Advisory Panels Complying with the IDE Regulation Clinical Trials and Labeling Claims Establishing a Training Program for Plant Personnel Complying with GMPs: Government Perspective Complying with GMPs: Industry Perspective Developing a Recall Program Complying with the Medical Device Reporting Regulation FDA/GMP/MDR Inspections: Obligations and Rights Product Liability Implications of Regulatory Compliance or Noncompliance Developing a Labeling Compliance Program Home Use Diagnostics: Special Considerations Sterility and Bioburden: An Issue for In Vitro Diagnostic Products Current and Emerging Issues in the Regulatory Environment Process/Design/Facility Validation Use of Risk Assessment Procedures for Evaluating Risks of Ethylene Oxide Residues in Medical Devices Medical Device Risk Assessment The AIDS Epidemic: Its Impact on Manufacture and Use of Medical Devices The Animal Testing Issue New Challenges in Medical Product Sterilization Legislation Needed to Improve the Medical Devices Law The 1989 Waxman/Dingell Medical Devices Bill Software Regulation Maintaining Your Competitive Edge at Home and Abroad Accessing New Technologies: The Federal Connection Responding to the Challenge of Education of Nurses and Allied Health Personnel on the Safe Use of Medical Devices Historic Overview/Legal Framework of Occupational and Environmental Safety and Health An Overview of Regulations Governing Occupational Exposure Right-to-Know Regulations Safe Handling of Biologically Contaminated Medical Devices Current and Emerging Issues in Occupational and Environmental Safety and Health Government Initiatives in the Environmental and Occupational Safety and Health Arena Historic Overview/Legal Framework of Coverage, Payment, and Marketing Medicare's Policy Perspective on Coverage and Payment for Medical Technology The Impact of Cost Control in Restructuring of the Health-Care Industry The Structure of the Medicare Program: Legal Considerations of HCFA Regulation Basics of Medicare Payment for Hospital and Physician Services Payment Planning for New Medical Diagnostics: An Action Plan for the 1990s Medical Standard Setting in the Current Malpractice Environment: Problems and Possibilities Afterword Responding as Companies to Coverage, Payment, and Marketing Understanding and Securing Medicare Coverage for New Medical Technology Avoiding Fraud and Abuse Complying with Antitrust/FTC Restrictions Current and Emerging Issues in Coverage, Payment, and Marketing Megamarketing: An Expanded Approach for the 1990s Historical Overview/Legal Framework of the International Environment Trends in International Regulations and Their Growing Impact U.S. and Foreign Requirements: A Legal Overview Responding as Organizations to International Issues Industry Role in International Standards Networking Internationally Economics of U.S. Trade in Medical Technology and Export Promotion Activities of the U.S. Trade in Medical Technology and Export Promotion Activities of the U.S. Department of Commerce Responding as Companies to International Issues Using Partnerships and Other Joint Ventures Current and Emerging Issues in the International Environment An Overview of the European Community's 1992 Program ANSI---Its Role in the Rapidly Changing Marketplace "

Centralized maintenance responsibilities: a case study.

Abstract: This paper reviews a total equipment management program that has been documented since 1983. One department was given responsibility for all maintenance activities needed for the hospital's electronic equipment, including many items that were, at the time, not maintained by most biomedical engineering departments. The department combined customer satisfaction and cost-effectiveness into a single goal and produced excellent results. Costs decreased, customers were satisfied, and effectiveness increased. The program has saved over $1,000/bed/year for the last seven years, and total documented savings are over $5,000,000. The cost/unit was almost 30% below the average values for many other biomedical engineering departments.

Productivity, efficiency, & effectiveness in the management of healthcare technology: an incentive pay proposal.

Abstract: Modern healthcare managers are looking for better ways to motivate their employees as well as document and evaluate employee performance. The term productivity is familiar to most healthcare managers. The term efficiency is less familiar. These terms are defined and their significance for use as unique and valuable indicators of effective employee performance is discussed. Similar criteria were applied to make a general comparison between biomedical technician performance in two different hospitals in Tegucigalpa, Honduras, in Central America. A performance-based incentive program using an Incentive Pay Index chart is proposed as a tool through which hospital or company managers can provide technicians or technologists with ongoing motivation to improve both their productivity and efficiency on the job.

Instrument to test patency of lacrimal drainage system.

Abstract: The lacrimal drainage system drains fluid that exists normally on the surface of the eye into the nasal cavity. This paper describes a hand-held, personal-computer-based instrument to quantitatively estimate the resistance to fluid flow through the lacrimal drainage system. This resistance measurement is proposed as a possible means to diagnose blockage of the system and to verify the degree of change in resistance after clinical treatment. The instrument system consists of a hand-held syringe attached to pressure and flow transducers. Resistance is calculated as the ratio of differential pressure to flow rate and is displayed in real time on a computer monitor.

The medical information bus: overview of the medical device data language.

Abstract: The Medical Information Bus (MIB) reference model defines a new, object-oriented Medical Device Data Language (MDDL), under development by the Institute of Electrical and Electronic Engineers Society (IEEE) P1073 MIB Standard Committee. The MDDL treats medical devices, host computers, humans and device parameters as objects, and provides a flexible and extensible language for describing and passing messages between objects. This paper describes the MDDL semantic reference model and presents an overview of the MDDL structure, within the framework of the International Standards Organization (ISO) System Management Overview (SMO) model. A simple example of how the MDDL can be used to construct a device event report is also described.

Quality assurance in biomedical or clinical engineering.

Abstract: Biomedical department directors must begin serious consideration of quality assurance (QA) implementation if they are to satisfy JCAHO directives. This consideration need not be approached with fear or anxiety. The purpose of this paper is to focus attention on the need and purpose of quality assurance in the biomedical or clinical engineering discipline while demonstrating the ease with which QA may be integrated into an existing biomedical environment. Because every biomedical program is unique, the approach described here can serve as a basic guide for tailoring essential components into a working quality assurance system.

Theoretical and Practical Aspects of Monopolar Right-Ventricular Impedance Stroke Volume

Abstract: A spherical electrical-conduction model was used to predict the stroke-volume (SV) induced impedance change (ΔZ), measured with a monopolar electrode. Insights from the model showed that for an impedance change to occur, the resistivity of the ventricular wall must be different from that of the blood therein. The predicted values for the ratio ΔZ/SV were compared with those measured between a catheter-borne, monopolar electrode positioned in the middle of the right ventricles of eight dogs (24.1 – 37.7 kg) and a large indifferent electrode (8.5 cm) placed on the right chest. Two catheter electrode widths (0.4 and 1.2 cm) were evaluated. True stroke volume was measured with an electromagnetic flowmeter on the pulmonary artery. The relationship between impedance change and stroke volume was determined by varying venous return with an inflatable balloon in the inferior vena cava. The measured values for ΔZ/SV ranged from 0.07 to 0.32 (av. 0.16) ohm/mL for the 0.4 cm electrode (r = 0.81–0.99) and 0.04 to 0.26 (av. 0.14) ohm/mL (r = 0.74 – 0.92) for the 1.2-cm electrode. The predicted values for the same electrodes were shown to depend on ventricular volume. For a volume of 60 mL and SV = 30 mL, the average predicted value for ΔZ/SV was 0.146. The linearity between ΔZ and SV is best with large ventricles and small stroke volumes. It is concluded that a right-ventricular, monopolar electrode offers a simple and practical method of tracking changes in stroke volume by impedance change.

Testing of central nervous system shunt devices.

Abstract: This paper presents the results of a study performed by the U.S. Food & Drug Administration (FDA) under the Conformance Assessment to Voluntary Standards program. The ASTM voluntary standard F647-85 (American Society for Testing and Materials: Standard Practice for Evaluating and Specifying Implantable Shunt Assemblies for Neurological Applications) was evaluated as to the adequacy of its test methods and the reasonableness of its application to currently marketed shunt devices. The objective of this study was to assess the impact of ASTM: F647-85 on the safety and effectiveness of shunt devices and thereby assist the FDA in setting priorities for its mandatory standards development activities. By searching the FDA's postmarketing surveillance database and by testing seventeen shunt devices and three catheters from six manufacturers, it was determined that these devices conform with most of the ASTM standard requirements. However, no single device conformed to all of the requirements of the standard. Suggestions for improving the voluntary standard's impact on the safety of shunt devices are presented.

Prosthetic valve selection for a pulsatile LVAD.

Abstract: During the final development of a unique Magnetically Actuated Left Ventricle Assist Device (MALVAD), three of the most widely used clinical prosthetic valves were evaluated to determine their suitability for the stringent requirements for LVAD use, in both the inflow and outflow positions. The three valves (St. Jude Medical-SJM; Medtronic Hall-MH; Bjork-Shiley Convex-Concave-BSCC), with lumen size of 25 mm, were tested in the same appropriate mock loop to the following set of hydraulic parameters: 1) after-load systemic pressure = constant 100 mmHg; 2) preload pressure ranged from 3 mm to 18 mmHg; 3) beat rate ranged from 60 bpm to 80 bpm. Pump actuator power was held constant, correspondent with specific bpm rate, for all valves tested. Results from a series of 10 bench tests per valve showed that the SJM was significantly better, on a statistical basis, than both the MH and BSCC valves, at fill pressures of 5 mmHg. At 10-mm fill pressure, however, the statistical flow rates for both the SJM and the MH valves were significantly superior to the BSCC valve, so that the BSCC valve was classified as a marginal candidate for LVAD use. The SJM and MH valves had bench test flow-rate values whose numerical difference was too small to serve conclusively as an arbitrary basis for valve choice. Because of this, the two valves were further evaluated in terms of two widely recognized, mandatory LVAD valve design criteria: (1) comparative mechanical ruggedness, and (2) relative ease and simplicity of LVAD design inclusion.(ABSTRACT TRUNCATED AT 250 WORDS)

The training and use of an artificial neural network to monitor use of medication in treatment of complex patients.

Abstract: An artificial-neural-network-based drug interaction warning system was developed for use with a computerized real-time entry medical records system. The goal of the study was to provide physicians and nurses with timely warnings of potential drug interactions as therapies were prescribed. In a dialysis unit, physicians and clinical pharmacists defined rules of proper drug therapy, then trained a neural network with those rules. When the network was used to review the therapies of this patient population, a number of inconsistencies were discovered, and medication orders were changed on several patients. Real-time implementation of this monitoring system could provide messages to assure that drug therapy is consistent and proper, according to rules created by the providers of healthcare, thus preventing occasional mistakes in drug therapy.

The Safe Medical Devices Act of 1990: are hospitals ready to deal with the FDA?

Abstract: The Safe Medical Devices Act of 1990, long anticipated by regulatory affairs and compliance professionals in the medical device manufacturing industry, was signed by President George Bush on November 28, 1990. The law will significantly alter the structure of medical device regulatory mechanisms, and will expand the scope of the FDA's activities. The new medical device legislation sets requirements for hospitals as well as industry.

Technology assessment, transfer, and management: the implications to the professional development of clinical engineering.

Abstract: Technology, as applied in healthcare, is an encompassing term for products, equipment, procedures and services allied in some way with healthcare. This paper discusses technology as the word applies to healthcare. Areas of activity under the umbrella of technology--technology transfer, technology assessment and technology management--will be defined and discussed from the standpoint of their interaction with clinical engineering. The clinical engineering profession has approached participation in each of these activities in a nonsystematic manner, resulting in limited impact and a limited role. To go beyond its present role, the profession must study the processes of technology assessment, transfer, and management to understand their components, critical paths, strengths and weaknesses. This research should be undertaken by a joint group of clinical engineers representing practitioners and academia. Existing key players or professions should be identified, the role clinical engineers wish to pursue as a professional group and the skills required to assure competency should be declared, and appropriate resources for acquiring knowledge and experience identified.

Internally developed medical equipment management system: a viable alternative.

Abstract: A medical equipment management computer system, internally developed by Rhode Island Hospital, is presented. Hospital biomedical engineering departments must contend with ever-increasing regulatory requirements for patient-care equipment. Computerization is a viable solution to meeting the documentation standards dictated by healthcare governing bodies. Rhode Island Hospital's system consists of a Macintosh computer, Panorama database software, and Psion LZ64 Organiser handheld computer. Files were set up on equipment data, JCAHO-required historical documentation, service, inspections, part codes and locations, and vendor contact information. Technician inspection data recording time was reduced by approximately 30%.

A defective unidirectional dome valve was not discovered during normal testing.

Abstract: An incompetent unidirectional dome valve, that is, a valve which allows a significant amount of retrograde gas flow, was inadvertently discovered on an anesthesia machine that had been in daily clinical service for five years. The defective valve was not previously discovered during daily pre-use machine checkout or quarterly preventive maintenance. A review of the literature revealed that valve incompetence is prevalent and has caused patient morbidity; published daily pre-use checkout and preventive maintenance procedures do not test for valve incompetence. A simple procedure is proposed that positively tests unidirectional dome valves for both obstruction and incompetence.