ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

The combined effects of reduced sampling rate and precision on electrocardiographic measurements were studied for Frank-lead electrocardiograms from 120 male adults using a 100-Hz recording bandwidth. The data were digitized at 2-millisecond equal intervals with 12-bit precision. Amplitudes, time durations, and intervals were determined using the Veterans Administration automated electrocardiographic analysis program. These measurements were compared with those obtained after reducing the sampling rate and precision to 250 Hz and 8 bits. For an individual cardiac cycle, measurement changes ranged up to 46 milliseconds for P-R interval and 65 microvolts of resolution for R-wave amplitude. When computed from averages of several beats over a ten-second period, measurement changes ranged up to 11 milliseconds for P-R interval and 45 microvolts for R-wave amplitude. It is concluded that measurement changes introduced by 250-Hz, 8-bit sampling are generally tolerable when measurements are determined from averages over a ten-second period. Their effects on electrocardiographic interpretations can only be determined by testing individual programs. However, for the Veterans Administration's automated program, no diagnostic statement changes were caused by this data reduction.

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Electrosurgical devices and equipment are in widespread use in today's hospitals. Their ability to perform surgical procedures not otherwise accomplishable makes them indispensable tools for the medical profession. They are used in almost every hospital in the United States, and for that matter, in the world. Beginning in the 1920's such devices have performed countless surgical procedures.This article brings into perspective the parameters of electrosurgical units and their effects. It defines the electrosurgical unit's external circuit path, and the effects created along this path due to physical phenomenon. Topics covered include radiated energy, conducted energy, and capacitive coupling effects which cause concern within the overall operating room environment.A discussion of precautionary techniques, present operating room equipment performance reviews, and plans for future equipment purchases is included in order to review what can be done to minimize the effects of high-frequency physical phenomenon. These topics are presented in order to stimulate thought so that decisions can be made based on common background material.A summary is included of what the future may hold for electrosurgery. A review of the clinical benefits is made and compared to new technological advances; particularly laser surgery, plasma scalpel, and cryosurgery. The conclusion is reached that the use of the high-frequency electrosurgical modality is here to stay and will not change dramatically in the near future.

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

This paper describes a novel tester for electrosurgical machines that has the capability of giving a relative output indication when used with microcoagulators or other low-power electrosurgical machines. The design overcomes most of the limitations of conventional testers and may be easily expanded to cover higher power ranges.

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

An easy-to-build and low-cost infant heartbeat monitor is described. The battery-powered portable monitor provides both visual and audible indications of each heartbeat by sensing the ECG signal. Heart-rate indication and alarm limits are not provided.The monitor is constructed from readily available parts and uses standard batteries for its operation. It is designed using reliable and low-powered solid-state devices, is simple to operate and service, and is electrically safe. It can be made quite compact and durable and its application is not solely limited to infant monitoring.

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

A patient-lead fault interruptor (PLFI) is presented that behaves as a current-controlled device. It is normally “closed,” and “opens” if a fixed threshold current level is exceeded. It is self-protecting in that it opens up before it can exceed its own current rating. Once the trip point of the current-controlled device is exceeded, the voltage-current relationship shows a negative slope during the transition to the open circuit state. The trip time under fault condition is of the order of a few microseconds. Applications of PLFIs are described in this article.

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

New, nonlinear, “switching” current limiters are being offered to medical equipment manufacturers and servicemen as a means to protect patients from shock hazards associated with electrical leakage or risk currents. Although the new switching-type current limiters appear to give 20-fold reductions in current through the patient, AC waveforms can still induce pulses of current which are large enough to create a potential shock hazard. The article illustrates this situation, and suggests some courses of action for manufacturers, CEs, and BMETs using such devices, or performing electrical safety tests on equipment which utilize such devices.

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Technology Assessment (TA) is a relatively new concept with a heterogeneous “community” of practitioners and advocates. Consequently, there is much confusion about this new analytic strategy. Many people, for example, confuse TA with other technology studies such as engineering feasibility, market research, clinical trials, cost-benefit, environmental impact, technology forecasting, or technology transfer. This article, which draws most of its examples from the field of health, attempts to allay the confusion by showing how TA differs significantly from other technology studies and by describing both the opportunities and the obstacles involved in conducting comprehensive assessments.

ISSN:0363-8855    

出版商:OVID    

年代:1977

数据来源: OVID