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At least 37 records · Page 2Linked to original sources
PubMed1979

Applications of totally implantable telemetry systems to chronic medical research.

The motivation for the development of advanced totally implantable telemetry systems is to improve the quality of medical care through a more detailed understanding of basic physiological processes. Three research protocols in electrophysiology, hepatic hemodynamics, and cardiac pharmacology are described which rely on new implantable instrumentation; these devices allow chronic measurements in the conscious animal of such diverse parameters as aortic and ventricular pressures; atrial, ventricular, and bundle of HIS electrograms; aortic and coronary blood flow, and total hepatic blood flow by measuring velocity profiles in the portal vein and the hepatic artery. The compact size and high reliability now achievable with these telemetry systems provides new tools to the researcher for the study of the body in health and disease.

Animals↗
PubMed1977

Evaluation of the model 78100A adult telemetry unit for use in fetal heart rate monitoring.

A commercially available adult telemetry unit was adapted for use in fetal heart rate monitoring. Advantages included permitting the mother to ambulate during labor, monitoring the fetus while the mother was in transit from the labor to the delivery area and reducing electrical noise levels. Patient as well as physician acceptance has been uniformly excellent. Patients who normally would not have accepted monitoring acceded to the use of the telemetry system when informed that they could move about while in labor. The equipment is easy to adapt, widely available, relatively inexpensive and simple to use.

Electrocardiography↗
PubMed1991

128-channel cable-telemetry EEG recording system for long-term invasive monitoring.

A 128-channel cable-telemetry EEG monitoring system has been developed for use on patients undergoing intensive neurodiagnostic monitoring with invasive intracranial electrodes. A unique head mounted preamplifier/multiplexor design allows continuous recording from any combination of intracerebral, subdural, epidural or surface electrodes. A computer is used to delay or buffer all 128 channels by 2 min or more. This computer is connected to a fileserver via a local area network and is used exclusively for data acquisition. Seizure files created by the activation of the seizure/event push button or detected by a second computer containing on-line seizure/spike detection algorithms are written directly on to the fileserver by the acquisition computer. The 128 channels of EEG recorded on the fileserver can then be remotely reviewed on a high resolution graphics terminal, printed out on a laser jet printer, archived or played out on paper, 16 channels at a time on any EEG machine. A time of day signal is also generated by the computer to permit time correlation with a continuous audio/video VCR unit which permits comparison of the EEG and clinical events. This system allows continuous EEG monitoring of extensive multichannel arrays not previously possible with conventional 16-, 32- or even 64-channel systems.

Electroencephalography↗
PubMed1991

Four-channel telemetry system for in vivo measurement of hip joint forces.

The long-term loosening of artificial hip joints remains a serious clinical problem. Optimization of implant design and material will improve the fixation, but it requires a detailed knowledge of the forces which act on the implant. A four-channel telemetric transmitter was developed and arranged completely inside a hermetically closed artificial hip joint. This permits long term in vivo measurements of the three-dimensional forces without endangering the patient. The external telemetry system consists of an inductive power supply, an RF receiver, a microcomputer with hardware extension and a VHS video system. The personal computer offers real-time data processing of three orthogonal force components as well as slow motion analysis of recorded measurements. After several years of animal tests, two instrumented prostheses were implanted in the first patient (male) in May and August of 1988. In March 1990 a third prosthesis was implanted in a second patient (female). Joint force measurements have regularly been performed from the first post-operative day until now for several kinds of activity.

Biomechanical Phenomena↗
PubMed1976

An inexpensive receiver for ECG telemetry.

A simple, inexpensive ECG demodulator circuit has been described which may be used in conjunction with an ECG telephone transmitter, telephone amplifier, and ECG recorder to form a telemetry system capable of ECG monitoring.

Electrocardiography↗
PubMed1977

Cardiac telemetry exercise program.

To train cardiac consultants who interpret electrocardiogram rhythm strips from the field, we designed a series of prerecorded telemetered rhythms and discussions which can be sent into telemetry consoles. The patterns represent cardiac arrhythmias (eg, ventricular tachycardia, complete heart block, etc), as well as equipment problems (loose leads, misplaced leads, etc). We selected and modified some of the patterns of "Arrhythmia Resusci Anne" (Laerdal Medical Corporation), sent these through ambulance radios (to create a tone), recorded the signal on a standard tape recorder and dubbed in the monologue. The physician is asked to interpret the pattern and give instructions to the ambulance attendant. The answers and response times are recorded by the technician running the taped exercise. At the end of the quiz, the rhythms are replayed along with a discussion of each pattern.

Ambulances↗
PubMedDate not supplied

[A comparative study of standard electroencephalographic techniques and telemetry (author's transl)].

The authors have used radio-telemetry to perform long duration studies and to study the variations in cerebral electrical activity. They presented a quantitative study of the distribution of paroxysmal activity in the epileptic, based on an experimental observation and confirmed as a result of the methods used. They were able to show a relationship between the severity and temporal distribution of paroxysmal activity which was confirmed statistically. Further observations were made on the distribution and onset of epileptic discharges but more detailed analysis is required before general electrophysiological conclusions can be made.

Adolescent↗
PubMed1975

An intra-oral telemetry system for the continuous recording of vertical jaw movement.

Continuous measurement of the separation between upper and lower dental arches, the so-called interocclusal distance (10D), is of interest in dentistry. Criteria for making such measurements by radio telemetry are discussed. It is concluded that a transmitter small enough to fit in a molar tooth gap is necessary in order to minimize interference with normal function; other design factors are related to obtaining adequate frequency stability, on which measurement accuracy depends. A transmitter fulfilling these requirements is described which sensed the instantaneous value of 10D by the frequency change produced when a metallic object (dental filling, gold crown, shorted turn of wire or piece of ferrite) in one dental arch moved relative to the transmitter in the other. Errors due to lateral and protrusive jaw movements were measured. Careful design and the use of high grade ceramic chip capacitors resulted in a transmitter of good frequency stability (+/- 0.03% in 10 h, +/- 0.02%/degrees c) and small size (10 X 7 X 5 mm). An example is given illustrating 10D movements due to swallowing, speech and respiration.

Humans↗
PubMed1977

Urine marking and territoriality in Galago alleni (Waterhouse, 1837--Lorisoidea, Primates)--a field study by radio-telemetry.

A wild population of Galago alleni was controlled by trapping and followed by radio-tracking in the equatorial rainforest of Gaboon during three study periods of 3 months each in 1972, 73 and 75. The disposition of territories and the social organization are described, as well as their evolution through time. A new technique of radio telemetry permitted identification and localization of urine marking in wild galagos. Urine marking took place throughout the territory, with a fourfold increase in frequency in zones where there is a slight overlap with neighbouring territories (female--female or male--male). The function of urine washing (wetting of the soles of the feet with urine) is discussed in relation to five hypotheses proposed by different authors, and th data obtained in the field in Gaboon. We interpret this behaviour as a means of dispersal of urine marks (social signals) in a three-dimensional milieu where displacement by a combination of leaping and running creates numerous pathways.

Animals↗
PubMed1975

Electrical activity of grafted myometrium and its recording by radio-telemetry in unrestrained rabbits.

1. The electrical activity in myometrial grafts in fifty-one female rabbits with ear chambers fitted with pick-up electrodes has been monitored. An FM telemetry system has made long-term studies possible in the freely moving animal. 2. Two distinct patterns of electrical activity were observed either arising spontaneously or provoked by oxytocin. These were the 'long-duration burst' containing about 50-150 spikes, and the 'short-duration burst' containing 1-10 spikes. 3. The spike frequency within the long-duration bursts varied between 0-9 and 1-3 spikes sec-1 and was fairly constant during the first half of the burst. The frequency of the bursts in the long series of short-duration bursts was about 2-3 min-1. 4. When activity from grafts in two chambers in the same animal was monitored for long periods, spontaneous activity occurred at random throughout the day in each graft, indicating that the spontaneous activity was probably myogenic.

Animals↗
PubMed1979

A multichannel telemetry system for recording cardiovascular neural signals.

A multichannel telemetry system was developed for use with chronically instrumented unrestrained cats. This system can simultaneously record efferent and afferent cardiovascular neural signals, bioelectrical noise arising near the electrode recording the neural signals, EEG, ECG, and a standard calibration signal. The miniature (18 cm3), lightweight (24 g), telemeter is a five-channel, time-multiplexed, pulse width modulation (PWM)/FM device employing a high frequency subcarrier (60 kHz) and two sampling frequencies (30 kHz and 6 kHz). The device is powered by two small 120 mA . h silver oxide cells; it has an indoor transmission range of 10 m and can operate for 48 h. One channel transmits a standard signal (a square wave of 100 Hz and 200 mVp-p) used to monitor and regulate the system's performance. When the variation in either the amplitude or frequency of the standard signal is greater than 10% of the control value, the transmitted bioelectrical signals are automatically discarded.

Animals↗
PubMed1975

A multichannel implantable telemetry system for flow, pressure, and ECG measurements.

The design of telemetry systems for chronic implantation within the body have progressed from simple single-channel devices to complex multichannel systems over the last 15 yr. Although chronic measurements of temperature, ECG, and pressure have been reported with good results, measurements such as dimension and blood flow have been difficult because of heavy power requirements. The design to be described is a multiplex system that will measure up to eight individual parameters simultaneously, including blood flow. Flow is measured using an electromagnetic transducer, and by special design, the normal high power requirements of the electromagnetic technique have been reduced to a few hundred milliwatts. The system is powered by two NiCad, rechargeable batteries which are periodically recharged through the intact skin by induction at 250 kHz to an implanted pickup coil. The presently constructed units have been configured to measure ECG, two pressures, temperature and ascending aortic flow.

Animals↗
PubMed1991

The clinical features and prognosis of pseudoseizures diagnosed using video-EEG telemetry.

A total of 110 patients underwent diagnostic evaluation for attacks of uncertain origin by means of video-EEG telemetry and had a diagnosis of pseudoseizures confirmed. Eighty-six patients (78%) were female, mean age of onset 25 years, and mean duration of attacks was 3 years. Many of the patients had erroneously been thought to be suffering from epilepsy. The attacks could be divided into two broad categories: attacks of collapse (one-third) and attacks with prominent motor activity (two-thirds). In some patients, the attacks were associated with incontinence and injury. The differential diagnosis and clinical features of the attacks are described. Additional psychiatric features were present in 52 (47%) patients. Follow-up (for a median 5 years; range, 1 to 14 years) showed that 40% of these patients stopped having pseudoseizures. This favorable outcome was associated with being female, leading an independent life, a formal psychological approach to therapy and counseling, and the absence of coexisting epilepsy, but not with the duration of pseudoepilepsy, prior episodes of pseudostatus, the coexistence of overt psychiatric disease, or the clinical features of the attacks.

Adult↗
PubMed1991

A new method for continuous chronic measurement and recording of blood pressure, heart rate and activity in the rat via radio-telemetry.

Accurate continuous chronic measurements of blood pressure from conscious laboratory rats are critical to many experimental protocols but have been difficult or impossible to acquire. A system consisting of an implantable radio-telemetry device, receiver, and computer-based data acquisition system that allows such measurements to be easily obtained has been developed. This system is capable of monitoring and recording arterial pressure (waveform, systolic, diastolic, and mean), heart rate, and activity from rats weighing greater than 175 gm for periods in excess of 6 months. Chronic patency has been achieved through a patented design which includes an antithrombogenic film and a gel membrane located at the catheter tip. Validation of telemetered measurements via carotid catheter has demonstrated the accuracy to be better than +/- 5 mmHg in 85% (N = 20) tested at 3 weeks post implantation, 86% (N = 15) tested at 8 weeks, and 78% (N = 9) at 12 weeks. Incidence of loss of patency was 2.3% (N = 44). This system has a demonstrated ability to obtain accurate continuous chronic measurements of arterial pressure free of the stressors associated with conventional systems.

Animals↗
PubMed1976

Electrocardiographic and respiratory responses to viscerotropic and neurotropic strains of Newcastle disease virus measured by radio telemetry.

Two groups each of White Rock chickens from 6 to 23 weeks old were monitored by radio telemetry to determine their electrocardiogram and respiration response after they were infected with either a velogenic viscerotropic isolate of Newcastle disease virus (VVND) or the neurotropic GB strain of Newcastle disease virus (NGB). Significant changes were found in the heart rate, R wave amplitude, ST segment elevation, T wave amplitude, RS complex interval, ST segment duration T wave interval, TP segment duration, PR segment duration and TP interval of the birds infected with VVND, but no significant ECG changes were found in the birds infected with NGB. There were no significant changes in respiration rate in any birds.

Animals↗
PubMed1976

A 4-channel telemetry system for hospital patient monitoring.

A 4-channel radio telemetry system has been designed and implemented for use in the operating room on patients undergoing surgery. 30 such systems are in daily use throughout the Duke University Medical Cener. Relative simplicity, long battery life and a DC-response capability are the important features of these systems. The four physiological channels used are; electroencephalogram, electrocardiogram, peripheral pulse, and arterial blood pressure.

Blood Pressure Determination↗