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At least 19 recordsLinked to original sources
PubMed1979

A general-purpose implantable multichannel telemetry system for physiological research.

The majority of physiologically significant parameters can be accurately measured with relatively simple transducers and with a minimum of sophisticated electronics; such parameters include temperature, pressure, and electrical activity and generally require less than a 200 Hz bandwidth. In most experiments, however, measurements at multiple sites are needed to characterize fully a particular response, and the use of totally implantable telemetry systems becomes attractive as the problems of percutaneous leads in conscious animals are compounded in proportion to the number of sensors. These systems have been produced in limited quantities because a large number of components and long assembly times are necessary to provide simple amplifications and signal processing in a small implantable package. A new six-channel system incorporates all signal processing on a single integrated circuit, and only one CMOS divider chain and an integrated telemetry transmitter are required for support. This high level of integration accelerates assembly time and increases reliability by minimizing the interconnections. Such advancements are essential before the full potential of implantable telemetry can be realized. This paper details the performance of this system during initial applications requiring pressure, bioelectrical, or temperature telemetry.

Animals↗
PubMed1978

PCM telemetry for physiological data.

PCM technology offers significant advantages in the application of telemetry to medical and physiological studies. The requirements for less complicated handling, standardized system layout, improvement of weight, size and power supply by commercial battery modules, as well as different wireless data links are met better by a PCM encoder which was specially developed for physiological applications. The advantages of PCM are illustrated in this paper by relating the experimental requirements to technical specifications for the elements of a telemetry link. A newly designed 8-channel PCM-telemetry system satisfying these requirements is described.

Humans↗
PubMed1977

Studies of ambulance patients with ischemic heart disease. 1. The outcome of pre-hospital life-threatening arrhythmias in patients receiving electrocardiographic telemetry and therapeutic interventions.

Patient delay in seeking medical assistance for acute ischemic heart disease and the incidence of potentially life-threatening arrhythmias en route to the hospital were examined in a 22-month community trial of ambulance telemetry. Of 7,654 patients transported, 179 who had electrocardiograms (ECGS) transmitted were found to have had acute MIs or acute myocardial ischemic events. Fifty per cent of these patients summoned an ambulance within 30 minutes and 72 per cent within two hours after the onset of acute symptoms. Fifty-eight patients had potentially life-threatening arrhythmias. Interventions with drugs and/or defibrillation was required in 22 patients with or without cardiopulmonary resuscitation (CPR); intervention with CPR alone was required in six patients. Twelve of these 28 patients survived through hospital admission and six were alive at three months. The relatively low outcome/input ratio of this experience necessitates re-evaluation of the epidemiological characteristics and patient selection criteria in populations considered for telemetry.

Aged↗
PubMed1975

A new hyrogen ion telemetry technique for evaluating gastroesophageal reflux.

A new pH capsule telemetry technique was used to measure the pH fluxes in the upper part of the gastrointestinal tract in normal volunteers, symptomatic patients and in those with hiatal herniorrhaphy during the preoperative and postoperative period. The Darvon-sized pH capsule is swallowed with ease and with minimal discomfort by a fasting patient. The pH of the surrounding media activates an FM radio transmitter within the capsule to emit a continuous radio signal which is converted by a receiver to a linear graph on a strip chart recorder. This pH capsule telemetry test is easy to perform on an ambulatory basis and allows an accurate and reproducible determination of the presence or absence of esophageal reflux in patients with and without a hiatal hernia. Its correlation with symptomatic reflux is higher than that found with a conventional gastrointestinal series examination. The technique allows a much clearer distinction to be made between those patients with real symptomatic esophagitis secondary to actual reflux and those with other esophageal, cardiac or pulmonary symptoms existing withour reflux. This study also reveals a consistently lower fasting gastric pH in patients with signs and symptoms of reflux than in normal individuals without reflux. The technique enabled a more accurate assessment of the efficacy of hiatal hernia repair and revealed a reduced degree of esophageal reflux in those patients who had undergone successful repair with fundic plication.

Clinical Trials as Topic↗
PubMed1979

Evaluation of fetal monitoring by telemetry.

A radiotelemetry system for the direct monitoring of fetal heart rate and intrauterine pressure during labor has been evaluated at 5 different institutions. A conventional fetal scalp electrode and a special intrauterine pressure sensor are connected to a radio transmitter placed on the patient's thigh. The receiver can be located up to 50 feet away from the transmitter and is either a self-contained monitor or a unit that converts a conventional fetal monitor to a telemetric one. The telemetry recordings are of similar quality to those obtained from conventional monitors. Telemetry allows for greater patient comfort and mobility as well as greater convenience to the clinical staff. Continuous data can be obtained from patients while they are ambulatory or sitting in a chair as well as while they are in bed.

Electrodes↗
PubMed1979

Integrated power controllers and RF data transmitters for totally implantable telemetry.

Data transmitters and power/source controllers are common elements in all totally implantable instrumentation systems. Two custom-designed integrated circuits have been developed for these elements and have significant impact on the realization of compact reliable telemetry packages. The first is an elapsed-time power switch that can remotely turn on implanted battery-powered systems with a short RF burst; to prevent accidental battery drainage, it will automatically turn off after a preprogrammed time (1-5 min). The second is a precision RF transmitter capable of operation up to 125 MHz in either FM or pulse-coded format and requires only two nonintegrated inductors. These IC systems are basic building blocks for a large number of totally implantable telemetry applications.

Electric Power Supplies↗
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↗
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↗
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↗
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↗
PubMed1979

Totally implantable dimension telemetry.

A totally implantable dimension telemetry system has been developed to instrument animals for chronic physiological research. Implantable signal processing electronics allow free-roaming animals with no percutaneous leads while retaining the long-term redproducibility of fixed implanted transducers. Two low-powered, custom-integrated circuits have been developed and assembled into an implantable package capable of measuring one dimension channel. The system has been operated in the amplitude modes of through-transmission and reflection as well as in a new Doppler-power configuration and aimed at determining interfaces between blood and surrounding structures. In a addition to single channel systems, these ICs are key elements in multimode, multidimensional implants capable of more accurate characterization of deep body structures.

Anatomy↗
PubMed1979

An integrated circuit approach to totally implantable telemetry systems.

A series of totally implantable telemetry systems has been developed to determine such key physiological parameters as blood flow, pressure, dimensions, temperature, and bioelectrical activity in chronic research animals. Custom integrated circuits provide the signal-processing complexity and performance required to sufficiently instrument the animals for an accurate prediction of human responses. Additional implant and transducer technologies are necessary to complete the instrument package. Although the costs of these technologies are high, they are more than offset by the unique information obtained and overall reduction in the expenses of medical research because fewer animals can be studied over longer periods. A number of the IC-based implants are in use in several physiology and experimental drug studies where adequate reliability and performance could not be achieved by alternate approaches.

Animals↗