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PubMed1975

Multichannel biotelemetry.

A summary of considerations for design and application of multichannel biotelemetry systems is given. The advantages but also the problems of wired, wireless, combined and storage telemetry are discussed in connection with its application. Modulation and multiplexing techniques are described extensively; however, this review focuses not only on the transmission of biological data but also on the important aspects of connection of the transmission equipment to the biological subject and display of the biological information. The topic of multichannel biotelemetry is rounded off by a few additional subjects such as telecontrol, information source and classification.

Telemetry↗

PubMedDate not supplied

A novel aortic coarctation model for studying hypertension in the pig.

We have developed a reproducible renovascular model of hypertension via a controllable, suprarenal aortic coarctation in the pig. This model has many potential applications, including investigation of the effects of acute hypertension in the conscious animal; identification of cardiac and vascular adaptations to chronic hypertension and their reversal; determining the effect of pharmacologic agents or other interventions on hypertension; and furthering our understanding of the implications of chronic hypertension on neurologic function. A totally implantable system was devised by attaching a reinforced silicone vascular occluder to a vascular access port. The occluder was placed around the suprarenal aorta proximal to the diaphragm. Ten pigs were made hypertensive by sequentially inflating the occluder. In six pigs, telemetric monitoring of blood pressure was used to determine when the pigs had reached target pressures (mean arterial blood pressure >150 mm Hg). Four pigs did not have telemetry units placed and blood pressure and heart rate were monitored for 4 weeks by periodically restraining the pigs in a sling. Two pigs reversed their occlusion due to presumed technical errors; the remaining pigs were studied for 4 (n = 5) or 8 (n = 3) weeks and then euthanized. Advantages of this model of aortic coarctation are that the occlusions are performed in awake animals and excessive occlusion of the aorta resulting in neurologic dysfunction or other distress to the animal can be easily corrected by simply withdrawing a small amount of the fluid used for inflation of the occluder. Additionally, removal of the constriction does not require a second surgical procedure.

Aldosterone↗

PubMed2003

Deluged with inpatient holds? Avoid violations.

To comply with standards of the Joint Commission on Accreditation of Healthcare Organizations, you must provide the same level of care to inpatients held in your ED as they would receive in critical care units. Train the entire staff in telemetry monitoring. Give patients the same level of services from radiology, laboratory, and pharmacy as they would receive upstairs. Have ED nurse work occasional shifts in critical care units.

Critical Care↗

PubMed2003

[Core body temperature monitoring using the telemetric pill].

Exposure to extreme weather or physical work conditions can lead to dangerous core temperature changes, and to the clinical syndromes accompanying them. Core temperature measurement is the main tool for diagnosing these syndromes. Recent technological advances particularly NASA's telemetry and miniaturizing technologies, have led to the development of a CorTemp Ingestible Temperature Sensor, or "pill". The pill is a small electronic device, which senses the body's temperature and transmits it through a radio wave signal to an external receiver. The advantage of the pill over other temperature measurement devices is that it is a simple device that enables core temperature measurement for many hours without the need of any wire connections or other cumbersome instruments. For this reason, the pill is an ideal tool for core temperature measurements in field locales or for continuous long duration temperature monitoring of ambulatory patients. The following study reviews available literature concerning the use of the pill and the validity of its measurements. A high correlation has been revealed between pill temperature measurements and rectal or esophageal measurements. Pill temperature values usually fall between the high rectal and the low esophageal measurements, considered the gold standard for core temperature measurement. A number of studies emphasizing the advantage of the pill are presented in this review.

Administration, Oral↗

PubMed2003

[Effects of 50 to 60 Hz and of 20 to 50 kHz magnetic fields on the operation of implanted cardiac pacemakers].

UNLABELLED: The effect of 50 Hz and 60 Hz (frequencies of current distribution) and 20 kHz to 50 kHz (frequencies of induction cooktop) magnetic interference on implanted pacemakers have been assessed with the present generation of device technology. Sixty patients implanted in 1998 and 1999 with dual chamber pacemakers from 9 different manufacturers were monitored with telemetry while passing through, and standing between a system of two coils. They generated a 50 Hz or a 60 Hz magnetic field at 50 microT. Then, patients used a cooktop at different power. The recordings were made with the standard setting of "medically correct" sensing parameters chosen for the patients. Then pacemakers were reprogrammed to the unipolar mode, with the highest atrial (A) and ventricular (V) sensitivity that did not induce muscular inhibition while moving. Between each exposure (50 Hz, 60 Hz or 20 kHz to 50 kHz), the pacemaker programmation was controlled. At the end of the tests, pacemakers will be reprogrammed with the standard setting. The medical observer being blind to the existence or not of the magnetic field. No pacemaker was influenced by the vicinity of the magnetic field at medically correct settings. At unipolar high sensitivity, no inhibition nor reprogramming was observed. Transient reversion to interference mode was observed in 6 cases, 3 transient acceleration due to atrial detection of the interference, and one T wave detection by the ventricular lead. All were observed with the 60 Hz, and only 3 with the 50 Hz magnetic field. One device (Biotronik) shifted out of its special program (hysteresis research) during the tests with the induction cooktop, but it maintained its standard program, and the event could not be repeated despite further testing. CONCLUSION: Actual pacemakers do not present any electromagnetic interference with 50 Hz and 60 Hz or induction cooktop frequency working. They are insensitive with medically correct settings. Unusual high sensitivity leads only to noise reversion mode, or transient ventricular tracking.

Dose-Response Relationship, Radiation↗

PubMed2003

[Electrically evoked compound action potential thresholds of pediatric cochlear implant recipients and its clinical application].

OBJECTIVE: To investigate the possibility of using pediatric cochlear implant mapping protocol, to estimate the psychophysical levels based on the electrically evoked compound action potential (ECAP) threshold measured with the neural response telemetry (NRT) capabilities of cochlear corporation's CI24M device. METHODS: ECAP amplitude growth functions were regressed via NRT 3.0 software to determine ECAP threshold. 6 pediatric cochlear implant recipients' ECAP thresholds 1, 2 and 3 months after surgery were compared, meanwhile, intraoperative and postoperative ECAP thresholds in 7 pediatric recipients were compared. RESULTS: The ECAP amplitude growth functions were not linear when ECAP was close to threshold or saturation. There were no significant difference among the ECAP thresholds 1, 2 and 3 months after surgery. The average intraoperative ECAP threshold of 22 electrodes was 15 CL greater than postoperative threshold. It showed high relationship between them (R2 = 0.9154). CONCLUSION: ECAP threshold should be determined by regression of data from linear part of amplitude growth function. Only one NRT trial should be assessed when mapping protocol based on ECAP threshold to estimate pediatric map parameter. The intraoperative ECAP threshold can act as C-level at the initial mapping. Key words cochlear implant, electrically evoked compound action potential, mapping.

Action Potentials↗

PubMed2003

Within- and across-channel processing in auditory masking: a physiological study in the songbird forebrain.

Synchronous envelope fluctuations in different frequency ranges of an acoustic background enhance the detection of signals in background noise. This effect, termed comodulation masking release (CMR), is attributed to both processing within one frequency channel of the auditory system and comparisons across separate frequency channels. Here we present data on CMR from a study in field L2 of the auditory forebrain of the European starling (Sturnus vulgaris) using two 25-Hz-wide bands of masking noise that provide the opportunity to distinguish between within-channel and across-channel effects. Acoustically evoked responses were recorded from unrestrained birds via radio telemetry. The signal was a 800 msec pure tone presented at the most sensitive frequency of the units in a previously determined frequency-tuning curve (FTC). One band of masking noise was centered on the signal frequency while the flanking band of noise was presented either within the limits of the excitatory FTC (i.e., within the same frequency channel as the on-frequency masker) or in the suppression area of the FTC (i.e., in a separate channel). For flanking bands inside the excitatory FTC, signal detection thresholds based on the rate code were lower in noise maskers with identical envelope fluctuations (comodulated) than in maskers with uncorrelated envelopes resulting in a neural CMR of approximately 4-7 dB. For flanking bands inside the suppression areas, the neural CMR was reduced. Although the average neural CMR was below the behaviorally determined CMR, a subsample of between 11 and 26% of the recording sites resembled the behavioral performance.

Acoustic Stimulation↗

PubMed2003

Altered anxiety-related responses in mutant mice lacking the beta4 subunit of the nicotinic receptor.

Nicotine, acting at nicotinic acetylcholine receptors (nAChRs), is the primary addictive component of tobacco. Smokers often report an anxiolytic effect of cigarettes. This relief of anxiety, attributed to nicotine, is an important contributor to relapse when smokers try to quit. Hence, the study of the anxiolytic effects of nicotine is important for understanding the mechanisms underlying nicotine addiction. Mammalian nAChRs are pentameric ion channels usually composed of alpha andbeta subunits. Taking advantage of beta4-homozygous-null mice (beta4-/-), we examined the role of the nAChR beta4 subunit in anxiety-related behaviors. The beta4-/- mice behaved as though they were less anxious than wild-type littermates on the elevated-plus and staircase mazes, tests that measure anxiety-related behaviors. To obtain an independent, physiological indication of the stress produced by several tests, we measured changes in heart rate using telemetry. Consistently with the behavioral phenotype, beta4-/- mice had a smaller heart rate increase in the elevated-plus maze than did wild-type littermates. In contrast, during social isolation, a separate test for anxiety,beta4-/- mice exhibited a greater increase in heart rate than did wild-type littermates. Finally, beta4-/- mice were indistinguishable from their wild-type littermates in the open field, the light/dark box, and the mirrored chamber. The overall results demonstrate that beta4-containing (beta4*) nAChRs influence behavioral responses during anxiety-related tests, and that this effect depends on the type of anxiety-provoking experience. Through their influence on anxiety-related behavior, beta4* nAChRs might influence both tobacco consumption and smoking relapse.

Animals↗

PubMedDate not supplied

Championing change: lessons learned from one unit's struggle.

In an era that is primarily focused on cost reduction and outpatient facility development, justification for inpatient unit expansion projects is an issue that plagues most nurse managers. Championing Change encourages nursing leaders to develop business plans that highlights their endeavors. This concept was developed after witnessing first-hand a futile attempt to expand intermediate intensive care beds and telemetry monitoring capabilities on a neurology/neurosurgical unit. The experience of one unsuccessful quest of an expansion endeavor is discussed.

Hospitals, University↗

PubMed2004

The introduced free-ranging rhesus and patas monkey populations of southwestern Puerto Rico.

Rhesus (Macaca mulatta) and patas (Erythrocebus patas) monkeys escaped to the mainland of southwestern Puerto Rico (SWPR) from research colonies on small offshore islands during the 1960s and through 1982. A three year study (1990-1993) combined radio-telemetry with visual observations to collect information on population sizes, the composition of social groups, their daily movements, and their home ranges. Two populations of rhesus monkeys were identified in SWPR: one within the study area in Sierra Bermeja and a second population located 10 km north of the study area. The size of the Sierra Bermeja rhesus population was derived from escapees from research colonies and at the time of the study was 65-85 individuals. Within their home range area (3.7 km2) the density of this population was >>18.9 individuals/km2. A second rhesus population was found in a mountainous region 10 km north of the study area. This population consisted of one (or two) heterosexual groups with a total of 40-45 individuals. Although a primary characteristic of this species in India is its ability to live as a commensal with humans, the rhesus monkey populations of SWPR are extremely shy and elusive, they avoid contact with humans. The patas monkey population consisted of >>120 individuals in four heterosexual groups and several all-male bands. There was no evidence of patas monkeys outside the study area. Within their home ranges (26.8 km2) the population density was 4.47 individuals/km2). Patas monkeys have not previously been considered a territorial species, their behavior in SWPR suggested territoriality. In contrast to studies in Africa, where the amount of home range overlap between patas monkey groups in high, in SWPR the amount of range overlap between groups is small and each group uses areas with clearly defined boundaries.

Animals↗

PubMed2004

[Refractory recovery function of electrical auditory on the survival auditory nerve in cochlear implant recipients].

OBJECTIVE: To evaluate the cochlear implant recipient's electrical auditory temporal properties in order to estimate the maximum stimulating rate which can be reached when they adopted some speech coding strategies based on time mechanism, such as continuous interleaved sampling (CIS). METHODS: Thirty-eight Nucleus CI24 cochlear implant recipients were divided into 4 groups by etiology and history. Their survival auditory nerve fibers' refractory recovery time function was measured via neural response telemetry (NRT). Electrical pulses with the amplitude of recipient's loudest acceptable presentation were stimulated in mono-polar mode, with the width of 25 microseconds and the frequency of 80 Hz. Least-squares regression procedures were used to fit individual recovery functions with the equation A = C + K e(-t/tau), in which tau is the time constant of recovery from refractory state. Statistic analysis showed the relationship between the time constants of individuals and etiology as well as electrode position in the cochlea. RESULTS: Congenital deaf patient's recovery time constants were shorter than that of postnatal deaf groups of ototoxicity (P = 0.0056) and large vestibular aqueduct syndrome (P = 0.0349). There was no significant difference between the recovery time constants of congenital deaf patients and those of group with long history of deafness. The ANOVA of the recovery time constants of 5th, 10th, 15th electrode showed no significant statistical difference (P > 0.05). CONCLUSION: The recovery time constants are related with etiology. In mono-polar mode, the time constants of congenital deafness or subjects with short duration of deafness are shorter than those of postnatal deafness or subjects with long duration of deafness. Time constants do not vary systematically with electrode location along the implanted array. The reciprocal of individual electrode seems to be used in determining the maximum of stimulating rate of CIS strategy and as criteria of choosing the usable channels from 22 electrode bands.

Acoustic Stimulation↗

PubMed2004

Refinement techniques in experimental protocols involving Callitrichids.

The invasiveness of biomedical experiments on laboratory animals should be limited to the greatest extent possible yet without sacrificing the quality of the data collected. To this end, refinement techniques can be used. In the present work, we describe some of these techniques, focussing on the familiarity of the experimental environment, alternative sampling techniques (including the use of positive training), telemetry, and methods for improving ethological experiments. As a model, we have chosen the common marmoset (Callithrix jacchus), which is frequently used in biomedical research.

Animal Experimentation↗

PubMed2004

Cardiological telemonitoring in rehabilitation and sports medicine.

The paper presents the development results of teleconsultative cardiology systems and their application in rehabilitation and sport medicine. The first teleconsultative cardiology (TELECARD) system was developed for outpatient departments in the city of Kaunas, using Internet links. It was based on the CompCardioSignal terminal. One branch of the TELECARD system with a mobile CompCardioSignal terminal was used for functional state evaluation of Lithuanian sportsmen during the 2000 Sydney Olympic Games. The examined results have shown that every sportsman responded differently to acclimatization and the TELECARD system provided support to physicians and coaches for making optimal decisions regarding the sportsmen's adaptation and other situations. The final telemetry system was used for rower monitoring. It was based on the new CompCardioSignal terminal with three EASI ECG leads and synchronously recorded motion signals for evaluation of human reaction to physical load. The developed telemonitoring systems were a useful tool for evaluation of human reaction to physical load in rehabilitation and sports activities.

Computer Systems↗

PubMed2005

Periodic lateralized epileptiform discharges (PLEDs) as the sole electrographic correlate of a complex partial seizure.

We describe a patient in whom the only electrographic manifestation of a complex partial seizure recorded by video-EEG telemetry was periodic lateralized epileptiform discharges (PLEDs) with a left anterior temporal emphasis. The abnormality, which persisted throughout the whole recorded seizure, lends support to the claim that PLEDs can be an ictal phenomenon.

Adolescent↗

PubMed2005

FCC to begin issuing licenses for use of mobile radios in the 460 to 470 MHz band.

The U.S. Federal Communications Commission (FCC) has stated that after December 31, 2005, it will begin issuing licenses for use of private land mobile radios (PLMRs) in the 460 to 470 MHz frequency band. Medical telemetry systems operating in this band after December 31 will therefore be at increased risk for interference, which could compromise patient safety. Any medical facility in the vicinity of a PLMR could be affected.

Federal Government↗

PubMed2006

Prolonged assessment of sleep and daytime sleepiness in unrestrained Macaca mulatta.

STUDY OBJECTIVE: To establish a method for the prolonged recording of electrophysiologic variables of sleep in freely moving nonhuman primates. To establish and validate means for scoring nocturnal sleep and quantifying daytime alertness in these subjects. DESIGN: Four animals (M. mulatta) were permanently instrumented for the recording of electroencephalograms, electrooculograms, and electromyograms. A telemetry unit housed in a backpack transmitted these variables for several overnight periods to establish normal sleep. During the day, a modified Multiple Sleep Latency Test protocol was followed to quantify daytime alertness. High-quality recordings were maintained from a minimum of 8 months to a maximum of 5.5 years. MEASUREMENTS AND RESULTS: Across 6 to 7 nights per animal, average total sleep time was 522 minutes, with a sleep latency of 20 minutes. The proportion of total sleep spent in the various stages of sleep was 10.8%, stage 1; 56.4%, stage 2; 20.0%, stages 3-4; and 12.7%, rapid eye movement sleep. Mean sleep latency across testing sessions for each monkey was 12.5 minutes, 20 minutes (no daytime sleep), 14.6 minutes, and 8.6 minutes for animals 1 to 4, respectively. Intrarater and interrater reliabilities were high and similar to those obtained when the same scorers evaluated human sleep and Multiple Sleep Latency Tests. CONCLUSIONS: Similarities in sleep architecture between M. mulatta and humans make this an excellent animal model for investigations of normal and pathologic human sleep. This study confirms and extends previous findings in nonhuman primates. Stable, high-quality data were obtained for months to years using a telemetric system capable of long-term data collection.

Animals↗

PubMed2006

[The heart rate variability in mice: telemetric evaluation of endotoxin shock].

BACKGROUND: Recently, the knowledge regarding all types of shock has increased. In the critical period, the maintenance of perfusion to important organs and of autonomic cardiovascular control is a clue to improve outcome. The current investigation studied the effects of endotoxin shock on the heart rate variability (HRV), which might be an early marker of multiple organ dysfunction syntion. METHODS: CL 57 BL/6 J mice (30-32 g) were implanted with intra-abdominal telemetry transmitters and data collection began 7 days after surgery and continued for 5 hours after the treatment. In endotoxin group, 3 mg x kg(-1) of E. coli lipopylysaccharide (0127 : B 8) was administered intraperitoneally and the same dose of saline was administered in control group. From the beat-by-beat values, heart rate (HR), standard deviation and coefficients of variation (RMSSD) were calculated. Integrated values of power spectral density were derived by summing depending on the frequency ranges, which were chosen with respect to the results of the previous investigation as follows: very low frequency (VLF) < 0.15 Hz; low frequency (LF), 0.15-1.5 Hz; and high frequency (HF), 1.5-5.0 Hz. RESULTS: HR showed no difference between the groups. RMSSD, Total Power, VLF, LF and HF increased in control group throughout the experiments, but, decreased in endotoxin group even 5 hr after the treatment. CONCLUSIONS: There has been scarce information on mice HRV, but we have demonstrated that endotoxin administration significantly decreases RMSSD and spectral density at low and high frequencies.

Animals↗

PubMed2006

Initial clinical experience with telemetrically adjustable gastric banding.

BACKGROUND: The feasibility and safety of laparoscopic adjustable gastric banding for treatment of morbid obesity has been demonstrated in a large number of studies. Access port-related complications constitute a significant part of all complications related to gastric banding. Further, adjustment of hydraulic gastric bands can be fairly lengthy, uncomfortable, and is not a precise procedure. A study was performed to assess the usefulness and efficacy of a new type of band adjusted telemetrically without the need for an access port. The initial worldwide results of the first telemetrically adjustable gastric band for morbid obesity (EASYBAND EndoArt Medical Technologies, Switzerland) in two German academic centers are described herein. METHODS: EASYBAND is a purely mechanical gastric band, in which adjustment is achieved by means of an embedded micromotor, controlled by an external control unit using telemetry. The exact band diameter is displayed continuously during adjustment on the external control unit screen. Thirty-seven patients, means 36 +/- 8 (range: 22-60) years, 7 (19%) men and 30 (81%) women, with a mean body mass index (BMI) of 44.1 +/- 4.5 (range: 35.6-59.6), were implanted using the standard laparoscopic technique during the period from June 2005 to October 2005. Prospective data were collected on all morbidly obese patients who underwent laparoscopic telemetrically adjustable gastric banding (LTAGB). RESULTS: No serious adverse events occurred during the operative period or immediately postoperatively in relation to the device. A mean of 3.0 +/- 0.6 adjustments per patients were performed during the follow-up schedule at one, three and six months. The band diameter was set to 29 mm (fully open) at implantation, 24.5 mm +/- 0.5 mm at one month, 23.3 mm +/- 0.7 mm at three months, and 23.0 mm +/- 1.0 mm at six months. The mean percent excess weight loss was 10.2% +/- 4.5% at one month, 23.8% +/- 8.8% at three months, and 30.2% +/- 10.5% at six months. CONCLUSION: This initial study shows that the new telemetrically adjustable gastric banding device is implanted and operated safely, allows for atruamatic band adjustments with superior patient comfort, and leads to early excess weight loss comparable to that achieved by other gastric bands. Longer-term follows and larger population studies are needed to establish the final safety and performance profile of the telemetric gastric band.

Adult↗