Early response to pulse oximetry alarms with telemetry

Twenty ICU patients were monitored for an average of 45 hr each, with both bedside and nursing station monitors, which were set to alarm audibly if the patient’s oxygen saturation dropped below 90%. Bedside alarms alerted caregivers to 51 of the 74 hypoxemic events; central alarms alerted personnel to the other 23 events. The alarms led to a change in treatment in 35 of the 48 (73%) true desaturation episodes. We conclude that central oximetric monitoring may help with detection of arterial desaturation events even in a well-staffed ICU.     

Cardiovascular and autonomic responses to sexual activity in the rabbit

1. Sexual intercourse is associated with an increased risk of death from arrhythmia development, myocardial infarction or stroke. It is unclear whether this increased risk is due to physical exertion alone or whether it is an inherent aspect of sexual activity itself. 2. Using a telemetric approach, we show that sexual activity is associated with transient (8-14 s) but profound increases in renal sympathetic nerve activity (RSNA; up to 22-fold that of baseline) in both male and female rabbits. This increase was significantly greater than that observed during physical exertion (three- to sixfold increase in RSNA). 3. In addition, we observed rapid transitions in male rabbits from tachycardia (422 ± 21 b.p.m.; P < 0.01) to bradycardia (186 ± 28 b.p.m.; P < 0.05) during and immediately following coitus. This suggests simultaneous activation of both the sympathetic and parasympathetic nervous systems. 4. The present study provides the first real-time insight into the extreme variation in neural and cardiovascular function occurring during sexual activity in normal healthy rabbits. Little is known about how the physiological responses to sexual activity may change under disease or drug-treatment states, and these findings may prove of use to these areas in future.     

An Integrated Implantable Electrical Sacral Root Stimulator for Bladder Control

Objectives. The goal of this work is to study and develop an electrical integrated system that allows the control of the basic functions (such as micturition, defecation, and erection) by sacral root stimulation in paraplegic patients. Materials and Methods. The system has been implemented using a commercially available Mietec CMOS technology. It is based on an external transceiver unit, which provides data and energy to the implant device through a bi-directional inductive link, and an implantable batteryless module that generates the needed current pulses, according to the orders received from the external unit. To test the electrode–tissue interface and system performance, an impedance measurement circuit has been included. Results. The three independent channel stimulators allow an exhaustive control of the waveform parameters (amplitude, pulse width, frequency) independent of the placement of the external coil respect to the internal device. Conclusion. The architecture of the new stimulator, applied over the sacral roots, can be used to control the voiding of the bladder. The system allows an independent distance programmable stimulation. The impedance measurement circuit implemented allows an easy and systematic performance test.     

Continuous Holter telemetry of atrial electrograms and marker annotations using a common Holter recording system: impact on Holter electrocardiogram interpretation in patients with dual chamber pacemakers

The impact of continuous telemetry of atrial electrogram and marker annotations on Holter ECG interpretation was assessed in 98 patients with bipolar dual chamber pacemakers (VDD pacemakers n = 29, DDD(R) systems n = 69). Atrial electrogram and marker annotations were continuously sampled by a telemetry coil that was externally positioned on the pacemaker pocket, amplified, and transduced to a three-channel Holter ECG recorder in addition to an ECG recording. Holter tapes were analyzed by two experienced investigators for quality of P wave recognition and episodes suspicious of pacemaker dysfunction. Initially, only the ECG channel was analyzed. Thereafter, results were compared to those achieved on the basis of the complete recording including atrial electrogram and marker annotations. Recognition of atrial rhythm was markedly improved by Holter telemetry. During 99.3% of recording time telemetry showed a satisfying quality, whereas ECG alone allowed a reliable P wave recognition only during 84.4% of recording time (P < 0.001). One hundred twenty-nine episodes suspicious of pacemaker malfunction occurred in 17 of 98 patients. By analysis of ECG, only 78.3% of episodes were concordantly classified by the investigators. However, 98.4% of all episodes were properly identified when atrial electrogram and marker annotations were added to the analysis (P < 0.001). In particular, discrimination between atrial undersensing, sinus bradycardia, and atrial sensed events within the refractory periods was facilitated. Holter telemetry of atrial electrogram and marker annotations facilitates the analysis of Holter ECGs in pacemaker recipients and improves the detection of pacemaker dysfunctions.     

Computerized Vectorcardiography Telemetry: A New Device for Continuous Multilead ST‐Segment Monitoring of Ambulatory Patients. A Preliminary Report

Background: Continuous vectorcardiography ST‐segment monitoring has become a well‐established method in the surveillance of patients with acute myocardial ischemia. However, immobility of the vectorcardiography technique prevents monitoring of patients during ambulatory activities. Computerized vectorcardiography telemetry (CVT) with the capacity of real‐time ST‐segment analysis has been developed in an attempt to overcome this shortcoming. Recent data, however, indicate that changes in body position occasionally lead to pseudo‐ischemic ST‐segment changes during continuous ST‐segment monitoring. Aims: This report describes the technical features of the CVT system, presents clinical examples using CVT, and assesses the influence of changes in body position on ST‐vector magnitude (ST‐VM) during CVT, respectively. Methods: Clinical cases involving CVT are presented. The influence of changing body position during CVT monitoring was evaluated on 24 patients with suspected acute coronary syndromes, i.e., unstable angina or acute myocardial infarction. Each patient performed a specific body positional schedule. Results: We present three discrete clinical cases where CVT provided early and valuable evidence of ongoing myocardial ischemia. The consequences of different recumbent and ambulatory body positions on ST‐VM during CVT monitoring appear to be limited. Conclusion: Computerized vectorcardiography telemetry is a promising new tool for disclosing residual myocardial ischemic activity during the mobilization phase of patients with acute coronary syndromes. The clinical value of CVT needs further investigation in future trials. A.N.E. 2002;7(3):204–210     

Telemetry Bed Usage for Patients with Low-risk Chest Pain: Review of the Literature for the Clinician

Background

Telemetry monitoring in patients with low-risk chest pain is highly utilized, despite the lack of quality data to support its use.

Study Objectives

To review the medical literature on the utility of telemetry monitoring in patients with low-risk chest pain and to offer evidence-based recommendations to emergency physicians.

Methods

A PubMed literature search was performed and limited to human studies written in English language articles with keywords of “telemetry” and “chest pain.” Studies identified then underwent a structured review from which results could be evaluated.

Results

There were 114 paper abstracts on telemetry monitoring screened; 30 articles were considered relevant. Twelve appropriate articles were rigorously reviewed and recommendations given.

Conclusions

Insufficient data exist to support telemetry use in low-risk chest pain patients. Telemetry monitoring is unlikely to benefit low-risk chest pain patients with a normal/nondiagnostic electrocardiogram, a normal first set of cardiac enzymes, and none of the following: hypotension, rales above the bases, or pain worse than baseline angina.     

Impact of Interventions for Patients Refusing Emergency Medical Services Transport

Objective: To evaluate the effect of a documentation checklist and on–line medical control contact on ambulance transport of out–of–hospital patients refusing medical assistance. Methods: Consecutive patients served by four suburban ambulance services who initially refused emergency medical services (EMS) transport to the hospital were prospectively enrolled. In phase 1 (control phase), all patients who initially refused medical attention or transport had an identifying data card completed. In phase 2 (documentation phase), out–of–hospital providers completed a similar data card that contained a checklist of high–risk criteria for a poor outcome if not transported. In phase 3 (intervention phase), a data card similar to that used in phase 2 was completed, and on–line medical control was contacted for all patients with high–risk criteria who refused transport. The primary endpoint was the percentage of patients transported to the hospital. Results: A total of 361 patients were enrolled. Transport rate varied by phase: control, 17 of 144 (12%); documentation, 11 of 150 (7%); and intervention, 12 of 67 (18%) (chi–square, p = 0. 023). Transport of high–risk patients improved with each intervention: control, two of 60 (3%); documentation, seven of 70 (10%); and intervention, 12 of 34 (35%) (chi–square, p = 0. 00003). Transport of patients without high–risk criteria decreased with each intervention: control, 15 of 84 (18%); documentation, four of 80 (5%); and intervention, 0 of 33 (0%) (p = 0. 0025). Of the 28 patients for whom medical control was contacted, 12 (43%) were transported to the hospital, and only three of these 12 patients (25%) were released from the ED. Conclusion: Contact with on–line medical control increased the likelihood of transport of high–risk patients who initially refused medical assistance. The appropriateness of the decreased transport rate of patients not meeting high–risk criteria needs further evaluation.     

A Fast Passive Data Transmission Method for ENG Telemetry

The objective of this study was to develop a high bit‐rate passive method for conveying ENG signals from implants which would work over a wide range of coupling coefficients. A novel method, Passive Phase Shift Modulation, was studied in theory, by simulation, and implemented in the laboratory. A binary signal of 222 kbit/s was passed on a 4‐MHz carrier (ratio 1:18) with coil‐coil spacings up to 70 mm (coil diameters are 45 and 60 mm) with an addition to the power consumption equivalent to 2 mW in the implant. We conclude that this is a satisfactory method to be used as part an implant for conditional neuromodulation that we are designing.