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PubMed1992

Tinnitus of TMJ origin: a preliminary report.

Twenty patients whose chief complaint was tinnitus were examined. They were not known to have temporomandibular disorders. They did not have pain or dysfunction. They were examined by physicians for ear disorders and the results were considered negative. Each of these patients had a complete history and clinical temporomandibular joint examination. The clinical examination included muscle and joint palpation and stethoscopic examination of the joint. This examination also included selected computerized mandibular scans and electromyographic studies of selected facial muscles. Each subject had eight views of transcranial lateral oblique x-rays taken. It was determined that 19 of these individuals had one or more clinical, electromyographic, and radiographic indications of a temporomandibular disorder. From this study, it appears that individuals who have tinnitus with no apparent otologic basis for this symptom should have a careful evaluation of the temporomandibular apparatus. A temporomandibular disorder may be one of the primary causes of this symptom.

Adult↗
PubMed1976

Cardiovascular nuclear medicine: a progress report.

Providing insights into the functional state of the myocardium not available from other techniques, cardiovascular nuclear medicine is being applied more and more in coronary care units, where it makes possible frequent monitoring of function, and in exercise testing of outpatients. In addition, a nuclear "stethoscope" that generates a left ventricular volume curve may soon bring this valuable resource into office practice.

Cardiomegaly↗
PubMed2004

Disinfection and sterilization in health care facilities: what clinicians need to know.

All invasive procedures involve contact between a medical device or surgical instrument and a patient's sterile tissue or mucous membranes. A major risk of all such procedures is the introduction of pathogenic microbes that could lead to infection. Failure to properly disinfect or sterilize reusable medical equipment carries a risk associated with breach of the host barriers. The level of disinfection or sterilization is dependent on the intended use of the object: critical items (such as surgical instruments, which contact sterile tissue), semicritical items (such as endoscopes, which contact mucous membranes), and noncritical items (such as stethoscopes, which contact only intact skin) require sterilization, high-level disinfection, and low-level disinfection, respectively. Cleaning must always precede high-level disinfection and sterilization. Users must consider the advantages and disadvantages of specific methods when choosing a disinfection or sterilization process. Adherence to these recommendations should improve disinfection and sterilization practices in health care facilities, thereby reducing infections associated with contaminated patient-care items.

Cross Infection↗
PubMed2004

Outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a neonatal intensive care unit linked to artificial nails.

BACKGROUND: From April to June 2001, an outbreak of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae infections was investigated in our neonatal intensive care unit. METHODS: Cultures of the gastrointestinal tracts of patients, the hands of healthcare workers (HCWs), and the environment were performed to detect potential reservoirs for ESBL-producing K. pneumoniae. Strains of K. pneumoniae were typed by pulsed-field gel electrophoresis using XbaI. A case-control study was performed to determine risk factors for acquisition of the outbreak clone (clone A); cases were infants infected or colonized with clone A and controls (3 per case) were infants with negative surveillance cultures. RESULTS: During the study period, 19 case-infants, of whom 13 were detected by surveillance cultures, harbored clone A. The overall attack rate for the outbreak strain was 45%; 9 of 19 infants presented with invasive disease (n = 6) or developed invasive disease (n = 3) after colonization was detected. Clone A was found on the hands of 2 HCWs, 1 of whom wore artificial nails, and on the designated stethoscope of a case-infant. Multiple logistic regression analysis revealed that length of stay per day (odds ratio [OR], 1.05; 95% confidence interval [CI95], 1.02 to 1.09) and exposure to the HCW wearing artificial fingernails (OR, 7.87; CI95, 1.75 to 35.36) were associated with infection or colonization with clone A. CONCLUSION: Short, well-groomed, natural nails should be mandatory for HCWs with direct patient contact

Case-Control Studies↗
PubMed2006

Cluster of cases of severe acute respiratory syndrome among Toronto healthcare workers after implementation of infection control precautions: a case series.

OBJECTIVE: To review the severe acute respiratory syndrome (SARS) infection control practices, the types of exposure to patients with SARS, and the activities associated with treatment of such patients among healthcare workers (HCWs) who developed SARS in Toronto, Canada, after SARS-specific infection control precautions had been implemented. METHODS: A retrospective review of work logs and patient assignments, detailed review of medical records of patients with SARS, and comprehensive telephone-based interviews of HCWs who met the case definition for SARS after implementation of infection control precautions. RESULTS: Seventeen HCWs from 6 hospitals developed disease that met the case definition for SARS after implementation of infection control precautions. These HCWs had a mean age (+/-SD) of 39+/-2.3 years. Two HCWs were not interviewed because of illness. Of the remaining 15, only 9 (60%) reported that they had received formal infection control training. Thirteen HCWs (87%) were unsure of proper order in which personal protective equipment should be donned and doffed. Six HCWs (40%) reused items (eg, stethoscopes, goggles, and cleaning equipment) elsewhere on the ward after initial use in a room in which a patient with SARS was staying. Use of masks, gowns, gloves, and eyewear was inconsistent among HCWs. Eight (54%) reported that they were aware of a breach in infection control precautions. HCWs reported fatigue due to an increased number and length of shifts; participants worked a median of 10 shifts during the 10 days before onset of symptoms. Seven HCWs were involved in the intubation of a patient with SARS. One HCW died, and the remaining 16 recovered. CONCLUSION: Multiple factors were likely responsible for SARS in these HCWs, including the performance of high-risk patient care procedures, inconsistent use of personal protective equipment, fatigue, and lack of adequate infection control training.

Adult↗
PubMed1995

[Preliminary study of an implantable device powered by an inductive link for telemetry of the epicardial electrocardiogram and the radionuclide activity of the left ventricle].

In nuclear cardiology, radionuclide data concerning the cardiac function are presently collected using external detectors, providing scintigraphic images or activity curves with respect to time. This paper presents a new approach to the latter kind of instruments, which are often called nuclear stethoscopes. This proposed system is composed of a cardiac implant, a miniature transmitter positioned externally on the chest and a remote receiver system allowing the processing of the cardiac function data. The transcutaneous magnetic link permits the power transfer in order to energize the electronic implant, and permits the telemetry of the electrocardiogram and the radionuclide data between the implant and the external receiver system. The nuclear activity measured by a photodiode for gamma rays based on cadmium telluride, with pulse width modulation, constitutes the carrier of the electrocardiographic activity. The composite signal is transmitted by means of the implant impedance modulation. The use of this transmission concept reduces to a minimum the volume of the implant. Furthermore, this system, allowing the correct positioning of the external transmitter facing the left ventricle, increases the performance of the global transmission system. Theoretical results on the design of the magnetic link are presented.

Electrocardiography↗
PubMed1995

A system for non-invasively measuring blood pressure on a treadmill.

Measurement of signal to artifact ratio yielded optimal frequencies for a Korotkoff-based automatic system for measuring blood pressure on a treadmill. Maximal Korotkoff sounds occurred just above the crease of the elbow over the brachial artery. Output of a piezoelectric microphone and charge amplifier was measured during treadmill exercise for frequency bands from 8 to 57 Hz. An automatic system filtered output from 40 to 45 Hz, rectified it, then compared it to a threshold that had fixed and exponentially decaying components. For five subjects, the system decisions of systolic and diastolic pressures compared well with those of two observers using stethoscopes. The system shows promise for improved measurements of blood pressure during treadmill exercise.

Blood Pressure Determination↗
PubMed2004

Characterization of the Korotkoff sounds using joint time-frequency analysis.

The sounds associated with the five classical Korotkoff phases are clinically important for measuring systolic and diastolic blood pressures. The frequency ranges of the sounds have already been described simply using the overall peak frequencies within each phase by Fourier methods. However, such analysis may be missing potentially useful clinical information. The aim of this study was to compare features associated with the different phases of the Korotkoff sounds obtained during blood pressure measurement using a joint time-frequency analysis (JTFA) technique. A single operator recorded Korotkoff sounds from 25 healthy subjects using a measurement system comprising cardiology stethoscope, microphone, amplifier and recording system for computer sound digitization, and a MiniDisc system for playback to the cardiologist for Korotkoff phase classification. We have shown that using this system the phase classification by the cardiologist is repeatable, with no significant differences found in the number of sounds allocated to phases on two separate recording assessments. The digitized sounds were processed using a MATLAB-based short-time Fourier transform JTFA technique and differences in time, frequency and amplitude characteristics between the phases compared. It was found that on average, phase III had the largest overall amplitude and high frequency energy. Phase II had the greatest high frequency component and longest murmur, and was visibly the most complex phase in terms of time and frequency content. In contrast, phases IV and V had the lowest amplitude and frequency components. Overall, the statistically significant transitions between phases were: phase I to II with increases in high frequency (224 to 275 Hz) (p < 0.01) and sound duration (49 to 98 ms) (p < 0.0001), II to III with a significant decrease in sound duration (to 37 ms) (p < 0.0001), III to IV with decreases in maximum amplitude (0.95 to 0.25), highest frequency (262 to 95 Hz), and relative high frequency energy of the sounds (0.61 to 0.10) (all p < 0.0001), and IV to V with decreases in the maximum amplitude (0.25 to 0.13) (p < 0.0002) and high frequency energy (0.10 to 0.03) (p < 0.005). This study has demonstrated that joint time-frequency analysis of Korotkoff sounds was able to identify characteristic differences associated with the different phases classified by the expert cardiologist. Ultimately, exploiting the joint time and frequency characteristics of the sounds may improve blood pressure measurement and help to assess the stiffness of the peripheral arteries.

Arteries↗
PubMed2005

Evaluation of arterial endothelial function using transit times of artificially induced pulses.

Impairment of arterial endothelial function is an early event in atherosclerosis and correlates with the major risk factors for cardiovascular disease. The most widely employed non-invasive measure of endothelial function involves brachial artery (BA) diameter measurement using ultrasound imaging before and after several minutes of blood flow occlusion. The change in arterial diameter is a measure of flow-mediated vasorelaxation (FMVR). The high between-laboratory variability of results and cost of instrumentation render this technique unsuitable for routine clinical use. We induce artificial pulses at the superficial radial artery using a linear actuator. An ultrasonic Doppler stethoscope detects these pulses 10-30 cm proximal to the point of pulse induction. The delay between pulse application and detection provides the pulse transit time (PTT). By measuring PTT before and after 5 min of BA occlusion and ensuing reactive hyperemia, FMVR may be measured based on the changes in PTT caused by changes in vessel caliber, smooth muscle tone and wall thickness. We (1) validate the sensitivity of this technique to arterial wall tone using sublingual nitroglycerin and (2) compare measurements of endothelial function to ultrasound BA diameter measurements in 12 human subjects. The PTT-based method is verified to measure arterial wall tone and is shown to provide 37% greater sensitivity (p < 0.05) to FMVR than BA diameter measurements. By measuring the change in pulse transit time before and after endothelial stimulus, a sensitive, reproducible and convenient measure of endothelial function may be obtained at a low cost.

Blood Flow Velocity↗
PubMed1989

A phase I study of human natural interferon-beta in cancer patients.

In this phase I study 15 patients with metastatic tumors were given interferon (IFN)-beta by i.v. bolus injections. Twelve individual doses of 1, 2, 3.3, 5, 7, 9, 12, 16, 21, 27, 35, and 46 x 10(6) IU were administered every other day. The single maximal tolerated dose ranged from 9 to 46 x 10(6) IU. Eight patients tolerated the dose of 46 x 10(6) IU without side effects. Disturbances of cardiac rhythm were observed, but were closely related temporally to severe chills and appeared to be the consequence of adrenergic stimulation associated with this side-effect. In addition, no significant variations in the left ventricular function as assessed by nuclear stethoscope were observed. Neurotoxicity was not a major side-effect. The toxicity of IFN-beta given as scheduled in this study was significant, but acceptable.

Adult↗
PubMed1998

The Ottawa telehealth project.

OBJECTIVE: To examine the telehealth system as a means of improving access to cardiac consultations and specialized health services in remote areas of Ontario. METHODS: The University of Ottawa Heart Institute has set up a telehealth test program, Healthcare and Education Access for Remote Residents by Telecommunications (HEARRT), in collaboration with industry and the provincial and federal government, as well as several remote clinical test sites. The program makes off-site cardiology consultations possible. History taking and physical examinations are conducted by video and electronic stethoscope. Laboratory results and echocardiograms are transmitted by document camera and VCR. The technology is being tested in both stable outpatient and emergency situations. Various telecommunications bandwidths and encoding systems are being evaluated, including satellite and terrestrial-based asynchronous transfer-mode circuits. Patient satisfaction and cost-effectiveness are also being assessed. RESULTS: Bandwidths from as low as 384 kbps using H.320 encoders to 40 Mbps using digital transport of NTSC video signals have been evaluated. Although lower bandwidths are sufficient for sending echocardiographic and electrocardiogram data, bandwidths with transport speeds of 4 to 6 Mbps appear necessary to capture the nuances of the cardiac physical examination. A preliminary satisfaction survey of 19 patients noted that all felt that they could communicate effectively with the cardiologist by video, and each had confidence in the advice offered. None reported that he or she would rather have traveled to the doctor in person. Initial and projected examination of the costs suggested that telehealth will effectively reduce overall health care spending while decreasing travel expenses for rural patients. CONCLUSION: Telehealth technology is sufficiently sophisticated to allow off-site cardiology assessments. Preliminary results suggest there is a sound business case for the implementation of telehealth technology to meet the needs of remote residents in northern Ontario. Working closely with government and industry, we will develop a marketing and commercialization plan to support the use of this technology throughout Ontario and expand application to patient education and continuing medical education.

Cardiology↗
PubMed1991

A multicenter evaluation of the A&D TM-2420 ambulatory blood pressure recorder.

The A&D TM-2420 (A&D Engineering, Milpitas, CA) is an automatic, portable, noninvasive blood pressure (BP) recorder which uses a dual microphone system for the detection of Korotkoff sounds. Its accuracy and clinical performance were assessed in a multicenter study that also addressed issues such as observer agreement and the effects of age, arm circumference, heart rate, posture, and blood pressure level on the observer-device differences. We compared 906 simultaneous, same-arm BP measurements in 151 subjects using the TM-2420 versus two skilled clinicians per site using a teaching stethoscope. The agreement between the TM-2420 and mercury column determinations were within 10 mm Hg for 86 to 91% of systolic readings and 91 to 94% of diastolic readings, depending on the posture; a level of agreement which would receive a 'B+' grade from the recent British Hypertension Society guidelines. The limits of agreement (2 standard deviations about the mean difference) for systolic BP between observers and the TM-2420 tended to be greater for the standing position (-20 to 15 mm Hg) compared to supine (-14 to 12 mm Hg) and seated (-13 to 8 mm Hg) positions. Limits of agreement between the observers and device were not dependent upon age, heart rate, arm size, or blood pressure level. Twenty-four-hour blood pressure monitoring in two of the four centers demonstrated an error code rate of 3.4%, excluding 'retries' that are one of the device's features. These data demonstrate an acceptable level of accuracy and performance of the sixth generation of the TM-2420 for use in clinical practice and research.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Multicenter assessment of the QuietTrak ambulatory blood pressure recorder according to the 1992 AAMI guidelines.

To clinically evaluate the QuietTrak ambulatory blood pressure (BP) recorder (Tycos-Welch-Allyn, Arden, NC), we assessed the device according to the performance criteria set out by the 1992 Association for the Advancement of Medical Instrumentation (AAMI) guidelines. The QuietTrak is a portable, noninvasive recorder that uses an auscultatory measuring system. As recommended in the 1992 AAMI guidelines, a large, heterogeneous population was recruited for the study using three clinic sites to assess accuracy and clinical performance. In addition, observer agreement and the effects of age, arm circumference, heart rate, posture, and blood pressure level on the observer-device differences were analyzed. There were 1098 simultaneous, same arm BP measurements performed in 122 subjects by the QuietTrak recorder versus two skilled clinicians per site using a teaching stethoscope and 24-h blood pressure recordings performed in 46 subjects to assess reliability of the monitor. The differences in observers for all sites were 0.7/-0.5 +/- 3.8/3.5 mm Hg with 89% of the BPs within 5 mm Hg. The mean difference between observer average and the device (all positions) was 0.3/-1.5 +/- 5.0/7.5 mm Hg. The agreement between the QuietTrak and mercury column determinations was within 10 mm Hg for 92 to 94% of systolic readings and 91 to 93% of diastolic readings, depending on the posture. The limits of agreement (2 standard deviations about the mean difference) between observers and the device for systolic BP tended to be lower for the sitting position (-11 to 10 mm Hg) compared to supine (-14 to 13 mm Hg) and standing (-14 to 14 mm Hg) positions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1996

Cricoid pressure applied after placement of the laryngeal mask prevents gastric insufflation but inhibits ventilation.

We studied 50 patients, in a blind, crossover study, to assess if cricoid pressure applied after placement of the laryngeal mask prevented gastric insufflation without affecting ventilation. After induction of anaesthesia and neuromuscular block, a laryngeal mask was inserted and confirmed to be placed correctly. The lungs were ventilated with a maximum inflation pressure of 15 cm H2O. In the first 25 patients, expiratory volumes were measured with and without cricoid pressure (30 N). On both occasions, a free hand was placed under the patient's neck. In the next 25 patients, the effect of cricoid pressure on ventilation without support of the neck was also studied. The effect of cricoid pressure with support of the neck on gastric insufflation was then assessed using a stethoscope in all 50 patients, while the lungs were ventilated with a maximum inflation pressure of 30 cm H2O. At the end of the study, the position of the mask was re-assessed. Cricoid pressure significantly decreased mean expiratory volume (P << 0.001). This inhibitory effect was significantly greater when the pressure was applied without support of the neck (P << 0.001). Cricoid pressure significantly reduced the incidence of gastric insufflation (12 patients vs one patient; P << 0.001; 95% CI for difference 10.5-33.5%). In no patient was the mask dislodged after these procedures. Thus, although cricoid pressure applied after insertion of the laryngeal mask prevented gastric insufflation, it also decreased ventilation. The inhibitory effect of cricoid pressure on ventilation without support of the neck was greater than cricoid pressure with support of the neck.

Adolescent↗
PubMed1998

Accuracy and precision of "deep sternal" and tracheal temperatures at high- and low-fresh-gas flows.

The accuracy of tracheal temperature as a measure of core temperature is relatively poor during high-flow ventilation (6 litre min-1 fresh-gas flow). It is unknown if accuracy improves when lower fresh-gas flow rates are used. We tested the hypothesis that tracheal temperature accuracy would improve with low-flow ventilation (1 litre min-1). We studied 20 ASA Physical Status I and II patients undergoing general anaesthesia for lower abdominal surgery. Deep body temperatures were measured at the middle of the sternum using a Coretemp "deep-tissue" thermometer. Tracheal temperatures were monitored from thermistors incorporated into the tracheal tube cuffs. Oesophageal temperatures were measured from thermocouples incorporated into stethoscopes positioned at the point of maximal heart sounds. Sternal temperature correlated reasonably well with distal oesophageal temperatures, both being within the 0.5 degree C cut-off for accuracy and precision. Tracheal temperatures were lower than oesophageal temperatures during both high- and low-flow ventilation. Tracheal temperatures were 0.7 degree C less during high-flow ventilation and 0.9 degree C less during low-flow ventilation. The precision in both cases was adequate. We conclude that tracheal temperatures were insufficiently accurate for routine clinical use, even when fresh- gas flow was restricted to 1 litre min-1. In contrast, the deep temperatures were sufficiently accurate and precise for routine clinical use.

Adult↗
PubMed2002

Reliability of epigastric auscultation to detect gastric insufflation.

BACKGROUND: We studied the reliability of epigastric auscultation to detect gastric insufflation in 30 anaesthetized, paralysed intubated patients. METHODS: A 16FG gastric tube was positioned with the tip in the mid-oesophagus with the proximal end attached to an injection port with a one-way valve. Four observers participated in the study. Observers were paired and each pair studied 15 patients. Each patient underwent four test sequences in random order, two by each observer. Each test sequence comprised one observer injecting different volumes of air (0.25 ml, 0.5 ml, 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 10 ml, 15 ml and 0 ml as a control) in random order whilst the second blinded observer listened with a stethoscope over the epigastrium. Each randomized volume was injected rapidly at 5 s intervals for 1 min. The number of injections required to detect air entering the stomach was recorded. The stomach was deflated between each test sequence. RESULTS: To detect air entering the stomach with 95% confidence, 11 injections were required for 0.25 ml; 7 for 0.5 ml; 3 for 1 ml; 2 for 2 ml and 3 ml, and I for > or =4 ml. The mean (range) inter- and intraobserver reliability was 0.73 (0.71-0.75) and 0.76 (0.76-0.89), respectively. The incidence of false positives was 21% (25/120) and the incidence of false negatives was 10% (103/1080), making the specificity and sensitivity 79% and 91%, respectively. CONCLUSIONS: We conclude that epigastric auscultation can detect gastric insufflation of 0.25 ml air after 11 breaths and > or = 4 ml air after one breath with 95% confidence. Inter- and intraobserver reliability is moderate to excellent. Epigastric auscultation should be repeated to reduce the risk of false positives.

Adolescent↗
PubMed2004

Randomized controlled trial of effects of the airflow through the upper respiratory tract of intubated brain-injured patients on brain temperature and selective brain cooling.

BACKGROUND: Pyrexia is common after brain injury; it is generally believed to affect outcome adversely and the usual clinical methods of reducing temperature are not effective. The normal physiological mechanisms of brain cooling are heat loss from the upper airways and through the skull, and these can produce selective brain cooling. METHODS: Air at room temperature and humidity was continuously administered to 15 brain-injured, intubated and mechanically ventilated patients via a sponge-tipped oxygen catheter in each nostril at a combined rate of 115 ml kg(-1) min(-1). Brain temperature was measured using a pressure-temperature Camino catheter which is designed to site the thermistor 1 cm into the parenchyma in the frontal lobe. Oesophageal temperature was measured using an oesophageal stethoscope with a thermistor. After establishing baseline for 30 min, patients were randomized to receive airflow or no airflow for 6 h and then crossed over for a further 6 h. RESULTS: Airflow replicating normal resting minute volume did not produce clinically relevant or statistically significant reductions in brain temperature [0.13 (SD 0.55) degrees C; 95% CI, 0.43-0.17 degrees C]. However, we serendipitously found some evidence of selective brain cooling via the skull, but this needs further substantiation. CONCLUSIONS: A flow of humidified air at room temperature through the upper respiratory tracts of intubated brain-injured patients did not produce clinically relevant or statistically significant reductions in brain temperature measured in the frontal lobe.

Adolescent↗