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At least 109 records · Page 6Linked to original sources
PubMed1997

In vivo electron spin resonance analysis of nitroxide radicals injected into a rat by a flexible surface-coil-type resonator as an endoscope- or a stethoscope-like device.

The flexible surface-coil-type resonator (FSCR) operating in a 700 MHz microwave electron spin resonance (ESR) system was applied to measure the nitroxide radicals at a specific area in rats. The FSCR was composed of a single-turn coil with a diameter of 5 mm and two flexible coaxial lines of 450 mm in length. For an endoscope-like application, the FSCR was inserted into the rectum of the rat and sequential changes in the ESR signals of the intravenously injected nitroxide radical (4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl; TEMPOL or 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-yloxy; carbamoyl-PROXYL) were measured. The ESR signal intensity of the nitroxide decreased according to first-order kinetics. For a stethoscope-like application, the FSCR was placed at several sites on the abdominal skin of the rats receiving a subcutaneous injection of carbamoyl-PROXYL, and diffusion and/or metabolism of the radical in the skin was observed.

Animals↗
PubMed1988

Use of a Doppler ultrasound stethoscope for intercostal nerve block.

Two cases with rib injuries are reported where intercostal nerve block without rib palpation was safely and successfully performed on six separate occasions using a Doppler blood-flow detector ultrasound stethoscope. A third case studied by a radiologist using a pulsed Doppler flowmeter, determined the source of the Doppler signals as originating from the intercostal artery. The significance of these findings is discussed.

Adult↗
PubMed1988

Hypoxaemia produced by an oesophageal stethoscope: a case report.

A seven-month-old child with complex cyanotic heart disease desaturated dramatically following induction of anaesthesia. While a degree of hypoxaemia would have been acceptable in this infant, pulse oximetry detected an abrupt desaturation prompting the anaesthetist to consider other less common causes of cyanosis. This episode of desaturation subsided with the removal of a 12 french oesophageal stethoscope which had been inserted following induction. Further attempts to re-insert this oesophageal probe led to repeated episodes of desaturation. The most likely cause of this desaturation was a reduction in pulmonary blood flow due to compression by the oesophageal probe of an aorto-pulmonary collateral posterior to the oesophagus.

Esophagus↗
PubMed1976

The Doppler stethoscope and the diagnosis of the acute scrotum.

We evaluated 30 patients who had acute scrotal swelling with the Doppler stethoscope. Every case of epididymitis and torsion of the appendix testis demonstrated an increased testicular blood flow. The cases of spermatic cord torsion had no blood flow on ultrasound examination.

Acute Disease↗
PubMed1980

Potential pitfalls of the nuclear stethoscope.

Eleven patients (three with coronary artery disease, one with mitral valve prolapse, one with atrial septal defect, two with rheumatic mitral valve disease, one with rheumatic aortic valve disease, and three normal individuals) underwent determination of global left ventricular ejection fraction (LVEF) by 1) nuclear stethoscope (cardiac probe), 2) Tc-99m-labeled-erythrocyte gated nuclear angiocardiographic gamma camera-computer techniques, and 3) single plane RAO contrast left ventriculography--all within a 6-hour period without concurrent drug intervention. In addition, global right ventricular ejection fraction (RVEF) was determined by a similar gated technique with gamma camera-computer techniques. LVEF as determined by camera-computer techniques correlated well with that of contrast ventriculography (r = 0.95) in this heterogenous group of subjects. LVEF as determined by cardiac probe correlated somewhat less well with that of contrast ventriculography (r = 0.59). Two cases are described in which, although cardiac probe data were highly reproducible, gross overestimation of the true global LVEF was thought to occur due to the malpositioning of the probe over either the right ventricle or the most contractile portion of the left ventricle in patients with coronary artery disease.

Adult↗
PubMed1994

Effect of isradipine and nifedipine on diastolic function in patients with left ventricular dysfunction due to coronary artery disease: a randomized, double-blind, nuclear, stethoscope study.

To elucidate the effect of isradipine and nifedipine on left ventricular (LV) systolic and diastolic function, each drug was given intravenously (i.v.) in equihypotensive doses to 10 patients accepted for coronary arteriography for stable angina pectoris. All 20 patients had LV ejection fraction (LVEF) of < 40% owing to previous myocardial infarction (MI). Systolic and diastolic function was assessed by standard hemodynamic parameters and pressure-volume relations measured by nuclear stethoscope. All measurements were taken at rest and during ischemia caused by right atrial pacing. Both systolic and diastolic parameters improved equally with isradipine and nifedipine. LVEF and cardiac output (CO) increased owing to peripheral vasodilatation. A decrease in P/Vmax, indicating a negative inotropic effect, was noted in patients at rest with both medications, but not during pacing-induced ischemia. With either medication, the time constant of relaxation and the end-diastolic elasticity constant decreased during pacing, indicating improvement in diastolic function, probably owing to relief of myocardial ischemia.

Adult↗
PubMed1986

Left ventricular ejection fraction determined with the nuclear stethoscope, gamma camera and contrast ventriculography.

Left ventricular ejection fractions (EF) were measured with a nuclear stethoscope (NSt, beat-to-beat and ECG gated summation method) and contrast ventriculography (VG) immediately following one another (IFOA) (r X 0.96 and 0.95, respectively, n = 13). NSt and ECG gated gamma camera (MUGA) recordings IFOA were compared (r = 0.97 and 0.96, respectively, n = 23) as were non-IFOA recordings (r = 0.90 and 0.91, respectively, n = 13). Correlation between repeated NSt EF measurements gave: r = 0.91 (n = 22) for both methods. Paired NSt recordings in an invasive test situation (during invasive angiocardiography) and in a noninvasive situation (supine, 30 min of rest) gave for patients with EF less than 50 (mean +/- S.D.): EF invasive = 36 +/- 12, EF noninvasive = 41 +/- 13 (n = 4, p less than 0.05), and for patients with EF greater than or equal to 50: EF invasive = 59 +/- 7, EF noninvasive = 57 +/- 7 (n = 9, N.S.). The mean paired differences (EF noninvasive -EF invasive) in the low (less than 50) and high (greater than or equal to 50) EF range differed significantly: +5.3 versus -1.3, respectively (p less than 0.001). The recordings with the ECG-gated summation method gave similar results. The heart rate (beats min-1) in the noninvasive and invasive situation were (mean +/- S.D.): 68 +/- 11 and 78 +/- 16, respectively (p less than 0.01). We conclude that the patients were in a higher level of stress in the invasive situation. Accordingly ventricles with normal contractility (EF greater than or equal to 50) reacted with a slight increase in EF, and ventricles with compromised function (EF less than 50) reacted with a decrease in EF, compared to the values in the noninvasive situation. Incorporated in a correlation between MUGA and VG are, besides methodologically based differences, test-situation based systematical differences. Consequently the results of MUGA method should be given uncorrected. The results documents the accuracy and reliability of the NSt.

Adolescent↗
PubMed1994

The oesophageal and precordial stethoscope transducer as a monitoring and teaching aid.

We describe a low cost, easy to construct monitoring and teaching aid for the oesophageal and precordial stethoscopes. It is constructed from two readily available 'state of the art' integrated circuits. The aid allows more than one observer simultaneously to hear heart and breath sounds, without being acoustically isolated from the other monitoring. In addition it is possible to record from the device to audiotape.

Anesthesiology↗
PubMed1978

The development of a radio-stethoscope for use in the horse at rest and during exercise.

The development of a radio-stethoscope for horses is described. The equipment consisted of a sound transducer applied to the skin adjacent to the trachea and a radio transmitter attached to the saddle. The signals emitted were detected by telemetry and recorded on a magnetic tape-recorder. The recorder incorporated a monitor earphone so that sounds could be reproduced at the time of recording. The frequency response obtainable ranged from a few Hz to 4 KHz. This technique provided an objective means of studying the respiratory sounds generated during exercise although absolute values could not be measured.

Animals↗
PubMed1978

Respiratory sounds recorded by radio-stethoscope from normal horses at exercise.

A graphic representation is presented of respiratory sounds recorded by a radio-stethoscope from normal horses exercised at the walk, trot, canter and gallop. Methods whereby inspiratory and expiratory sounds were distinguished are discussed. The form of amplitude envelopes of the sounds recorded at different gaits are compared. Certain measurements of relative amplitudes and the form of amplitude envelopes of the recorded respiratory sounds can be recognised as typical of normal horses when exercised at the canter and gallop. The influence of some physiological events (e.g. deglutition on the rhythm of normal respiration at the canter and gallop) is indicated.

Animals↗
PubMed1975

The calibration of stethoscopes and phonocardiographic microphones.

The response of stethoscopes and chest microphones depends on the impedance of the sound source, which must therefore have the same impedance as the body, and must emit a signal related to the sound intensity in the body when no instrument is applied. Body impedance depends on the geometry of the instrument and on the force of application, etc. The source impedance must, therefore, be variable to suit test conditions. Unexplained discrepancies in published impedance measurements hinder standardisation of source impedance. The impedance of an electromagnetic vibrator can be modified electronically to meet these requirements.

Electronics, Medical↗
PubMed1996

Asian Pacific American Medical Students: Beyond the 'golden stethoscope'

PURPOSE OF THE PAPER: The purpose of this paper is to present a keynote address given in 1995 immediately prior to the formal inauguration of the Asian Pacific American Medical Student Association &lpar;APAMSA&rpar; in New York. PRINCIPAL FINDINGS: Asian Pacific American &lpar;APA&rpar; medical students have increased ten&shy;fold as a percentage of the entering class from 1975&shy;1995 to its current level of 18.2%. The recent history of the APA medical student movement is traced from its inception in regional conferences in 1993 to the formation of a national electronic mail bulletin board &lpar;"AAMSnet"&rpar; in 1994, and its culmination in the first national conference and inauguration of the Asian Pacific AMerican Medical Student Association &lpar;APAMSA&rpar; at New York University in 1995. CONCLUSIONS: Although the "golden stethoscope" image is used to represent the pinnacle for APA students entering the medical profession, beneath the image lie difficult challenges specific to APAs including those of family and culture, academic performance, professional acceptance, and community responsibility. The potential of the APAMSA organization to address local, regional, and national APA health issues is explored.

Journal Article↗
PubMed1992

[Changes in left ventricular function during exercise after lung resection--study with a nuclear stethoscope].

In 29 cases undergoing lung resection, effects of the surgery on left ventricular function were investigated indirectly with a Nuclear Stethoscope. Various parameters were measured following an exercise load before and after surgery. There were significant decreases in post-operative resting levels of stroke volume (SV) (p < 0.001), end-diastolic volume (EDV) (p < 0.001), ejection fraction (EF) (p < 0.05) and ejection rate (ER) (p < 0.001) and significant increase in heart rate (HR) (p < 0.001) when compared to pre-operative resting levels. Neither filling rate (FR) nor cardiac output (CO) showed significant difference. At maximum exercise load, there were significant decreases in post-operative EDV (p < 0.005), SV (p < 0.005), ER (p < 0.001) and FR (p < 0.005), but no significant differences were detected in HR and EF; consequently, there was a significant decrease in CO (p < 0.005). Ratio of the levels at maximum load to those at resting of each parameter did not show significant difference between before and after operation with regard to any parameters except CO and FR which showed significant decrease (p < 0.005 and p < 0.001, respectively). Effects of the surgery on left ventricular function were studied according to amount of lung resection. In 13 cases where more than two lobes were resected, similar significant differences to those mentioned above were found in all parameters except EF. In cases where a single lobe was resected, only ER and FR showed similar tendency to that described above. Effects of the surgery on left ventricular function were also studied according to age of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

[Echocardiography--a stethoscope of the 21st century].

The goal of this article is to provide a report of a current potential of an ultrasound examination of heart and to outline future development of echocardiography and its use in clinical practice. Since echocardiography appearance in the middle of the 20th century till today, the method has undergone a very dynamic development. From a simple one-dimensional image (M-mode), through two-dimensional image (2D) complemented with Doppler imaging of blood flows, echocardiography developed into currently up to date methods such as contrast echocardiography, tissue Doppler imaging, assessment of myocardial strain and strain rate, methods based on detection of ultrasonic backscatter (acoustic densitometry, automated border detection, colored image of wall motion--"color kinesis") and others. Possibility of an ultrasonic assessment of heart significantly supplemented transesophageal echocardiography and newly emerging three-dimensional imaging of heart structures. As a routine method to prove myocardial ischemia and viability a stress echocardiography is currently used. Its results significantly improved after technical innovations enabling simultaneous monitoring and evaluation of images at various projection displays and at various levels of stress. A big promise for further bigger use of echocardiography has become a miniaturisation of devices enabling one man to carry the device to a patient outside a health care facility. These small, more affordable ultrasound devices can soon become real stethoscopes of the 21st century.

Echocardiography↗
PubMed1991

[Functional state of the myocardium during transesophageal cardiac pacing in patients with ischemic heart disease selected for surgical treatment based on nuclear stethoscope findings].

A nuclear stethoscope was used to examine central hemodynamic parameters and myocardial contractility in 70 patients with coronary heart disease (CHD). The findings were analyzed according to the degree of cicatricial changes in the myocardium and coronary atherosclerotic lesion. The patients, unlike apparently healthy individuals, were found to show an increase in systolic cardiac output and a decrease in left ventricular ejection fraction in response to transesophageal cardiac pacing. As the cicatricial changes in the myocardium became profound, the maximum left ventricular performance decreased mainly due to the myocardial factor, while there was a reduction in the chronotropic reserve along with relatively slight signs of myocardial dysfunction when coronary atherosclerotic lesion progressed.

Adult↗
PubMed1991

Auscultation with an esophageal stethoscope. A new test for pneumoperitoneum.

Auscultation for the tympanic sound characteristic of developing pneumoperitoneum during insufflation of the abdomen at laparoscopy was performed with an esophageal stethoscope. Such auscultation detected pneumoperitoneum as soon as or sooner than did the other, standard methods to which it was compared. This test requires no additional maneuvers beyond those routine in standard laparoscopic and anesthetic procedures, providing a useful adjunctive test for pneumoperitoneum acquisition.

Adult↗
PubMed1977

Electronic stethoscope for detection of cerebral aneurysm, vasospasm and arterial disease.

A specially designed acoustic stethoscope electronic-computer-analysis system has repeatedly detected and identified angiographically demonstrated anteriorly located intracranial aneurysms by their characteristic signals. The system has detected and measured clinically significant disease in the carotid siphon and bifurcation, even in cases with normal angiograms, and has recorded the onset and disappearance of cerebral vasospasm. Our data suggests that an aneurysm may act as a flexible Helmholtz resonator, possibly being driven by vortex shed or turbulence. Our goal is the development of a safe, non-invasive method by which the physician could investigate warning symptoms of aneurysms, cerebral vasospasm, and arterial disease in order to recommend preventive surgery or medical treatment early before the patient's condition might deteriorate. Individual cases, falsely positive and negative results are discussed.

Adult↗