Stethoscope System Research Articles

Fiber-optic stethoscope: a cardiac monitoring and gating system for magnetic resonance microscopy.

A fundamental problem associated with using the conventional electrocardiograph (ECG) to monitor a subject's cardiac activity during magnetic resonance imaging (MRI) is the distortion of the ECG due to electromagnetic interference. This problem is particularly pronounced in MR microscopy (MRI of small animals at microscopic resolutions (< 0.03 mm(3))) because the strong, rapidly-switching magnetic field gradients induce artifacts in the animal's ECG that often mimic electrophysiologic activity, impairing the use of the ECG for cardiac monitoring and gating purposes. The fiber-optic stethoscope system offers a novel approach to measuring cardiac activity that, unlike the ECG, is immune to electromagnetic effects. The fiber-optic stethoscope is perorally inserted into the esophagus of small animals to optically detect pulsatile compression of the esophageal wall. The optical system is shown to provide a robust cardiac monitoring and gating signal in rats and mice during routine cardiac MR microscopy.

Stethoscope and headset system

A stethoscope and headset system comprising a stethoscope having a monitor mechanism for monitoring internal bodily vibrations of a patient and conversion circuitry coupled to the monitor mechanism for receiving the internal bodily vibrations and transmitting internal bodily indication signals based upon the internal bodily vibrations, a headset having a headband, a pair of earpieces coupled to the headband, a microphone for receiving a user's voice and transmitting a plurality of intercom signals; and a pair of speakers with each speaker coupled to an earpiece for transmitting audible sounds upon actuation by internal bodily indication signals and intercom signals; and a user-orientable selector switch coupled with the stethoscope and headset and coupleable with an intercom system of an aircraft, the selector switch having one orientation for enabling a user to listen to a patient's internal bodily vibrations and another orientation for enabling a user to communicate through the intercom system.

Remote stethoscope signal processing system

The present invention relates to a remote stethoscope system that allows a doctor at one location to listen to the stethoscope sounds coming from a stethoscope being used by a patient in his or her remotely-located home. The acoustic stethoscope sounds are converted into electrical signals, frequency shifted up to the telephone band, and then conveyed over a conventional telephone line. At the doctor's location, the signals are shifted down to their original frequencies and then converted back to audible sound for the doctor's analysis. The sensor used by the patient picks up a wide range of frequencies without any manipulation by the patient.

Stethoscope system for high-noise environments

An electronic stethoscopic system is described which permits detection of auscultory sounds in a patient in high noise environments such as ambulances and aircraft. The stethoscope employs an electroacoustical transducer, an acoustical driver mounted in a headset providing acoustical isolation from exterior noise, a summing microphone positioned within the insulating headset, and active noise reduction circuitry to feed an error signal back from the summing microphone to the acoustical driver so as to effectively cancel the unwanted acoustical noise originating external to the insulating headset. The stethoscopic system includes circuitry permitting the headset to selectively receive the audio output from a vehicular intercom system whenever a voice signal is present, thereby allowing treating medical personnel to monitor the patient while participating in the conversation being conducted on the vehicle's intercom system.

Electronic stethoscope system and method

A microprocessor based sound enhancement system in which frequencies outside of the auditory range of the human ear are translated into sound within the auditory range by translating each frequency component of the entire frequency spectrum of the input signal by a time scale compression factor. Preferably, a microprocessor transforms an electrical signal corresponding to the input signal into a frequency spectrum signal comprising frequency components having frequency, phase, and amplitude elements by performing a fast Fourier transform (FFT) operation on the input signal. The frequency components of this transformed signal are translated and the resulting translated frequency spectrum signal is transformed into a time varying output signal by performing an inverse FFT operation on the translated frequency spectrum signal. When heart pulses or similar periodic waveforms are monitored, the pulse rate of the signal is maintained in the output signal. Alternatively, the time varying signal is compressed in the time scale and then transformed into audible sound, while maintaining the original pulse rate in the output signal, thereby resulting in the same output signal as that resulting from translating the entire frequency spectrum by the time scale compression factor.

The First Heart Sound Amplitude Using Digital Esophageal Stethoscope System is Proportional to The Change in Cardiac Output

Objective: The use of an esophageal stethoscope is a basic heart sounds monitoring procedure performed in patients under general anesthesia. As the size of the first heart sound can express the left ventricle function, its correlation with cardiac output should be investigated. The aim of this study was to investigate the effects of cardiac output (CO) on the first heart sound (S1) amplitude.Methods: Six male beagles were chosen. The S1 was obtained with the newly developed esophageal stethoscope system. CO was measured using NICOM, a non-invasive CO measuring device. Ephedrine and beta blockers were administered to the subjects to compare changes in figures, and the change from using an inhalation anesthetic was also compared.Results: The S1 amplitude displayed positive correlation with the change rate of CO (r = 0.935, p < 0.001). The heart rate measured using the esophageal stethoscope and ECG showed considerably close figures through the Bland-Altman plot and showed a high positive correlation (r = 0.988, p < 0.001).Conclusion: In beagles, the amplitude of S1 had a significant correlation with changes in CO in a variety of situations.doi: http://dx.doi.org/10.12669/pjms.302.4383How to cite this:Shin YD, Yim KH, Park SH, Jeon YW, Bae JH, Lee TS, et al. The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia. Pak J Med Sci 2014;30(2):276-281. doi: http://dx.doi.org/10.12669/pjms.302.4383This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.