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PubMed1985

Effect of nitroglycerin on left ventricular function in patients with ischemic heart disease.

To evaluate the effects of nitroglycerin on left ventricular function in 27 patients with ischemic heart disease, ejection fraction (EF) was measured every 1 to 5 min by a nuclear stethoscope after sublingual administration of nitroglycerin (0.3 mg). There was a good correlation between EF determined by the nuclear stethoscope and EF by left ventriculography (r = 0.80, p less than 0.001). EF showed a rise after sublingual nitroglycerin, which was most marked at 4 to 7 min and returned to the control level in 20 to 25 min. There were no significant differences in the maximum percent increase in EF among patients with 0, 1, 2 and 3 vessel disease. The maximum percent increases in EF were 34.0 +/- 10.0% in the normal contraction group, 24.0 +/- 8.5% in the hypokinesis group (p less than 0.05 vs the normal contraction group) and 15.2 +/- 8.5% in the akinesis group (p less than 0.01 vs the normal contraction group, p less than 0.05 vs the hypokinesis group). There was a weak correlation between the maximum percent increase in EF and the changes in heart rate (r = 0.49, p less than 0.05) and there was an inverse correlation between the maximum percent increase in EF and the changes in systolic blood pressure (r = -0.65, p less than 0.01). It was shown that the improvement in EF by sublingual nitroglycerin was greatest in the normal contraction group, somewhat less in the hypokinesis group and least in the akinesis group. The nuclear stethoscope is useful in monitoring changes in left ventricular function during intervention.

Adult↗
PubMed1992

Pediatric cardiology: auscultation from 280 miles away.

New long-distance audio/video and data communications links among health-care facilities promise to reduce rural patients' travel time and waiting time for subspecialty consultations. To offer a satisfactory alternative to face-to-face examination, the long-distance system must meet the subspecialty's minimum criteria. For pediatric cardiology in particular, the system has to permit satisfactory cardiac auscultation. A preliminary test of remote auscultation that uses an electronic stethoscope involved two pediatric cardiologists, one listening hands-on with an acoustic stethoscope, the other listening independently at long distance with the electronic instrument. Taking the acoustic findings as the reference standard, the electronic stethoscope did not miss the one case of heart disease, correctly recommended echocardiogram follow-up in the two cases requiring it, and agreed on 80% of the murmurs' qualitative specifics. The patients' parents also indicated that the system was highly acceptable. We are following up these results with a full-scale study of the effectiveness and parental acceptance of remote auscultation.

Cardiology↗
PubMed1993

Clinical and communication access through amplification for a medical student with severe hearing loss: case report.

This case report focuses on the communication difficulties of a 21-year-old medical student with severe-to-profound sensorineural hearing loss. The greatest difficulties reported by the patient were for stethoscope use and slide presentations in darkened rooms. Successful audiologic management was accomplished for this patient via use of a behind-the-ear (BTE) FM system for classroom use and a "homemade" amplified stethoscope that enabled him to hear diagnostic heart sounds for clinical use. The amplified stethoscope provided greater low-frequency gain for this patient than was available through other commercial units.

Adult↗
PubMed1995

Evaluation of remote stethoscopy for pediatric telecardiology.

OBJECTIVE: To investigate the interobserver reliability and diagnostic validity of a commercial electronic stethoscope for pediatric telecardiology. MATERIALS AND METHODS: Pairs of blinded pediatric cardiologists made independent diagnoses, recommendations concerning follow-up echocardiography, and specific judgments regarding heart sounds, murmurs, and congenital heart disease using an electronic (ES) or an acoustic (AS) stethoscope on 78 pediatric cardiology outpatients and at a distance of 450 km (280 miles) with 38 telemedicine cardiology outpatients. The kappa statistic (K) indexed the instruments' interexaminer reliabilities. The validity of ES was measured by K for ES versus AS and by the percentage of cases where the findings for ES and AS differed sufficiently to suggest an important ES screening error. RESULTS: For heart disease, AS, ES, and tele-ES reliabilities were satisfactory (K = 0.80, 0.67, and 0.80, respectively), as were AS agreement with hands-on ES (K = 0.65) and with tele-ES (K = 0.64). The AS and ES reliabilities and ES/AS agreement were also satisfactory for systolic regurgitant and diastolic pulmonic murmurs (K = 0.63-0.78) but were unsatisfactory for evaluable heart sounds and other murmurs (K = 0.16-0.60). The ES yielded clinically important disagreements with AS in 5.4% of the clinic cases and 10.5% of the telemedicine cases (P = 0.67). In determining the need for additional work-up (echocardiography) or follow-up appointments, hands-on ES and tele-ES had a combined accuracy of 92%, with a sensitivity of 88% and a specificity of 97%. CONCLUSIONS: Hands-on ES provided reliable and valid screening for congenital heart disease. Tele-ES was highly reliable but had reduced diagnostic validity. Examiner blinding, bandwidth limitations, and artificial restrictions on the remote assistant may have contributed to this reduced performance. As these factors are easily correctable, we regard the ES as a highly promising tool for pediatric telecardiology.

Child↗
PubMed1995

What family physicians need in their doctor's bag.

Our objective was to determine what family physicians need in their doctor's bag for urgent and non-urgent house calls. In a prospective survey, family physicians completed a structured report form after consecutive house calls, recording what equipment they needed for each. Thirteen doctors from two urban practices, making a total of 111 house calls, took part. Frequency of reported need of diagnostic equipment, therapeutic agents and administrative supplies was measured. Items required more than 70% of the time were: stethoscope; sphygmomanometer; patient's medical chart; and prescription pad. All other items were required in less than 30% of house calls. We conclude that doctors should carry a stethoscope, sphygmomanometer and prescription pad with them at all times; the patient's medical chart is also essential. Additional equipment should be accessible as prepared kits and taken as needed, depending on the particular patient's problem.

Adolescent↗
PubMed1998

Airway auscultation. A new method of confirming tracheal intubation.

Unrecognised accidental oesophageal intubation remains an important cause of morbidity and mortality in anaesthetic practice. We have evaluated a new method of distinguishing tracheal from oesophageal intubation using a simple adaptation of an ordinary stethoscope which is inserted into the patient end of the breathing system. We call this technique 'airway auscultation'. Characteristic sounds are heard with the stethoscope during inflation and deflation which allow the observer to diagnose the position of the tube. When the tube is in the trachea loud breath sounds are heard. In contrast, when the tube is in the oesophagus either squeaks or a flatus-like noise is heard or else there is no sound. In 100 healthy adults two observers rapidly identified 99 intubations correctly in a randomised single-blind trial. We recommend further widespread evaluation of this device as it appears to be an effective, simple and rapid method of detecting oesophageal intubation and confirming tracheal intubation which may be of particular use in situations where capnography is not available.

Adolescent↗
PubMed2000

A new pocket-sized transcranial ultrasound device (NeuroDop): comparison with standard TCD.

The NeuroDop is a new bedside assessment tool consisting of a continuous wave ultrasound probe attached to a stethoscope earpiece. This study was designed to compare middle cerebral artery (MCA) velocity assessment obtained with the NeuroDop versus standard transcranial Doppler (TCD). TCD technologists performed continuous wave NeuroDop studies followed by standard TCD studies on 60 subjects. Technologists recorded presence of MCA signal and estimated velocity based on NeuroDop auditory characteristics. Signal was obtained in 108 MCA vessels with the portable unit and in 112 vessels using standard TCD. For detection of patency, sensitivity was 96%, specificity 88%, positive predictive value 99%, and negative predictive value 58%. Auditorially estimated velocities from the NeuroDop strongly correlated with TCD velocity measures (r = 0.71). Categorical estimates of velocity as decreased (< 37 cm/sec), normal (37-81 cm/sec), or increased (> 81 cm/sec) demonstrated an accuracy rate of 85%. This novel stethoscope-continuous wave unit has excellent sensitivity in detecting presence of MCA patency. Moreover, MCA velocities can be characterized to a reasonable degree of accuracy based on NeuroDop auditory characteristics. The NeuroDop shows promise as a tool to rapidly assess and serially monitor presence and amplitude of MCA velocity and may help guide thrombolytic and other emergency management decisions in stroke patients.

Blood Flow Velocity↗
PubMed2001

[Auscultation of the lungs--still a useful examination?].

Auscultation of the lungs has been a central element in clinical examination since the early part of the nineteenth century. However, the role of the stethoscope in our diagnostic work-up has more and more been challenged by newer diagnostic equipment. Research carried out over the last 30 years has given us new knowledge about the physical basis of lung sounds and the meaning of the sounds. Electronic stethoscopes and computer-based analysis of digital lung sounds are now available. Lungs auscultation findings should be interpreted with caution and be related to the case history and other clinical findings.

Auscultation↗
PubMed2005

Computerised analysis of auscultatory sounds associated with vascular patency of haemodialysis access.

Vascular access for renal dialysis is a lifeline for about 120 000 individuals in the United States. Stethoscope auscultation of vascular sounds has some utility in the assessment of access patency, yet can be highly skill-dependent. The objective of the study was to identify acoustic parameters that are related to changes in vascular access patency. The underlying hypothesis is that stenoses of haemodialysis access vessels or grafts cause vascular sound changes that are detectable using computerised data acquisition and analysis. Eleven patients participated in the study. Their vascular sounds were recorded before and after angiography, which was accompanied by angioplasty in most patients. The sounds were acquired using two electronic stethoscopes and then digitised and analysed on a personal computer. Vessel stenosis changes were found to be associated with changes in acoustic amplitude and/or spectral energy distribution. Certain acoustic parameters correlated well (correlation coefficient = 0.98, p < 0.0001) with the change in the degree of stenosis, suggesting that stenosis severity may be predictable from these parameters. Parameters also appeared to be sensitive to modest diameter changes (> 20%), (p < 0.005, Wilcoxon rank sum test). These results suggest that computerised analysis of vascular sounds may be useful in vessel patency surveillance. Further testing using longitudinal studies may be warranted.

Arteriovenous Shunt, Surgical↗
PubMed1990

Passive warming of airway gases (artificial nose) improves accuracy of esophageal temperature monitoring.

The most efficient site for monitoring heart and lung sounds by esophageal stethoscope is not the warmest segment of the esophagus. This study investigated the ability of passive warming of airway gases to increase the accuracy of temperatures measured at this site (i.e., to decrease their difference from core temperature). In 15 adult patients undergoing general anesthesia and endotracheal intubation, esophageal temperatures were measured before and after use of a heat and moisture exchanger (an artificial nose) that passively warmed inspired gases. The resulting values were compared with nasopharyngeal temperatures, which represented core temperature. Before use of the heat and moisture exchanger, esophageal and nasopharyngeal temperatures differed significantly (mean difference +/- SD, 0.9 +/- 0.4 degrees C; P less than or equal to 0.001). After passive warming of inspired gases, esophageal temperatures increased significantly (mean increase +/- SD, 0.5 +/- 0.2 degrees C; P less than or equal to 0.001) but inconsistently (range, 0.1 to 1.2 degrees C). However, the mean difference between esophageal and nasopharyngeal temperatures was still significant (0.5 +/- 0.3 degrees C; P less than 0.001). Discrepancies between esophageal and core temperatures persist when a currently available esophageal stethoscope with adjacent auscultation chamber and temperature probe is used, despite passive warming of airway gases.

Adult↗
PubMed1997

Auscultation revisited: the waveform and spectral characteristics of breath sounds during general anesthesia.

Although auscultation is commonly used as a continuous monitoring tool during anesthesia, the breath sounds of anesthetized patients have never been systematically studied. In this investigation we used digital audio technology to record and analyze the breath sounds of 14 healthy adult patients receiving general anesthesia with positive pressure ventilation. Sounds recorded from inside the esophagus were compared to those recorded from the surface of the chest, and corresponding airflow was measured with a pneumotachograph. The sound samples associated with inspiratory and expiratory phases were analyzed in the time domain (RMS amplitude) and frequency domain (peak frequency, spectral edge, and power ratios). There was a positive linear correlation (R2 > 0.9) between inspiratory flow and sound amplitude in the precordial and esophageal samples of all patients. The RMS amplitude of the inspiratory and expiratory sounds was approximately 13 times greater when recorded from inside the esophagus than from the surface of the chest in all patients at all flows (p < 0.001). The peak frequency (Hz) was significantly higher in the esophageal recordings than the precordial samples (298 +/- 9 vs 181 +/- 10, P < 0.0001), as was the 97% spectral edge (Hz) (740 +/- 7 vs 348 +/- 16, P < 0.0001). In the adult population esophageal stethoscopes yield higher frequencies and greater amplitude than precordial stethoscopes. Quantification of lung sounds may provide for improved monitoring and diagnostic capability during anesthesia and surgery.

Adolescent↗
PubMed1975

Handy heart sound simulator.

A simple bedside technique of heart sound simulation using hand and stethoscope is described. The technique utilizes tissue vibration and sound conduction with the usual air column of a stethoscope to reproduce auscultatory events accurately without the distortion that often accompanies electrical production of heart sounds.

Aortic Valve Stenosis↗
PubMed1994

Cardiac pearls.

Most diagnoses of cardiovascular disease are made in the office or at the bedside. For example, in pulsus alternans of the radial pulse, observed when first greeting a patient, alteration of intensity of the second sound and systolic murmur and a ventricular (S3) gallop are clinical pearls--often subtle--that diagnose cardiac decompensation. A faint gallop, ventricular (S3) or atrial (S4), might be overlooked in a patient who has an emphysematous chest and an increase in anteroposterior diameter if one listens over the usual areas of the precordium. However, the gallop might be detected easily by listening over the xiphoid or epigastric area. How do you tell the difference between an S4, a split first sound, and an ejection sound? The S4 is eliminated with pressure on the stethoscope, but pressure does not eliminate the ejection sound or the splitting of S1. The atrial sound (S4) is most frequently found in patients who have coronary heart disease, and it is a constant finding in patients who have hypertension. It does not denote heart failure, as does the S3 (ventricular) gallop. In some patients, both atrial (S4) and ventricular (S3) diastolic gallops may be present. This occurrence is common in patients with cardiac decompensation associated with coronary heart disease, hypertensive heart disease, and dilated cardiomyopathy. When these diastolic filling sounds occur in close proximity, a short rumbling murmur may be heard, which causes confusion of this sound with that of a valvular or congenital lesion. When both sounds occur exactly simultaneously, a single sound results. Often, this sound is louder than either the first or second sound and can be misinterpreted as either a valvular or congenital lesion. This, however, is a summation gallop, which is rare. For the most accurate timing of heart sounds and murmurs, the simple technique called "inching" is the best. Keeping the second sound in mind as a reference, the physician moves (inches) the stethoscope from the aortic area to the apex. An extra sound may be noted to occur in systole before the second sound, thereby diagnosing a systolic click. If the sound occurs after the second sound, however, it is an S3 or ventricular diastolic gallop. If a murmur appears before S2, it is a systolic murmur; if it appears after S2, it is a diastolic murmur. When the Austin-Flint murmur is heard, significant aortic regurgitation exists.(ABSTRACT TRUNCATED AT 400 WORDS)

Anti-Bacterial Agents↗
PubMed1994

Ketamine in the treatment of bronchospasm during mechanical ventilation.

The effect of ketamine on bronchospasm during mechanical ventilation was evaluated in a prospective, placebo-controlled, double-blind trial. Fourteen mechanically ventilated patients with bronchospasm were randomly allocated to either ketamine 1 mg/kg or saline placebo. In the ketamine-treated patients, PO2 increased from 10.5 (+/- 0.5) kPa to 16.4 (+/- 2.7) kPa (P < .05), whereas PO2 in the placebo-treated patients remained unchanged. The PCO2 was constant in the ketamine group, although it increased from 5.6 (+/- 0.9) kPa to 6.1 (+/- 0.9) kPa in the placebo group (P < .05). The pulmonary stethoscopic bronchospasm improved immediately after the administration of ketamine, whereas the thoracic compliance remained unchanged. In conclusion, the ketamine-treated patients showed an improvement by stethoscopic examination, in PO2 and in PCO2, suggesting that ketamine might be useful in the treatment of bronchospasm during mechanical ventilation. However, further studies are required to decide whether ketamine should be considered the drug of choice in patients with severe bronchospasm during ventilator treatment.

Adult↗
PubMedDate not supplied

Fetal evaluation for transport by ultrasound performed by air medical teams: A case series.

The air medical team has limited options when evaluating the obstetrical patient and assessing fetal health during air transport to a high-risk obstetrical unit. Traditionally, physical examination and a Doppler stethoscope have been used to determine fetal heart rates and movement. However, with the advent of portable ultrasound technology, new information about the mother and child are available to the air medical crew. The Fetal Evaluation for Transport with Ultrasound (FETUS) is a screening examination that consists of an evaluation of the fetal heart rate, position, and movement and general condition of the placenta. The examination can be repeated in flight with no acoustic distortion from rotor noise. The additional information can be advantageous when transport decisions need to be made or when conditions do not allow Doppler stethoscope use.

Adult↗
PubMed2003

Validation of heart and lung teleauscultation on an Internet-based system.

The feasibility and accuracy of an Internet-based system for teleauscultation was evaluated in 103 cardiac patients, who were auscultated by the same cardiologist with a conventional stethoscope and with an Internet-based method, using an electronic stethoscope and transmitting heart and lung sounds between computer work stations. In 92% of patients, the results of electronic and acoustic auscultation coincided, indicating that teleauscultation may be considered a reliable method for assessing cardiac patients and could, therefore, be adopted in the context of comprehensive telecare programs.

Aged↗
PubMed2004

Ultrasound stethoscopy.

Miniaturization and digital techniques have resulted in the development of high-resolution, battery-powered personal ultrasound devices with excellent grey-scale and color blood flow imaging capabilities. These devices are appropriately called "ultrasound stethoscopes" and are practical to use. They extend our physical perception during a clinical examination by "seeing the invisible pathology" and allow the user to address specific clinical problems anywhere at the point-of-care. Murmurs and abnormal precordial movements can be directly related to cardiac structural, functional, and flow abnormalities. A cardiac abnormality (pericardial effusion, dilated heart, valvular disease, mass lesion) is rapidly confirmed during the clinical examination and often a specific diagnosis is made. The device can effectively assist in the initial evaluation and rapid diagnosis of potentially life-threatening conditions or in situations where quick decision-making is essential. Overall, they strengthen our clinical diagnostic accuracy and also add quantitative information. The ultrasound stethoscope allows rapid screening for left ventricular dysfunction and occult aortic abdominal aneurysm and left ventricular hypertrophy in patients with hypertension. Training may become an important issue and should focus on criteria of normalcy and identifying specific and major cardiac disorders. There is no doubt, however, that these devices will revolutionize the physical cardiac examination and diagnosis.

Journal Article↗
PubMed2004

Development of an ultra-portable echo device connected to USB port.

In practical cardiology, a stethoscope based auscultation has been used to reveal the patient's clinical status. Recently, several hand-held echo devices are going on market and they are expected to play a role as "visible" auscultation instead of stethoscope. We have developed a portable and inexpensive echo device which can be used for screening of cardiac function. Two single element transducers were attached 180 degrees apart to a rotor with 14-mm diameter. The mechanical scanner, integrated circuits for transmitting and receiving ultrasonic signals and an A/D converter were encapsulated in a 150 x 40 mm probe weighing 200 g. The scan was started and the image was displayed on a Windows based personal computer (PC) as soon as the probe was connected to USB 2.0 port of the PC. The central frequency was available between 2.5 and 7.5 MHz, the image depth was 15 cm and the frame rate was 30/s. The estimated price of this ultra-portable ultrasound is about 3000 US dollars with software. For 69 cardiac patients with informed consent, image quality was compared with those obtained with basic range diagnostic echo machines. Left ventricular ejection fraction (EF) derived from normal M-mode image of standard machines (EFm) were compared with visual EF of the ultra-portable ultrasound device (EFv). The image quality was comparable to the basic range diagnostic echo machines although short axis view of aortic root was not clearly visualized because the probe was too large for intercostal approach. EFv agreed well with EFm. The ultra-portable ultrasound may provide useful information on screening and health care.

Echocardiography↗