This paper reviews a humanistic risk management policy that includes early injury review, steadfast maintenance of the relationship between the hospital and the patient, proactive full disclosure to patients who have been injured because of accidents or medical negligence, and fair compensation for injuries. The financial consequences of this type of policy are not yet known; however, one Veterans Affairs medical center, which has been using humanistic risk management since 1987, has had encouragingly moderate liability payments. The Department of Veterans Affairs now requires such a policy for all of its facilities; therefore, comprehensive experience may be only a few years away.

With the emerging use of tracheal sound analysis to detect and monitor respiratory tract changes such as those found in asthma and obstructive sleep apnea, there is a need to link the attributes of these easily measured sounds first to the underlying anatomy, and then to specific pathophysiology. To begin this process, we have developed a model of the acoustic properties of the entire respiratory tract (supraglottal plus subglottal airways) over the frequency range of tracheal sound measurements, 100 to 3000 Hz. The respiratory tract is represented by a transmission line acoustical analogy with varying cross sectional area, yielding walls, and dichotomous branching in the subglottal component. The model predicts the location in frequency of the natural acoustic resonances of components or the entire tract. Individually, the supra and subglottal portions of the model predict well the distinct locations of the spectral peaks (formants) from speech sounds such as /a/ as measured at the mouth and the trachea, respectively, in healthy subjects. When combining the supraglottic and subglottic portions to form a complete tract model, the predicted peak locations compare favorably with those of tracheal sounds measured during normal breathing. This modeling effort provides the first insights into the complex relationships between the spectral peaks of tracheal sounds and the underlying anatomy of the respiratory tract.

Many different transducers are employed for recording respiratory sounds including accelerometers and microphones in couplers. However, there is no standard lung sound transducer or any device to compare transducers so that measurements from different laboratories can be determined to be of physiologic origin rather than technical artifacts of the transducers. To address this problem, we designed and constructed a prototype of a device that can be used to compare accelerometers, microphones enclosed in couplers, and stethoscopes. The prototype device consists of a rigid chamber containing a loudspeaker that opens to an antechamber covered by a viscoelastic material with mechanical properties similar to human skin and subcutaneous tissue. When driven by a white noise source, we found the sound output at the surface to be useful to comparatively evaluate sensors between 100 and 1200 Hz where lung sounds have most of their spectral energy. We compared the viscoelastic layer to similar thicknesses of fresh meat and fat and found them to produce similar acoustic spectra. This device allows air-coupled transducers, accelerometers, and stethoscopes used in respiratory sounds measurements to be compared under physical conditions similar to their intended use.

bioacoustic transducer testing system Comparison of lung sound transducers using a You might find this additional info useful... 45 articles, 8 of which you can access for free at: This article cites http://jap.physiology.org/content/101/2/469.full#ref-list-1 1 other HighWire-hosted articles: This article has been cited by http://jap.physiology.org/content/101/2/469#cited-by including high resolution figures, can be found at: Updated information and services http://jap.physiology.org/content/101/2/469.full can be found at: Journal of Applied Physiology about Additional material and information http://www.the-aps.org/publications/jappl This information is current as of June 3, 2013. http://www.the-aps.org/. Pasterkamp. Comparison of lung sound transducers using a bioacoustic transducer testing system.

The spectra of sounds recorded over the trachea of adults typically reveal peaks near 700 and 1500 Hz. We assessed the anatomical determinants of these peaks and the conditions contributing to their presence. We studied five adult subjects with normal lung function, measuring sounds at the suprasternal notch and on the right cheek. The subjects breathed at target airflows of 15 and at 30 ml sec(-1) kg(-1) both through the mouth with nose clips and then through the mouth and nose using a cushioned face mask. The mouth breathing maneuvers were performed with three lengths (3.6, 21.1 and 38.6 cm) of 2.6 cm diameter tubing between the mouth and the pneumotachograph. The nose breathing maneuver was performed with the longest tube (between the mask and pneumotachograph). The signals occurring at the target flows +/- 20% were used to create averaged, spectral estimates. We found that all subjects had two predominant spectral peaks; a approximately 700 Hz peak loudest over the cheek and a a...

After the Veterans Affairs Medical Center (VAMC) in Lexington, Kentucky, lost two major malpractice cases in the mid-1980s, leaders started taking a more proactive approach to identifying and investigating incidents that could result in litigation. An informal risk management team met regularly to discuss litigation-prone incidents. During one in-depth review, the team learned that a medication error had caused the patient's death. Although the family would probably never have found out, the team decided to honestly inform the family of exactly what had happened and assist in filing for any financial settlement that might be appropriate. This decision evolved into an organization wide full disclosure policy and procedure. The Lexington VAMC's policy on full disclosure includes informing patients and/or their families of adverse events known to have caused harm or injury to the patient as a result of medical error or negligence. The disclosure includes discussions of liabilit...

We assessed the performance of three air-coupled and four contact sensors under standardized conditions of lung sound recording. Recordings were obtained from three of the investigators at the best site on the posterior lower chest as determined by auscultation. Lung sounds were band-pass filtered between 100 and 2,000 Hz and sampled simultaneously with calibrated airflow at a rate of 10 kHz. Fourier techniques were used for power spectral analysis. Average spectra for inspiratory sounds at flows of 2 +/- 0.5 L/s were referenced against background noise at zero flow. Air-coupled and contact sensors had comparable maximum signal-to-noise ratios and gave similar values for most spectral parameters. Unexpectedly, less sensitivity (lower signal-to-noise ratio) at high frequencies was observed in the air-coupled devices. Sensor performance needs to be characterized in studies of lung sounds. We suggest that lung sound spectra should be averaged at known airflows over several breaths and ...

Study objective: We have previously investigated the effects of microphone type and coupler air chamber depth on lung sound characteristics. We now report the results of experiments exploring the effects of air chamber width, shape, and venting on lung sounds. Design: We used a single electret microphone with a variety of plastic couplers. The couplers were identical except for the diameter and shape of the air chamber. We used cylindrical chambers of 5, 10, and 15 mm in diameter at the skin and conical chambers of 8,10, and 15 mm in diameter. We compared the inspiratory lung sound spectra obtained using each ofthe couplers. We also examined the tendency of various needle vents to transmit ambient noise into the microphone chamber.

Study objective: We have previously investigated the effects of microphone type and coupler air chamber depth on lung sound characteristics. We now report the results of experiments exploring the effects of air chamber width, shape, and venting on lung sounds. Design: We used a single electret microphone with a variety of plastic couplers. The couplers were identical except for the diameter and shape of the air chamber. We used cylindrical chambers of 5, 10, and 15 mm in diameter at the skin and conical chambers of 8,10, and 15 mm in diameter. We compared the inspiratory lung sound spectra obtained using each ofthe couplers. We also examined the tendency of various needle vents to transmit ambient noise into the microphone chamber.

This article describes one hospital's development of a proactive, patient centered program, which emphasizes total honesty in dealing with all aspects of patient care. This process includes the full and timely disclosure of errors which affect the patient's health and well being. The article describes the process by which the medical facility identifies errors and works with healthcare providers to arrive at a consensus on the management of these errors. Included is a step by step analysis of how disclosure can be successfully accomplished.

There is a growing expectation in health systems around the world that patients will be fully informed when adverse events occur. However, current disclosure practices often fall short of this expectation. We reviewed trends in policy and practice in 5 countries with extensive experience with adverse event disclosure: the United States, the United Kingdom, Canada, New Zealand, and Australia. We identified 5 themes that reflect key challenges to disclosure: (1) the challenge of putting policy into large-scale practice, (2) the conflict between patient safety theory and patient expectations, (3) the conflict between legal privilege for quality improvement and open disclosure, (4) the challenge of aligning open disclosure with liability compensation, and (5) the challenge of measurement related to disclosure. Potential solutions include health worker education coupled with incentives to embed policy into practice, better communication about approaches beyond the punitive, legislation t...

Few investigators have examined the relationship between airflow and lung sound amplitude; the available data are contradictory. I measured airflow at the mouth and compared the peak flow (Vmax) to mean and peak lung sound amplitude (mean AMP and peak AMP) at four sites on the chest wall (right and left anterior apices and posterior bases) in four healthy young adults. At each site, the sounds produced by 20 breaths at Vmax ranging between 1.5 and 4 L/s (Vvar) were measured by an automated technique. Ten breaths during nearly constant Vmax breathing (Vcon) also were measured at each site. The lung sound amplitudes at the four sites in each subject were grouped and compared to Vmax by linear regression analysis. The same sounds were also submitted to an automated V-correction procedure to evaluate its adequacy in automatically adjusting for the effect of variations in Vmax on lung sound amplitude. The data showed that lung sound amplitude (mean or peak) was linearly related to V in all subjects (r for mean AMP vs Vmax:0.77, 0.85, 0.69, 0.89; r for peak AMP vs Vmax:0.80, 0.83, 0.79, 0.88), p less than 1 X 10(-7) in all cases. The average mean AMP vs Vmax regression line slope was 0.42, and the average peak AMP vs Vmax regression line slope was 0.45. V-correction decreased the coefficient of variation of the Vvar sounds by 61 percent and flattened the average regression line slopes to 0.128. For the Vcon series, V-correction diminished the coefficient of variation from 12.2 to 10.0 percent. The relationship between lung sound amplitude and airflow appears to be substantially linear and this relationship can be used to adjust effectively for variations in airflow.