Influence of carvedilol on hospitalizations in heart failure: incidence, resource utilization and costs. U.S. Carvedilol Heart Failure Study Group.

BACKGROUND: Carvedilol reduces disease progression in heart failure, but to our knowledge, its effects on hospitalizations and costs have not been evaluated. OBJECTIVES: We examined the effects on hospitalization frequency and costs in the U.S. Carvedilol Heart Failure Trials Program. This program consisted of four concurrent, multicenter, double-blind, placebo-controlled studies involving 1,094 patients with New York Heart Association class II to IV heart failure, which treated patients with placebo or carvedilol for up to 15 months (median, 6.5 months). METHODS: Detailed resource utilization data were collected for all hospitalizations occurring between randomization and the end of follow-up. In-patient care costs were estimated based on observed levels of resource use. RESULTS: Compared with placebo, carvedilol reduced the risk of hospitalization for any reason by 29% (p = 0.009), cardiovascular hospitalizations by 28% (p = 0.034) and heart failure hospitalizations by 38% (p = 0.041). Carvedilol also decreased the mean number of hospitalizations per patient (for cardiovascular reasons 30% [p = 0.02], for heart failure 53% [p = 0.03]). Among hospitalized patients, carvedilol reduced severity of illness during hospital admission, as reflected by shorter length of stay and less frequent use of intensive care. For heart failure hospital admissions, carvedilol decreased mean length of stay by 37% (p = 0.03) and mean number of intensive care unit/coronary care unit days by 83% (p = 0.001), with similar effects on cardiovascular admissions. As a result, estimated inpatient care costs with carvedilol were 57% lower for cardiovascular admissions (p = 0.016) and 81% lower for heart failure admissions (p = 0.022). CONCLUSIONS: Carvedilol added to angiotensin-converting enzyme inhibition reduces hospitalization risk as well as severity of illness and resource utilization during admission in patients with chronic heart failure.

Industrial wideband noise reduction for hearing aids using a headset with adaptive-feedback active noise cancellation.

High-intensity noises are a health hazard for industrial workers, and hearing protection is necessary to prevent hearing loss. Passive methods, such as ear muffs, are ineffective against low-frequency noise. Moreover, many hearing-impaired workers must wear hearing aids to enable communication at their workplace, and such aids can amplify ambient noise. To overcome this problem, the present study developed a headset equipped with a digital signal processing system to implement adaptive-feedback active noise cancellation (AFANC) to reduce low-frequency noise. The proposed AFANC headset was effective against wideband industrial noise, with a maximum noise spectrum power reduction of 30 dB. Furthermore, when used with a hearing aid, it improved the speech signal-to-noise ratio by up to 14 dB. These results suggest that a headset with AFANC would be useful for hearing protection in workplaces with high levels of low-frequency industrial noise, especially for hearing-impaired workers.

Genetic algorithm for the efficient selection of disyllabic word lists used in Mandarin speech discrimination tests.

Speech audiometric tests have been widely used for advanced hearing diagnoses and in rehabilitation. However, there are no standardised speech tests for more than 90% of the world's population, who do not speak English. A major problem in the design of a speech audiometric test is that the selection of test materials is subject to multiple criteria, and its complexity rises dramatically as the structure of test items changes from phonemic or monosyllabic forms to disyllabic or polysyllabic forms. A genetic algorithm is presented that can automatically select a set of disyllabic words from a large Mandarin corpus. The selection accords with the following principal criteria for the items constituting a speech discrimination test: similarity in structure, familiarity to the subjects, and a phonemically balanced composition. The performance of the genetic algorithm was evaluated by computation of the distance between a target vector, specifying the desired distribution of initial and final syllables and tone patterns for daily disyllabic word usage, and the vector derived by the search results of the algorithm. The use of the genetic algorithm was illustrated by its application to the selection of test lists from two Mandarin corpora. The results showed that, for a given corpus, at least 12 disyllabic word lists with a distance of less than 20 could be generated within 72 h. The genetic algorithm performed an efficient, robust and low-complexity search of the problem space and can be easily modified to adapt to the material selection of other languages.

Specific frequency properties of renal and superior mesenteric arterial beds in rats.

In order to investigate the effects of arterial beds on pressure waveforms in arteries, the pressure waves observed in the rat tail artery were resolved into their Fourier moduli before and during ligation of the left renal artery and the superior mesenteric artery. Consistently different patterns of waveform changes in the tail artery were seen on occlusion of these vessels. Ligation of the renal artery reduced, and of the superior mesenteric artery increased, the pressure harmonics over most of the spectra. These results imply that to study the changes in the pressure contours as the observation point is moved downstream, one may have to account separately for the contributions of individual arterial beds. This is relevant in considering the degree to which it is appropriate for data to be amalgamated in models of the systemic arterial bed.

Real-time display of the stomach slow wave and its parameters in a newly designed electrogastrographic system.

We designed a new three-channel electrogastrographic (EGG) system, which was easily operated on the Windows 95 platform and could automatically provide slow wave parameters. The purpose of the present study was to test its reliability and accuracy in clinical recording. The system included a signal acquisition device assembled on a printed circuit board. Recorded myoelectrical signals were filtered, amplified, digitized, and transmitted via this device into a notebook personal computer (PC). Based on the short-term Fourier transform the software could transfer the time domain of the signal into the frequency domain. Real-time displayed slow wave parameters, including dominant frequency/power, percent of normal frequency (2-4 cpm), instability coefficient in frequency/power, and power ratio, were automatically renewed every 64s. Twenty healthy subjects (M/F, 12/8; age, 23-51 years) were enrolled to measure both fast and postprandial myoelectrical activities for each 30-min recording. Our results indicated that meal ingestion significantly increased dominant frequency (3.15+/-0.20 vs 3.23+/-0.23 cpm; P < 0.05) and power (26.1+/-3.8 vs 28.4+/-3.9 dB; P < 0.05). The power ratio of the meal effect was 2.02+/-2.07. Other parameters, including instability coefficient and percent of normal frequency, remained similar despite food ingestion. This newly designed EGG system is acceptable for clinically measuring gastric myoelectrical activity; the real-time display of many EGG parameters is an advantage with this new system.

A probability-based multivariate statistical algorithm for autofluorescence spectroscopic identification of oral carcinogenesis.

A probability-based multivariate statistical algorithm combining partial least-squares (PLS) and logistic regression was developed to identify the development stages of oral cancer through analysis of autofluorescence spectra of oral tissues. Tissues were taken from a 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis model. Analyses were conducted at various excitation wavelengths, ranging from 280 nm to 400 nm in 20 nm increments, to assess classification performance at different excitations. For each excitation the PLS analysis and logistic regression were combined, on the basis of cross validation, to calculate the posterior probabilities of samples belonging to four stages of cancer development: normal tissues, hyperplasia, dysplasia and early cancers and frankly invasive cancers. Results showed that the 320 nm excitation wavelength optimally classified the cancer development stages: the accuracy rates for identifying samples at that excitation were 91.7%, 83.3%, 66.7% and 83.3% for the four respective stages. The average accuracy rate was 81.3%. These results suggest that the algorithm described in this study might be useful for the detection of human oral cancers.

Rapid prototyping strategy for a surgical data warehouse.

OBJECTIVES: Healthcare processes typically generate an enormous volume of patient information. This information largely represents unexploited knowledge, since current hospital operational systems (e.g., HIS, RIS) are not suitable for knowledge exploitation. Data warehousing provides an attractive method for solving these problems, but the process is very complicated. This study presents a novel strategy for effectively implementing a healthcare data warehouse. METHODS: This study adopted the rapid prototyping (RP) method, which involves intensive interactions. System developers and users were closely linked throughout the life cycle of the system development. The presence of iterative RP loops meant that the system requirements were increasingly integrated and problems were gradually solved, such that the prototype system evolved into the final operational system. RESULTS: The results were analyzed by monitoring the series of iterative RP loops. First a definite workflow for ensuring data completeness was established, taking a patient-oriented viewpoint when collecting the data. Subsequently the system architecture was determined for data retrieval, storage, and manipulation. This architecture also clarifies the relationships among the novel system and legacy systems. Finally, a graphic user interface for data presentation was implemented. CONCLUSIONS: Our results clearly demonstrate the potential for adopting an RP strategy in the successful establishment of a healthcare data warehouse. The strategy can be modified and expanded to provide new services or support new application domains. The design patterns and modular architecture used in the framework will be useful in solving problems in different healthcare domains.

Modification of the wavelet method used in transiently evoked otoacoustic emission pass/fail criterion to increase its accuracy.

Transiently evoked otoacoustic emissions (TEOAEs) are widely used in newborn hearing screening programmes for early detection of hearing losses. To increase the accuracy of a TEOAE pass/fail criterion that uses the wavelet method, it was demonstrated that the large estimation variance is a possible reason for the inaccuracy, and a modified wavelet method is proposed to solve the inaccuracy problem. In the modified wavelet method, N paired buffers, instead of only one, were used to store the total 512 subaveraged responses, and then the average of the calculated N cross-correlation coefficients between N pairs of TEOAE signals was taken in the pass/fail criterion. Four sets of 256 synthesised noise and eight sets of 256 synthesised noisy TEOAE signals were tested, and each set was tested 1,000 times. The results showed that the standard deviation of the correlation estimation was greatly reduced by using this average value with N selected as 4. As a result, the total number of single-scale cross-correlation coefficients below 50% decreased from 1281 to 195 for noisy TEOAE signals, and the total number of single-scale cross-correlation coefficients above 50% decreased from 90 to 0 for synthesised noise.

Effects of noise on transient-evoked oto-acoustic emission pass/fail criteria.

This study investigated the effects of noise on typical transient-evoked oto-acoustic emission (TEOAE) pass/fail criteria. Different levels of synthesised noise were added to one TEOAE signal, to determine the relationship between the signal-to-noise ratio (SNR) and typical TEOAE parameters: reproducibility, TEOAE level and corrected TEOAE level. Results showed that, with the same TEOAE signal, if the SNR decreased from 19 dB to -7 dB, the means of estimated reproducibility decreased from 97% to 7%, and the means of estimated TEOAE levels were doubled. Only the means of estimated corrected TEOAE levels were relatively insensitive to SNR. The standard deviations of all TEOAE parameter estimators increased with decreasing SNR. With these results, this study proposed that each typical TEOAE parameter alone should not be taken as the absolute pass/fail criterion. A combination of the corrected TEOAE level and the reproducibility would be better.

A possible relation between pressure loading and thickened leaflets of the aortic valve: a model simulation.

A much smaller percentage of thickened leaflets of the aortic valve have been found in the right or left coronary leaflet than in the noncoronary leaflet. This study investigated the pressure loading transferring to the leaflets of the aortic valve and their effects on the valvular thickening. A simple ascending aorta model was established, and a simulation was made. The pressure loading in the coronary and noncoronary leaflets then were estimated. The simulation results showed that 5.8% to 17.% percentage of pressure loading to the coronary leaflet may be decreased by the coronary perfusion in diastole. The coronary arteries play an important role on pressures in the sinuses of Valsalva. The smaller pressure loading transferring to the coronary leaflet than that to the noncoronary leaflet is one reasonable explanation related to the thickened leaflets of the aortic valve.

A flexible pressure pump for cardiovascular studies.

Pressure pumps are useful in cardiovascular studies and in the evaluation of many circulatory devices. Currently available pumps are, however, far from perfect in their methods of syncrhonization, flexibility, and frequency response. To overcome these disadvantages, this study reports the design of a new pressure pump based on a linear motor. The pump can accurately synchronize with an animal's heart beats by using a phase-lock loop (PLL) technique. It has great flexibility and the ability to generate both arbitrary pressure waves and pure sinusoidal waves. The pressure pump has a frequency response of up to 50 Hz which is suitable for cardiovascular studies on rats, rabbits, cats and dogs.

Intracavernosal pressure characteristics analyzed by power spectral density for identifying the phase of penile erection.

Knowledge of the time course of penile erection is very important to understanding erection physiology. The changes in the intracavernosal pressure (ICP) and the different phases of an erection are pivotal to the ability to produce and maintain a rigid penile erection. This study investigated an objective and low-invasiveness method for identifying different erection phases based on an innovative ICP analysis technique. Blood infuses into the corpora cavernosa and causes the ICP to increase. The ICP usually exhibits tiny oscillations at the frequency of the heartbeat when it increases from diastole to systole. The characteristic oscillation amplitudes corresponding to the period when the full and rigid erection phases begin can be extracted by power spectral density analysis. The reliability and accuracy of the proposed method was verified by the Bland-Altman graphs indicating a good agreement with the existing method that compares the ICP with the arterial pressure. Moreover, all of the intraclass correlation coefficient values were close to 1.00, with the lower limit of the 95% confidence interval exceeding 0.75. The described novel objective and low-invasiveness method can therefore be used for identifying the full and rigid erection phases of the penis in urological investigations during different erection phases.

Materials management in investor-owned, nonprofit government, and other general hospitals.

This article compares investor-owned, nonprofit government, and other general hospitals in Georgia in the areas of materials management practices, systems, and performance. Findings reveal investor-owned hospitals paid less for supplies but did not demonstrate performance in other areas that was superior to that of other types of hospitals.

Multiple productivity measurement approaches for management.

Managers may desire an approach to combining multiple productivity measurements into one score. This article demonstrates two approaches to aggregating multiple measurements, data envelope analysis (DEA) and the Multicriteria Performance/Productivity Measurement Technique (MCP/PMT). These methods are applied to actual hospital materials management data and do not result in significantly different results. The productivity analysis must then be tempered according to managerial judgement.

Transurethral prostatectomy with computer-monitored resectoscope.

Based on the difference in electrical conductivity between hyperplastic prostatic tissue and tissue of the surgical capsule, we have developed a monitoring computer that distinguishes the former from the latter. The computer sounds an alarm when the cutting loop of the resectoscope touches the capsule, followed by an automatic cut-off of the power source 0.4 s later; thus inadvertent perforation of the surgical capsule can be avoided in most cases. The function of the computer has been tested in 73 patients with benign prostatic hyperplasia. The results show that, with Nesbit's technique of transurethral resection, tiny perforations of the surgical capsule, usually 1 to 2 mm in diameter, occurred in all 30 patients operated on without computer monitoring, but only 3 of 73 computer-monitored patients had such an occurrence. There was a slight increase in the weight of resected prostatic tissue among the computer-monitored patients, but the difference between the time spent on the procedure between the two groups of patients was not significant. Apart from its monitoring function, the computer may reduce eye strain and mental stress in the surgeon, especially when resecting a large hyperplastic prostate.

Implementation of a patient-centred and physician-oriented healthcare information system.

Integration of information has enabled expeditious operation in air transfer, banking, shopping, and stock brokerage, but not in healthcare. Existing health information systems (HIS) are concerned too much with departmental performance and charge billing, and neglect the end users--the patients and the physicians. The resultant HIS then has divergent operation to antagonize the physicians, and has fragmented data to the disadvantage of patients. Recognizing the problems and the trend of HIS, this study proposed and implemented a patient-centred and physician-oriented HIS in a Urology clinic. The proposed HIS had patient care as its core, and accurately coded the patient's diagnoses and therapy information. It also offered a friendly environment and complete function for the physician to administrate medical records and to provide healthcare services. The HIS had client/server structure and an open system to protect the hardware investment and the software implementation. It will be the key to success in complete hospital environments.

Cocaine induces striatal c-fos-immunoreactive proteins via dopaminergic D1 receptors.

The protooncogene c-fos produces a phosphoprotein, Fos, which regulates gene transcription processes. In neuronal systems, Fos has been proposed to couple synaptic transmission to changes in gene expression by acting in the cell nucleus in concert with other proteins to form complexes in the promoter regions of target genes. We report here that the acute administration of a single dose of the indirect-acting dopaminergic agonist cocaine increases multiple Fos proteins in rat caudate nucleus. The increase is dose-dependent and is apparent immunocytochemically at 1 hr, maximal at 2 hr, and absent 48 hr after treatment. The increase seen immunocytochemically is composed of several molecular weight species as assessed by Western blotting of proteins from isolated striatal cell nuclei. Administration of the specific dopaminergic receptor antagonists sulpiride and SCH-23390 prior to cocaine support a significant role for D1 but not for D2 receptors in mediating this effect. These data indicate that D1 dopamine receptors are linked to a cellular immediate-early gene system(s) and suggest an action of cocaine at one or more levels of gene expression via modulation of transcriptional processes in activated cells.

An instrument using variation of resistance to aid in needle tip insertion in epidural block in monkeys.

A new method is proposed to detect the entrance of a needle into the epidural space. Measuring the changes in electric resistance during the insertion of the needle through different tissues in the interspinal space can help anesthesiologists judge whether and when the needle has entered the epidural space. This preliminary, animal study showed that the proposed method performed quite satisfactorily. The electric resistance of the tissues in the interspinal space varied from 1.57 +/- 1.22 k omega to 2.93 +/- 1.14 k omega, and the resistance of the epidural space varied from 9.00 +/- 1.12 k omega to 14.64 +/- 1.25 k omega. The difference was statistically significant (p less than 0.001). This difference in the resistance can be used to verify placement of the tip of the needle in the epidural space and help anesthesiologists administer epidural anesthesia.