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Biomedical subjects

L F Muscarella

Publications and source records attributed to L F Muscarella.

At least 19 recordsLinked to original sources
PubMed2000

Automatic flexible endoscope reprocessors.

Reprocessing medical instruments is a complex and controversial discipline. If all instruments were constructed of materials not damaged by heat, pressure, and moisture, instrument reprocessing would be greatly simplified. As the number of novel and complex instruments entering the market continues to increase, periodic review of the health care facility's instrument reprocessing protocols to ensure their safety and effectiveness is important. This article reviews the advantages and the limitations of automatic flexible endoscope reprocessors.

Automation↗
PubMed1998

Are all sterilization processes alike?

Automated processes designed to sterilize reusable medical instruments use heat and low-temperature chemicals. Several factors, including the physical properties of the sterilizing agents and whether all of the instruments' surfaces can be adequately cleaned, can cause significant variations in the reliability and effectiveness of the sterilization processes. Instruments exposed to heat-based sterilization processes pose the lowest probability of transmitting diseases between patients. Heat can conduct through many different types of materials and can destroy microorganisms embedded under layers of patient debris. Studies have demonstrated, however, that--unlike heat--low-temperature chemicals require direct contact with the microorganisms to be effective. Moreover, the complex designs of some instruments can adversely affect the low-temperature sterilization processes' outcomes by hindering cleaning and preventing the flow of low-temperature chemicals to all of the instruments' contaminated surfaces. This article will explore the differences between heat-based and low-temperature chemical processes to help health care providers minimize the risk of cross-infection.

Algorithms↗
PubMed1998

Instrument design and cross-infection.

This article reviews recently reported patient-to-patient transmission of disease during endoscopic procedures and discusses several important instrument reprocessing issues. In addition, the author offers several infection control recommendations to minimize the risk of patient infection during endoscopic procedures.

Colonoscopes↗
PubMed1996

Advantages and limitations of automatic flexible endoscope reprocessors.

The advantages and limitations of automatic flexible endoscope reprocessors (AFERs) are presented. These medical devices can increase patient safety and minimize personnel exposure to the liquid chemical germicide and its vapors. Some models feature a printer to document important reprocessing parameters, an in-line tap water filtration system to reduce the likelihood of endoscope (and patient) contamination, and a heater to satisfy the elevated temperature requirements of some liquid chemical germicide labels. Although they offer significant advantages compared with manual reprocessing, AFERs have their limitations. Current models do not automate every endoscope reprocessing step and are not typically designed to reprocess every endoscope channel. Some AFER models may have to be periodically decontaminated to ensure that their internal components do not support microbial colonization. Moreover, their cost per cycle can be considerably more than manual reprocessing without necessarily reducing overall reprocessing time. Its limitations notwithstanding, an AFER is likely to be an asset in a busy endoscopy center. In addition to comparing automated and manual reprocessing, this article addresses important reprocessing issues and purchasing concerns.

Automation↗
PubMed1996

High-level disinfection or "sterilization" of endoscopes?

Controversy has surrounded the use of liquid chemical germicides to reprocess medical instruments that are damaged by heat sterilization. A review of the literature was performed to assess and compare the efficacy of disinfection and sterilization processes. The results of this review demonstrate that high-level disinfection of thoroughly cleaned endoscopes is not associated with a higher infection rate than is "sterilization". While there may be a theoretical distinction between the highest level of disinfection and sterilization, thorough cleaning eliminates clinical differences between the two. High-level disinfection is quick, effective, inexpensive, and recommended whenever heat sterilization is not feasible. A low-temperature sterilization process should be considered only if it is comparable in cost to disinfection or if it offers demonstrated advantages without damaging the instrument. Neither disinfection nor sterilization is likely to be effective if the instrument is not cleaned thoroughly after use.

Cross Infection↗
PubMed1993

Quantitative analysis of the Landis method.

Landis developed the single capillary micro-occlusion method for the determination of the capillary filtration coefficient, Lp. More recently, several modified versions of Landis's original procedure have been introduced in an attempt to measure Lp with greater ease and accuracy. Each of the techniques assumes that the capillary is a uniformly cylindrical indistensible tube. Since recently obtained experimental data have demonstrated that the capillary is compliant, a distributed mathematical model of the capillary was developed to reveal the extent to which capillary distensibility influences the measurement of Lp at different sites along the capillary. After assigning physiologic values to this modeled capillary, including Lp and the capillary wall's modulus of elasticity, Landis's method and two of its modified versions were performed on the modeled capillary, with each yielding values for Lp at 10 different locations along the capillary. Comparison of these 10 computed Lp values with the corresponding Lp values defined in the modeled capillary demonstrates that capillary distensibility can introduce significant error into the measurement of Lp.

Animals↗
PubMed1991

Effect of ultrasound on regional cerebral blood flow in neonatal rats.

By employing a laser-Doppler flowmeter, an investigation was performed to determine whether ultrasound causes a change in regional cerebral blood flow (rCBF). rCBF in neonatal rats (age: 2-6 days postgestation) was measured before, during, and after exposure of both cerebral hemispheres to continuous-wave ultrasound (1.0 MHz) at an intensity of 2.0 W/cm2 (SATA) for a period of 5 min. After 3 min of ultrasound treatment, there was a statistically significant augmentation in rCBF (p less than 0.05) with rCBF increasing by a factor of 2.7 +/- 0.4 (mean +/- SEM) after 5 min of ultrasound. This response was demonstrated to be a transient effect, because rCBF returned to its original value 4-6 min after termination of the ultrasound treatment.

Animals↗
PubMed1986

Pressure pulse transmission into vascular beds.

Observations at the microcirculatory level have revealed that (a) the pressure pulse reaches the smallest vessel, and (b) the pulse wave velocity alters from a value in the order of meters/second in large arteries to a value in the order of centimeters/second in the microvessels. We investigate, herein, whether these experimental findings are consonant with linear pulse wave transmission theory in a branching system of vessels. Our computations, utilizing available data, show that this is indeed the case. For low frequency (1 Hz), cumulative attenuation is such that about one-third of the pulse, originating at the heart, reaches the capillary. A 10-Hz pulse, however, is virtually completely attenuated by the time the capillary is reached. Transmission time for a pulse, from heart to capillary, is also frequency dependent, with higher frequencies propagating more rapidly. Vasoconstriction, at the arteriolar level in the absence of reflection, can also strongly attenuate the pulse remnant at that site.

Blood Pressure↗
PubMedDate not supplied

Biopsy forceps: disposable or reusable?

Current debate surrounds the cost-effectiveness of disposable and reusable biopsy forceps. Although a complex and arduous task, performing a cost analysis may be necessary to determine which forcep type is more cost-effective. Costs associated with disposable biopsy forceps include their initial cost as well as storage and disposal costs. In addition to initial cost, costs associated with reusable biopsy forceps include reprocessing, maintenance, and repair costs. Estimating the number of times forceps are likely to be reused is also essential to evaluating the cost-effectiveness of reusable biopsy forceps. In general, once a reusable biopsy forcep performs a threshold number of procedures, it becomes more cost-effective than a disposable forcep. While reusable biopsy forceps may be more suitable and cost-effective for larger gastrointestinal endoscopy centers that perform many procedures per day, the convenience of disposable biopsy forceps may make them the more appropriate choice for centers that are smaller and perform only a few procedures each day. Due to significant decreases in the initial cost of disposable biopsy forceps, the cost-effectiveness of reusable biopsy forceps is waning. This article reviews the various issues associated with disposable versus reusable biopsy forceps and provides readers with guidelines for evaluating the appropriateness of both forcep designs in their unique practice setting.

Biopsy↗