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PubMed1985

Microwave sterilization of nitrous oxide nasal hoods contaminated with virus.

Although there exists a desire to eliminate the possibility of cross-infection from microbial contaminated nitrous oxide nasal hoods, effective and practical methods of sterilization in a dental office are unsatisfactory. Microwaves have been used to sterilize certain contaminated dental instruments without damage. In this study nasal hoods contaminated with rhinovirus, parainfluenza virus, adenovirus, and herpes simplex virus were sterilized in a modified microwave oven. Ninety-five percent of the virus activity was destroyed after 1 minute of exposure of the contaminated nasal hoods to microwaves. By the end of 4 minutes, complete inactivation of all four viruses was found. Repeated exposure of the nasal hoods to microwaves resulted in no damage to their texture and flexibility. Microwave sterilization may potentially provide a simple and practical method of sterilizing nitrous oxide anesthesia equipment in a dental or medical practice.

Adenoviruses, Human↗

PubMed1988

Self-sterilization of the electrosurgery electrode.

Sterilization of the electrode used in electrosurgery has been assumed to occur at the instant of contact of the energized electrode tip to a grounded source. This study evaluated whether the time of electrode activation or the amount of energy delivered is important in the self-sterilization process. Standard bacteriologic culturing techniques were employed to assess sterility of the electrode tip following activation. Total time of application of the current and the energy used were recorded on audiotape and later tabulated. The data indicate that the time of energizing and the energy units used are critical in the sterilization of the electrode tip. These results confirm that self-sterilization of the electrosurgery electrode tip occurs, but full confidence is not realized with the time intervals commonly employed in clinical practice. The electrode tip must be considered a potential source of bacterial contamination of electrosurgically managed dental procedures.

Electric Conductivity↗

PubMed1984

Technical aspects of gaseous formaldehyde as a sterilant.

The design of a sterilizer for sterilization of heat sensitive items using gaseous formaldehyde and steam is described. The sterilizer is able to create a constant formaldehyde-steam concentration over a period of at least one hour. It is further able to operate at formaldehyde concentrations close to saturation with only small residues on sterilized plastic materials. The autoclave is used for measurement of formaldehyde solubility in polyolefines and poly(vinyl chloride) being approx. 15 and 250 ppm, respectively, at 70 degrees C and 30 mg HCHO I-1. The diffusion coefficient of formaldehyde in poly(vinyl chloride) is measured and is in the same order of magnitude as for ethylene oxide in poly(methyl methacrylate) i.e. 10(-10) cm2 s-1. Measurements of airborne formaldehyde in front of different sterilizers show that it is possible to design facilities meeting occupational exposure limits.

Diffusion↗

PubMed1995

Effectiveness of ethylene oxide for sterilization of dental handpieces.

Ethylene oxide gas has been utilized as an alternative method for sterilization of dental handpieces, as it is less corrosive than steam. However, its effectiveness for sterilization of the internal components of dental handpieces has not been established. The objective of this study was to compare the effectiveness of ethylene oxide and steam for sterilization of dental handpieces. Unused handpieces and handpieces which had been exposed to clinical dental procedures ('clinical') were contaminated with Streptococcus mutans, exposed to steam or ethylene oxide, and flushed with sterile saline. Washings were plated on mitis-salivarius agar, and colonies identified and counted. No viable colonies could be established from washings from 'clinical' or 'unused' handpieces exposed to steam. However, viable colonies could be established from 'clinical' handpieces exposed to ethylene oxide. This data suggests that a substance entrapped within 'clinical' handpieces (possibly the biofilm) may protect bacteria from ethylene oxide gas, preventing adequate sterilization.

Biofilms↗

PubMed1992

Load-deflection characteristics of nickel-titanium alloy wires after clinical recycling and dry heat sterilization.

The desirable mechanical properties of nickel-titanium alloy wires and their relatively high cost has prompted many clinicians to recycle these wires. Clinical recycling exposes the wires to several weeks or months of mechanical stresses and elements of the oral environment, as well as sterilization between uses. In a previous study it was noted that clinical recycling combined with cold sterilization alters the load-deflection characteristics and surface topography of nickel-titanium wires. Whether similar changes in mechanical properties occur in wires subjected to repeated clinical use and dry heat sterilization is not yet clear. The purpose of this investigation was to determine the effects of in vivo recycling interposed by dry heat sterilization (together referred to as clinical recycling, CR) on the load-deflection characteristics of nickel-titanium alloy wires. To differentiate the effects of dry heat sterilization (DHS) from those of CR on the behavior of these wires, a series of wires were also subjected to DHS only. Two types of nickel-titanium wires, namely Nitinol and NiTi were subjected to a three-point bending test in an as-received condition (T0), after one cycle (T1), and two cycles (T2) of DHS or CR. Ten wires comprised each subsample. Statistical analyses were done by one-factor repeated measures analysis of variance and Scheffe F test. Both DHS alone, as well as CR, produced significant changes in the loading and unloading characteristics of Nitinol and NiTi wires. However, the changes in the load-deflection characteristics of these wires after DHS only were relatively small, and the clinical significance of these changes is open to question.(ABSTRACT TRUNCATED AT 250 WORDS)

Alloys↗

PubMed1994

Sterilization of Fuji pressure-sensitive film.

Fuji Prescale film is a pressure-sensitive medium which produces a characteristic pink stain on the application of pressure. Up to a saturation level, increases in pressure will produce a denser stain, thereby providing a method of determining pressures within the interface between two articulating surfaces. The relationship between the magnitude of applied pressure and the optical density of the resulting stain is non-linear; this relationship also varies with ambient temperature and humidity, in addition to load rate, and therefore requires a calibration procedure prior to use. The use of Fuji prescale film for recording interface pressures within the joint space in vivo has been widely reported; however, the object of this study was to assess the effects of sterilizing this medium, with a view to future in vivo applications. Samples of Fuji film were sterilized using a standard ethylene oxide (ETO) gas process and their subsequent pressure-recording properties were compared to a control group of samples. The 'optical-density vs pressure' relationship for the sterilized group was significantly different from that of the control group (paired Student's t-test, P < = 0.001); however, both groups provided reliable data across the same pressure-range and both exhibited an excellent degree of repeatability (coefficient of variation < 2.5%). It was concluded that Fuji film will continue to produce pressure-stains following ETO sterilization; however, the calibration of this film will only be valid if it is conducted using film from the sterilized group.

Calibration↗

PubMed2006

Measurement of the microbial barrier effectiveness of sterilization containers in terms of the log reduction value for prevention of nosocomial infections.

BACKGROUND: The microbial barrier properties of 216 sterilization containers of 4 central sterile supply departments of different hospitals were measured using a microbial challenge test. METHODS: Uncovered thermoresistant plates filled with Sabouraud agar were placed on the base of the containers prior to sterilization. After sterilization, the containers were exposed to a defined microbial aerosol and periodic atmospheric pressure reductions of 10 to 70 hPa in an exposure chamber. After exposure and incubation of the entire containers, colony growth was registered as colony forming units (CFU) on the plates and the control plates to calculate the barrier effectiveness in terms of the logarithmic reduction value (LRV). RESULTS: Two out of 11 standard containers with paper filters and 9 out of 79 containers with textile filters showed no growth on the plates. The mean colony numbers were 222 CFU/600 cm(2) (standard container with paper filter) and 209 CFU/ 600 cm(2) (container with textile filter). Fourteen out of 15 containers with permanent plastic filters did not show any growth on the plates. No recontamination was observed in 18 of 111 half-size containers. The mean colony numbers of the recontaminated half-size containers were 110 (paper filter) and 34 CFU per 300 cm(2) (textile filter). The LRVs of the full-size and half-size containers tested ranged between 1.08 and >4. CONCLUSION: As shown in this study, the microbial barrier effectiveness of sterilization containers in the routine clinical setting can be tested with a quantitative microbial challenge test at intervals of 1 year to eliminate defect or ineffective containers as potential causal factors for nosocomial infections. An LRV of >4 should be envisaged as the target assurance level.

Cross Infection↗

PubMed2006

Barriers to obtaining a desired postpartum tubal sterilization.

OBJECTIVE: To determine why women do not undergo postpartum sterilization despite expressing desire during antepartum care. METHODS: In a retrospective chart review, we identified all women between March 2002 and November 2003 who requested postpartum sterilization during antepartum care but did not undergo the procedure. We report the reasons why sterilizations were not performed. RESULTS: We reviewed 6,589 prenatal care and delivery records identifying 324 women meeting inclusion criteria. One hundred and four women changed their mind. Of women still desiring sterilization at discharge, the most common reasons for not undergoing the procedure were lack of valid Medicaid sterilization consent forms [n=121; 37.3%, 95% confidence interval (CI) 32.0-42.6%]; a medical condition precluding the procedure (n=47; 14.5%, 95% CI 10.7-18.3%); lack of availability of an operating room (n=2; 6.5%, 95% CI 3.8-9.2%). CONCLUSION: We found that the Medicaid consent process, medical conditions and insufficient operating room space prevented women from having the desired surgery.

Adult↗

PubMed2006

Identifying women who will request sterilization reversal in a military population.

OBJECTIVE: We sought to identify the characteristics of women in a military population who are likely to seek a tubal anastomosis after a previous bilateral tubal ligation (BTL). METHOD: A written investigational review board-approved questionnaire was administered to 56 women, ages 18-40 years, requesting evaluation for a reversal of a prior BTL and 52 women of the same age range not seeking reversal. The questionnaire identified demographics and relationship characteristics of volunteers at the time of their decision to have a BTL and at the present time. RESULTS: Age 25 years or younger, sterilization due to pressure from a partner, poor marital relationship at the time of the BTL and a new marriage are highly predictive of tubal sterilization regret and a request for sterilization reversal in a military population. In addition, women requesting a tubal anastomosis reported less preoperative counseling on the permanence of a BTL and of the male alternative for permanent female sterilization, vasectomy. CONCLUSION: Women with these characteristics should have extensive counseling before undergoing tubal sterilization.

Adult↗

PubMed2006

Efficiency in endotoxin removal by a reprocessing protocol for electrophysiology catheters based on hydrogen peroxide plasma sterilization.

Electrophysiology and ablation cardiac catheters, which come in contact with blood during clinical use, are required to be non-pyrogenic (<20 endotoxin units (EU)/device). This study aimed to quantify the residual endotoxin load in reprocessed devices as a mandatory step to guarantee safe reuse. We monitored the pyrogenic status of the device (n=61) in three fundamental steps of the reprocessing protocol: after clinical use, after decontamination-cleaning treatments and after complete reprocessing, including sterilization by hydrogen peroxide gas plasma. Finally, a depyrogenation test was produced for evaluating the depyrogenation efficiency of the sole hydrogen peroxide sterilization treatment. Results showed that standard clinical use did not represent a source for endotoxin contamination, while the use of tap water and manual cleaning processing could increase the pyrogenic load in a significant way. The introduction of the sterilization by hydrogen peroxide gas plasma resulted in effective reduction of the endotoxin contamination and in safe reprocessing of 15 of 15 clinically used catheters. In addition, tests conducted on in vitro spiked catheters showed that initial pyrogenic loads of 40, 80, 200EU/device were reduced to less than 11EU/device. Depyrogenation testing demonstrated efficiency in endotoxin reduction of more than 62 times (1.8log). These results show the determining role of hydrogen peroxide gas-plasma sterilization in the reduction of pyrogenic load on medical devices. Considering actual hygienic requirements at single-use device reprocessing, hydrogen peroxide gas-plasma sterilization can be considered as an efficient treatment at non-lumen cardiac electrophysiology catheter reprocessing.

Anti-Infective Agents, Local↗

PubMedDate not supplied

A comparative study of hysteroscopic sterilization performed in-office versus a hospital operating room.

STUDY OBJECTIVE: To compare hysteroscopic female sterilization procedures performed in-office versus a hospital operating room (OR) among newly trained physicians. DESIGN: Multisite hospital operating rooms and physician offices. PATIENTS: Women desiring permanent hysteroscopic sterilization. INTERVENTION: Hysteroscopic female sterilization with the Essure system. MEASUREMENTS AND MAIN RESULTS: Procedure time (scope in/scope out time), device placement rates, and incidence of complications and adverse events were compared. There was no significant difference in scope time between the 2 settings. There was no significant difference in placement rates, although the placement rate was somewhat higher in-office (91% vs 88%). There were no complications among any of the procedures, and the incidence of minor adverse events was extremely low in both settings (OR=2%, in-office=1%). CONCLUSION: There is no clear advantage to performing hysteroscopic sterilization in a hospital OR. Hysteroscopic sterilization can be performed safely and efficiently in an office setting.

Adult↗

PubMed2005

Free radical scavenging alleviates the biomechanical impairment of gamma radiation sterilized bone tissue.

Terminal sterilization of bone allografts by gamma radiation is often essential prior to their clinical use to minimize the risk of infection and disease transmission. While gamma radiation has efficacy superior to other sterilization methods it also impairs the material properties of bone allografts, which may result in premature clinical failure of the allograft. The mechanisms by which gamma radiation sterilization damages bone tissue are not well known although there is evidence that the damage is induced via free radical attack on the collagen. In the light of the existing literature, it was hypothesized that gamma radiation induced biochemical damage to bone's collagen that can be reduced by scavenging for the free radicals generated during the ionizing radiation. It was also hypothesized that this lessening of the extent of biochemical degradation of collagen will be accompanied by alleviation in the extent of biomechanical impairment secondary to gamma radiation sterilization. Standardized tensile test specimens machined from human femoral cortical bone and specimens were assigned to four treatment groups: control, scavenger treated-control, irradiated and scavenger treated-irradiated. Thiourea was selected as the free radical scavenger and it was applied in aqueous form at the concentration of 1.5 M. Monotonic and cyclic mechanical tests were conducted to evaluate the mechanical performance of the treatment groups and the biochemical integrity of collagen molecules were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The native mechanical properties of bone tissue did not change by thiourea treatment only. The effect of thiourea treatment on mechanical properties of irradiated specimens were such that the post-yield energy, the fracture energy and the fatigue life of thiourea treated-irradiated treatment group were 1.9-fold, 3.3-fold and 4.7-fold greater than those of the irradiated treatment group, respectively. However, the mechanical function of thiourea treated and irradiated specimens was not to the level of unirradiated controls. The damage occurred through the cleavage of the collagen backbone as revealed by SDS PAGE analysis. Irradiated specimens did not exhibit a noteworthy amount of intact alpha-chains whereas those irradiated in the presence of thiourea demonstrated intact alpha-chains. Results demonstrated that free radical damage is an important pathway of damage, caused by cleaving the collagen backbone. Blocking the activity of free radicals using the scavenger thiourea reduces the extent of damage to collagen, helping to maintain the mechanical strength of sterilized tissue. Therefore, free radical scavenger thiourea has the potential to improve the functional life-time of the allograft component following transplantation.

Adult↗

PubMedDate not supplied

Biomechanical analysis of allograft bone treated with a novel tissue sterilization process.

BACKGROUND CONTEXT: Several methods to sterilize allograft bone exist, including gamma irradiation and freeze-drying, which can alter the mechanical properties of the graft. Efforts are under way to develop a method for processing osseous allograft that maintains structural integrity. Herein is presented one such method. PURPOSE: To analyze the mechanical properties, compared with nontreated controls, of a novel sterilization process for allograft cortical bone. STUDY DESIGN/SETTING: A controlled biomechanical evaluation of allograft bone under various types of loading after a novel sterilization treatment. PATIENT SAMPLE: Not applicable; basic science. OUTCOME MEASURES: The load to failure was recorded for both the study and control groups, and statistical analysis of these results was performed. Significance level (alpha) and power (beta) were set to 0.05 and 0.90, respectively. Single-factor analysis of variance (ANOVA) was used to detect significant differences between the treated and untreated groups. A post-experimental power analysis was performed for each of the response variables. METHODS: Cortical tibia and femur samples from seven cadaveric donors (mean age 68.7 years) were treated with Biocleanse and compared with untreated samples with regard to density and strength. All samples were loaded to failure under diametral and biaxial compression, shear, and three-point bending. RESULTS: Statistical analysis was done on the density and failure stress for all modes of loading. ANOVA did not indicate a significant (p>.05) effect of treatment on the density except for the axial and biaxial specimens (p<.05). ANOVA analysis of failure stress demonstrated no significant differences (p>.05) between cortical bone treated with Biocleanse and untreated specimens under all four types of mechanical loading. Post-experimental power analysis revealed power to be greater than 0.9 for each test. CONCLUSIONS: Sterilization of allograft bone with Biocleanse does not significantly alter the mechanical properties when compared with untreated samples. The effect of this sterilization process on the osteoconductive and osteoinductive properties of allograft bone must be determined.

Aged↗

PubMed2002

A process for improving flash sterilization.

In reviewing OR policies and procedures for flash sterilization, staff members at Presbyterian Hospital of Dallas discovered that their process of biological monitoring and flash sterilization needed improvement, and they implemented changes to correct the process. These changes led to questions regarding biological indicators and the flash sterilization container systems being used. As a result, the overall time required for flash sterilization was increased to validate the sterilization process.

Environmental Monitoring↗

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↗

PubMed1987

Unintended laparotomy associated with laparoscopic tubal sterilization.

Although the complication rate for laparoscopic tubal sterilization is generally low, laparotomy is sometimes necessary to complete the sterilization or manage complications. To better characterize factors that predispose women to unintended laparotomy, we analyzed data from the Collaborative Review of Sterilization. Of the 5027 women undergoing laparoscopic tubal sterilization, 12 had unintended laparotomies to manage complications, whereas 39 women had unintended laparotomies because of technical inability to complete the laparoscopic procedure. Women with prior abdominal or pelvic surgery had an increased risk of unintended laparotomy (relative risk = 10.2, 95% confidence interval = 5.3 to 19.7). Women with a history of intrauterine device use or pelvic inflammatory disease had elevated risks that were not statistically significant (relative risk = 2.2 and 1.5, respectively). Comparative studies of alternative surgical approaches for tubal sterilization are needed to formulate recommendations for women who may be at increased risk of unintended laparotomy associated with the laparoscopic approach.

Adult↗

PubMed1999

Women's satisfaction with birth control: a population survey of physical and psychological effects of oral contraceptives, intrauterine devices, condoms, natural family planning, and sterilization among 1466 women.

User satisfaction and the physical and psychological effects of five commonly used contraceptive methods were investigated in a population survey among 1466 West German women. The focus was on effects attributed by current and past users to these methods, rather than objectively assessed effects, to shed further light on personal experiences that are highly relevant to the user but often remain unknown to prescribers and unreported in the medical literature. Within the overall sample, 1303 women were surveyed concerning their current or past use of oral contraceptives (OC), 996 regarding condoms, 342 with respect to intrauterine devices (IUD), 428 in regard to natural family planning (NFP), and 139 in relation to sterilization (respondents completed questions about each method used). It emerged that satisfaction was greatest with sterilization (92% of users), followed by OC (68% of ever users), IUD (59%), NFP (43%), and condoms (30%). Almost one in three NFP users had experienced an unwanted pregnancy during use of this method, as compared with one in 20 OC and condom users. The majority of users reported no mood changes during use of the methods studied. The percentages reporting negative mood changes (various items were scored) were up to 16% among OC users, 23% among condom users, and 30% among NFP users. The latter observations suggested that subjective side effects of a contraceptive agent on mood generally reflected, at least in part, the user's sense of confidence in the method concerned (notably, with regard to efficacy and safety). Oral contraceptives, IUD, and sterilization had a broadly positive impact on sex life, whereas that of condoms was often negative. Whereas OC users often reported less heavy and painful menstruation (in up to 56% of cases), IUD were associated with heavier, prolonged, and more painful menstruation (in up to 65% of cases), as also was sterilization, although to a lesser extent (in up to 32% of cases). Overall, the study findings indicated that OC and sterilization had less negative impact on physical and psychological functioning than the other methods studied, in contrast to what the general public often believes.

Adult↗

PubMed2000

Voluntary and involuntary sterilization: denials and abuses of rights.

Laws that allow competent persons to make free and informed decisions for sterilization serve their entitlements to reproductive choice. Laws that allow others to consent to sterilization of disadvantaged persons who cannot freely consent risk oppression and denial of human rights. Laws that prohibit competent persons' choices for their own sterilization are comparably oppressive and violative of human rights to decide whether and how often to have children. Whether laws approach sterilization as a procedure done for patients, or to patients, is often ambivalent. Details of laws may indicate their liberating and oppressive potential. Programs offering inducements to persons to be sterilized may assist those who are disadvantaged to achieve their goals, but may appear to coerce those who, through poverty or dependency, cannot resist the inducement.

Decision Making↗