Glutaraldehyde inhibits biological treatment of organic additives in hydraulic fracturing produced water

Water generated by hydraulic fracturing for the production of oil and gas, commonly termed 'produced water', may contain residual organic compounds from the fracturing process or the subsurface formation. Biological treatment is a potential technology to remove residual organic compounds in produced water. Biocides are often added to both fracturing fluids and produced water to limit undesirable microbiological activity, and glutaraldehyde is the most commonly used biocide in hydraulic fracturing. Residual biocides in produced water can limit biological treatment efficiency. We evaluated the effect of glutaraldehyde on the biodegradation of five of the most commonly reported organic compounds in hydraulic fracturing fluids in an engineered biofilm treatment. Our results demonstrated that glutaraldehyde delays biological organic compound removal by introducing a biodegradation lag phase. In addition, the effects of glutaraldehyde were more pronounced for more rapidly degraded compounds. Finally, the presence of glutaraldehyde did not decrease microbial abundance nor drive microbial community structure, suggesting that observed effects were due to altered microbial activity. These results highlight the necessity to consider co-contaminant interactions during treatment of complex waste streams where residual biocide may be present.

Mitral Valve Stenosis Progression Due to Severe Calcification on Glutaraldehyde-Treated Autologous Pericardium: Word of Caution for an Attractive Repair Technique

A 42-year-old woman presented with a 6-month history of palpitations and progressive dyspnea on exertion. She had undergone aortic and mitral valve repair using glutaraldehyde-treated autologous pericardium for active infective endocarditis 5 years prior. Transthoracic echocardiography showed mitral valve stenosis with limited movement of the anterior leaflet. At redo surgery, severe calcification of the glutaraldehyde-treated pericardial patch on the anterior mitral leaflet was observed. Double valve replacement was performed with pulmonary vein isolation. Pathologic examination showed calcification of the glutaraldehyde-treated autologous pericardium. The patient was discharged on postoperative day 11 with oral anticoagulant therapy.

Gluteraldehyde-induced colitis: a rare cause of lower gastrointestinal bleeding

Gluteraldehyde is an effective and widely used disinfectant. Despite the large volume of endoscopic procedures carried out, gluteraldehyde-induced colitis is rare. It typically presents with acute onset of lower abdominal pain, fever, and bloody stool, within hours to up to 2 days of endoscopy. Even though a self-limiting condition, it is important for front line clinicians to be aware of this entity as procedure related complications is of major concern to patients and healthcare providers.

Biocompatibility of genipin and glutaraldehyde cross-linked chitosan materials in the anterior chamber of the eye

Chitosan is a naturally occurring cationic polysaccharide and has attracted much attention in the past decade as an important ophthalmic biomaterial. We recently demonstrated that the genipin (GP) cross-linked chitosan is compatible with human retinal pigment epithelial cells. The present work aims to further investigate the in vivo biocompatibility of GP-treated chitosan (GP-chi group) by adopting the anterior chamber of a rabbit eye model. The glutaraldehyde (GTA) cross-linked samples (GTA-chi group) were used for comparison. The 7-mm-diameter membrane implants made from either non-cross-linked chitosan or chemically modified materials with a cross-linking degree of around 80% were inserted in the ocular anterior chamber for 24 weeks and characterized by slit-lamp and specular microscopic examinations, intraocular pressure measurements, and corneal thickness measurements. The interleukin-6 expressions at mRNA level were also detected by quantitative real-time reverse transcription polymerase chain reaction. Results of clinical observations showed that the overall ocular scores in the GTA-chi groups were relatively high. In contrast, the rabbits bearing GP-chi implants in the anterior chamber of the eye exhibited no signs of ocular inflammation. As compared to the non-cross-linked counterparts, the GP-chi samples improved the preservation of corneal endothelial cell density and possessed better anti-inflammatory activities, indicating the benefit action of the GP cross-linker. In summary, the intracameral tissue response to the chemically modified chitosan materials strongly depends on the selection of cross-linking agents.

Chemical colitis due to glutaraldehyde: case series and review of the literature

Chemical colitis can occur as a result of accidental contamination of endoscopes or by intentional/accidental administration of enemas containing various chemicals.We present three cases of glutaraldehyde induced colitis and review the cases in the literature. Glutaraldehyde induced colitis presents clinically with severe abdominal pain, bloody and mucoid diarrhea, rectal bleeding, and tenesmus 48-72 h after colonoscopy. Endoscopic findings are nonspecific and mimic ischemic colitis, inflammatory bowel disease, and infectious colitis. The timing of symptoms and the knowledge that glutaraldehyde is a chemical irritant to colonic mucosa is important for the diagnosis. The treatment is mainly supportive but sometimes necessitates mesalamine, prednisolone, or metronidazole and the resolution is rapid. In endoscopy units, strict adherence to published disinfection protocols is very important and the cleaning, rinsing and drying protocols also deserve the same attention.

Stentless valves treated by the L-hydro process in the aortic position in sheep

Calcification of glutaraldehyde-treated bioprosthetic heart valves is a major cause of long-term failure. We studied porcine aortic valves treated by the L-Hydro process and implanted into 14 juvenile sheep (group 1). Another 10 sheep were implanted with glutaraldehyde-treated porcine bioprostheses (group 2). The animals were sacrificed after 150 days and the explanted valves were analyzed for calcification. Hemodynamic measurements by echocardiography and angiography were carried out prior to sacrifice. Macroscopic analysis showed calcification and loss of mobility of the leaflets in all group 2 implants and in one group 1 implant. Light microscopy showed foci of calcification in all group 2 implants and in 3 valves from group 1. A significant reduction in the level of calcification was found in porcine bioprostheses treated by the L-Hydro process and implanted into the juvenile sheep model.

Chemical colitis

Chemical colitis can occur as a result of accidental contamination of endoscopes or by intentional or accidental administration of enemas containing various chemicals. Most cases have occurred after accidental contamination of endoscopes with glutaraldehyde and/or hydrogen peroxide. There have been multiple case reports of chemical colitis resulting from unintentional administration of caustic chemicals. Intentional administration of corrosive enemas has been implicated in sexual practices, bowel cleansing, or in suicide attempts. Patients present with nonspecific symptoms including abdominal pain, rectal bleeding, and/or diarrhea. As chemical colitis remains rare, the literature consists of scattered case reports and small series. Agents implicated in chemical colitis that are covered in this review include alcohol, radiocontrast agents, glutaraldehyde, formalin, ergotamine, hydrofluoric acid, sulfuric acid, acetic acid, ammonia, soap, sodium hydroxide, hydrogen peroxide, herbal medicines, chloro-m-xylenol, and potassium permanganate. Clinical, endoscopic, and histologic features are outlined for each agent in addition to the existing literature. Given the nonspecific presentation of many cases of chemically induced colitis, the diagnosis can be challenging if the pertinent history is not obtained. Most patients demonstrate the resolution of chemical-induced colitis after conservative or medical therapy. Depending on the depth and extent of injury, patients rarely require colectomy for ischemic colitis and/or peritonitis. Other postingestion complications include colonic strictures and rectovaginal fistulae. The benefits of medical therapy compared with conservative therapy are not known, as comparative clinical management trials have not been performed.

[Dysphonia and cacosmia in a worker in sterilized rooms]

A 39 year male pharmaceutical worker employed in a clean-room developed in 2003 acute dysphonia after environmental disinfection with glutaric aldehyde and isopropyl alcohol. Laryngoscopic examination showed glottis edema; the syndrome healed after a cycle of cortisone. In subsequent years, withdrawal from exposure to irritating chemicals was observed. The worker, however, complained for recurrent episodes of dysphonia, in the absence of abnormalities of the larynx, and gradually developed intolerance for perfume, solvents, and other smelling substances. He came to our observation in 2007, showing strong conviction that occupational exposure had a causative effect in his complaints. He was working in an office open to public, and fragrance exposure appeared to be the main cause of dysphonic episodes. We rejected the hypothesis of association between complaint and job exposure, and advised him to work in a well defined working situation, such as in a clean room, where chemical contamination may be effectively controlled over time.

A multi-step approach in anti-calcification of glutaraldehyde-preserved bovine pericardium

AIM

Bioprosthetic cardiovascular substitutes, manufactured from glutaraldehyde-preserved bovine or porcine tissues, are prone to calcification after implantation. The aim of the study was to evaluate the ultrastructure, material stability and calcification behaviour of glutaraldehyde-preserved bovine pericardium, treated with a multi-step anti-calcification process which addresses each of the major causes of calcification and tissue degeneration.

METHODS

Bovine pericardium samples were divided into 2 groups. Group I (control) consisted of tissue fixed with 0.625% glutaraldehyde and Group II (study group) consisted of tissue fixed with 0.625% glutaraldehyde and exposed to a multi-step anti-calcification process. Ultrastructure was examined by scanning electron microscopy and material stability was assessed by mechanical testing, shrinkage temperature and enzymatic degradation. Calcification was assessed by histology (Von Kossa stain) and by atomic absorption spectrophotometry in the subcutaneous rat model.

RESULTS

Bovine pericardium in the study group revealed less visible changes in the ultrastructure of the collagen matrix, improved material stability (P<0.05) and significantly (P<0.001) reduced calcification compared to control tissues (4.5+/-1.2 versus 136.03+/-11.39 ug/mg tissue).

CONCLUSIONS

In conclusion, results demonstrate that the multi-step anticalcification process improved the material stability and reduced the calcification potential of bovine pericardial tissue. These improvements in the quality of the bovine pericardium should enhance the long-term durability of the tissue as a bioprosthetic substitute for cardiovascular application.

Outbreak of toxic anterior segment syndrome associated with glutaraldehyde after cataract surgery

PURPOSE

To present clinical findings of a cluster of cases of toxic anterior segment syndrome (TASS) after uneventful phacoemulsification cataract surgery.

SETTING

Department of Ophthalmology, Akdeniz University, Antalya, Turkey.

METHODS

Six eyes of 6 patients developed TASS after uneventful phacoemulsification cataract surgery with implantation of a 3-piece acrylic IOL performed by 2 ophthalmologists on the same day. Clinical findings included corneal edema, Descemet's membrane folds, anterior chamber reaction, fibrin formation, and irregular, dilated, and unreactive pupils.

RESULTS

Glutaraldehyde 2% solution was used inadvertently by the operating room staff who cleaned and sterilized reusable ocular instruments before autoclaving. None of the affected corneas improved. Additional surgical procedures were required and included penetrating keratoplasty, trabeculectomy, and glaucoma tube implantation.

CONCLUSIONS

Glutaraldehyde in concentrations generally used for cold sterilization is highly toxic to the corneal endothelium. The operating room staff involved in sterilizing instruments should be well educated about and careful to follow the protocols to properly clean and sterilize reusable ocular instruments.

Aortic root necrosis after surgical treatment using gelatin-resorcinol-formaldehyde (GRF) glue in patients with acute type A aortic dissection

BACKGROUND

Although gelatin-resorcinol-formaldehyde (GRF) glue is used for surgical repair of acute type A aortic dissections, late complications possibly ascribed to toxic effects of GRF glue have been reported. We analyzed the benefits and risks of using GRF glue.

PATIENTS AND METHODS

Between January 1990 and August 2003, 269 consecutive patients underwent emergency operations for acute type A aortic dissection. GRF glue was not used in 47 patients (non-GRF group) who were operated on until May 1995 and was used in the 222 (GRF group) who underwent operation subsequently.

RESULTS

The rate of in-hospital mortality was significantly higher in the non-GRF group (31.9%) than in the GRF group (12.6%) (p<0.0001). In the GRF group, false aneurysms were found in 31 patients (31/194 survivors, 16.0%) 1-65 (mean, 30+/-18) months after initial operation. Reoperation was done in 24 of these patients. At reoperation, the site to which GRF glue was applied had degenerated, and the anastomosis between the aortic root and prosthesis had opened widely, creating a false aneurysm and resulting in aortic regurgitation with prolapse of the coronary cusps. The mortality rate of reoperation was 4.2% (1/24).

CONCLUSION

The use of GRF glue improved the short-term outcome of surgery for acute type A aortic dissection, but was associated with a high incidence of false aneurysms forming at the site of proximal anastomosis, where GRF glue had been applied. Patients in whom GRF glue has been used should be carefully followed up after surgery.

[Occupational health of endoscope sterilization workers in medical institutions in Osaka Prefecture]

To clarify the actual condition of endoscope sterilization work and the adverse health effects of disinfectants on personnel, a questionnaire was sent to 173 medical institutions in Osaka Prefecture. Glutaraldehyde (GA), ortho-phtalaldehyde (OPA), and hyperacetic acid were used as disinfectants of endoscopes by 55.5%, 32.4%, and 8.7% of the medical institutions respectively. The kind of disinfectant used had been changed in 57.8% of these institutions during the past five years, and it was confirmed that the use of substitutes for GA, such as OPA and hyperacetic acid, has increased. Personnel in 35.8% of the institutions complained about symptoms during sterilization work. The kind of disinfectant being used when they complained was GA in many cases and OPA in others. A general ventilation system has now been installed in 72.3% of the institutions; local exhaust systems have been installed in fewer, only 23.4%. Protective gloves were used at about half of the institutions, but protective masks and glasses were seldom used. This study shows that the occupational health problems of endoscope sterilization work have not been resolved. Consequently, it is necessary to promote the installation of ventilation systems and the use of protective devices in all institutions. Health education in regard to the handling of disinfectants is also necessary. Because little information is available about the toxic effects of OPA and hyperacetic acid, epidemiological studies must be conducted to clarify the human health effect of these disinfectants.

Worker safety and glutaraldehyde in the gastrointestinal lab environment

Glutaraldehyde is considered a high-level surgical disinfectant commonly used in the United States in gastrointestinal lab environments. Glutaraldehyde requires proper ventilation when used as glutaraldehyde vapors are known irritants to the skin, eyes, nose, and lungs without proper ventilation in the work environment. Vapor concentration is the unit of measurement for the environmental presence of glutaraldehyde. Safe levels of glutaraldehyde vapor concentrations are a significant issue in the work environment. The American Conference of Governmental Hygienists has established and reported safe and allowable limits for vapor concentration of glutaraldehyde. Unfortunately, uncontrolled glutaraldehyde exposure in selected work environments is contributing to occupational asthma. Environmental exposure to glutaraldehyde has been linked to respiratory sensitization of the workers exposed and suggests the need for safe work environments anywhere glutaraldehyde is in use. Gastrointestinal labs use high-level disinfectants like glutaraldehyde to safely and thoroughly disinfect endoscopic instruments and accessories; however, there are worker-safety considerations relevant to glutaraldehyde use. The purpose of this article is to identify and describe clinical issues and challenges associated with worker safety and proper ventilation of glutaraldehyde in a gastrointestinal environment. A multidisciplinary problem-solving approach for use in identification and intervention for glutaraldehyde exposure and safety recommendations related to glutaraldehyde use as a high-level disinfectant in one gastroenterology lab environment will be highlighted.

Glutaraldehyde-induced bowel injury after laparoscopy

We document the sequelae of the inadvertent introduction of glutaraldehyde into the peritoneal cavity. It describes the clinical course, progressive histological changes to the bowel at different periods over the course of 1 year, and what long-term morbidity remains. The chemical structure, effects, and pathogenesis of glutaraldehyde are described as well as suggestions for avoiding similar problems in the future.

Respiratory Cancer Risks Among Workers With Glutaraldehyde Exposure

OBJECTIVE

Glutaraldehyde is a substance that represents a substantial portion of the human exposure to aldehydes in medicine and industry. Other aldehydes such as formaldehyde have been associated with increased cancer rates of the upper respiratory tract and leukemia. Our study is the only one, to our knowledge, to examine cancer rates among exposed glutaraldehyde workers.

METHODS

In an extended follow up using death certificates, we calculated standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) for three cumulative exposure categories of glutaraldehyde. There were 99,730 person-years of observation among unexposed workers, 2934 person-years in the lower exposure category, < 0-100.0 parts per billion (ppb)-years, and 2805 person-years in the higher exposure category of 100.0+ ppb-years.

RESULTS

For all respiratory cancers for these exposure categories, the SMRs were 0.9 (95% CI = 0.7-1.1), 1.0 (95% CI = 0.2-3.0), and 0.3 (95% CI = 0.0-1.5). No increasing trend of SMR with increasing exposure is observed for any cause of death examined. We observed no cancers of the nasal cavity and sinus (0.03 expected), nasopharynx (0.02 expected), or leukemia (0.6 expected) among all glutaraldehyde-exposed workers.

CONCLUSIONS

Although our study findings should be tempered by the small size and the potentially low prevalence of smoking among glutaraldehyde workers, we found no increased rates of respiratory tract cancer or leukemia related to glutaraldehyde exposure.

Immunotherapy with depigmented glutaraldehyde-polymerized extracts: changes in quality of life

BACKGROUND

Immunotherapy (IT) with modified allergens reduces allergic rhinitis (AR) symptoms and medications requirements. Improvement of quality of life (QOL) is a key point in the treatment of AR. The aim of this study was to provide evidence of changes related to the patient's QOL (well-being) induced by a modified (depigmented glutaraldehyde-polymerized) therapeutic vaccine and of its safety.

MATERIAL AND METHODS

Fifty-three patients with a well-documented clinical history of seasonal AR sensitized to Dactylis glomerata and Olea europaea pollens were included in a randomized clinical trial. Twenty-five patients (Group-A) received a mixture of D. glomerata and O. europaea pollen extracts and 28 patients received placebo (group-C). Any adverse event was recorded and graded in accordance with EAACI guidelines. RQLQ was recorded before the treatment (pollen season 2000) and after 1 year of treatment (pollen season 2001). Dose-response skin prick test with each allergen extract was conducted at baseline and at the end of the study.

RESULTS

Each patient received 17 injections during this period. All patients completed the trial and no systemic adverse reactions were recorded. Symptom scores (P<0.001) and medication requirements (P<0.001) were significantly reduced in the IT group during the pollen season. This patient group also experienced greater and statistically significant improvement in overall RQLQ score and in five of the seven domains, all of them surpassing the threshold of 'minimal important difference' of 0.5 points.

CONCLUSIONS

Results of this study provided evidence that IT with depigmented, glutaraldehyde-modified allergen extracts was well-tolerated and added beneficial effects to AR treatment in pollen allergic patients eliciting an improvement in QOL enough to justify a change in the patient's treatment.

Irritant vocal cord dysfunction at first misdiagnosed as reactive airway dysfunction syndrome

OBJECTIVES

This report describes a case of vocal cord dysfunction at first misdiagnosed as reactive airway dysfunction syndrome (RADS).

METHODS

A woman developed recurrent episodes of cough, dyspnea, and wheezing unresponsive to asthma therapy after irritant exposure to glutaraldehyde. Direct laryngoscopy was performed immediately after the induction of symptoms.

RESULTS

Laryngoscopy showed a paradoxical adduction of the vocal cord on inspiration. Vocal cord dysfunction was diagnosed.

CONCLUSIONS

A case of vocal cord dysfunction occurred after exposure to glutaraldhyde in a person with a history highly suggestive of RADS. Vocal cord dysfunction should always be considered in the differential diagnosis of patients with acute respiratory symptoms after exposure to irritants and with asthma-like symptoms that fail to respond to conventional asthma therapy.

Kangaroo vs. Porcine Aortic Valves: Calcification Potential after Glutaraldehyde Fixation

The aim of this study was to evaluate and compare the calcification potential of kangaroo and porcine aortic valves after glutaraldehyde fixation at both low (0.6%) and high (2.0%) concentrations of glutaraldehyde in the rat subcutaneous model. To our knowledge this is the first report comparing the time-related, progressive calcification of these two species in the rat subcutaneous model. Twenty-two Sprague-Dawley rats were each implanted with two aortic valve leaflets (porcine and kangaroo) after fixation in 0.6% glutaraldehyde and two aortic valve leaflets (porcine and kangaroo) after fixation in 2% glutaraldehyde respectively. Animals were sacrificed after 24 h and thereafter weekly for up to 10 weeks after implantation. Calcium content was determined using inductively coupled plasma-mass spectrometry and confirmed histologically. Mean calcium content per milligram of tissue (dry weight) treated with 0.6 and 2% glutaraldehyde was 116.2 and 110.4 microg/mg tissue for kangaroo and 95.0 and 106.8 microg/mg tissue for porcine valves. Calcium content increased significantly over time (8.8 microg/mg tissue per week) and was not significantly different between groups. Regression analysis of calcification over time showed no significant difference in calcification of valves treated with 0.6 or 2% glutaraldehyde within and between the two species. Using the subcutaneous model, we did not detect a difference in calcification potential between kangaroo and porcine aortic valves treated with either high or low concentrations of glutaraldehyde.

Hazards in the radiology department

OBJECTIVE

This article views, collectively, the problems associated with darkroom disease, multiple chemical sensitivity and latex allergy. Each is discussed individually to establish a case definition.

METHOD

Common threads and similarities are identified among the 3 conditions along with potential sources.

RESULTS

A model is proposed to change attitudes among radiographers in individual departments to improve workplace safety.

CONCLUSION

We propose the use of an established health education/disease prevention model to change the attitudes of radiographers toward chemical threats.

Occupational allergens in dentistry

PURPOSE OF REVIEW

Dental professionals and their physicians frequently do not recognize, accurately diagnose or appropriately manage occupational allergies. Dental allergen identification, diagnostics and practical avoidance strategies are summarized in this review.

RECENT FINDINGS

Methacrylates, natural rubber latex proteins, rubber glove allergens, and glutaraldehyde are the predominant allergens in dentistry. Reactions range from cell-mediated contact allergy to urticaria and occupational asthma.

SUMMARY

Despite recent advances in allergen characterization and increased awareness of selected allergens, treatment of occupational allergies can be improved. Better information and improved cooperation between dental workers and their clinicians is needed.

Calcification of Tissue Heart Valve Substitutes: Progress Toward Understanding and Prevention

Calcification plays a major role in the failure of bioprosthetic and other tissue heart valve substitutes. Tissue valve calcification is initiated primarily within residual cells that have been devitalized, usually by glutaraldehyde pretreatment. The mechanism involves reaction of calcium-containing extracellular fluid with membrane-associated phosphorus to yield calcium phosphate mineral deposits. Calcification is accelerated by young recipient age, valve factors such as glutaraldehyde fixation, and increased mechanical stress. Recent studies have suggested that pathologic calcification is regulated by inductive and inhibitory factors, similar to the physiologic mineralization of bone. The most promising preventive strategies have included binding of calcification inhibitors to glutaraldehyde fixed tissue, removal or modification of calcifiable components, modification of glutaraldehyde fixation, and use of tissue cross linking agents other than glutaraldehyde. This review summarizes current concepts in the pathophysiology of tissue valve calcification, including emerging concepts of endogenous regulation, progress toward prevention of calcification, and issues related to calcification of the aortic wall of stentless bioprosthetic valves.

Work-related asthma among health care workers: surveillance data from California, Massachusetts, Michigan, and New Jersey, 1993-1997

BACKGROUND

Asthma morbidity has increased, posing a public health burden. Work-related asthma (WRA) accounts for a significant proportion of adult asthma that causes serious personal and economic consequences.

METHODS

Cases were identified using physician reports and hospital discharge data, as part of four state-based surveillance systems. We used structured interviews to confirm cases and identify occupations and exposures associated with WRA.

RESULTS

Health care workers (HCWs) accounted for 16% (n = 305) of the 1,879 confirmed WRA cases, but only 8% of the states' workforce. Cases primarily were employed in hospitals and were nurses. The most commonly reported exposures were cleaning products, latex, and poor air quality.

CONCLUSIONS

Health care workers are at risk for work-related asthma. Health care providers need to recognize this risk of WRA, as early diagnosis will decrease the morbidity associated with WRA. Careful product purchasing and facility maintenance by health care institutions will decrease the risk.

Influence of the Organic Matrix on Root Dentine Erosion by Citric Acid

This investigation was conducted in an attempt to clarify the role of the organic matrix in bovine dentine demineralisation by 1% citric acid. Dentine slabs (n = 15) were treated for 2 min with 10% sodium hypochlorite (NaOCl, a strong protein solvent), 2% glutaraldehyde (GDA, a protein fixative) or deionised water (DIW, as negative control) prior to each of 5 demineralisation periods of 30 min. The mineral loss (DeltaZ), lesion depth (LD) and surface loss (SL) were determined after each period of demineralisation, by transverse microradiography. The NaOCl-treated group showed higher DeltaZ and LD than the GDA- and DIW-treated groups. No differences between GDA and DIW groups were found. The DeltaZ and LD profiles were explained by quadratic fits (r(2) >0.80; p = 0.001) in all groups. SL was detected only in the NaOCl-treated group. The data suggested that the maintenance of the organic matrix in the lesion might be important to reduce the erosion progression rate.

Finding an alternative endoscope disinfectant to glutaraldehyde

Glutaraldehyde poses an occupational health hazard or risk for staff, with up to 15% of UK hospitals using it as their first-choice endoscope disinfectant. One NHS trust yielded unexpected additional savings by introducing a safer alternative in a bid to reduce potential health, safety and environmental risks.

Tissue Adhesives for a Sutureless Fadenoperation: An Experimental Study in a Rabbit Model

PURPOSE

To use tissue adhesives for a sutureless Fadenoperation to eliminate perioperative risks related to the sutures.

METHODS

In an in vivo procedure, 120 superior recti muscles in New Zealand White rabbits were subjected to the posterior fixation procedure, at a distance of 6 mm from the insertion point of the muscle. They were divided into four groups of 30 muscles, according to the material used to perform a myopexy: group 1 (control): nonabsorbable 5-0 polyester sutures; group 2: n-butyl-2-cyanoacrylate adhesive; group 3: fibrin glue; group 4: gelatin-resorcin-formaldehyde-glutaraldehyde (GRFG) adhesive. The animals were examined at 1, 7, 14, and 21 days after surgery. Afterward, they were killed, and their eyes were enucleated to measure the distance between the myopexy and the anatomic insertion point and to assure the strength of the bond with a dynamometer. Finally, a histologic examination was performed.

RESULTS

Almost all eyes were clear after the third week, although group 4 presented the most intense inflammatory reaction. In histologic examination, groups 1 and 2 showed a chronic inflammatory reaction of the foreign-body type, with similar intensity. Fibrin glue induced minimal inflammation, but GRFG adhesive produced a pronounced reaction. Concerning the distance of the myopexy, groups 1 and 2 presented measures close to the expected distance of 6 mm, whereas groups 3 and 4 showed a greater variability. All groups performed well in the strength test, with no statistically significant differences among them.

CONCLUSIONS

n-Butyl-2-cyanoacrylate adhesive performed best in the sutureless Fadenoperation, characterized by precision in the expected distance of myopexy, sufficient resistance to separation, and acceptable inflammatory reaction.

Effect of chemical disinfectants on the transverse strength of heat-polymerized acrylic resins submitted to mechanical and chemical polishing

STATEMENT OF PROBLEM

Immersion in chemical solutions used for cleansing and disinfecting prostheses can decrease the strength of denture base resins, making them more prone to fracture during use.

PURPOSE

The purpose of this study was to assess the effect of immersion in different chemical disinfectants for varying time periods on the transverse strength of 3 mechanically or chemically polished heat-polymerized acrylic resins.

MATERIAL AND METHODS

A total of 630 rectangular specimens (65 x 10 x 3 mm), 210 per resin (Classico, Lucitone 550, and QC-20), were fabricated. One side of each specimen was not polished and the other was either mechanically (n=300) or chemically (n=300) polished, and immersed for 10, 20, 30, 45, or 60 minutes in either 1%, 2.5%, or 5.25% sodium hypochlorite or 2% glutaraldehyde. Mechanically polished (n=15) and chemically polished (n=15) control specimens were immersed only in distilled water. The transverse strength (N/mm 2 ) was tested for failure in a universal testing machine, at a crosshead speed of 5 mm/min. Data were statistically analyzed using 2-way ANOVA and Student t test. Multiple comparisons were performed using Tukey and Scheffe tests (alpha=.05).

RESULTS

There was significant difference (P < .01) between types of polishing, with chemical polishing resulting in lower transverse strength. ANOVA identified significant differences (P < .01) in strength between mechanically polished Lucitone 550 and QC-20, and among all 3 chemically polished resins. No significant differences were observed between resins submitted to both types of polishing or between different immersion periods (10 to 60 minutes), disinfectants, or interaction.

CONCLUSIONS

Lucitone 550 resin presented the greatest transverse strength values with both types of polishing. Among the mechanically and chemically polished specimens, transverse strength was not affected after immersion in the disinfectants for the immersion periods tested (10 to 60 minutes). Chemically polished control and experimental (immersed in all solutions) QC-20 specimens showed significant differences in transverse strength values.

Nine episodes of anaphylaxis following cystoscopy caused by Cidex OPA (ortho-phthalaldehyde) high-level disinfectant in 4 patients after cytoscopy

BACKGROUND

Ortho-phthalaldehyde (OPA) is a high-level disinfectant commonly used for processing heat-sensitive medical devices.

OBJECTIVE

We report 4 patients who experienced 9 episodes of anaphylaxis following cystoscopy after a urology practice switched from using Cidex (glutaraldehyde [GTA]) to OPA for disinfecting their cystoscopes.

METHODS

Allergic evaluations consisted of: skin testing to saline, histamine, glycerin, lidocaine, latex, GTA, and OPA and blood tests for total immunoglobulin E (IgE) and latex specific IgE.

FINDINGS

The 4 patients were evaluated after 3 of them had experienced 2 episodes of anaphylaxis and one of them 3 episodes following outpatient cystoscopy for ongoing evaluation of bladder cancer. Skin testing of subjects and controls to lidocaine, latex, latex specific IgE, and GTA was negative. Skin testing to OPA resulted in immediate wheal and flare reactions in all 4 patients within 20 minutes and late reactions at 24 hours but negative reactions in controls. Subsequent to the testing, 3 of the patients returned for repeat cystoscopy in which GTA but not OPA was used to disinfect the cystoscopes and tolerated the procedure.

CONCLUSIONS

OPA solution should be considered a cause of anaphylactic/allergic reactions following cystoscopy and possibly following instrumentation with other medical devices disinfected by this material.

Colite hémorragique avec choc après une coloscopie

We report the case of a 43-year-old woman with an acute haemorrhagic colitis after colonoscopy with ambulatory anaesthesia. The diagnosis is likely to have been glutaraldehyde induced colitis (used for disinfection of the endoscope). The patient recovered spontaneously completely.

[Significance of working environment improvement based on determination of source of harmful substance--example of an endoscope syringe room using glutaraldehyde]

Because a worker complained of irritated eyes and throat due to glutaraldehyde (GA) in an endoscope syringe room, the automated endoscope washers and GA liquid stored in reserve were isolated in a separate room. A ventilation system was installed in this room, and the packing of the automated endoscope washers was changed. However, since the obnoxious smell of GA still remained in the endoscope syringe room, we had to determine the source of the smell. A plastic bucket with a cap was found to be filled with GA for disinfection of the endoscope apparatus. GA had evaporated when dispersed around the bucket, resulting in the obnoxious smell. The plastic bucket was replaced with a different type of container. Moreover, GA from the separate room did not affect the concentration of GA in the working area because the separate room for the automated endoscope washers had twice the ventilation volume proposed by the guidelines of the Society of Gastroenterology Nurses and Associates of the USA and the Healthcare Engineering Association of Japan. Consequently, we reconfirmed the significance of working environment improvement after clarifying the source of the harmful substance.

Glutaraldehyde-induced and formaldehyde-induced allergic contact dermatitis among dental hygienists and assistants

BACKGROUND

Research has found that among health care workers, dental personnel are especially likely to have reactions to glutaraldehyde and formaldehyde.

METHODS

The authors conducted patch test evaluations with a voluntary cohort of randomly recruited, healthy dental hygienists, or DHs, and dental assistants, or DAs, and nondental professionals to determine the incidence of glutaraldehyde-induced and formaldehyde-induced allergic contact dermatitis, or ACD; the potential for coreactivity between glutaraldehyde and formaldehyde; and the correlation between training methods in safe handling of sterilizing solutions and the sensitivity to glutaraldehyde and formaldehyde among DHs and DAs.

RESULTS

The researchers enrolled 101 DHs and DAs and 51 nondental professionals in the study. All except one DH/DA subject were female. The dental subjects' mean age was 34.3 +/- standard deviation of 10.7 years; the nondental subjects', 33.8 +/- 11.0 years. DHs and DAs had worked in their profession for a mean of 11.0 +/- 9.3 years. Among the dental professionals, 80 (79.2 percent) had had a known exposure to cold sterilizing solutions, while the remainder were unable to provide a known history of exposure. Eleven (10.9 percent) dental professionals had clear reactions to glutaraldehyde, four (4.0 percent) were questionably allergic to glutaraldehyde, and two (2 percent) were definitively allergic to formaldehyde. One (2 percent) control subject had a reaction to glutaraldehyde, and one other (2 percent) had a reaction to formaldehyde. CONCLUSIONS AND CLINICAL:

IMPLICATIONS

The authors found a statistically significant disparity in the rates of glutaraldehyde sensitivity among healthy DHs and DAs versus healthy control subjects (10.9 percent versus 2 percent reactively; P = .02). They found no evidence of cross-reactivity between glutaraldehyde and formaldehyde. The preponderance of reactions among the DHs and DAs suggests that their present safety practices are largely ineffective in protecting against sensitization to glutaraldehyde in sterilizing solutions.

Best practice forum: standard high level disinfection protocol development

Gluteraldehyde-based high-level disinfection (HLD) poses significant safety risks for staff and patients as well as institutional cost concerns. A value analysis team reviewed HLD practices, available products, and environmental requirements in view of the literature and standards developed by the Occupational Safety and Health Administration (OSHA). Institutional areas were identified and standardized unit-specific educational and competency programs were established. The overall use of gluteraldehyde-based HLD was decreased in this institution based on the findings and policy and procedure modification.

Symptoms and lung function in health care personnel exposed to glutaraldehyde

BACKGROUND

Glutaraldehyde is widely used as a disinfectant for endoscopic equipment. The aim of this study was to investigate work practices and glutaraldehyde exposure in relation to symptoms and lung function.

METHODS

A questionnaire was administered to 76 nurses. Exposed nurses (n = 38) also completed lung function tests and visual analogue scales before and after a work session in which glutaraldehyde exposure occurred. Disinfection activities were timed and counted, personal exposures established, and control measures documented.

RESULTS

Exposure values above the exposure limit (0.10 ppm) were found for all exposure control methods except for the enclosed washing machine. Skin symptoms were 3.6 times more likely to be reported by exposed workers. None of the other symptoms were significantly associated with glutaraldehyde exposure. There were significant cross-shift reductions in FVC and FEV(1) in the exposed group. No evidence of a dose-response relationship for symptoms or lung function was found.

CONCLUSIONS

Further exposure controls for both glutaraldehyde and gloves are required to improve skin care in glutaraldehyde exposed nurses. Exposure monitoring methods also need review.

Allergic contact dermatitis in dental professionals: effective diagnosis and treatment

BACKGROUND

Like other health care workers, dental professionals are at risk of developing allergic contact dermatitis, or ACD, after exposure to allergenic chemicals. Common allergens include antimicrobials, preservatives, rubber additives and methacrylates.

CASE DESCRIPTION

The authors describe an orthodontic assistant with severe skin disease, whose symptoms included redness, cracking and bleeding that persisted for 10 years. The patient had previously received an incomplete diagnosis. After performing patch testing, assessing symptoms and evaluating the patient's medical history, the authors diagnosed ACD resulting from exposure to several dental allergens. The patient received appropriate treatment and counseling to better manage her allergies; this resulted in resolution of all symptoms and averted permanent occupational disability.

CLINICAL IMPLICATIONS

Not all skin reactions are related to gloves or natural rubber latex. Dental professionals should be aware of common chemical allergens, symptoms of ACD and the appropriate treatment of occupational skin disease.

Inflammatory and immune processes: the neglected villain of bioprosthetic degeneration?

In an attempt to avoid the destructive process of bioprosthetic heart-valve calcification associated with the use of glutaraldehyde, valves are today prepared using low concentrations of the crosslinking reagent. In this review, we summarize our findings and those of others that confirm that the immunogenicity of such tissue is not sufficiently masked and that a defined humoral response is indeed mounted against a repertoire of antigens unrelated to those associated with vascularized and non-cross-linked xenograft organs. We demonstrate the need for increased cross-linking of tissue to satisfactorily mitigate that response; furthermore, we examine the impact of increased cross-link density on the macrophage as antigen presenting cell with respect to its involvement in both tissue erosion and pannus overgrowth. Finally we present evidence for a role of circulating antibodies in bioprosthesis calcification.

Alternative fixation of bioprostheses

The glutaraldehyde fixation technique for bioprosthetic tissue valves has been used for about 30 years. It is more or less generally recognized, however, that a solution to the ongoing problems of calcification and immunomodulated inflammation can only be achieved with the development of alternative fixation techniques that differ from fixation with glutaraldehyde. This review reports on the chemistry behind newly developed tissue-fixation processes and the preliminary results achieved with these.

Assessment of and intervention for the misuse of aldehyde disinfectants in Japan

A survey of 145 Japanese hospitals revealed the use of 4 inappropriate aldehyde disinfection methods in 5.5% to 16.8%. Following education, there was discontinuation of 3 of these practices in 26 of 28 affected centers, but only 4 of 18 affected centers stopped the use of formaldehyde vapor cabinets. There is a need to inform hospitals about inappropriate disinfection methods that pose chemical risks to patients and staff.

Instrument reprocessing in theatres. Drivers for change

It is well known that long-term exposure to chemical disinfectants can have adverse effects on an individual, and can even result in ill health requiring premature retirement. Jim Miller highlights some of the dangers of chemical disinfectants and reports on the relative merits of newer technologies, including low temperature hydrogen peroxide.

Occupational asthma and rhinitis due to glutaraldehyde: changes in nasal lavage fluid after specific inhalatory challenge test

BACKGROUNDd: Glutaraldehyde (GA) is a known respiratory sensitizers, and some studies have reported occupational asthma in exposed workers. Specific changes in nasal lavage fluid (NLF) induced by high-molecular-weight allergen provocation in sensitized subjects were described previously. The purpose of this study was to evaluate the changes in cytogram, protein content, eosinophil cationic protein (ECP), and mast-cell tryptase concentrations in NLF after GA inhalation challenge in patients with a positive history of GA-induced asthma and late or dual asthmatic response due to exposure to low-level GA.

METHODS

A single-blind, placebo-controlled study was performed on 11 health workers with occupational asthma and rhinitis due to GA. The control groups comprised 10 atopic subjects with perennial asthma and rhinitis and 10 healthy ones. A "nasal pool" technique was used to evaluate the examined parameters in nasal washings before and 30 min, 4 h, and 24 h after the inhalatory provocation with GA and placebo.

RESULTS

There was a significant increase in eosinophil number and percentage, and albumin, ECP, and tryptase concentrations in NLF from patients with occupational asthma and rhinitis when compared to controls.

CONCLUSIONS

The results indicate the immunologic mechanism of GA-induced asthma and the applicability of the "nasal pool" technique as the diagnostic procedure in GA-induced airway allergy.

Fixation-related autolysis and bioprosthetic aortic wall calcification

BACKGROUND AND AIM OF THE STUDY

It has been established previously that immediate fixation and increased glutaraldehyde (GA) concentrations are required to prevent severe autolytic tissue damage during bioprosthetic aortic root production. The study aim was to verify that structure-preserving fixation also reduces aortic wall calcification.

METHODS

Porcine aortic roots were fixed either instantly or after being kept on ice for 48 h (phosphate-buffered saline, PBS). Two concentrations of GA (0.2% and 3.0%) were chosen (4 degrees C, seven days, PBS). Discs of aortic wall tissue (1.2 cm diameter) were implanted subcutaneously in rats for 60 days (n = 10 per group), while aortic roots were implanted in the distal aortic arch of sheep for six weeks (n = 3 per group) and six months (n = 4 per group). Calcification was assessed by atomic absorption spectrophotometry and light microscopy. Fixation-related tissue damage was determined by transmission electron microscopy, and correlated with calcification.

RESULTS

No significant difference in calcification was found between immediate and delayed fixation if tissue was fixed with 0.2% GA. In the 3.0% GA group, both animal models showed a significantly lower level of calcification if tissue was immediately fixed. In the subcutaneous rat model, immediate fixation reduced calcification by 26% (p <0.0001). In the circulatory sheep model immediate fixation did not affect calcification in the short-term six-week implants, but markedly lowered it by 37% (p = 0.035) after six months. Ultrastructurally, there was a significant correlation between membrane damage, vacuolization and vesicle shedding on the one hand, and calcification on the other.

CONCLUSION

Coincidental fixation-related ultrastructural damage and increased calcification was demonstrated in bioprosthetic aortic wall tissue.