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.