Survey of symptoms, respiratory function, and immunology and their relation to glutaraldehyde and other occupational exposures among endoscopy nursing staff

A Vyas; C A C Pickering; L A Oldham; H C Francis; A M Fletcher; T Merrett; R McL Niven

doi:10.1136/oem.57.11.752

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Survey of symptoms, respiratory function, and immunology and their relation to glutaraldehyde and other occupational exposures among endoscopy nursing staff

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Re: Glutaraldehyde induced asthma in endoscopy nursing staff
A Vyas
Published on: 27 April 2016
Glutaraldehyde induced asthma in endoscopy nursing staff
Wasif Anees
Published on: 27 April 2016
Symptoms among endoscopy nursing staff
Eugene R Waclawski
Published on: 27 April 2016

Published on: 27 April 2016
Re: Glutaraldehyde induced asthma in endoscopy nursing staff
- A Vyas
- Other Contributors:
  "R McL Niven, CAC Pickering"
Editor
Dr Burge and his coworkers raise a very important issue in terms of the physiological criteria on which a diagnosis of occupational asthma should be based, and in particular, the clinical significance of small work related declines in peak expiratory flow. We fully accept that a lack of an increase in diurnal variation does not exclude a diagnosis of occupational asthma. The pattern of peak flow measurements...
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Editor
Dr Burge and his coworkers raise a very important issue in terms of the physiological criteria on which a diagnosis of occupational asthma should be based, and in particular, the clinical significance of small work related declines in peak expiratory flow. We fully accept that a lack of an increase in diurnal variation does not exclude a diagnosis of occupational asthma. The pattern of peak flow measurements in occupational asthma quite frequently reveals a marked difference in the mean peak flow on working days compared to days away from work without any increase in diurnal variation. Dr Burge and his colleagues refer to the phenomenon of small work related changes and raise the question as to whether this represents asthma or other lung pathology.[1] At that time, their opinion was that the significance of these small changes was unclear. The example that they gave showed that taking the lowest peak flow recording during the working week and the highest peak flow recording on days away from work, a variation in peak flow in excess of 20% which we would accept as compatible with asthma and from the pattern illustrated probable occupational asthma. The small group of workers that we studied had diurnal variations in peak flow ranging between 5.7% and 9.8% and taking the worst working day peak flow and the best day off work peak flows, a variation between 11% and 13.5% (our peak flow recordings were linearised). This degree of variation does not satisfy the BTS criteria for a diagnosis of bronchial asthma, neither do they satisfy a positive challenge response in bronchial challenge study. We have seen similar patterns of peak flow recordings in textile workers exposed to dust, both with and without, significant contamination with endotoxin.
We took the view that the small peak flow changes were due to an irritant effect and postulate the same mechanism in this group exposed to glutaraldehyde. The clinical histories provided by these workers does not suggest increasing respiratory symptoms with continued exposure. While it is possible that the changes that we have reported may represent a very mild form of occupational asthma, the clinical picture and the small physiological variation in peak flow, in our opinion is more consistent with an irritant airway response than the development of occupational asthma. Our paper is not intended to suggest that glutaraldehyde is not capable of inducing occupational asthma, for which there is convincing published evidence, in addition to our own personal experience. Our paper reports the findings of an epidemiological survey of a large population of currently exposed endoscopy nurses and has demonstrated that while respiratory symptoms occur in this group, that the lung physiology and the immunology has not supported a suggestion of a high prevalence of occupational asthma at current exposure levels.
A Vyas
R.McL Niven
CAC Pickering
1. Occup Environ Med 1999;56:758
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Conflict of Interest:
None declared.
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Published on: 27 April 2016
Glutaraldehyde induced asthma in endoscopy nursing staff
- Wasif Anees
Editor
We read with interest the paper on glutaraldehyde and symptoms in endoscopy nursing staff.[1] It is reported that there was an absence of objective evidence of the physiological changes associated with asthma. Peak expiratory flow (PEF) records from 17 cases were analysed by the Oasys 2 computer program, and three of these had Oasys-2 Scores >2.5. These cases were felt not to show asthma because PEF d...
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Editor
We read with interest the paper on glutaraldehyde and symptoms in endoscopy nursing staff.[1] It is reported that there was an absence of objective evidence of the physiological changes associated with asthma. Peak expiratory flow (PEF) records from 17 cases were analysed by the Oasys 2 computer program, and three of these had Oasys-2 Scores >2.5. These cases were felt not to show asthma because PEF diurnal variability was less than 15%. We have recently shown that increased diurnal variability is not found in the majority of workers with occupational asthma.[2] Part of the explanation may be that the acrophase (time of maximum PEF in a 24 hour period) in normal and asthmatic individuals occurs at around 16:00 hours with a trough about 12 hours later. Any deterioration in lung function due to exposure in the workplace is superimposed on the normal circadian rhythm. Thus, if a worker starting work in the morning has a fall in PEF that continued throughout the day whilst at work, the maximum PEF occurring at the time of the acrophase might be reduced. This would tend to reduce the diurnal variability. Even in non-occupational asthma there is considerable overlap of PEF variability with that occurring in normal individuals.[3] Use of non- linear PEF meters significantly underestimates PEF variability [4] but even when PEF readings are linearised, an absence of an increase in diurnal variability does not exclude asthma. An Oasys-2 score of >2.5 has a specificity of 94% for diagnosing occupational asthma.[5] We suspect that, provided peak flow records were of adequate quality, the three cases with Oasys-2 scores >2.5 did indeed have occupational asthma.
Since 1995, 29 cases of occupational asthma due to glutaraldehyde have been reported to SHIELD, the West Midlands reporting scheme for occupational asthma. A study of 24 workers referred to the Occupational Lung Disease Clinic in Birmingham with respiratory symptoms temporally related to glutaraldehyde exposure found that 16 had a definite occupational effect evident on their PEF records.[6] Five of eight workers with equivocal PEF records underwent specific bronchial provocation tests to 2% glutaraldehyde, all of which were positive as were three challenge tests in workers with suggestive PEF records. The challenge subjects included two in whom PEF diurnal variability was less than 10%. Of the subjects, 7 out of 24 also had positive specific IgE to glutaraldehyde.
The sensitivity of serial PEF records in showing occupational asthma drops dramatically if less than three to four weeks of recordings are performed or if they are of inadequate quality, for example-less than four readings per day. We have found that objective evidence of glutaraldehyde induced asthma can be obtained in a large proportion of workers with respiratory tract symptoms temporally related to glutaraldehyde exposure when adequately sought after.
W Anees
A S Robertson
P S Burge
Occupational Lung Disease Unit
Birmingham Heartlands Hospital
Birmingham B9 5SS
1. Vyas A, Pickering CAC, Oldham LA, et al. Survey of symptoms, respiratory function, and immunology and their relation to glutaraldehyde and other occupational exposures among endoscopy nursing staff. Occup Environ Med 2000;7:752-9.
2. Anees W, Burge PS. Diurnal variability of peak expiratory flow and non -specific bronchial reactivity in workers with occupational asthma. Eur Respir J 2000;16:520s
3. Higgins BG, Britton JR, Chinn S, et al: The distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989;140:1368-72.
4. Miles JF, Miller MR: Influence of peak flow meter non-linearity on recorded PEF variability. Thorax 1992;47:891
5. Burge PS, Pantin CF, Newton DT, et al. Development of an expert system for the interpretation of serial peak expiratory flow measurements in the diagnosis of occupational asthma. Occup Environ Med 1999;56:758-64.
6. Di Stefano F, Siriruttanapruk S, McCoach JS, Burge PS. Glutaraldehyde: an occupational hazard in the hospital setting. Allergy 1999;54:1105-9.
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Conflict of Interest:
None declared.
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Published on: 27 April 2016
Symptoms among endoscopy nursing staff
- Eugene R Waclawski, Consultant Occupational Physician
The recent article by Vyas, et al.[1] raises some concerns to which I would be grateful if they could respond.
1) In the abstract one of the objectives is stated as finding the nature and incidence of symptoms experienced by a large sample of hospital endoscopy nurses. The study design is cross-sectional and used an adapted version of the MRC questionnaire for respiratory symptoms. This study design normally re...
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The recent article by Vyas, et al.[1] raises some concerns to which I would be grateful if they could respond.
1) In the abstract one of the objectives is stated as finding the nature and incidence of symptoms experienced by a large sample of hospital endoscopy nurses. The study design is cross-sectional and used an adapted version of the MRC questionnaire for respiratory symptoms. This study design normally records disease prevalence rather than incidence.[2] It would be helpful to know if the questionnaire sought information on new symptoms in a given time period in the past, or the presence of symptoms.
2) For the purposes of the study, work related symptoms (WRSs) of contact dermatitis were defined as contact skin rash, which occurred when working on the endoscopy unit and could not be attributed to known non-occupational agents. It is not clear what validation process was performed prior to using this section of the questionnaire in the study. The authors have indicated that 8 of the 13 subjects with a positive test to IgE specific to latex had WRSs of dermatitis, and indicate this is non-significant. The authors definition of contact dermatitis would have resulted in staff with contact urticaria answering positively to this section. As such, the presence of IgE specific to latex could well be of significance as staff would have used latex gloves.
3) Cross-sectional studies are enhanced by the inclusion of ex-employees. In this study only 18 of 68 ex-employees participated in this study. All 18 were among 26 staff who had left within the past five years for health reasons. As such a selection bias exists and the interpretation of the frequency of WRSs in ex-employees should be cautious. In addition, it is noted that 8 of the 18 ex-employees continue to work as nurses and may experience WRSs from circumstances related to current workplaces rather than endoscopy suites. The absence of a control group of nurses working in areas without exposure to glutaraldehyde would have been of help in interpreting the results obtained.
References
1. A Vyas, C A C Pickering, L A Oldham, H C Francis, A M Fletcher, T Merrett, and R McL Niven. Survey of symptoms, respiratory function, and immunology and their relation to glutaraldehyde and other occupational exposures among endoscopy nursing staff Occup Environ Med 2000;57:752-759
2. Last JM. A Dictionary of Epidemiology. Oxford: Oxford University Press, 1995
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Conflict of Interest:
None declared.
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