Serial Peak Expiratory Flow Measurements Research Articles

Prevalence and Risk Factors of Work-Related Asthma in Hospital Cleaning Workers.

OBJECTIVE:This study aimed to determine the prevalence and evaluate the risk factors of work-related asthma among professional hospital cleaning workers.MATERIAL AND METHODS:In total, 278 cleaning workers were interviewed (response rate: 75.7%), and pulmonary function tests were performed. The presence of asthma and its work-relatedness was evaluated. Serial peak expiratory flow measurements were planned according to symptoms increased at work or spirometric findings.Results:Totally 40 cleaning workers had asthma (14.3%); of these, 17 (6.1%) had work-related asthma, and 23 (8.2%) had non-work-related asthma. Non-work-related asthma and work-related asthma were significantly associated with the females(odds ratio 95% CI: 3.0, 1.1-8.4, and 3.2, 1.0-10.3, respectively). Non-work-related asthma was significantly associated with a family history of asthma (odds ratio 95%CI: 5.1, 2.0-13.2 and 2.8, 0.99-7.9, respectively) and limescale remover use at work (odds ratio, 95% CI: 0.21, 0.04-0.97, and 1.7, 0.5-5.2, respectively). Only 7 (28.0%) of 25 cleaning workers who were suggested serial peak expiratory flow measurements could complete the measurements. Of those, measurements of 2 cleaning workers were consistent with occupational asthma.Conclusion:The negative association between limescale remover use at work and non-work-related asthma suggested health selection bias (avoidance behavior) due to the asthmatic effects of these chemicals.

Occupational asthma; the limited role of air-fed respiratory protective equipment

Evidence-based reviews have found that evidence for the efficacy of respiratory protective equipment (RPE) in the management of occupational asthma (OA) is lacking. To quantify the effectiveness of air-fed RPE in workers with sensitizer-induced OA exposed to metal-working fluid aerosols in a car engine and transmission manufacturing facility. All workers from an outbreak of metal-working fluid-induced OA who had continuing peak expiratory flow (PEF) evidence of sensitizer-induced OA after steam cleaning and replacement of all metal-working fluid were included. Workers kept 2-hourly PEF measurements at home and work, before and after a strictly enforced programme of RPE with air-fed respirators with charcoal filters. The area-between-curve (ABC) score from the Oasys plotter was used to assess the effectiveness of the RPE. Twenty workers met the inclusion criteria. Records were kept for a mean of 24.6 day shifts and rest days before and 24.7 after the institution of RPE. The ABC score improved from 26.6 (SD 16.2) to 17.7 (SD 25.4) l/min/h (P > 0.05) post-RPE; however, work-related decline was <15 l/min/h in only 12 of 20 workers, despite increased asthma treatment in 5 workers. Serial PEF measurements assessed with the ABC score from the Oasys system allowed quantification of the effect of RPE in sensitized workers. The RPE reduced falls in PEF associated with work exposure, but this was rarely complete. This study suggests that RPE use cannot be relied on to replace source control in workers with OA, and that monitoring post-RPE introduction is needed.

Occupational asthma caused by peracetic acid-hydrogen peroxide mixture.

Healthcare practice in the UK has moved away from using aldehyde disinfectants for the decontamination of endoscopes, in part due to the risk of respiratory sensitization. Peracetic acid (PAA) in combination with hydrogen peroxide (HP) is a commonly used alternative. We describe a case of occupational asthma (OA) diagnosed at our specialist occupational lung disease clinic and caused by occupational exposure to PAA-HP mixture, used as a disinfectant in an endoscope washer-disinfector machine. A 48-year-old man employed as a mycologist and environmental microbiologist at a Birmingham city hospital, UK, presented following an acute exposure to PAA-HP mixture causing lacrimation, burning optic pain and headache. He had also experienced symptoms suggestive of OA for the preceding 10 months, and the diagnosis was confirmed through OASYS analysis of serial peak expiratory flow measurements. He had been exposed to PAA-HP mixture whilst working in the endoscopy department for 12 months prior to the acute episode, and a subsequent specific inhalation challenge test was positive with a late asthmatic response to PAA-HP mixture. This case provides evidence for a sensitization mechanism in OA caused by PAA-HP mixture.

Cleaning agent occupational asthma in the West Midlands, UK: 2000–16

Cleaning agents are now a common cause of occupational asthma (OA) worldwide. Irritant airway and sensitization mechanisms are implicated for a variety of old and new agents. To describe the exposures responsible for cleaning agent OA diagnosed within a UK specialist occupational lung disease service between 2000 and 2016. The Birmingham NHS Occupational Lung Disease Service clinical database was searched for cases of OA caused by cleaning agents, and data were gathered on age, gender, atopic status, smoking history, symptom onset, diagnostic investigations (including Occupational Asthma SYStem analysis of workplace serial peak expiratory flow measurements and specific inhalational challenge), proposed mechanism, industry, occupation and causative agent. Eighty patients with cleaning agent OA (77% female, 76% arising de novo) were identified. The median annual number of cases was 4 (interquartile range = 2-7). The commonest cleaning agents causing OA were chloramines (31%), glutaraldehyde (26%) and quaternary ammonium compounds (11%) and frequently implicated industries were healthcare (55%), education (18%) and leisure (8%). Certain cleaning agents in common usage, such as chlorine-releasing agents, quaternary ammonium compounds and aldehydes, are associated with sensitization and asthma. Their use alters over time, and this is particularly evident in UK healthcare where cleaning and decontamination practice and policy have changed. Vigilance for OA in workplaces such as hospitals, nursing homes, leisure centres and swimming pools, where these cleaning agents are regularly used, is therefore essential.

Does the medical diagnosis of occupational asthma coincide with the legal diagnosis?

ABSTRACTObjective: The incidence of occupational asthma (OA) is increasing worldwide. In this study, we first aimed to document the rate of diagnosis of OA among patients who were referred to our clinic from the Social Security Institution and the factors that affected diagnosis; secondly, we aimed to assess the consistency of the medical and legal diagnoses. Methods: The study involved 132 consecutive patients who were referred to our clinic for the evaluation of OA between 2010 and 2015. Detailed workplace history, the tools used in the diagnosis such as peak expiratory flow (PEF) monitoring and bronchial provocation tests, and the final medical diagnosis were recorded from case files. Results: Asthma was diagnosed in 75% (n = 99) of the patients. Among them, 22.2% were diagnosed as having OA. The diagnosis was confirmed by serial PEF measurements, non-specific bronchial hyperreactivity assessment or both of the tests both at work and off-work periods. OA diagnosis was mostly established in active workers (72.7%). The legal diagnosis period was completed in 54.5% of these 22 patients, and 50% (n = 11) were officially diagnosed as having OA with a 91.6% concordance with medical diagnosis. Conclusion: This study verifies the importance of diagnosing asthma correctly as a first step in the evaluation of OA. Diagnostic tests other than specific provocation tests could be preferential in patients who still work in the same field. We believe that cooperation with the patient's occupational physician and adequate recognition of the work environment will improve the consistency of legal and medical diagnoses.

Are serum eosinophilic cationic protein levels of toll collectors affected by diesel exhaust exposure?

Objective:There are few studies on the diesel exhaust particulates (DEP) / eosinophilic cationic protein (ECP) level relationship. This study aimed to detect ECP levels in a highly DE exposed group, named as toll collectors.Methods:In a cross-sectional study, levels of serum ECP, rates of respiratory symptoms, mean levels of respiratory functions, smoking status, and variations in peak expiratory flow (PEF) during weekends and working days were compared for 68 toll collectors (TC) (range of age, 24-48 years) and 28 controls (range of age, 25-61 years). All subjects in the study group were men.Results:No significant difference was observed in terms of symptoms and smoking rates between the toll collectors and control group. The number of toll collectors [12/68 (17.7%) vs 1/28 (3.5%)] with diurnal PEF variability in the working period was higher than that of controls (p=0.058). Mean ECP level of toll collectors was higher than that of controls (32.8 vs 21.4 ng/L), but the difference was not significant. Mean ECP levels were higher in subjects experiencing diurnal PEF variability during work and off-work periods (34.9 vs 28.3 ng/L, p=0.410).Conclusions:Serial PEF measurements combined with serum ECP measurements did not add a new tool to detect the sensitivity of workers dealing with DE. Much more diesel exhaust exposed workers should be included to search for cheap and available methods when evaluating airway.

Can serial PEF measurements separate occupational asthma from allergic alveolitis?

Occupational asthma commonly results in work-related changes in serial peak expiratory flow (PEF) measurements. Whether alveolitis can result in similar changes is unknown. To identify differences and similarities of serial PEF between workers with occupational alveolitis and asthma seen during an outbreak investigation in a factory with metal-working fluid exposure. Workers with respiratory symptoms and rest-day improvement were identified by questionnaire. Each was asked to measure PEF 8 times daily for 4 weeks at home and work. Alveolitis was subsequently diagnosed from a validated scoring system including radiological changes, carbon monoxide diffusing capacity, bronchoalveolar lavage and biopsy results. Occupational asthma was confirmed with a positive Oasys score >2.5 and a mean rest-work PEF >16 l/min from serial 2-hourly PEF measurements. The Oasys PEF plotter calculated differences between rest and workdays for mean PEF, diurnal variation and the scores were used to confirm an occupational effect (Oasys, area between curve and time point). Records were compared between the alveolitis group and the group with occupational asthma without alveolitis. Forty workers with occupational asthma and 16 with alveolitis had indistinguishable PEF changes on workdays in terms of magnitude (median reduction 18.5 and 16.1 l/min, respectively) and diurnal variation. Immediate reactions were more common with occupational asthma and late reactions more common with alveolitis. PEF responses to metal-working fluid aerosols do not distinguish occupational asthma from alveolitis except in timing. They can be used to identify the workplace as the cause of asthma and also alveolitis.

S131 Identifying Occupational Asthma Among a Cohort of Cleaners in the North East England

IntroductionWe have demonstrated a prevalence of asthma of 14% in a survey of 1400 UK hospital and university cleaners, and an estimated incidence of asthma of 3.3/1000 person-years. 26% of...

An outbreak of occupational asthma due to chromium and cobalt

Five metal turners employed by an aerospace manufacturer presented to the Birmingham Chest Clinic occupational lung disease unit. Four cases of occupational asthma (OA) due to chromium salt (3) and cobalt (1) were diagnosed by serial peak-expiratory flow measurements and specific inhalation challenge testing. To measure the extent of the outbreak and to provide epidemiological data to ascertain the aetiology. Participants answered a detailed, self-administered questionnaire, designed to detect occupational lung disease. Urine chromium and cobalt excretion, spirometry and exhaled nitric oxide measurements were taken. Those with possible, probable or definite non-OA or OA, after questionnaire, were invited to undertake two-hourly peak flow measurements and received specialist follow-up. A total of 62 workers (95% of workforce) participated. Sixty-one per cent of employees were working in higher metalworking fluid (MWF) exposure areas. Ninety per cent of workers had urinary chromium excretion indicating occupational exposure. Sixty-six per cent of workers reported active respiratory symptoms, although there were no significant differences between exposure groups. Two further workers with probable OA were identified and had significantly higher urinary chromium and cobalt concentration than asymptomatic controls. Eighteen cases of occupational rhinitis (OR) were identified, with significantly raised urinary chromium concentration compared with asymptomatic controls. Chromium salt and cobalt can be responsible for OA and OR in workers exposed to MWF aerosols. Onset of symptoms in those with positive specific challenges followed change in MWF brand. Workers with OA had increased urinary concentrations of chromium and cobalt, and those with OR had increased urinary concentrations of chromium.

Shift work effects on serial PEF measurements for occupational asthma

Diurnal variation (DV) affects lung function but the changes are thought to be related to sleep patterns rather than time of day. When diagnosing occupational asthma (OA), serial peak expiratory flow (PEF) measurements are the recommended first line investigation, but could be confounded by shift work. The aim of the study was to investigate the effects of shift work on PEF measurements used for diagnosing OA. PEF records containing more than one shift pattern with ≥ 4 days per shift were identified. OA diagnosis was based on an Oasys-2 score ≥ 2.51 and non-OA on having an alternative clinical diagnosis and Oasys-2 score <2.51. The mean area between curves (ABC) score, mean PEF DV and cross-shift PEF changes were calculated for each shift. Records from 123 workers with OA and 69 without OA satisfied inclusion criteria. In the OA group, PEF declined more on afternoon and night shifts than days (P < 0.001). The ABC score was lower in the OA group on night (P < 0.05) and afternoon shifts (P < 0.05) as compared with days, without significant differences in DV. Among those without OA, cross-shift PEF increased more on day shifts (mean + 25 l/min) than afternoon or night shifts (+1 l/min) (P < 0.001). The sensitivity for the ABC score and DV were good and similar across shifts, but specificity was reduced using DV (DV mean 39%; ABC 98%). PEF responses between work and rest show small differences according to shift type. The ABC score has a high sensitivity and specificity for all shifts; differences in DV have lower specificity.

S160 The effect of shift work on serial peak expiratory flow measurements used to diagnose occupational asthma

We investigated the effects of shift work on Peak Expiratory Flow (PEF) measurements used for diagnosing occupational asthma (OA). In a clinic database of workers investigated for OA, 123 workers...

Occupational asthma caused by heated triglycidyl isocyanurate

Six workers exposed as bystanders to heated triglycidyl isocyanurate (TGIC) developed occupational asthma confirmed by serial peak expiratory flow measurement and Oasys analysis. Specific inhalation challenge testing resulted in late or dual asthmatic reactions to heated TGIC in four of four tested and was negative in three control asthmatics. One worker tested only with unheated TGIC had a negative specific challenge test. Heated TGIC can cause occupational asthma from bystander exposure.

Diagnosis of occupational asthma from time point differences in serial PEF measurements

Background:The diagnosis of occupational asthma requires objective confirmation. Analysis of serial measurements of peak expiratory flow (PEF) is usually the most convenient first step in the diagnostic process. A new...

Diesel exhaust causing low-dose irritant asthma with latency?

Diesel exhaust exposure may cause acute irritant-induced asthma and potentiate allergen-induced asthma. There are no previous reports of occupational asthma due to diesel exhaust. To describe occupational asthma with latency in workers exposed to diesel exhaust in bus garages. The Shield database of occupational asthma notifications in the West Midlands, UK, was searched between 1990 and 2006 for workers where diesel exhaust exposure was thought to be the cause of the occupational asthma. Those without other confounding exposures whose occupational asthma was validated by serial peak expiratory flow (PEF) analysis using Oasys software were included. Fifteen workers were identified with occupational asthma attributed to diesel exhaust. Three had validated new-onset asthma with latency. All worked in bus garages where diesel exhaust exposure was the only likely cause of their occupational asthma. Occupational asthma was confirmed by measures of non-specific reactivity and serial measurements of PEF with Oasys scores of 2.9, 3.73 and 4 (positive score > 2.5). The known non-specific irritant effects of diesel exhaust suggest that this is an example of low-dose irritant-induced asthma and that exposures to diesel exhaust in at least some bus garages are at a sufficient level to cause this.

Serial PEF measurement is superior to cross-shift change in diagnosing occupational asthma

Cross-shift measurements of peak expiratory flow (PEF) are commonly employed in the diagnosis of occupational asthma, although evidence for this approach is lacking. The current paper presents an evaluation of the technique. Mean changes in PEF across morning/day shifts were compared between workers with occupational asthma, confirmed using specific challenge testing, and non-working asthmatics. Individuals were divided into a development set, used to identify the optimum cross-shift change for diagnosing occupational asthma, and an evaluation set, used to test the sensitivity and specificity of this value. Comparative analysis of serial PEF records was performed using the Oasys-2 computerised system. A cross-shift decrease in PEF of 5 L.min(-1) achieved acceptable specificity in the development set. Applied to the evaluation set, this cut-off had a specificity of 90.9% and a sensitivity of 50%. Sensitivity could not be improved without unacceptable compromise to specificity. Analysis of serial PEF records using linear discriminant analysis identified occupational asthma with a sensitivity of 83.3% and a specificity of 90.9%. Serial analysis using mean work/rest day PEF comparison had a sensitivity of 66.7% and a specificity of 100%. Cross-shift changes in PEF in morning/day-shift workers have poor sensitivity in diagnosing occupational asthma, and are inferior to serial techniques.

Audit of quality of diagnostic procedures for occupational asthma

Previous studies have reported deficiencies in the quality of the diagnosis of occupational asthma. A low quality of diagnostic procedures means that the occupational cause of asthma is less likely to be revealed. To assess the current quality of the diagnosis of occupational asthma before referral to a specialist occupational medicine centre. The quality of diagnostic procedures was assessed by reviewing the files of 150 patients who were referred to the Finnish Institute of Occupational Health in 2003 with a suspicion of an occupational cause of their asthma. The quality indicators used were assessment of workplace exposures, spirometric studies, bronchodilator response, serial workplace measurements of peak expiratory flow (PEF) and the time since first symptoms to the final diagnosis. For each indicator, criteria to differentiate between sufficient and insufficient care were developed. Exposure assessments, spirometric studies and bronchodilator responses were performed in 92, 87 and 79% of cases in the total study group, respectively. Workplace measurements of PEF had been performed in 51% of the cases, and the quality of measurements was sufficient in 52%. Workplace exposures had been assessed significantly more often in occupational health care than in other health care units. The median time from the beginning of symptoms to the final diagnosis was 3.2 years. Although the diagnostic procedures were mostly of sufficient quality, the performance of serial measurements of PEF at the workplace and the time to diagnosis should be substantially improved.

The validation of work-related self-reported asthma exacerbation

Objective: To determine the validity of work-related self-reported exacerbation of asthma using the findings from serial peak expiratory flow (PEF) measurements as the standard. Methods: Adults with asthma treated in...

Occupational asthma in apprentice adolescent car painters

Occupational asthma (OA) is one of the leading causes of pulmonary diseases and has been extensively studied in adults. Childhood employment, a significant problem in many developing countries, should be studied to determine and evaluate its effects on psychosocial and lung health. In order to investigate the presence of work-related asthma-like symptoms and OA in apprentice adolescent car painters, 72 adolescents between the ages of 15-20 yr studying in Vocational Training Centres of Ankara were investigated using questionnaire, pulmonary function test (PFT), serial peak expiratory flow (PEF) measurements and methacholine inhalation tests. As a control group, 72 adolescents studying in Industrial and Commercial Training Centres located in the same environment were investigated with questionnaire and PFT. Almost 50% of the study group had work-related asthma-like symptoms for which occupational dermatitis history was predictive [odds ratio: 2.9 (1.026-8.13) (95% confidence interval)]. Seventeen of 22 with serial PEF measurements showed a variability of > or =20% and three (4.2%) of 12 tested with methacholine inhalation test had a PC20 < or = 8 mg/ml, which led to the diagnosis of OA. There was no statistically significant difference between study and control groups in terms of PFT. In conclusion, the high prevalence of work-related asthma-like symptoms among adolescent car painters clearly indicates the need for routine follow-up of adolescent workers for lung health.

Chronic cough: a rational approach to investigation and management

Chronic cough is a common problem: community surveys suggest a prevalence of recurrent cough of up to 40% and persistent cough of up to 10% 1–3. Approximately 10% of new patients seen in respiratory clinics are referred with an isolated chronic cough 4. Most patients referred for a specialist opinion are nonsmokers with normal findings on basic screening investigations, such as chest radiograph, serial peak expiratory flow measurements and spirometry. Females account for 60–70%, and many report a long-standing cough, which started at around the time of the menopause 5. The current evaluation of chronic cough is based on the “anatomic, diagnostic” protocol originally described by Irwin et al. 6 >20 yrs ago. This investigation protocol is based on the view that most cases of nonasthmatic chronic cough are caused by rhinosinusitus and/or gastro-oesophageal reflux 6, 7. The investigation protocol remains largely based on expert opinion, and there is a lack of evidence from randomised, double-blind, placebo-controlled trials supporting central tenants of the anatomic, diagnostic protocol 8, 9. Nevertheless, there are multiple reports of the successful management of cohorts of patients with chronic cough using variants of the anatomic, diagnostic approach to investigation, and the protocol has largely stood the test of time 10. Despite this, many clinicians view chronic cough as a difficult clinical problem 11. Amongst the most significant problems is the …

Occupational Asthma in the Furniture Industry: Is It Due to Styrene?

Background: Styrene, a volatile monomer, has been reported as a cause of occupational asthma in a few case reports. Objective: The aim of this study was to investigate the risk for asthma in relation to exposure to styrene in a large number of workers. Methods: A total of 47 workers with a history of exposure to styrene were included in the study. To establish whether asthma was present, each patient underwent a clinical interview, pulmonary function testing and bronchial challenge with methacholine. Specific bronchial challenges with styrene and serial peak expiratory flow (PEF) measurement at home and at work were carried out in subjects with a diagnosis of asthma to evaluate the relationship between their asthma and exposure to styrene in the workplace. Results: Among the 47 subjects, 5 workers had given a history of work-related symptoms, and 3 of them had a positive methacholine challenge test. Specific bronchial challenges with styrene and serial PEF measurement were subsequently carried out in these 3 subjects. Although provocation tests with styrene were negative in the 3 workers, 1 worker had PEF rate records compatible with occupational asthma. Conclusion: We established one patient with occupational asthma from a group of people who have excessive styrene exposure. This finding may be suggestive but is not conclusive about the causative role of styrene in occupational asthma. Since styrene is a frequently used substance in the furniture industry, it is worth performing further studies to investigate the relationship between styrene and occupational asthma.