Anthony M. Brown

Hearing impairment in F-111 maintenance workers: The study of health outcomes in aircraft maintenance personnel (SHOAMP) general health and medical study

BACKGROUND We sought to examine hearing loss in a group from the Royal Australian Air Force who undertook fuel tank maintenance on F-111 aircraft, with exposure to formulations containing ototoxins, relative to two different comparison groups. METHODS Using pure-tone audiometry, hearing thresholds were assessed in 614 exposed personnel, 513 technical-trade comparisons (different base, same job), and 403 non-technical comparisons (same base, different job). We calculated percentage loss of hearing (PLH) and used regression models to examine whether there was an association between PLH and F-111 fuel tank maintenance, adjusting for possible confounders. In addition, the difference between the observed hearing thresholds and the expected thresholds based on an otologically normal population (ISO-7029-2003) was determined. RESULTS The PLH ranged from nil to 96 (median 1.5, quartiles 0.3, 5.5). A logistic regression model showed no statistically significant difference in PLH among the three exposure groups (exposed vs. non-technical controls 1.1: 95% CI 0.7, 2.0 and exposed vs. technical OR 0.9: 95% CI 0.6, 1.3). The model also highlighted a number of other risk factors for PLH including age, tinnitus, smoking, depression, and use of depression medications. However, at all eight frequencies measured, all populations had lower than expected hearing thresholds based on published ISO-7029 medians. CONCLUSIONS Although there was no difference in PLH between the three exposure groups, the study did reveal a high degree of hearing loss between the 3 groups and a normal population.

Mental health in F-111 maintenance workers: the study of Health Outcomes in Aircraft Maintenance Personnel (SHOAMP) general health and medical study.

Objective: We sought to contrast mood disorder symptoms in F-111 aircraft Deseal/Reseal maintenance personnel with appropriate comparisons. Methods: Participants completed a comprehensive health assessment, including measures of mood disorder, self-reported mood symptom questionnaire items, and review of anxiolytic and depression medication. Multiple logistic regression was conducted for each outcome using exposure group and potential confounders as explanatory variables. Results: There was high agreement between self-reported mood disturbance and objective tests. The exposed group was more likely to self-report previous diagnoses of depression/anxiety, had higher use of antidepressant medications, and had increased risk of diagnosis of depression/anxiety. Results were consistently strong against both comparison groups, with the exposed more likely to have mental distress and social dysfunction when compared with the Australian population. Conclusions: There is robust evidence for an association between F-111 Deseal/Reseal exposure and impaired mental health.

Endotracheal Tube Cuff Pressure before, during, and after Fixed-Wing Air Medical Retrieval

Abstract Background. Increased endotracheal tube (ETT) cuff pressure is associated with compromised tracheal mucosal perfusion and injuries. No published data are available for Australia on pressures in the fixed-wing air medical retrieval setting. Objective. After introduction of a cuff pressure manometer (Mallinckrodt, Hennef, Germany) at the Royal Flying Doctor Service (RFDS) Base in Dubbo, New South Wales (NSW), Australia, we assessed the prevalence of increased cuff pressures before, during, and after air medical retrieval. Methods. This was a retrospective audit in 35 ventilated patients during fixed-wing retrievals by the RFDS in NSW, Australia. Explicit chart review of ventilated patients was performed for cuff pressures and changes during medical retrievals with pressurized aircrafts. Pearson correlation was calculated to determine the relation of ascent and ETT cuff pressure change from ground to flight level. Results. The mean (± standard deviation) of the first ETT cuff pressure measurement on the ground was 44 ± 20 cmH2O. Prior to retrieval in 11 patients, the ETT cuff pressure was >30 cmH2O and in 11 patients >50 cmH2O. After ascent to cruising altitude, the cuff pressure was >30 cmH2O in 22 patients and >50 cmH2O in eight patients. The cuff pressure was reduced 1) in 72% of cases prior to take off and 2) in 85% of cases during flight, and 3) after landing, the cuff pressure increased in 85% of cases. The correlation between ascent in cabin altitude and ETT cuff pressure was r = 0.3901, p = 0.0205. Conclusions. The high prevalence of excessive cuff pressures during air medical retrieval can be avoided by the use of cuff pressure manometers. Key words: cuff pressure; air medical retrieval; prehospital

Impairment of color vision in aircraft maintenance workers

PurposeThe purpose of the study was to examine possible persisting effects to color vision in a group from the Royal Australian Air Force who had exposure to formulations containing neurotoxins during F-111 fuel tank maintenance, relative to two contemporaneous comparison groups.MethodsColor vision was tested in 512 exposed personnel, 458 technical-trade comparisons, and 330 non-technical comparisons using the Ishihara test plates and the Lanthony D-15 Desaturated Color disk arrangement test. Participants were excluded if they failed the Ishihara test as this indicates congenital color blindness. From the Lanthony results, the type of color deficient vision (CDV) was diagnosed, and additionally, the Bowman’s color confusion index (CCI) was calculated. Regression models were used to examine whether there was an association between color vision deficiencies and F-111 fuel tank maintenance, adjusting for possible confounders.ResultsThe CCI ranged from 1 to 2.8 (median 1.2, quartiles 1.1, 1.4) in the 2,600 eyes tested. Forty five percent of all participants had blue-yellow CDV in at least one eye. Deficiencies of this nature are caused by environmental exposures. Logistic regression demonstrated statistically significant differences in CCI category in the exposed group versus technical group (odds ratio 1.7: 95% CI 1.3–2.0) and a blue-yellow confusion in the exposed group versus technical group (odds ratio 1.4: 95% CI 1.1–1.7). No differences were observed between the exposed group and the non-technical group.ConclusionThe results indicate reduced color discrimination among the exposed subjects compared to one of two control groups. The findings may be due to previous exposure to solvents among the air force personnel.

An observed relationship between vestibular function and auditory thresholds in aircraft-maintenance workers

Objective: We sought to examine the vestibular function and whether an association exists between vestibular function and hearing thresholds in a group of military aircraft-maintenance workers with exposures to high levels of noise and organic solvents, relative to two different comparison groups. Methods: Vestibular function (using functional reach) and hearing (with pure-tone audiometry) were assessed in 601 exposed personnel, compared with two unexposed groups (500 technical trade and 391 nontrade). Results: Linear regression model showed that functional reach was slightly better for the comparison groups than the exposed group, with only one group being statistically significant, and there was a significant association between vestibular function and auditory thresholds at 500 and 1000 Hz. Conclusion: This study has demonstrated a relationship between low-frequency hearing loss, vestibular dysfunction, anxiety, and depression in an occupational population.

Evidence of pertussis clusters in three aged-care facilities in the former Macquarie Area Health Service, NSW.

During a limited outbreak of pertussis in an area health service in NSW, three clusters occurred in aged-care facilities--the first reported outbreaks of pertussis in Australian nursing homes. The attack rates across the three clusters were 16.7% for staff and 15.7% for residents. Our investigation revealed that older adults are not immune to pertussis. We suggest methods for controlling a pertussis outbreak in an aged-care facility.

Eye health services for Aboriginal people in the western region of NSW, 2010

AIM To assess the availability, accessibility and uptake of eye health services for Aboriginal people in western NSW in 2010. METHODS The use of document review, observational visits, key stakeholder consultation and service data reviews, including number of cataract operations performed, to determine regional service availability and use. RESULTS Aboriginal people in western NSW have a lower uptake of tertiary eye health services, with cataract surgery rates of 1750 per million for Aboriginal people and 9702 per million for non-Aboriginal people. Public ophthalmology clinics increase access to tertiary services for Aboriginal people. CONCLUSION Eye health services are not equally available and accessible for Aboriginal people in western NSW. Increasing the availability of culturally competent public ophthalmology clinics may increase access to tertiary ophthalmology services for Aboriginal people. The report of the review was published online, and outlines a list of recommendations.

Peripheral Neuropathy in Military Aircraft Maintenance Workers in Australia

Objective: This study aimed to examine possible persisting peripheral neuropathy in a group who undertook fuel tank repairs on F-111 aircraft, relative to two contemporaneous comparison groups. Methods: Vibration perception threshold (VPT) was tested using biothesiometry in 614 exposed personnel, compared with two unexposed groups (513 technical trades and 403 nontrades). Regression modeling was used to examine associations, adjusting for possible confounders. Results: We observed that 26% of participants had chronic persistent increased VPT in the great toe. In contrast, statistically significant higher VPT of the great toe was observed in the comparison groups; however, the effect was small, about 1/4 the magnitude of diabetes. Age, height, and diabetes were all significant and strong predictors in most models. Conclusion: This study highlights chronic persisting peripheral neuropathy in a population of aircraft maintainers.

Ross River virus disease in inland NSW: higher than average notifications in 2007–08

This study showed that Ross River virus notifications in the Greater Western Area Health Service of NSW were higher in 2007-08 than any other financial year for the 1997-2009 period. The study also examined the epidemiology of those notifications. Notification and population data were retrieved from the NSW Health Notifiable Diseases Database and HOIST Populations Library respectively. Age-standardised notification rates were highest in Bogan, Bourke, Brewarrina, Gilgandra, Narromine, Walgett and Warren. Notifications peaked for the 35-39-year age group and were evenly distributed between the sexes. Notifications peaked in February. Aboriginal status was under-reported.