Prevalence of Noise Induced Hearing Loss in Indian Air Force Personnel

Background

Noise exposure is an inherent part of duty of the aircrew and maintenance staff in the Indian Air Force (IAF). An audiometric survey of IAF personnel was carried out to analyze the prevalence and severity of noise induced hearing loss (NIHL).

Methods

An audiometric study of 1000 IAF personnel of various trades, age and exposure groups were carried out at an operational base. Age related correction of 5 dB per decade was applied for personnel above SO years of age. Personal factors like smoking, blood group and use of ear defenders were analysed for their effect on the prevalence of NIHL.

Result

The study revealed an overall incidence of NIHL of 22.9 % in the personnel with a higher prevalence among the technical trades (26.18 %) as compared to non technical trades (12.5 %). There was a significant increase in prevalence of hearing loss with duration of exposure with 50.8% of personnel above 30 years of exposure having hearing loss. A higher incidence of hearing loss was observed in personnel of blood group O and smokers whereas use of ear defenders was protective.

Conclusion

The study reveals a significantly increased prevalence of NIHL among the technical trades of the IAF personnel. The deleterious effects of smoking and protective effect of regular use of ear defenders are emphasized.Key Words: Noise induced hearing loss, Smoking, Ear defenders     

Meeting oxygen needs in Africa: an options analysis from the?Gambia

Objective

To compare oxygen supply options for health facilities in the Gambia and develop a decision-making algorithm for choosing oxygen delivery systems in Africa and the rest of the developing world.

Methods

Oxygen cylinders and concentrators were compared in terms of functionality and cost. Interviews with key informants using locally developed and adapted WHO instruments, operational assessments, cost-modelling and cost measurements were undertaken to determine whether oxygen cylinders or concentrators were the better choice. An algorithm and a software tool to guide the choice of oxygen delivery system were constructed.

Findings

In the Gambia, oxygen concentrators have significant advantages compared to cylinders where power is reliable; in other settings, cylinders are preferable as long as transporting them is feasible. Cylinder costs are greatly influenced by leakage, which is common, whereas concentrator costs are affected by the cost of power far more than by capital costs. Only two of 12 facilities in the Gambia were found suitable for concentrators; at the remaining 10 facilities, cylinders were the better option.

Conclusion

Neither concentrators nor cylinders are well suited to every situation, but a simple options assessment can determine which is better in each setting. Nationally this would result in improved supply and lower costs by comparison with conventional cylinders alone, although ensuring a reliable supply would remain a challenge. The decision algorithm and software tool designed for the Gambia could be applied in other developing countries.     

Use of the Global Test Statistic as a Performance Measurement in a Reananlysis of Environmental Health Data

Performance measurement is increasingly viewed as an essential component of environmental and public health protection programs. In characterizing program performance over time, investigators often observe multiple changes resulting from a single intervention across a range of categories. Although a variety of statistical tools allow evaluation of data one variable at a time, the global test statistic is uniquely suited for analyses of categories or groups of interrelated variables. Here we demonstrate how the global test statistic can be applied to environmental and occupational health data for the purpose of making overall statements on the success of targeted intervention strategies.In a previous study, Enander et al.¹ evaluated the compliance of the Rhode Island automotive refinishing industry sector with state and federal environmental, health, and safety regulations. Baseline and postintervention data were collected on 24 performance indicator variables at 82 randomly sampled facilities. The Fisher exact test was used in making statistical comparisons of proportions between baseline and postintervention data on each performance indicator. In addition to assessing each P value against the nominal .05 level of significance to determine the indicators that showed improvement, the authors used a modified Bonferroni adjustment to control the overall type 1 error rate.We describe global test statistics that we used to reach an overall conclusion about auto body compliance in performance categories identified by Enander et al. This statistical approach represents an additional method that public and environmental health professionals can use to analyze categorical data and make overall statements on the success of targeted intervention strategies. The global test statistic was originally proposed by O''Brien,² with further work by Pocock et al.³ In clinical trials or in the context of an inspection program, the objective is to show improvements in postsetting indicator variables. The traditional procedure is to test all variables simultaneously via the Hotelling T² approach when the variables have a multivariate normal distribution. However, the T² test is 2 sided, and therefore conclusions on overall improvement cannot be made.In Bonferroni procedures, conclusions are made one variable at a time. In reviewing global test procedures, Geller⁴ and others have noted that the intercorrelations among variables can range from moderate to high. In the Bonferroni methods, information about the relationship between variables is not used, and thus there is a loss of power. In the case of highly correlated variables, global procedures are much less conservative than the Bonferroni procedures. A variable-specific method is more appropriate in answering questions relating to effectiveness as measured by individual variables, whereas a global method might be more appropriate in answering questions relating to effectiveness as measured by uniform improvement across all variables. Thus, the 2 methods complement each other.To assist in computing global statistics, the University of Rhode Island''s Computer Science and Statistics Department has posted the program online at http://www.cs.uri.edu/∼dymo-van. Because the program uses MATLAB, users need to have access to this package.     

A case of near‐drowning: a case for routine cerebral monitoring

A 6‐week‐old infant presenting with near‐drowning was medically paralysed and ventilated on admission. Status epilepticus was found on cerebral function monitoring, without which the diagnosis would have been missed or delayed for many hours. This case illustrates the value of cerebral function monitoring for patients in intensive care, where clinical signs of seizure activity are frequently masked by paralysis and sedation. Conclusion: Limited availability of electroencephalogram (EEG) and cerebral function monitoring (CFM) in paediatric intensive care may inadvertently delay diagnosis and appropriate treatments and so adversely affect outcomes. We propose that round‐the‐clock cerebral function and/or EEG monitoring should be available in all centres that provide paediatric intensive care.     

OFLOXACIN VERSUS TRIMETHOPRIM AND CO-TRIMOXAZOLE IN THE TREATMENT OF UNCOMPLICATED URINARY TRACT INFECTION IN GENERAL PRACTICE

A large-scale, randomised, multicentre single-blind clinical trial was conducted to assess the comparative efficacy and tolerance of ofloxacin, trimethoprim and co-trimoxazole in the treatment of uncomplicated urinary tract infection in general practice. A total of 1,069 patients from 76 centres across the UK were enrolled in the study, and randomised to one of the following treatment groups: ofloxacin (200 mg od), trimethoprim (200 mg bd) or co-trimoxazole (trimethoprim 160 mg and sulphamethoxazole 800 mg bd). Each patient received five days of medication. Clinically, ofloxacin was as effective as trimethoprim and co-trimoxazole. However, the bacteriological cure rate was significantly better for ofloxacin, with eradication of the initial causative pathogen by the end of treatment in 92% of patients in the ofloxacin group, compared with 81% for trimethoprim and co-trimoxazole (P = 0.0002). There was also a lower relapse rate for ofloxacin. Ofloxacin was well tolerated: adverse events were reported by 67 (12.4%) patients in the ofloxacin group, compared with 48 (18.7%) patients in the co-trimoxazole group and 37 (13.6%) patients in the trimethoprim group. Ofloxacin can therefore be considered a suitable alternative for the treatment of uncomplicated urinary tract infection.