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Case-control studies are retrospective observational studies designed to determine the relationship between the outcome of interest and its potential cause. This study design has known disadvantages: possible bias in the results, selection bias in the control group, etc. In order to avoid inconsistency between the study and control groups and thus underestimating of the possible influence of intervening factors (confounder), a whole class of methods is used to ensure that case-control matching pairs are selected and matched. Objective. To discuss and demonstrate the possibility of forming groups of research subjects (impact and control) on the basis of matching variables using the optimal matching procedure and compare the results of paired and unpaired analysis. Materials and methods. The baseline data were the results of a cross-sectional study of the impact of pandemic COVID-19 on health worker behavior. An example algorithm was used to assess the impact of awareness of different aspects of SARS-CoV-2 on health professionals. The processing was done in the R software environment. Discussion. The present study had two objectives: to demonstrate a method for optimal matching of case-control pairs for specific data and to estimate the effect of certain factors on the outcome of interest. Using this method allows for maximum consistency between study and control groups on selected matching variables. This tool simplifies and automates data preparation for subsequent analysis when case and potential control data are presented in a single dataset. Thus, the example shows that with different values of the number of controls per case indicator the point and interval estimate of the odds ratio varies slightly and indicates a statistically insignificant association between the need for more information and the forced use of leave by the health professional due to various concerns about the impact of COVID-19.

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Introduction. The integration of special acoustic means into the safety system makes it relevant to conduct biomedical research to evaluate the impact of their effects on the hearing organs.   Objective. To study the characteristics of a special sound signal and its effect on the hearing organ of an experimental biological model.   Materials and methods. The study was conducted on 6 males (12 ears) guinea pigs (Cavia porcellus) weighing 200–250 grams at the age of 4 weeks. A set of special audio equipment was used to generate an acoustic signal. The study was conducted in a room with an area of about 47 m2. The time of a single exposure to experimental animals was 3 minutes at a sound level of 127–128 dBA. Before exposure and at different times after exposure (after 24 and 72 hours), the otoscopic picture was evaluated, a Preyer’s reflex and distortion-product otoacoustic emissions (DPOAEs) was carried out.   Results. The special sound signal was characterized by distinct frequency components and can be attributed to tonal noises. After acoustic exposure to a special sound signal, a normal otoscopic picture was observed in experimental animals. Restoration of the Preyer’s reflex occurred 24 hours after exposure. The restoration of the DPOAEs to background values at frequencies from 1.5 to 3.3 kHz occurred 24 hours after acoustic exposure, at a frequency of 4.2 kHz there was a significant tendency to recovery.   Conclusions. With a short-term (within three minutes) single exposure to a special sound signal with a sound level of 127 to 128 dBA on biological models (guinea pigs), no pathology of the hearing organ was detected. Given the greater resistance of humans to acoustic effects, compared to guinea pigs, this can equally be extended to humans.

For a long time for otolaryngologists, the issues of identifying and treating such a formidable disease as chronic suppurative otitis media (CSOM) have been topical. This disease still haunts many specialists, as it leads to acquired hearing loss in people of working age. Only in the last ten years, the number of children of younger age groups with already manifested acquired hearing loss has increased. Along with the correct and timely diagnosis, it is very important to cure this disease once and for all, since exacerbations often disrupt not only the performance, but also the quality of life of the patient. The gold standard for the treatment of patients with CHSO is surgical – tympanoplasty. In the process of studying the pathological process in chronic suppurative otitis media and methods of its more effective surgical treatment, the results of tympanoplasty were analyzed. An illustrative clinical example has been chosen, with the help of which it is possible to trace all the stages of surgical intervention in chronic suppurative otitis media. An otoscopic examination was carried out at several stages of observation of this patient, as well as the determination of auditory function. The presented clinical case shows step by step the effectiveness of the scheme of surgical treatment and postoperative management. Thus, these steps are applicable to any myringoplasty with tympanic membrane defects of any size. It is tympanoplasty and control in the postoperative period that makes it possible to completely close the defect of the tympanic membrane and prevent chronic otitis media from recurring.