Negative effects of the increasing number of toxic substances in the external environment affecting the human organism are highly reflected in everyday forensic practice. In parallel with new circumstances also the methods enabling identification of heterogeneous substances have been developing. Demonstrating evidence is more challenging and sophisticated particularly in cases with proving several xenobiotics including metabolites and their possible interaction. Poison intoxications of unknown origin can represent a diagnostic problem. Consequently close collaboration between involved forensic professionals i.e. medical examiner and forensic toxicologist-analyst is inevitable. The data provided by police investigators are significant as well--investigated circumstances, testimonies and in case of hospitalization detailed data from clinicians. In everyday forensic practice the shortage of medical examiners specialised in toxicology and knowledgeable toxicologists-analysts has been increasingly experienced. The urgent requirement for more specialists arises more frequently not only in suspected fatal poisonings but also in assessing of analysis results particularly in cases of persons directly involved in road traffic accidents, work-related injuries, etc. The number of cases requiring detecting psychoactive substances is also increasing. On the other hand recent experience demands expanding the spectrum and increasing the number of indications of toxicological analyses from medical examiners involved in performing autopsies. At present the Slovak forensic workplaces are in the process of being equipped with instrumentation designed for expanding the spectrum of toxicological analyses and improving their quality. There hence emerges a need for developing the contemporary concept of Slovak forensic toxicology with respect to both organizational and methodological aspects focused on better interaction of activities carried out by medical examiners and toxicologist-analysts. The essential part of developing the coordination of both expert groups is also postgraduate education with an emphasis on improving mutual recognition principles of their work.

INTRODUCTION:Cases of fatal hydrogen sulfide poisonings are rarely presented in forensic medicine practice. They mostly occur in occupational settings and occasionally are mass. Due to occupational poisonings caused by gases, hydrogen sulfide is ranked second regarding frequency-dependent incidence. Hydrogen sulfide at high concentrations is undetectable to human senses resulting in increased risk of fatal poisoning. Such poisonings represent a particular group with respect to their objectification by toxicological analysis.AIM:The aim of this paper is to demonstrate possibilities of laboratory diagnostics of fatal hydrogen sulfide poisonings.PATIENTS AND METHODS:The paper provides a retrospective overview of 15 cases of fatal hydrogen sulfide poisonings which occurred in the history of the Institute of Forensic Medicine of the School of Medicine, Comenius University in Bratislava. All cases were completely analysed by morphological and toxicological methods. The samples of blood and pulmonary tissue were examined in the toxicological analysis. The method of analysis of alveolar air was developed by Bauer. An experiment for detection of post-mortem production of hydrogen sulfide in the body was performed.RESULTS:Morphological findings in all autopsied and analysed cases were similar and nonspecific for poisoning diagnosis. A significant change in possibilities of toxicological analysis occurred in 1968. Since then a direct identification of toxic gas through the analysis of alveolar air has been possible.CONCLUSION:Taking into consideration summarization and comparison of the analysis results of the cases from archive materials of the authors, it is possible to claim that at the workplace in Bratislava a unique objective method of proving this gaseous poison in biological material used so far has been developed. Some negative or unconvincing results of toxicological analysis again refer to pitfalls of diagnostics of hydrogen sulfide poisonings, which must be complex and based upon an efficient collaboration particularly between a medical examiner and toxicologist-analyst together with other bodies complementing the required spectrum of investigated circumstances and clinical data.