Accidental iatrogenic intoxications by cytotoxic drugs - Error analysis and practical preventive strategies

Objectives: Drug errors are quite common. Many of them become harmful only if they remain undetected, ultimately resulting in injury to the patient. E rrors with cytotoxic drugs are especially dangerous because of the highly t oxic potential of the drugs involved. For medico-legal reasons, only 1 case of accidental iatrogenic intoxication by cytotoxic drugs tends to be inves tigated at a time, because the focus is placed on individual responsibility rather than on system errors. The aim of our study was to investigate whet her accidental iatrogenic intoxications by cytotoxic drugs are faults of ei ther the individual or the system. The statistical analysis of distribution and quality of such errors, and the in-depth analysis of contributing fact ors delivered a rational basis for the development of practical preventive strategies. Methods: A total of 134 cases of accidental iatrogenic intoxication by a cy totoxic drug (from literature reports since 1966 identified by an electroni c literature survey, as well as our own unpublished cases) underwent a syst ematic error analysis based on a 2-dimensional model of error generation. I ncidents were classified by error characteristics and point in time of occu rrence, and their distribution was statistically evaluated. The theories of error research, informatics, sensory physiology, cognitive psychology, occ upational medicine and management have helped to classify and depict potent ial sources of error as well as reveal clues for error prevention. Results: Monocausal errors were the exception. In the majority of cases, a confluence of unfavourable circumstances either brought about the error, or prevented its timely interception. Most cases with a fatal outcome involve d erroneous drug administration. Object-inherent factors were the predomina nt causes. A lack of expert as well as general knowledge was a contributing element. In error detection and prevention of error sequelae, supervision and back-checking are essential. Improvement of both the individual trainin g and work environment, enhanced object identification by manufacturers and hospitals, increased redundancy, proper usage of technical aids, and restr ucturing of systems are the hallmarks for error prevention. Conclusions: Errors follow general patterns even in oncology. Complex inter dependencies of contributing factors are the rule. Thus, system changes of the working environment are most promising with regard to error prevention. Effective error control involves adapting a set of basic principles to the specific work environment. The work environment should allow for rectifica tion of errors without penalty. Regular and ongoing intra-organisational er ror analysis needs to be an integral part of any error prevention strategy. However, it seems impossible to totally eliminate errors. Instead, if the environment guarantees timely error interception, most sequelae are avoided , and errors transform into a system-wide learning tool.