Patients with acute poisoning in Emergency Department – Presentation of modern data search and results of pilot analysis

Background: When studying Emergency Department (ED) visits due to intoxications, it is essential to have comprehensive and accurate baseline data. Electronic health record systems of hospitals provide a good basis for retrospective studies. However, many intoxication patients arriving at the ED may not be identified retrospectively if only one single search method is applied, such as reason for attending, laboratory findings, or International Classification of Diseases (ICD-10) code. Methods In this single centre study, a novel four-way combined patient search method was used to retrospectively identify intoxication patients attending the ED of Kanta-Häme Central Hospital, Finland, in 2019. The search included reason for attending, laboratory results related to intoxication diagnostics, ICD-10 codes, and a novel free word search in the patient records. After the automated search, the researcher read the medical records of potential intoxication patients to form comprehensive profiles and to exclude irrelevant cases. Results When retrospectively extracting patient data from electronic hospital records, addition of a free word search identified 36% more intoxication patients than the combination of the three methods listed above. The leading substances causing intoxication were ethanol and benzodiazepines, followed by prescription and over-the-counter medications, such as antidepressants and paracetamol. Amphetamine was the most used illegal substance. Conclusion Free word search complemented and, in many ways, replaced traditional patient search methods, such as ICD-10 code search. These results highlight the importance of a combined patient search method for retrospective data collection.