Wikipedia, an online, open source encyclopedia hosted by a nonprofit organization Wikimedia Foundation, is the sixth most visited website in the world [2]. In addition to being the biggest and most-read reference work in history, Wikipedia is one of the most frequently accessed health information resources [3]. Although this encyclopedia includes numerous cardiac arrest- and resuscitation-related articles, the role of Wikipedia as an information resource on CPR has not been determined. This study was carried out to obtain insight into the public use of Wikipedia for information on CPR, as well as to characterize Wikipedia’s content on CPR and its appropriateness for lay people.

In January 2024, a search engine results page analysis was conducted using Mangools suite (itrinity) to determine the ranking of Wikipedia’s article on CPR in web search results. The Mangools suite provides detailed insights into search engine result statistics for any search query, including an option to examine top-ranking pages for a specific keyword. For the English-language search independent of the geography, the CPR article appeared in the fourth position in response to the “cardiopulmonary resuscitation” search query and the eighth position in response to the “CPR” query. Because the first 10 results on a search results page receive more than 90% of all clicks for a search query [4], many users select the Wikipedia article as the preferred source of information regarding CPR. This action is further increased by search engine recognition of CPR as a popular topic and provision of additional featured results on the top of the search results page that refer to Wikipedia’s article on CPR. Based on the Mangools data, the numbers of the article visits per month for “cardiopulmonary resuscitation” and “CPR” search queries were 29,540 and 6,440, respectively. Although the search engine results page analysis may not reflect the actual popularity of the web resource (in particular, the same people may access the website numerous times), the above-mentioned values probably underestimate the actual readership of the article because many people are accessing it through other less popular search queries or backlinks.

To determine the actual number of views for the Wikipedia’s CPR article, the Wikipedia Pageviews Analysis tool (pageviews.wmcloud.org) was utilized. This tool shows the number of times a particular Wikipedia article has been viewed in a specific time period. In the last 5 years (January 01, 2019–December 31, 2023), the CPR article was viewed 2,590,694 times, with yearly, monthly, and daily average numbers of views of 518,139, 43,178, and 1,419, respectively.

The timeline graph revealed two spikes of monthly pageviews in June 2021 and January 2023 (+79% and +57% increment vs. the 5-year mean, respectively) (Fig. 1A). Based on the temporal analysis using daily pageviews, Google Trends (Google LLC), and a review of online news articles, the key triggering events that provoked these increases were cardiac arrest of the Danish footballer Christian Eriksen on June 12, 2021, during the Union of European Football Association Euro 2020 match and a cardiac arrest of the US American football player Damar Hamlin that occurred on January 2, 2023, during a National Football League Monday Night Football game. Both athletes received immediate help on the field and were successfully resuscitated. Because these matches were broadcast live on TV and watched by millions of people, the incidents acutely and significantly increased public demand for information on CPR. As shown in the Google Trends data on search traffic (Fig. 1B), people started to actively search CPR online. Subsequently, the search led them to the Wikipedia's CPR article. It is reasonable to assume that future incidents of cardiac arrest in famous people will induce new surges of interest in CPR and that people would continue to access Wikipedia to satisfy their information demand. However, the question remains as to what information is provided to the reader by Wikipedia’s article on CPR.

The CPR article is rated by Wikipedia as a B-class article (mostly complete and does not have major problems) and a high-importance medical article (less than 10% of medical articles achieve this rating). Excluding references, the article is 6,712 words and 389 sentences. According to the Flesch Reading Ease Score (a well-established instrument that quantifies the readability level based on the numbers of words, syllables, and sentences in a piece of text; the result is graded on a scale from 0 to 100, with lower scores indicating lower readability), the article has a readability of 45 points, meaning that more than 12 years of education are required to read and comprehend the material. The article contains an introduction and 15 sections: Medical uses, Pathophysiology, Methods, Use of devices, Effectivity rate, Consequences, Prevalence, Society and culture, History, On animals, Research, See also, References, Further reading, and External links. Based on the XTool (a suite of statistics tools for Wikipedia) data, the article has received a total of 3,030 edits from 1,398 editors and was edited for the first time more than two decades previously on July 31, 2002. The article’s average number of edits per month is 11.8, and the average time between edits is 2.6 days, indicating a very dynamic nature. As of January 2024, the article had 176 references, including 15 national and international guidelines and consensus documents; 14 of these documents were published in 2015 or before and nine in 2010 or earlier. Assessment of the article for quality of content on lay-rescuer adult basic life support using the ERC Research NET checklist [5] showed that the article contained incomplete coverage of the lifesaving procedure (Supplementary Table 1). Among the 53 evaluated checklist criteria, only 19 (35.8%) were completely satisfied, nine (17.0%) were partially satisfied, and 25 (47.2%) were not satisfied. In particular, important details on how to recognize cardiac arrest, how to perform chest compressions, and how to perform rescue breathing were omitted.

In summary, considering Wikipedia’s popularity and dominance in search engine results, this open encyclopedia might play an important role in the broad dissemination of information on CPR, consequently influencing people’s attitudes regarding bystander help and possibly their decisions on further resuscitation education. Annual readership of the English-language Wikipedia article on CPR exceeds half a million, and a significant number of people views the content to learn about CPR. Although acknowledging the aim of a comprehensive review of the topic, many and probably most people access the CPR article to obtain a brief and clear explanation of CPR and how to perform it. However, the article in its current form is inappropriate for the latter purpose. In addition, the article is long and the language is too sophisticated for people with lower literacy; besides that the article content does not ensure full coverage of basic lifesaving interventions in cardiac arrest. The article should be adapted for the lay public to receive the maximum benefit from its extensive readership.

To satisfy the public information demand, the article could start with an eye-catching featured section written in plain and accessible language that should focus on the importance of bystander response in cardiac arrest, explain key evidence-based principles of lay-rescuer intervention, and address common barriers to bystander CPR. An addition of short self-explanatory videos and external resources for self-education would also be useful. Because Wikipedia is a collaboratively edited encyclopedia that anyone with internet access can edit, the featured section should optimally be originally developed, periodically updated, and continuously supervised by experts familiar with the latest resuscitation guidelines. Because Wikipedia contains over 60 articles on CPR in languages other than English, active participation of national resuscitation councils in the assessment and optimization of the articles’ content is advisable.

Finally, more research is needed to better understand public online information-seeking behavior in relation to health emergencies and their management. In addition, the full potential of Wikipedia and other popular web resources as a tool to significantly enhance public awareness, knowledge, and attitudes pertaining to bystander assistance in health crises should be determined.