Introduction

Background

The emergency management of terrorist attacks has been one of the prominent topics in disaster and emergency medicine before the SARS-CoV-2 pandemic. The most recent attacks have shown that this particular threat is still present and highly relevant today [1,2,3,4]. The idea of “stopping the dying as well as the killing”, which has been coined by Park et al. after the London Bridge and Borough Market attacks in 2017, emphasizes the urgent need to focus on emergency management and early medical and surgical intervention [5].

Rescue systems and hospitals must prepare themselves to manage terrorist attacks in order to save as many lives as possible and to return rescue forces from the missions unscathed. As it is impossible to conduct prospective, high-quality scientific studies, the definition of these medical and tactical strategies relies on the analysis of real incidents and the lessons learned derived from them. After the Paris terror attacks in 2015 for example, important publications, describing the events of the night of the 13th of November 2015, were published [6, 7]. Two publications, one by the French Health Ministry and one by Carli et al., about the “Parisian night of terror” have gone a step further and have clearly described the lessons learned from these attacks [8, 9]. Importantly, experts agree on the importance of the scientific and systematic evaluation of the most recent terror attacks [10]. Challen et al. proved the existence of a large body of literature on the topic in 2012 already, but questioned its validity and generalisability. The authors based their conclusion on a review, which focused on emergency planning for any kind of disaster [11].

More than ever, the principle applies, that the preparation for extraordinary disastrous incidents is the decisive prerequisite for successful management. The lack of preparedness for the SARS-CoV-2 pandemic has taught modern society this lesson.

With the aim to identify and systematically report the lessons learned from terrorist attacks as an important basis for preparation, we conducted the presented systematic review of the literature.

Materials and methods

Study design and search strategy

This is a systematic review of the literature with the focus on lessons learned from terror attacks. A comprehensive literature search was performed to identify articles reporting medical and surgical management of terrorist attacks and lessons learned derived from them. PubMed was used as database. The first search term concentrated on terrorism, the second on medical/surgical management and the third on evaluation and lessons learned. Adapted PRISMA guidelines were used and all articles were checked and reported against its checklist [12].

The search terms were formulated as an advanced search in PubMed in the following way: Search: ((Terror* OR Terror* Attack* OR Terrorism* OR Mass Casult* Incident* OR Mass Shooting* OR Suicide Attack* OR Suicide Bomb* OR Rampage* OR Amok*) AND (Prehospital* Care* OR Emergenc* Medical* Service* OR Emergenc* Service* OR Emergenc* Care* OR Rescue Mission* OR Triage* OR Disaster* Management* OR First* Respon*)) AND (Lesson* Learn* OR Quality Indicator* OR Evaluation* OR Analysis* OR Review* OR Report* OR Deficit* OR Problem*).

Eligibility criteria and study selection

Time frame: The attack on the World Trade Centre in New York, the Pentagon in Arlington, and the crash of a hijacked airliner in 2001 is considered the event that brought international terrorism onto the world stage with the beginning of the new millennium. The attacks have been documented and analysed in great detail. For this reason, this analysis starts in 2001 and ends with the terrorist attacks in London and Manchester in 2017. The search history was extended to the year 2018.

Included countries: Terrorism is a worldwide phenomenon. Attempting to evaluate the data of all terrorist attacks that have occurred since 2001 seems impossible due to the extremely high number. The work therefore focuses mainly on Western-oriented democracies, for which a terrorist attack is still a relatively rare event and whose infrastructure and emergency services recently had to adapt to this challenge. The Organization for Economic Cooperation and Development (OECD)—countries therefore represent a reasonable selection of countries for this study.

Exclusion criteria:

  1. 1.

    Articles reporting mass casualty incidents without a terroristic background

  2. 2.

    Personal reports without any clear defined lessons learned

  3. 3.

    Articles dealing exclusively with chemical, biological, radiological and nuclear (CBRN) terrorism

  4. 4.

    Articles dealing with a narrow point of view and only dealing with specific types of injuries such as burns or psychiatry

  5. 5.

    Articles not written in English.

Articles dealing exclusively with chemical, biological, radiological and nuclear terrorism (CBRN-attacks) were excluded from the literature-search. The reason for this is the large number of special problems and issues associated with this type of incident. To address this adequately, a separate literature search would be necessary.

Data abstraction

The lessons learned from each included article were extracted according to the inclusion and exclusion criteria. Duplicated data was excluded. As expected, there was a vast number of individual lessons learned. To summarize the results, it was imperative to divide them into categories. As a basis for developing the categories existing systems were used. The reporting system of Fattah et al. defines 6 categories, but these were not sufficient to represent all types of lessons learned [13]. Wurmb et al. had recently developed 13 clusters of quality indicators [14], some of which we were able to adopt. However, both systems focused on categories that serve to describe the overall setting of a rescue mission and were therefore not fully suitable for clustering lessons learned. Finally these 15 categories were used for clustering the lessons learned:

  • Preparedness/planning/training

  • Tactics/organisation/logistics

  • Medical treatment and Injuries

  • Equipment and supplies

  • Staffing

  • Command

  • Communication

  • Zoning and safety scene

  • Triage

  • Patient flow and distribution

  • Team spirit

  • Role Understanding

  • Cooperation and multidisciplinary approach

  • Psychiatric support

  • Record keeping

After defining the categories, the lessons learned were assigned to them. Where applicable, the lessons learned were divided into “pre-incident”, “during incident” and “post-incident” within the different categories.

Results

The extended PubMed Search yielded 1635 articles out of which 1434 articles were excluded on title selection only. The abstracts of the remaining 201 articles were evaluated and finally 68 articles were included in the analysis (Fig. 1).

Fig. 1
figure 1

Process to identify the articles included in the systematic review

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To evaluate the quality of the included studies, the PRISMA evaluation was used and all articles were checked and reported against its checklist and then rated as either high quality (HQ), acceptable quality (AQ) or low quality (LQ) paper (Table 1) [12].

Table 1 Overview of all included articles with PRISMA evaluation
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A total of 616 lessons learned were assigned to the 15 categories. If a lesson matched more than one category, it was assigned to all matching categories. Therefore, multiple entries occur in some cases. Table 2 shows the distribution of categories across all included articles, while Fig. 2 shows the number of articles in which each category appears. In this figure, the publications are assigned to the respective categories. This provides an overview of the number of articles dealing with each category. An overview of the distribution over time is later given in Fig. 3. Lessons learned within the category “tactics/organisation/logistics” were mentioned most frequently, while the category “team spirit” was ranked last in this list.

Table 2 Distribution of the 15 clusters across all included articles
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Fig. 2
figure 2

Number of articles mentioning each of the 15 categories

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Fig. 3
figure 3

Categories of lessons learned from terror attacks—development since 2001

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To obtain a graphical overview over the entire study period, the frequency with which the categories were mentioned per year were colour-coded and presented in a matrix (Fig. 3).

A summary of all lessons learned assigned to the 15 categories can be found in Table 3.

Table 3 lessons learned assigned to the 15 overwhelming categories
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Discussion

This systematic review is the first of its kind to review the vast amount of literature dealing with lessons learned from terror attacks. It thus contributes to a better understanding of the consequences of terror attacks since 2001. It also brings order to the multitude of defined lessons learned and allows for an overview of all the important findings.

Our data has shown that, despite the difference in attacks, countries, social and political systems and casualties involved, many of the lessons learned and issues identified are similar. Important to note was the fact that time of article release did not relate to content. Many articles written after the London attacks in 2005 formulated similar if not the same lessons learned as articles written in 2017 about Utoya [36, 52]. This is a major point of concern as it indicates, that despite the knowledge about the issues and the existence of already developed, excellent concepts [56, 79, 80], their successful implementation and continuous improvements seem to be lacking.

One of these well-developed concepts, the Tactical Combat Casualty Care (TCCC), began as a special operations medical research programme in 1996 and is now an integral part of the US Army's trauma care [79]. The Committee on TCCC, which was established in 2001, ensures that the TCCC guidelines are regularly updated [79]. Many of the lessons learned listed in our review are an integral part of these guidelines and are addressed with concrete options for action. For Example, the principles of Tactical Evacuation Care provide detailed instructions on the management of casualties under the special conditions of evacuation from a danger zone [81]. Moreover, the lack of knowledge on how to deal with injuries caused by firearms or explosive devices, which was mentioned in many articles, could be remedied by a consistent integration of the TCCC guidelines into the training and drills of emergency service staff.

Another concept that deals with the management of terrorist attacks and mass shootings is the Medical Disaster Preparedness Concept “THREAT”, which was published after the Hartford Consensus Conference in 2013 [56]. The authors defined seven deficits as lessons learned and recommended concrete measures to address them. These lessons were included in our review and were mentioned in one form or the other in many of the articles. The defined THREAT concept components were:

  • T: Threat suppression

  • H: Haemorrhage control

  • RE: Rapid extraction to safety

  • A: Assessment by medical providers

  • T: Transport to definitive care.

Consistent implementation of these points in training and practice would be an important step towards improving preparation for terror attacks.

A good example of the successful implementation of an interprofessional concept is the 3 Echo concept (Enter, Evaluate, Evacuate) [80]. It was developed and introduced with the goal to optimize the management of mass shooting incidents. At the beginning of concept development stood the identification of deficits. Those deficits correspond to those that we found in the presented systematic review. The introduction of the concept in training and practice has led to successful management of a mass shooting event in Minneapolis, Minnesota, USA in 2012 [80]. This outlines once again the importance of translating lessons learned into concrete concepts, to integrate them into the training and to practice them regularly in interprofessional drills. Just as the 3 Echo concept is based on interprofessional cooperation, the Joint Emergency Services Interoperability Principles (JESIP) project is also based on this principle [82]. It is the standard in Great Britain for the interprofessional cooperation of emergency services in major emergencies or disasters. Through simple instructions and a clear concept, both the aspect of planning and preparation as well as the concrete management of operations are taken care of [82].

In interpreting the lessons learned in this systematic review, the question arises whether they are specific to terrorist attacks. Our review deals exclusively with lessons learned from terrorist attacks. Other publications, however, systematically addressed the management of terrorist and non-terrorist mass shootings and disasters. Turner et al. reported the results of a systematic review of the literature on prehospital management of mass casualty civilian shootings [83]. The authors identified the need for integration of tactical emergency medical services, improved cross-service education on effective haemorrhage control, the need for early and effective triage by senior clinicians and the need for regular mass casualty incident simulations [83] as key topics. Those correspond congruently with the lessons learned from terrorist attacks that were found and presented in this systematic review.

Hugelius et al. performed a review study and identified five challenges when managing mass casualty incidents or disaster situations [84]. These were “to identify the situation and deal with uncertainty”, “to balance the mismatch between contingency plan and reality”, “to establish functional crisis organisation”, “to adapt the medical response to actual and overall situation” and “to ensure a resilient response” [84]. The authors included 20 articles, of which 5 articles dealt with terror and mass shooting (including the terror attacks in Paris and Utoya). Although only 25% of the included articles dealt with terrorist attacks, the lessons learned are again very comparable to the results of this systematic review.

Challen et al. published the results from a scoping review in 2012 [11]. The authors stated that “although a large body of literature exists, its validity and generalisability is unclear” [11]. They concluded that the type and structure of evidence that would be of most value for emergency planners and policymakers has yet to be identified. If trying to summarise the development since that statement it can be assumed that on one hand sound concepts have been developed and implemented. On the other hand however, the lessons learned in recent terror attacks still emphasize similar issues as compared to those from the beginning of the analysis in 2001, showing that there is still work to be done. It should be mentioned at this point, that there was a federal conducted evaluation process in Germany after the European terror attacks in 2015/2016. The lessons learned were published in 2020 by Wurmb et al. and were very comparable to those of this systematic review [85]. Furthermore the terror and disaster surgical care (TDSC®) course was developed in 2017 by the Deployment, Disaster, Tactical Surgery Working Group of the German Trauma Society to enhance the preparation of hospitals to manage mass casualty incidents related to terror attacks [86]. Finally it is important to mention, that hospitals and rescue systems must prepare not only for terrorist attacks, but also for a wide spectrum of disasters. Ultimately, this is the key to increased resilience and successful mission management.

Limitations

This systematic review has several limitations. Due to the vast amount of information only PubMed was used as a source. From the authors' point of view, this is a formal disadvantage, but it does not change the significance of the study as in contrast to the question of therapy effectiveness or the comparison of two forms of therapy, the aim here is to systematically present lessons learned. To get even more information, the data search could have been extended to other databases (e.g. Cochrane Library, Web of science) and the grey literature. Given the number of included articles, it is questionable whether this would have significantly changed the central message of the study. It is even possible that this would have made a systematic presentation and discussion even more difficult. CBRN attacks have been excluded from the research. The reason for that was that many special aspects have to be taken into account in these attacks. Nevertheless CBRN attacks are an important topic, which would need further exploration in the future. The restriction to OECD countries certainly causes a special view on the lessons learned and is thus also a source of bias. However, the aim was to look specifically at countries where terror attacks are a rather rare event and rescue forces and hospitals are often unfamiliar with managing these challenges. Special injury patterns associated with terror attacks were not considered. This reduces the overall spectrum of included articles, but from the authors' point of view, a consideration of these would have exceeded the scope of this review.

Conclusion

The first thing that stands out is that most lessons learned followed a certain pattern which repeated itself over the entire time frame considered in the systematic review. It can be assumed that in many cases it is therefore less a matter of lessons learned than of lessons identified. Although sound concepts exist, they do not seem to be sufficiently implemented in training and practice. This clearly shows that the improvement process has not yet been completed and a great deal of work still needs to be done. The important practical consequence is to implement the lessons identified in training and preparation. This is mandatory to save as many victims of terrorist attacks as possible, to protect rescue forces from harm and to prepare hospitals and public health at the best possible level.