**1. Introduction**

Adequate preparedness efforts and proper contingency planning can mitigate and minimize the impact of major incidents and disasters (MID) in societies [1]. Contingency plans are the organized and coordinated courses of action that present institutional roles and resources, information processes, and operational arrangements based on scenarios of potential crises and hazard analyses [2]. Strategies for disaster managemen<sup>t</sup> include establishing command and control, reliable and efficient communication, information, organization, warning systems, stockpiling of resources, and response plans for the

mobilization and managemen<sup>t</sup> of resources such as personnel, equipment, volunteers, and emergency facilities. The efficiency of the organizational structure is paramount for the outcome of the event [3,4]. Disaster preparedness and contingency planning involve all actors in society. However, in particular, the healthcare sector is designated to respond in a planned and efficient manner to prevent mortality and morbidity, resulting from an increasing number of global and local threats, at the lowest possible cost to society [3–5].

The initial approach to proper managemen<sup>t</sup> of MID is to increase the managemen<sup>t</sup> system's capacity, i.e., Surge Capacity (SC). Three broad areas of healthcare demand SC in response to a MID [6]: Firstly, Public health Surge capacity (the ability of the public health system to increase capacity for patient care, epidemiological investigation, laboratory services, mass fatality management, etc.); secondly, Healthcare Facility-Based Surge Capacity (augments the response within the healthcare facility structure, e.g., triage-tent on hospital grounds); and finally, Community-based Surge Capacity (the public effort to support and augmen<sup>t</sup> the healthcare system). The four essential elements of SC, i.e., Staff, Stuff, Structure, and System (4S), should rapidly and effectively be surged in the affected areas. Staff refers to available/alternative personnel, Stuff refers to available/alternative equipment, Structures refer to hospitals, clinics and Alternate Care Facilities (ACF), and systems are procedures and guidelines that govern the emergency managemen<sup>t</sup> process [7,8].

The expansion of MID necessitates a new surge capacity (secondary SC), which underlines the need for increased effort to obtain additional resources still available within the managemen<sup>t</sup> system [9–11]. A further expansion of incidences demands new approaches, policies, and adjustable preparedness within the community to scale up and down resources in a quick and seamless manner, i.e., "flexible surge capacity" (FSC) [12]. The concept of FSC is concordant with the new paradigm of proactivity in disaster managemen<sup>t</sup> and emphasizes risk reduction rather than focusing on pure relief operations to reduce vulnerability and increase resilience within communities [13]. Therefore, risk assessment and focus on all four elements of SC is necessary for achieving a FSC. The disaster managemen<sup>t</sup> cycle should incorporate, recognize, and value the participation of affected communities [14], and it is therefore necessary that adequate infrastructure is in place to ensure access to emergency services [15]. In this perspective, the readiness of community-owned resources is essential and includes alternative facilities to take care of victims or to unburden hospitals [16–18].

Focus on all four elements of SC is necessary for achieving a FSC. Staff pools may be needed, and new staff categories should be considered to replace the regular staffing structure. Equipment and devices placed in different parts of a community should be registered and available for use. Buildings of opportunity, i.e., facilities with the capacity to hold a high number of people that can act as an ACF should be identified [4,6,18]. Finally, relevant systems and guidelines should be produced to link all these measures. The focus of this paper, however, is on ACFs at predesignated, strategic buildings. These untapped resources available within a community can be lifesaving and deserve recognition and support from all agencies within the emergency managemen<sup>t</sup> network [12,16]. A more comprehensive view of the Structure component of SC includes *buildings of opportunity* and *facilities of interest* that can be designated and converted to act as an ACF. Such buildings can consist of, but are not restricted to, outpatient clinics, dental and veterinary clinics, schools, hotels, convention centers, and sports facilities [6,10,12,17,18].

In the Swedish crisis and emergency managemen<sup>t</sup> system, the responsibility for crisis and disaster managemen<sup>t</sup> resides at national, regional, and local levels based on the principles of Responsibility, Parity, and Proximity [19]. According to these principles, all actors retain their responsibilities during MID managemen<sup>t</sup> while the methods and structures should be kept as similar as possible to those used in normal circumstances. The geographical responsibility to manage an event lies with those parties affected at the local level, i.e., close to the incident [19]. The Region Västra Götaland (VGR) in Sweden has about 1.6 million inhabitants in 49 municipalities in its 300 km long and 250 km wide area. VGR is responsible for healthcare, growth, and development within the region and is one of the largest employers in Sweden with over 50,000 employees. According to current legislation, the preparedness

of Swedish healthcare should be formed in close collaboration and cooperation between primary healthcare, hospitals, municipalities, county administrative boards (CAB), ambulance dispatch centers, and medical officers [19].
