The academic quality of the grey literature was very low, as the resources came from popular media, often representing opinions without reference to any standard or set of criteria. Several contributions gained face validity by being associated with health organizations by their creators, but only a few appeared to be endorsed by the organization (Disque Foundation, 2019; Eric Paredes Foundation, 2023; Grand Junction Fire Department, 2022; Singapore Heart Foundation, 2020). Most of the identified resources provided information on how to build the manikin but reporting generally lacked information on volume or dimensions. Many of the instructional videos included further explanations of how to practice CPR.

Based on the variety of measurement types, variables, and learning outcomes targeted in the existing studies on DIY devices, we realized that for future research to be consistent, we need to establish a common set of outcomes, outcome measures, and measurement tools. Based on agreed-upon measures, we would anticipate agreement on adequate measurement tools. Extremely precise measurements may not be necessary for studies that focus on other aspects of CPR education, such as readiness to act. All research should be informed by its related field (e.g., public health-survival, medicine-neurological impairment, sociology- motivation to help, education- health awareness).

We advocate for DIY device research to follow a Population, Intervention, Comparison, and Outcome (PICO) approach. Firstly, educational interventions should be clearly described in terms of duration, pedagogical approaches, and which CPR skills or behaviors are targeted. Second, intervention studies need to be rigorous and controlled, include pre-tests and ideally be randomized (e.g., if the goal of a study is to compare the effect of using DIY and commercial manikins, the didactic approach needs to be identical across intervention groups). Third, we recommend that anterior-posterior diameter, the force needed to compress the manikin by a certain depth, and the durability be reported. For potential comparisons and outcome measures in future studies, see Table 3.

With no industry standards for the design of CPR manikins, future designs may be based on emerging evidence. Organizations such as the American Red Cross specify required standards in terms of compression depth, lung volume, and feedback (American Red Cross, 2006) but do not specify required resistance or stiffness. Basic research on the attributes of the human body that affect the ideal provision of CPR needs to be conducted and used as a basis for design purposes.

The more people worldwide who can perform early CPR, the higher the survival rate and neurological outcomes of out-of-hospital-cardiac-arrest victims (Geri et al., 2017). A DIY device may provide better access to CPR education for people with barriers related to disability, cultural or linguistic factors, geographical location, or economic factors, as well as school-age children. Although various populations used or could use DIY devices, there is no population-based evidence. Qualitative research methods may provide insight into factors that determine expected learning outcomes in a population of interest, and how awareness and empowerment may best be achieved in each community, while quantitative research may describe the effects at the population level. Ethically, it is also important to initiate a discussion on whether the promotion of a DIY device for specific target groups might result in alienation.

Skill acquisition research may focus on aspects of the learning environment that generally help or hinder successful learning and transfer to real-life contexts. Neither DIY nor commercial devices can likely meet all of a learner’s needs (Van Raemdonck et al., 2014). We encourage research directed toward a fuller understanding of factors that motivate and facilitate CPR competencies in all laypeople (Pellegrino & Asselin, 2020) with the introduction of DIY devices.

This scoping review emphasizes the critical role of DIY manikin design features in understanding study outcomes. To enable appropriate interpretation of the findings and to facilitate informed decision-making by stakeholders, researchers must describe and justify the design of the DIY manikin utilized in their investigations, taking into account the learning objectives and target demographic of the intervention. The following considerations might be a useful tool in this process:

Physical Characteristics: If exact compression skills are an intended learning outcome, it is important to practice on a manikin with realistic stiffness and recoil ability for many repetitions. The exact requirements are not known, but Nysaether et al., (2008) reported that 500 N of force is needed to compress a human chest. Designs that use heavier materials such as plungers, springs, or high-quality foam could be more durable for extended use than lightweight PET bottles or toilet paper rolls (Wanner Osborne, & Greene, 2016). Wanner Osborne, & Greene’s (2016) device was modeled on the force needed (35.5 kg) to compress the CPR Anytime kit (AHA, Dallas, TX). This same force compressed their device to 46.6 mm. Mimicking the dampening effect of a human chest may be achieved by placing a pillow under the compression device. These factors are less important when the goal is simply to introduce a learner to the skill – indeed, for children or those with limited body mass, a DIY device that is easily compressed may even increase motivation.

Shape: The psychological fidelity of a simulation (i.e., the degree to which a simulation replicates the perceptual-cognitive demands of the real task (Gray, 2019) influences the effectiveness of a learning intervention (Harris et al., 2020). If a DIY compression device presents as non-humanoid (e.g., made from a towel folded into a square), it is much more difficult to link the device to a human chest, as the two do not look alike. Children especially may struggle to make analogical connections between concepts, as they have a lower ability for abstraction (Gentner & Hoyos, 2017). Similarly, the imitation of a human head and neck would also be advised, especially if the intended skills include airway opening and ventilation. Some suggestions found in the grey literature include using clothes pins for pinching the nose (Ypil, 2021) or plastic bags to represent a lung (Grupo Salvando Vidas, 2022; Masut, 2015). Furthermore, the option to modify or individualize a DIY device with gender or cultural characteristics might improve learning and retention (Moghimi et al., 2016).

Materials: Environmental sustainability can also be addressed when implementing DIY devices: most of the resources advocate for repurposing previously used materials. A wide range of materials allows flexibility between regions while reducing economic barriers. The most expensive option included a smartphone app which may not be accessible in lower-income communities.

Building Process: The time and complexity of constructing a device needs to be appropriate to the learner. Most of the DIY devices required fewer than four steps to build. To introduce CPR in a large group such as a school, an easy-to-build model may be preferred. The process of building the device may also lead to a better understanding of CPR physiology. For example, Barcala et al. (personal communications, 2023) had children build a device during science class, where they concurrently learned about blood flow and the brain.

Inclusion of Ventilation: A clear bias exists in the literature toward compression-only CPR; however, ventilation remains a valuable skill to address in developing a resuscitation system. DIY designs for ventilation practice should allow for ventilation up to 700–1000 ml of air in adult CPR manikins (American Red Cross, 2006) and offer the opportunity to practice manual airway opening maneuvers, see Szpilman (2019), Grupo Salvando Vidas (2022), or Masut (2013, 2015) as examples.

Provision of Feedback: The International Liaison Committee on Resuscitation included a weak recommendation for feedback on compression rate, depth, and hand position during CPR training (Greif et al., 2020). DIY design options for feedback include a jar lid that clicks (Ohle, Moskalyk, Boissonneault, Bilgasem, et al., 2021) and a tapping device (Masut, 2015). Augmentations for DIY devices, such as smartphone apps, may provide visual or auditory feedback (Chau et al., 2019; Lamboy & Donohue, 2015).

Gender Presentation: Racial, ethnic, and gender-related disparities exist in those who receive layperson CPR (Ok Ahn et al., 2023) and CPR education (Greif et al., 2020). A low-cost hack to simulate female breasts is a bisected foam football that can be placed inside a bra to promote comfort and skill (YMCA Aquatics, 2023). An interactive mat printed with a life-sized female figure may also reduce the stress of demonstrating skills on an actual female (Djajadiningrat et al., 2016). Further research is required to test augmentative tools in combination with DIY devices.

Augmentations: Several resources described low-cost augmentations that might further increase the effectiveness of compression devices. Arif et al. (2021) used a mobile app in combination with a pillow to practice compressions. Lamboy and Donohue (2015) showed that practice with a mobile app connected to a manikin provided a fuller CPR experience than without the app. Chau et al. (2019) reported that a wearable device for the wrist that collects objective feedback on compression depth and rate allows learners to share feedback with a trainer at a distance. Studies in which participants compressed a pillow while following a scenario in VR found that although the compression depth was inferior, the compression rate was non-inferior to that of manikin-trained learners (Nas et al., 2020). Combined with further development on DIY device efficacy, technology could render CPR education more accessible.