Karolinska Institutet

Assignment: save lives

Every year, about 900 people in Stockholm suffer cardiac arrests outside of hospitals. Only 90 survive. The most crucial factor for survival is immediate cardiopulmonary resuscitation (CPR). It’s also vital to use a defibrillator as soon as possible. For every minute the patient goes without treatment, chances of survival are reduced by a full 10 percent.

In 2010, the SMS-lifesaver was launched. It was born out of a research project carried out at Karolinska Institutet, examining the potential of surviving a cardiac arrest through the support of mobile technology.

“How can modern cellular-phone technology be used to increase the survival rate of cardiac arrest patients outside of a hospital?”

Emergency alarm

When a notification about a suspected cardiac arrest reaches 112 (the Swedish emergency alarm central), a text message is immediately sent to volunteers in the vicinity of the victim. The volunteers have all signed up to be involved with the SMS-lifesaver project and are all trained in CPR. Today, there are more than 13,000 volunteers in the project.

As of June 2015, there is also a smartphone app that provides the lifesavers with improved assistance and support. The service is also linked to the defibrillator register, a national registry covering defibrillators available outside of hospitals in Sweden. It is estimated that if a defibrillator is used within the first few minutes of a cardiac arrest, 70% of the patients will survive.

Daytona and the research team behind the SMS-lifesaver worked in close collaboration to create and design the best possible service.

What we did

Daytona was in charge of incorporating user needs into in the design and development of the lifesaver app. We also needed to ensure that all the content, functions and graphic design supported user needs before, during and after an emergency alarm. The main objective was to create an intuitive service that would provide clear and relevant information on how to get to the location of the suspected cardiac arrest during extremely stressful circumstances.

Interviews with lifesaver volunteers

To get a thorough understanding of both how the service worked out in the field and how it could be improved, in-depth interviews were conducted with lifesavers who had signed up to be involved with the service. It was vital to talk to both those who had actually responded to emergency alarms and to those who had not.

Charting the user process

The insights we gained from the interviews enabled us to chart the actual process. As we charted the user journey, we had a visual map of the key events linked to the whole lifesaving process – before, during and after an alarm. In addition to analyzing the app’s contents, we identified a number of channel-dependent insights that impacted communication, feedback and monitoring.

The design process

When it came to the design, the greatest challenge was to create a service that would make it crystal clear to the users exactly what had happened and exactly where they should go. The information would have to be displayed on a tiny screen with limited space. Add to this that the user would likely be in a state of high stress. As every second after a cardiac arrest can make a difference, it is crucial that the lifesaving volunteer gets to the emergency location as quickly as possible. There is no room for misunderstandings or a lack of clarity. Design is always important to us but here it can actually be the difference between life and death.

From sketch to prototype

During the design process, we needed to arrive at an interactive solution as quickly as possible. After sketching out the essential app functions and flow, we transformed the design work into a working prototype. The prototype not only served as the basis of discussions with the client and technical partners, but also functioned as an early-phase tool for collaborative design with the users.

Collaborating with the users

The user-centric perspective continued during the design phase and the prototype also functioned as a platform for user trials and collaborative design with end users. The trials led to further insights regarding features that required clarification and improvement. This subsequently resulted in new versions of the service that could then be tested and fine-tuned. And tested and fine-tuned.

Design principles

  • Scale down instead of augment

    A vital aspect of the design process was to identify and separate absolutely essential information from redundant information. Communication and functions were both trimmed down to a minimum.

  • Suitable speed

    When an alarm is issued, the user is required to take in a considerable amount of information: the assignment at hand, the location of the cardiac arrest and the location of the nearest defibrillator. Consequently, it was necessary to find a suitable speed for the information flow. To achieve this, we evaluated several different factors.

  • Simple framework

    Just as the app’s communication and functionality had to be scaled down, the visual framework also needed to be as simple and clear as possible, so as not to distract from the primary information. Unnecessary details were peeled away and care was taken to make the remaining components as easy to read as possible.

  • Testing in the right environment

    To gain an understanding of how the service actually worked within a relevant context, several trials were conducted with end users located around town. Test alarms were sent to the trial participants, who would then try to implement various assignments using the app. Following the trials, we interviewed the participants to identify areas of improvement.

  • Collaborative design x 2

    We designed the service in close collaboration with the client to ensure the compatibility of the solution with the research project and the client’s technical partner. We needed to guarantee d that the solution could and would be implemented practically.

Functions that make a difference

Volunteer ID

Based on the preliminary interviews with the lifesaving volunteers trained in CPR, we knew that there was a need to prove their legitimacy at the location of a cardiac arrest, so both next of kin and emergency personnel would allow them to perform the lifesaving actions. The solution was a special ID that could be displayed when needed.


The primary view displays a map as soon as an emergency alarm is issued. The map is clean and simple, and focuses entirely on the most essential information.

Test alarms

The alarm view is the most critical view of the app, but it is also the view that users will see the least as it’s only displayed when a cardiac arrest has occurred in the vicinity. As it is crucial that the volunteers will feel that they are prepared, willing and able to help in the event of an emergency, we developed an alarm simulation function. Furthermore, the app can be put in test mode, so that the lifesavers can personally practice and prepare for an actual alarm.

Click on the image to zoom.

SMS-lifesaver ID
Test alarm

Research project in the media

SVT News

The project received considerable attention from the media, including SVT: New app saves lives from heart failure and SMS-lifesavers increase the chance of survival.

New England Journal of Medicine

The research report was published in the New England Journal of Medicine and is available for reading here.

Honoree in category ”Best Use of GPS or Location Technology”

“Honorees like SMS Lifesavers are setting the standard for innovation and creativity on the Internet. It is an incredible achievement to be selected among the best from the nearly 13,000 entries we received this year.”

— David-Michel Davies, Executive Director, The Webby Awards