Development and validation of LoAD Calc, a mobile app for calculating the maximum safe single dose of local anesthetics (Preprint)
Authors: Suppan Mélanie , Beckmann Tal S. , Gercekci Cenan , Sigrist Thérèse , Savoldelli Georges L. , Fournier Roxane , Samer Caroline 
Published: December 2020

BACKGROUND

Misuse of local anesthetics (LAs) can lead to life-threatening situations. Intravascular injection and administration of an inappropriately large dose are two of the most frequent reasons leading to systemic toxicity. Correct calculation of the maximum safe dose of LAs is therefore paramount in preventing such complications. Calculation can however turn out to be a real conundrum when considering all potentially relevant variables. Lack of specific literature and clear standards further complexifies this task. Moreover, doses used in clinical practice are often determined without prior calculation of the ideal body weight or adaptation to specific health conditions.
Different solutions have already emerged to support anesthesiologists in LA dosage determination. They are seldom used in clinical practice as they require either access to a computer or specific documents to be at hand.
Nowadays, most anesthesiologists are equipped with smartphone at work. A mobile app could therefore be an easy and practical solution for computing the maximum safe dose of LA. The few apps already created for this purpose often lack key elements, allowing invalid data to be entered and suggesting doses that might exceed the maximum safe dose. They mainly give the user general advice on how the computed dose should be further adapted or simply state that it should be used with caution.

OBJECTIVE

Our aim was to design an mHealth app for the calculation of the maximum safe single dose of LAs.

METHODS

A modified version of the Information Systems Research (ISR) framework, which adds design thinking modes to the original framework, was used to define and describe the development process. Using this modified framework, we aimed to design an mHealth app intended to be used by anesthesiologists. The app was enhanced through multiple iterations and developed with the aid of contextual observations and interviews, brainswarming sessions, prototyping and continuous feedback.

RESULTS

The modified ISR framework led us to engage with end-users and identify their needs at each step of the development. A review of the literature was performed to gather the scientific evidence regarding LA dose calculation. A search for already existing solutions allowed us to identify key features to embed or improve in our app. The design process led to the creation of two prototypes which underwent thorough testing by a sample of 8 anesthesiologists. Continuous feedback allowed for rapid identification and correction of problems and led to constant adaptation of the design. The final version of the app, LoAD Calc, was deployed on Apple and Android mobile test platforms and tested again by the same sample until deemed fit for release.

CONCLUSIONS

LoAD Calc, an mHealth app designed to allow easy, fast and safe computation of the maximum single dose of LAs, was successfully created using the modified ISR framework.