JMIR Publications

ABSTRACT

Background:

Local anesthetics (LA) are regularly used to alleviate pain during medical or surgical procedures. Their use is generally considered safe but exceeding maximum recommended doses can lead to LA systemic toxicity, a rare but potentially lethal complication. Determining maximum safe doses is therefore mandatory prior to performing local anesthesia, but rules are often unclear and the factors affecting dose calculation are numerous. Mobile health apps have been shown to help clinical decision making, but most currently available apps present significant limitations. The LoAD Calc (Local Anesthetics Dose Calculator) app was designed to overcome these limitations by taking all relevant parameters into account. Before deploying this app in a clinical setting, it should be tested to determine its effectiveness and whether clinicians would be willing to use it on a regular basis.

Objective:

The primary objective will be to evaluate the effectiveness of the LoAD Calc app through written simulated cases. The secondary objective will be to determine whether physicians find this app easier, faster and safer than the methods they generally use.

Methods:

This protocol describes a parallel group randomized controlled trial (RCT). Anesthesiologists working at the Geneva University Hospitals will be invited to participate. Participants will be asked to compute the maximum dose of LA in 10 simulated clinical cases, using 3 different LA. The maximum safe dose will be determined manually using the same calculation rules which were used to develop LoAD Calc, without using the app itself. An overdose will be considered as any dose higher than the correct dose rounded to the superior integer while an under-dose will be defined as the optimal calculated dose minus 20%, rounded to the inferior integer. Randomization will be stratified according to current position (resident vs registrar). The participants allocated to the LoAD Calc (experimental) group will use the LoAD Calc app to compute maximum safe LA doses. Those allocated to the control group will be asked to use the method they generally use. The primary outcome will be the overall overdose rate. Secondary outcomes will include the overdose rate according to ideal and actual body weight and to each specific LA, the overall under-dose rate, and the time taken to complete these calculations. The app usability will also be assessed.

Results:

The regional ethics committee issued a “declaration of no objection” (CCER 2022-01577). A sample size of 46 participants will be needed to detect a difference of 10% with a power of 90%. Thus, a target of 50 participants was set to allow for attrition and exclusion criteria.

Conclusions:

This study should determine whether LoAD Calc, a mobile health app designed to compute maximum safe LA doses, is safer and more efficient than traditional LA calculation methods.