VipGrade^® electronic clinical tool: retrospective evaluation on a paediatric cohort of European viper bites

The VipGrade^® is a French electronic clinical tool that was created in 2022 to help frontline clinicians grade envenomations due to European Vipera spp. and decide whether to use specific immunotherapy. The aim of this study was to test VipGrade^® on a paediatric retrospective cohort (2001-2022) of cases of Vipera spp. envenomation and evaluate the concordance with the initial grading assigned by clinicians on admission.

For each child in the cohort (n = 116), VipGrade^® was applied by a single physician unaware of the initial clinical grading. We compared VipGrade^® results with those obtained at the time of admission using the Audebert-Boels classification system.

The proportion of discrepancies represented 26% of initial grade I (n = 39) cases, meaning that 10 children were upgraded to grade IIa (n = 9) or IIb (n = 1). The main reason was the VipGrade^® cut-off for oedema size (4 cm) to distinguish grade I from grade II, while oedema evaluation using the Audebert-Boels clinical classification differs in this regard. The global correlation κ score was equal to 0.78; 0.71 with the exception of grades 0 (which is not usually a diagnostic issue); 0.64 considering both results for young children (age <6 years, n = 51) and 0.79 for older ones.

Upgrading cases inappropriately could have a major impact on treatment and the use of the antivenom. Even if specific immunotherapy with Viperfav^® (MicroPharm Ltd, Newcastle Emlyn, Carmarthenshire, SA38 9BY, United Kingdom) is safe, its use when inappropriate cannot be justified, particularly in times of supply shortage, as we have experienced over the last 10 years.

The current version of the VipGrade^® electronic clinical tool produces a different distribution of envenomation grades, notably in grade I by overgrading a substantial number of cases. We suggest creating a paediatric version that incorporates the same oedema evaluation method as the Audebert-Boels clinical classification but also includes a more refined definition of "local or regional" oedema.