What dose of anti-snake venom should be given in severe neuroparalytic snake bite?

Clinical profile & complications of neurotoxic snake bite & comparison of two regimens of polyvalent anti-snake venom in its treatment

Background & objectives:

The optimal anti-snake venom (ASV) dose required to treat neurotoxic snake envenomation is not known. Low-dose ASV (national protocol: maximum dose 200 ml) may be as efficacious as the conventional regimen (100 ml six hourly till all symptoms disappear), but a direct comparison of the regimens is not available. The aim of this study was to test the efficacy of low-dose ASV regimen against the conventional high-dose regimen.

Methods:

The clinical profile of 51 patients with neurotoxic snake envenomation was studied. Patients were treated with either the national protocol or the conventional protocol for ASV administration. The time to complete recovery of symptoms, duration of mechanical ventilation and total dose of ASV were compared.

Results:

More patients were females (28 vs. 23) bitten in the early morning hours (2400-0600 h). Thirty nine of 51 (76.4%) patients required mechanical ventilation. In terms of progression of neuroparalysis, time to complete resolution of ptosis and occurrence of VAP and ASV reactions, there was no difference. Duration of mechanical ventilation was less with the national protocol (24 vs. 43.5 h). Significantly less amount of ASV was used with the national protocol (224 vs. 982 ml) per patient. There were no mortality or permanent neurological sequelae with either regimen.

Interpretation & conclusions:

In this preliminary study, it was found that the national ASV protocol was as effective as the conventional regimen for neurotoxic snake bites. However, the findings need to be tested in a larger randomized controlled trial for definitive conclusions.