Cryotherapy as a coadjuvant in crotaline snakebite management with F(ab’)2 antivenom: A randomized pilot study

•Short-term local cryotherapy of the limb affected by a snakebite is safe in patients with grade II envenomation.•Local cryotherapy used as a coadjuvant in the management of snakebite significantly reduces the length of hospitalization.•The number of doses of antivenom is significantly reduced when cryotherapy is used in patients with grade II snakebites. Local cryotherapy induces vasoconstriction, which leads to a reduction in the inflammatory process. However, the effectiveness of local cryotherapy as a coadjuvant in the treatment of snakebite with F(ab’)2 antivenom is unknown. To describe the clinical effectiveness of local cryotherapy as a coadjuvant in patients with snakebite treated with F(ab’)2 antivenom therapy at the Hospital Juárez de Mexico. Patients with grade II snakebite envenomation according to the Christopher-Rodning classification system were enrolled from the Clinical Toxicology Service of the Hospital Juárez de México. One group of patients received F(ab’)2 antivenom therapy (Antivipmyn®) plus local cryotherapy, and the other group received only F(ab’)2 antivenom therapy. Thirty-eight patients were included, of whom 86.8 % were male (n = 33). Approximately 81.5 % of the subjects were injured in an upper extremity, while 18.5 % were injured in a lower extremities; 47.3 % of the subjects reported treatment of the snakebite prior to hospitalization (suction, the application of a tourniquet, incision of the bite site, or the application of traditional medicine). No differences were found concerning edema, swelling, and pain between the groups. The group that received local cryotherapy as a coadjuvant to F(ab’)2 antivenom therapy had a shorter hospital stay (Cohen's d = 1.33; 95 % confidence interval [95 % CI] = 0.74–1.62; p < 0.01) and received fewer doses of F(ab’)2 antivenom therapy (Cohen's d = 0.69; 95 % CI = 0.19–3.80; p = 0.03). The use of adequate local cryotherapy as a coadjuvant to F(ab’)2 antivenom therapy reduces the length of hospital stay and the number of doses of F(ab’)2 antivenom therapy used.