Duration after Malayan Pit Viper Bite to Detect Coagulopathy in Songklanagarind Hospital

Objective: The main objective was to determine the duration from the bite of a Malayan pit viper (MPV) until a prolonged clotting time in order to create a practice protocol for the Emergency Department (ED) of a university hospital in southern Thailand. The secondary objective was to know the incidence of adverse reactions from the MPV antivenom. Material and Methods: This was a retrospective descriptive study of patients with MPV bite from 1 January 2006 to 30 November 2017 in the ED at Songklanagarind Hospital. Results: The study included 153 patients. The average age was 45 years. The median elapsed time from bite to the ED was 40 minutes (interquartile range 30, 80). Fifty nine patients (38.6%) had coagulopathy. The median elapsed time from bite to coagulopathy was 5 hours 30 minutes (range, 40 minutes to 48 hours 40 minutes). Four patients (6.8%) had coagulopathy within the first 2 hours. Thirty patients (50.8%) had coagulopathy within the first 6 hours. Coagulopathy was detected in most of the patients (83.1%) within the first 24 hours. Fifty patients (84.8%) received antivenom. Four patients had immediate hypersensitivity reactions. Conclusion: The ED protocol should follow-up with a 20-minute whole blood clotting test at 6 hours after a bite to determine the appropriate disposition. If the patients do not have coagulopathy after 6 hours from snake bite, it is safe to follow-up at 24 hours, 48 hours and 72 hours after the bite. The incidence of antivenom hypersensitivity was low