Management of thai cobra bites with a single bolus of antivenin

Between January 1981 and December 1991, 68 adults were treated at Chulalongkorn University for cobra bites. Respiratory failure developed in the bite victims even when an adequate genus-specific antivenin was administered at the onset of neuromuscular paralysis. The duration of time spent on a respirator was, however, significantly less in patients treated with an intravenous 100-ml antivenin bolus given at the onset of neurotoxic signs. We found that a bolus of 100 ml of purified equine antivenin produced by the Queen Saovabha Memorial Institute, Bangkok, from Naja kauthia venom was adequate and that increasing the dose did not lead to added benefits. Time spent on a respirator was approximately 10 h in antivenin-treated groups and 40 h if no antivenin or an inadequate dose was used. Competent respiratory and nursing care alone without antivenin will lead to eventual recovery and prevent death. Local bite site tissue necrosis and duration of hospitalization were not related to the dose of antivenin given. Hospitalization was prolonged in subjects who developed sepsis or who had severe tissue necrosis or other surgical or medical complications.