Is antivenom treatment for Naja kaouthia bites always necessary in high care hospitals?

Objective: The monocellate or monocled cobra (Naja kaouthia) is commonly held in captivity by amateur herpetologists. It is responsible for most venomous exotic snakebites incidents in the Netherlands. It can induce (severe) local effects and post-synaptic neurotoxicity. In the Netherlands, antivenoms are kept on stock in the National Serum Depot. After successful treatment, including mechanical ventilation, of a severely envenomated patient for whom no antivenom was ordered, we questioned whether antivenom treatment is always necessary for Naja kaouthia bites, especially in high care hospitals. More specifically, what would be the reduction in duration of mechanical ventilation between patients treated with and without antivenom? Methods: Analysis of case reports and case series concerning Naja kaouthia bites treated with and without antivenom available in the English medical literature (Pubmed; search terms: Naja kaouthia bites, cobra bites, antivenom, respiration). Cases were included when data concerning the duration of mechanical ventilation were available. Also, three unpublished Dutch cases with sufficient data were included. Results: One case report and 4 case series involving 31 patients treated without antivenom and 21 patients with antivenom were retrieved. The mean time until intubation was 4.1 hours (range 2–7 hours) in patients treated without antivenom and 4.8 hours (range 2–10 hours) in patient treated with antivenom. The mean duration of intubation was 50 hours (range 44–72 hours) without antivenom and 13.6 hours (range 10–24 hours) with antivenom. Treatment with specific Naja kaouthia antivenom reduced the mechanical ventilation duration by approximately 1.5 days. Conclusion: Antivenom to treat (post-synaptic) neurotoxicity is life-saving when administered outside hospital and in areas with poor medical facilities. If high care facilities are available, it seems that post-synaptic neurotoxicity can be treated without antivenom. In clinically stable and mechanically ventilated patients, decisions about whether to administer antivenom can be based not only on risks of adverse reactions, but also on cost-benefit aspects. Antivenoms vary in price from < 100 Euro to >2500 Euro per vial and often many vials are necessary. These costs are not covered by health insurance, and paid by the hospitals. Alternatives for expensive antivenom treatment could be anticholinesterase following pre-treatment with atropine, which can hasten neurological improvement and thereby shorten ventilation duration and intensive care unit stay. The total hospital stay is mainly determined by severity of the local effects. The neutralising effect of specific Naja kaouthia antivenom on the severity of the local effects is not well investigated and remains questionable.