Dr Anke Sandra Barta1
Dr Anke Sandra Barta1, Prof Dr Simon Brown1
1Ambulance Tasmania
Biography:
Biographies to come
Abstract:
Background
Snake bites are rare but high-risk events. Antivenom must be administered as early as possible if symptoms of significant envenomation are present to prevent progression and complications. Patient transfer to hospitals which stock antivenom causes significant delays especially in remote areas. Tiger snakes are the most venomous snakes in Tasmania with all envenomated patients developing Venom-Induced Consumption Coagulopathy (VICC), neurotoxicity and myotoxicity alone or in combination. Ambulance Tasmania is one of the rare retrieval services in Australia which stocks TSAV at their rotary and fixed wing bases and uses an “Antivenom for Snakebites” guideline to administer TSAV prehospital based on clinical features and circumstances.
Case
We present the case of a patient who sustained a witnessed tiger snake bite in a remote location in Tasmania. The patient collapsed post bite and then developed Diaphoresis, Vomiting, Diarrhoea, Coagulopathy and Respiratory depression. The patient received first aid by a local crew until the helicopter arrived. The patient required drug assisted intubation and ventilation and was given TSAV at the scene. She had a prolonged 4-week hospital stay but was discharged without major long-term effects. Due to the remote location of the snake bite without phone reception and unconfirmed helicopter landing site this case also required complex team interactions and coordination between multiple agencies.
Conclusion
This case not only highlights the feasibility of prehospital antivenom administration using clinical gestalt to reduce time to antivenom for patients in remote areas but also show casts the complex interactions and teamwork required between multiple agencies to make such a remote mission a success.
Aim
To assess our THS “Antivenom for Snakebites guideline for identification of snake envenomation prior to formal blood testing to enable prehospital administration of tiger snake antivenom (TSAV) early in the clinical course
Methods
We audited 27 suspected snake bite cases treated by the Critical Care and Retrieval team of Ambulance Tasmania (CCR-AT) within the last 6-years. Our guideline recommended on-scene administration of TSAV for witnessed snake bite plus one or more of collapse, seizure, cardiac arrest, paralysis, ptosis, ophthalmoplegia, vomiting, headache, abdominal pain and/or diarrhoea. If a bite was not witnessed but considered highly likely on the basis of symptoms and circumstances, clinical judgement by a senior clinician was permitted regarding the use of prehospital TSAV.
Results
Formal blood testing in hospital confirmed 10 envenomated patients. Of these, 8 patients met criteria for prehospital TSAV (Sensitivity 80%) while one patient remained asymptomatic and another patient did not witness the snake bite. Only one out of 17 patients in the non-envenomated group met criteria for TSAV (Specificity of 94%). A total of 10 patients received TSAV prehospital as per guideline: 7 (envenomated) patients met full guideline criteria, while 3 (non-envenomated) patients received TSAV according to clinical judgement. One envenomated patient suffered a life-threatening anaphylactic reaction to TSAV and required an adrenaline infusion while two other envenomated patients required drug-facilitated intubation and ventilation for respiratory failure in remote locations. Unfortunately, one of the intubated patients later died.
Conclusions
Our guideline provides reasonable diagnostic sensitivity and specificity for TSAV administration prior to hospital transfer and formal blood testing. TSAV administration can be safely performed in the prehospital setting by a medical team.