“It was just a big shock. I’ve lived [in Victoria's eastern Gippsland area] all my life and have only ever heard of one girl getting chased by a snake years ago.” Yet it was not the only death from a tiger snake in Victoria over that spring and summer of 2014 and 2015. Two months later, on an extremely hot January night, a noise like something thudding to the floor was heard in the bedroom of a couple living in Melton, a suburb on the western fringe of Melbourne. Soon after, the man woke to the sound of his partner gurgling, and a live tiger snake sitting in the doorway. The 70-year-old woman appeared to have three double-fang bite marks on her left big toe.

The venom of the Australian tiger snake has been known to kill humans. Credit:Jason South Is one dose of antivenom enough? Doctors were unable to save either snakebite victim, and now years later, two coronial investigations into the deaths have exposed controversy over exactly how much antivenom people should receive. Influential advice published in The Medical Journal of Australia based on research from the Australian Snakebite Project says that one vial of antivenom should be sufficient for all snakebites, as a single vial is designed to neutralise all the venom one snake can produce. But this has been disputed by some experts, who in their evidence to the coroner said multiple doses could be needed, especially in more severe bites.

Guidelines “dangerous” and “clinically unwise” Shane Tatti was initially given just one vial of tiger snake antivenom after he was rushed to Orbost Hospital in Victoria’s Gippsland region on November 6, 2014. Despite their concerns, doctors in Melbourne also held off providing more, on the advice of a toxicologist. Yet the court was told that at 3am on the day Mr Tatti died, the toxicologist agreed there was little to be lost from giving him one more dose of antivenom, as he was likely to die anyway. Intensive care consultant Dr Sam Radford said the toxicologist acknowledged to him that while one dose of tiger snake antivenom was supported by research as being no better than repeated doses, it “was an area of considerable debate”.

Shane Tatti was a keen hunter and fisher. His mother said he was always making people laugh. Testing would later reveal Mr Tatti still had active venom in his body after he died. And that finding led Associate Professor Mark Little, a clinical toxicologist at Cairns Hospital, to conclude he had not received enough antivenom. “Whilst it is likely that for many patients envenomed [poisoned] by a snake in Australia, one ampoule may be enough, this case would suggest that a higher initial dose (possibly two ampoules) might be required for tiger snake envenomings,” he said. Another hospital toxicologist, Professor Julian White, dubbed the guidelines recommending just one vial of antivenom to be “dangerous” and “clinically unwise”. He called for them to be “disavowed”.

The case of “Mrs Z” There was less criticism of the medical care of Mrs Z, the Melton victim, who was not named by the court. She was bitten while sleeping in her bed in the converted garage she had called home for 28 years, early on January 3, 2015. After being taken to the Royal Melbourne Hospital, the 70-year-old woman received two vials of antivenom about three hours after the initial bites, and a third vial as she continued to deteriorate. She died the following afternoon after going into cardiac arrest.

Conflicting advice However, the investigation into her death was also confused by conflicting evidence about what dose of antivenom would have been most appropriate. That concerned Coroner Caitlin English, who has called twice on the Victorian Health Department to review the state’s snakebite clinical guidelines, saying they do not acknowledge that there might be circumstances in which more than one ampoule of antivenom might be needed.

Yet in a meeting in October this year, the government’s expert group agreed it would not alter the guidelines, arguing that specific advice on the number of ampoules to be administered for severe bites was best given by clinical toxicologists. The group warned that giving more antivenom than was needed could result in anaphylaxis. Loading Meanwhile, in NSW, snakebite guidelines published online recommend that only one vial of snake antivenom is required to treat both children and adults, and that further antivenom will not speed up the process of recovery. Professor Geoff Isbister, a toxicologist who sits on the Victorian expert group and is an author of the controversial Medical Journal of Australia snakebite advice, said that in the case of Mr Tatti, it was unlikely the small amount of remaining venom in his body was the source of his severe deterioration.

Instead, he said the more likely explanation was that the damage occurred before the initial dose if antivenom was administered, as the huge venom load quickly spread through his body. Professor Isbister said while there needed to be consideration of larger doses of antivenom for severe cases, it was currently impossible to establish which patients had received extreme amounts of venom and which hadn't. He called for more research into the issue, an appeal echoed by the Victorian coroner. Mr Tatti's mother, Susan, said though she was satisfied with the coroner's findings, the death of her son had left a huge hole in her life. “He was so funny. He would put all these different wigs on and the hats,” she said.