Sydney - An Australian nurse has spoken about how he survived a bite from one of the world's deadliest snakes by using medical training to instruct his rescuers as he passed in and out of consciousness.Christian Wright, 33, was bitten on his foot by a brown snake at the bottom of a gorge in a remote part of Karijini National Park some 1 400 kilometres north of Perth in Western Australia last month."I looked at my foot, there was no puncture marks. No blood, no swelling, no nothing," Wright told commercial broadcaster Channel Seven on Saturday."I started losing my vision. I knew I was going to pass out."The hospital midwife shouted to his friend Alex Chia, who caught him as he passed out."His eyes were rolling back in his head, he was shaking and sweating, and then he went totally limp and heavy," Chia told The West Australian newspaper."We were down a deep gorge, 30 metres tall, there was no one in sight. The hardest part was being in front of his lifeless body."A nearby Austrian couple heard their cries for help and called emergency services with their satellite phone as they tended to Wright's leg using his own instructions."I was just coming and going. I started getting really agitated as the neurotoxins started getting to my head, I was writhing all over the place and yelling out from the pain in my head," Wright told The West Australian.A ranger was the first to arrive at the scene, followed by paramedics and other rescuers.But Wright's ordeal was not yet over, with the ranger having to enlist the help of 20 nearby tourists to carry the nurse out of the challenging terrain on a stretcher while keeping his head above his legs.It took more than an hour to carry him to an ambulance before he was driven to a hospital some 75 kilometres away and given anti-venom to counter the poison.Brown snakes, whose bite is often painless, are known as nervous reptiles that strike with little hesitation.Deaths from bites are rare despite Australia being home to 20 of the world's 25 most venomous snakes.According to official estimates there are about 3 000 snakebite cases in Australia every year, with 300-500 needing anti-venom treatment. Only an average of two a year prove fatal.