Pre-hospital treatment of snake envenomation
Spencer Greene, MD, MS, FACEP, FACMT, FAACT, FAAEM 16 July 2021
EMS personnel bravely enter scenes fraught with unknown challenges, and they initiate lifesaving treatment in often austere environments. Naturally, they would want to do the same for snakebite victims. Unfortunately, many of the interventions that have been recommended previously have proven to be useless and possibly dangerous. Sometimes, the best treatment is nothing more than safe, timely transportation to the hospital.
"Cutting +/- sucking": You won’t remove any venom. You’ll just convert an envenomation to a wound, and if you actually use your mouth, you’ll introduce bacteria into something which is otherwise rarely associated with infection.
Tourniquets and pressure bandages: When it comes to our native crotalids, you want to AVOID any technique that attempts to confine the venom in the affected extremity, including a tourniquet, a lymphatic constriction band, and pressure immobilization (PI).
A tourniquet is great when you want to stop life-threatening bleeding, but you don’t want to cut off the arterial blood supply to a bitten extremity. Although lymphatic constriction bands and PI don’t interrupt the blood supply, they do confine the venom to the affected extremity, which, particularly when combined with the increased swelling, increases local tissue injury. Because local injury is seen in > 95% of crotalid envenomations (and in many envenomations that’s the only significant manifestation), we need to avoid this. Major toxicology organizations issued a position statement condemning its use. Additionally, if you perform PI incorrectly (which is a common problem), you can actually enhance systemic venom absorption simultaneously!
Venom extraction device: These commercial devices are common in sporting goods stores, but I really wish they were not. They are not helpful in snake envenomation. They remove almost no venom following a bite, and there is good evidence that they are harmful. Many of us snakebite experts participated in a public awareness campaign to get these devices removed from the market. These kits are good for one thing: profits for the manufacturers. They need to go away.
Electrical therapy: I hate that I even need to address this, but enough people recommend this nonsense that I cannot let it go unanswered. Electricity is not the cure for an envenomation. Multiple studies have proven conclusively that “electrical therapy” causes local damage and can kill the victim. It may seem cool in a Tarantino sort of way to connect your friend to a car battery, but please don’t.
Benadryl (diphenhydramine): One of the most viral posts on social media recommends diphenhydramine for snakebites. You need to know that Benadryl provides no benefit for a snake envenomation.
Placing the affected extremity below heart level: It was once taught to keep the extremity below heart level to reduce the venom absorption. We now understand this makes little difference in venom absorption but will definitely increase the swelling of the extremity. Conversely, limb elevation improves outcomes (abstract 36) by reducing swelling and the accompanying hydrostatic pressures.
Establish airway patency. Ensure adequate oxygenation and ventilation. Fluid resuscitate as needed to maintain euvolemia and perfusion. Provide analgesia with parenteral opioids. Elevate the affected extremity unless the patient is exhibiting systemic signs and symptoms, in which case keep it at - never below – heart level. Lastly, transport the patient to the most appropriate facility. If the patient is having life-threatening signs, go to the closest hospital for stabilization. Otherwise, it makes more sense to get treated by your regional snakebite expert (do your research before you get bitten!). You don’t want to end up untreated, under-treated, or treated incorrectly, which may happen if your physician lacks snakebite expertise.
Dr. Greene is a paid consultant for BTG International Inc.
Spencer Greene, MD, MS, FACEP, FACMT, FAACT, FAAEM is a board-certified medical toxicologist and emergency physician. He currently serves as the Director of Toxicology and an attending emergency physician at HCA Houston Healthcare-Kingwood. He is a Clinical Professor at the University of Houston College of Medicine. Dr. Greene is a recognized expert in the management of snake envenomation in the US. He has treated more than 1000 snakebites at the bedside and has authored more than 50 scholarly articles and book chapters. He has also served as the course director for the Houston Venom Conference since 2013.
Expert report debunks venom extractor kits.