Human Snakebite Management
Please review the following guidelines for pre-hospital management for all North American pit vipers. Pit vipers in the United States include all rattlesnakes, copperheads, and cottonmouths (also known as water moccasins). You do not need to identify the species of snake in order to treat in the USA as both CroFab and Anavip are both FDA approved for all North American pit viper envenomations. While antivenom is most effective in the first six hours, it can still benefit if there are ongoing venom effects.
Pit viper envenomation is GENERALLY characterized by local tissue injury and, less commonly, hematologic abnormalities and systemic toxicity such as low blood pressure, vomiting, airway swelling. Some pit vipers, such as certain populations of Mojave rattlesnakes, cause neurological toxicity.
Pre-hospital Guidelines
NSS pre-hospital management
Notes on positioning a snakebite from Dr. Spencer Greene
When determining how to position the affected extremity following a snakebite, there are two things to consider: (1) the type of snake, and (2) whether you’re already at the hospital or still in the pre-hospital environment.
Experts agree that crotalid (copperhead, cottonmouth, rattlesnake) envenomations should be ELEVATED in the hospital. Elevate the extremity at least 45° (ideally at least 60°) without allowing the knee or elbow to bend. It’s one of the first recommendations in the unified treatment algorithm for the management of crotaline snakebite in the U.S.: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042971/
Pre-hospital positioning is a little controversial. Some people recommend keeping the affected extremity at heart level because they fear that elevation will increase the systemic absorption of the venom. Dr. Greene recommends early and aggressive elevation, because the volume of venom is so insignificant that elevation is unlikely to make a difference in absorption. On the other hand, the volume of fluids that accumulate in the affected extremity is significant, and elevation will reduce that swelling. He reports seeing dramatic improvement within 30 minutes of elevation.
The affected extremity should never be placed below heart level. This will increase the swelling and hydrostatic pressures that lead to tissue injury.
Coral snake envenomations do not cause significant swelling, and we recommend patients placing the affected extremity in whatever position is most comfortable.
You can read Dr. Greene’s article here: https://medium.com/natural-world/how-to-position-a-snakebite-9430fc988af
The most important steps following a bite are:
Arrange to get to the hospital as quickly as possible. That may mean calling a friend or 911. Definitely call 911 for any serious symptoms. Do not drive yourself.
Remove any constrictive clothing and jewelry.
Elevate the affected extremity (please see the article explaining why we elevate). Absolutely DO NOT place the affected extremity below heart level.
Take a picture of the snake IF YOU CAN DO IT QUICKLY AND SAFELY. It is helpful but not necessary. DO NOT bring the snake, whether dead or alive.
DO NOT do any of the following: tourniquets, lymphatic bandage, pressure immobilization, cut and suck, extraction device, electrical stimulation, packing the extremity in ice.