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<< Diagnosis And Management Of North American Snake And Scorpion Envenomations

Prehospital / Wilderness Care

Multiple methods for treating snakebites in the field have gone in and out of vogue over the years, and have been discussed at length both in the medical and non-medical literature. Recently, the recommended first aid measures for snakebites have been revised to exclude many treatments of the past. Arterial tourniquets, aggressive wound incision/excision, electric shock, and ice submersion/ cryotherapy may all worsen a patient's condition.16-17 Current recommendations for field care call for very little beyond rapid transportation; see Table 2.



Field care by bystanders or emergency medical services should include removing the patient from the area where the bite occurred. It is not recommended to try to catch or kill the offending snake simply to bring it to the hospital. In other words, common sense and discretion should prevail. A snake that has taken up residence under the slide on a school playground is very different from a snake that strikes because you stepped on its home in the middle of the woods. A good description of the snake in combination with the patient's signs and symptoms is generally adequate to initiate in-hospital treatment.

Patients should be reassured, placed at rest, kept warm, and transported immediately to the closest medical facility. The bitten extremity should be immobilized and kept at or below the level of the heart, and all constrictive clothing, jewelry and watches should be removed.4,15,26 Closely monitor vital signs to assess for hypotension as a sign of systemic toxicity and hypotension should prompt a bolus of intravenous isotonic fluids.5,17 Incision and suction, once the standard of care for the treatment of snakebites, is no longer recommended and may, in fact, pose more risk than benefit.27 Incision has never been shown to be beneficial for extracting venom and can cause unintended and potentially disabling injury to digital nerves, arteries, and tendons even when performed by an experienced provider.28 Oral suction of the venom is strongly discouraged both for its lack of effectiveness in removing venom and because of the possibility of introducing oral flora into the wound, potentially complicating treatment.

There are several commercial snakebite kits on the market containing a multitude of items for the treatment of snakebites. Generally there is some combination of venous and/or arterial tourniquets, lancets or scalpels, antiseptic wipes, and various suction devices. Most of the kits were developed and marketed since before the "incision and suction" treatment went out of vogue.

The most recognized and researched of these suction devices is the Sawyer Venom Extractor®. The marketing information available on the internet for this product references its ability to remove "up to 30%" of the snake venom based on two small studies (one animal in 1985 and one human in 1986) by Bronstein et al.29-30 A well-designed, 2004 human study by Alberts et al27 using simulated radiolabeled snake venom demonstrated minimal (0.04%) venom extraction from a simulated snakebite wound and only a 2% reduction of total body venom load. Given the poor performance of this device in the controlled trials and the elimination of most of the former interventions from the field treatment recommendations, Johnson said it best when he stated, "the best snakebite kit is probably the keys to a car that runs."15

EMS may be faced with a snakebite victim who has had one or more well-intentioned field interventions by a bystander and it is important to know which should be discontinued and which should remain until hospital evaluation is complete. Incision is one of the most likely field interventions the EMS provider may encounter. In cases where an incision has been made, control bleeding and apply a moist dressing.17 If an extractor device is correctly in place it should be left in place until the arrival at the hospital.17 Arterial tourniquets should be removed due to the potential for limb ischemia but venous tourniquets or "constriction bands," defined as wide, flat bands that restrict venous and lymphatic flow to impede absorption of venom, can be left in place. These constriction bands, which should be loose enough to allow two fingers to slip easily underneath, have shown some benefit in delaying absorption of venom in experimental models and have been suggested as therapy in patients with prolonged transport times.17,31 If a device has been applied and it is not causing vascular compromise, it should be left in place by EMS during transport. EMS personnel should frequently reassess the tension of any constrictive device to ensure that progressive limb edema does not result in a venous constriction band becoming an inadvertent arterial tourniquet.10




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Last Modified: 05/26/2017
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