Snake Bites

[CrotalidaeNE]

For coral snakes native to the US it's "red on black, venom lack..." There are coral snake species from central and south America that do not follow this pattern.

It's a misnomer that there is no available antivenom - the FDA extended the expiration date on the remaining stock until the fall of this year and there is available supply. Without antivenom, a severely envemomated patient might need prolonged ventilatory support.

I caught this thread very late and am glad that the original poster did not have any problems, but I thought I'd comment about some of the practices some of the respondents seem to be supporting for bites by pit vipers (subfamily Crotalinae), which includes rattlesnakes, copperheads, and water moccasins.

Tcripp, you asked about "what to expect" - it depends on the species, location of bite, patient comorbidities, and other factors. Many patients early on will have pain and local tissue swelling. Some develop signs and symptoms of systemic toxicity (e.g. nausea, parasthesias, etc) early on. Shock is usually from third spacing of platelets and plasma volume. Very rarely, someone who has been sensitized to proteins in the venom (e.g. someone who has handled snakes or venom or been previously bitten) may have a true anaphylactic reaction. We sometimes see anaphylactoid reactions with rapid onset shock and airway edema. Many patients develop coagulopathy, which can range from isolated thrombocytopenia or a syndrome of defibrination or a combination of the two that is DIC-like. Neurotropic findings, which can include neuromuscular blockade, can occur after bite by several species of rattlesnake, not just Mohave rattlesnakes.

In terms of first aid, do not apply tourniquets or lympathic constricting bands, or ice packs. Maintain the bite in a neutral position (some medical toxicologists think elevation is reasonable - others thing neutral until antivenom is started and then elevate. Do not apply any kind of suction. If a tourniquet, pressure bandage, or constricting band has been applied, do not remove it in the field. In general, when this is done, we get big lines in the patient, give them volume, and start antivenom before releasing this.

At least one IV should be started. Give fluids for hypoperfusion (obviously), but patients with intact perfusion and extremity swelling also need fluid boluses. Extremity swelling early after a bite is usually from the effect of polypeptides in the venom, and these cause tiny cracks in vessels that are large enough to allow platelets to leak out, but not large enough for red cells to leak out. This third spacing can be significant very early and cause significant hypovolemia and hemoconcentration. Very often, we see patients with rattlesnake bites who don't get enough IV fluid in the field. Give antiemetics for nausea, and treat pain (if you have fentanyl, I think it's preferred over morphine as the histamine release from the morphine can cloud close monitoring for development of allergic response to antivenom).

The destination hospital may not necessarily be the closest hospital, or even the closest hospital with antivenom, but this would obviously be region-specific. I have seen horrible outcomes when patients are taken to hospitals where arrogant physicians refuse to consult a toxicologist - we've seen patients diagnosed with compartment syndrome who get unnecessary fasciotomy and even amputations that were likely totally unnecessary. Where I work most hospitals have antivenom but we have centers available to us that have onsite toxicologsist and very large supplies of antivenom and we fly our patients to these centers.

The 2010 guidelines from AHA and ARC actually mention snakebite first aid, and they advocate using a pressure immobilization bandage for Crotalid envenomations. This recommendation is based on no evidence of any quality - in fact, one of the studies they cite as supporting the practice actually demonstrated worse limb outcomes when pressure bandages were applied (in a pig model). This practice turns what is very rarely a life threatening event into a limb-threatening one. This should be addressed locally, and hopefully administrators and medical directors will consult a medical toxicologist with snakebite expertise when establishing local or regional protocols. Pressure bandages seem reasonable for eastern and texas coral snake bites, and are standard for bites by neurotoxic snakes that cause rapid development of symptoms in Australia, but they will likely worsen injury when applied to victims of Crotalid snakebite.

Finally, you can not diagnose a dry bite (fang puncture mark without envenomation) in the field. This requires observation for at least 8 hours (and labs). Especially after Mohave Rattlesnake bite, patient can have a life-threatening, potentially fatal envenomation event with minimal local tissue injury, sometimes without significant pain. Patients with probable Mohave bites are admitted and watched for 24 hours at the tertiary center we work with.

[tcripp]

It's a misnomer that there is no available antivenom - the FDA extended the expiration date on the remaining stock until the fall of this year and there is available supply. Without antivenom, a severely envemomated patient might need prolonged ventilatory support.

Just to clarify, I didn't say it's no longer available, but rather that it is no longer manufactured. You are correct that the FDA is extending the expiration dates at this time. However, there could come a time...

Tcripp, you asked about "what to expect" - it depends on the species, location of bite, patient comorbidities, and other factors. Many patients early on will have pain and local tissue swelling. Some develop signs and symptoms of systemic toxicity (e.g. nausea, parasthesias, etc) early on. Shock is usually from third spacing of platelets and plasma volume. Very rarely, someone who has been sensitized to proteins in the venom (e.g. someone who has handled snakes or venom or been previously bitten) may have a true anaphylactic reaction. We sometimes see anaphylactoid reactions with rapid onset shock and airway edema. Many patients develop coagulopathy, which can range from isolated thrombocytopenia or a syndrome of defibrination or a combination of the two that is DIC-like. Neurotropic findings, which can include neuromuscular blockade, can occur after bite by several species of rattlesnake, not just Mohave rattlesnakes.

This was all great information. What I specifically was looking for was "real life experiences". I like to get the anecdotal type of information on top of school book learning.

You say, "we get" in your post. What is your position and where do you work? Sounds like you've seen many?

Finally, you can not diagnose a dry bite (fang puncture mark without envenomation) in the field. This requires observation for at least 8 hours (and labs). Especially after Mohave Rattlesnake bite, patient can have a life-threatening, potentially fatal envenomation event with minimal local tissue injury, sometimes without significant pain. Patients with probable Mohave bites are admitted and watched for 24 hours at the tertiary center we work with.

Absolutely agree and would never attempt to do so. However, the handlers know what they know and I simply told them I can not do anything they don't want me to do. They each have their own suction to remove venom and have experience enough that they felt they could make their own decisions. Now, as for myself or the crew...we'd be moving much faster.

Edited March 2, 2011 by tcripp

[Richard B the EMT]

Just remember, in the Peanuts comic strip, Linus is always afraid of nature hikes, becausew he believes he's going to get "chomped by a Queen Snake".

[DwayneEMTP]

I'm sick of all these m f'n snakes on this m f'n forum!

Fixed it man...

Dwayne

[Lone Star]

Whats the saying? Red on Black, you're dead, Jack. Red on Yellow, you're a lucky fellow? Its been a few years since boy scouts, I can't remember for sure.

The way I've always heard it was "red and black, friend of Jack; red and yellow, kill a fellow."

The coral snake is often confused with the king snake.

[Chief1C]

I got Pennsylvania's new, effective-as-you-read-it protocol sets today. It actually includes a snake bite protocol...and does allow for TK application, if the patient becomes hypotensive.

For Injected Poisons/ Snakebite:

1) Identify type of snake or animal (e.g. scorpion), if safe and possible. If identity of a snake is not known, all victims of snakebite should be treated as if the snake is poisonous. Do not delay transport while attempting to capture or kill a snake.

2) Calm patient.

3) Administer high-flow oxygen, if respiratory symptoms are present.

4) Remove jewelry and tight clothing. 5) Consider immobilizing the involved body part. For snakebite, when time to arrive at a hospital is extended, consider a pressure immobilization bandage using an elastic (ACE-type) bandage wrapped around the entire length of the bitten extremity – comfortably tight and snug but allowing for a finger to be slipped under it. If extremity involved, keep the extremity below the level of the patient’s heart.

6) Keep the patient as still as possible to reduce the circulation of the venom. Carry patient for transport, if possible.

7) Apply constricting band proximal to bite if patient is hypotensive.

8) DO NOT APPLY ICE.

9. Transport.

10. Monitor vital signs and reassess.

11. Contact Medical Command or Poison Control Center3 if additional direction is needed.

And... They finally took MAST out of the EMT Scope of Practice. I was still on the fence over whether or not it was effective for it's intended purpose.

[coolidge]

Elevation or Ice still or ever part of algorithm?

Antivenom doses?

[DwayneEMTP]

Ice and elevation were both part of many/most protocols before, but neither are now. I believe that the thinking is that it's better to get the toxins diluted into the central system instead of keeping them concentrated locally.

Antivenin doses are going to range widely based on type and patient presentation. I know, as I'm an expert from watching that snake bite doctor show a couple of times. :-)

But we'll never be giving it likely. It seem that some believe that you give antivenin the same way that we might give epi for anaphylaxis, one dose does it for pretty much everyone. I get the feeling that snake bites don't work like that at all...

Coolidge, welcome to the City brother...

[Just Plain Ruff]

I've encountered venomous snakes on wilderness missions. Rattlers tend to leave without a fight, they let you know they're around, possibly pissed off, but usually just slither away. Copperheads, on the other hand, they're mean bastards, and will stay and play, and usually, you don't know they're in your presence.

And Cottonmouths are the nastiest, they can actually aggresively attack you if I remember hearing that right somewhere.

I'm hearing of more and more exotic snakebites these days, cobras, vipers and their ilk, you get one of those bites and you better get them to the right hospital.

One other thing, there is a group of nationwide conferences on reptiles where reptile owners and dealers will bring their snakes and other poisonous animals to a convention center and sell them. If you have one of those conventions in your area and you will be the EMS agency responding, best to get your ducks in a row on where to send the unlucky contestant who gets bitten.

One bite from a mamba or exotic viper and the bitten one is more than likely gonna die. Have a plan in place. There is a reptile convention in Baltimore soon. I plan on going with my son.

[tcripp]

One other thing, there is a group of nationwide conferences on reptiles where reptile owners and dealers will bring their snakes and other poisonous animals to a convention center and sell them. If you have one of those conventions in your area and you will be the EMS agency responding, best to get your ducks in a row on where to send the unlucky contestant who gets bitten.

One bite from a mamba or exotic viper and the bitten one is more than likely gonna die. Have a plan in place. There is a reptile convention in Baltimore soon. I plan on going with my son.

Funny to see this thread come full circle. The original post was because of an event similar to the one the Captain just posted.

Toni