This is in line with my research on the subject matter. Good post.To formulate this response in a responsible manner, I augmented my on-board knowledge with information from Medscape and Physicians Online. Both are credible medical resources used by practitioners.
Pit Vipers (Crotalidae) have a combination of necrotoxic and hemolytic effects from their venom. Massive protein breakdown and coagulopathy (Hemorrhage d/t destruction of clotting factors) are the biggest complications of envenomation. Cold therapy is acknowledged, but poorly understood and mildly helpful, if at all. Use of tourniquets is contraindicated as it confines the toxins to the extremity involved and leads to tissue necrosis and compartment syndrome which become systemic once the tourniquet is released, as opposed to allowing it to distribute slowly throughout a patient's vascular system while lying quietly.
Splint the extremity and place a lymphatic constricting band in the field no tighter than a watch band or socks. Maintain the extremity at, or slightly below the level of the heart. The constricting band helps to preserve the liver (as lymphatic drainage returns directly to the liver for filtration via the hepatic portal system) prior to administration of CroFab, antivenin that has fewer systemic effects than the traditional protein derived Antivenin Crotalidae Polyvalent. Most experts recommend that CroFab or traditional antivenin be administered even to dry bite victims prophylactically rather than waiting for signs of envenomation to emerge.
NOWHERE is Adrenalin indicated without presentation of anaphylactic shock. History of prior anaphylaxis (Best indicator) Difficulty breathing, Wheezes, Edema (Swelling) of the tongue and lips (Best indicator of what's happening in the airway, known as angioedema) and itching and hives (Can be present with minor to moderate allergy without respiratory involvement). Un-necessarily taxing the cardiovascular system of a victim of pit envenomation is asking for problems and is not indicated as routine therapy, or for minor allergic reactions without evidence of respiratory distress.
This is a situation in which it is particularly smart to have GPS locaters, Cell/Sat. phones, etc.. It is also a good reason to mobilize air evacuation if there is terrain, or the location is remote. If you're going to be in an area frequented by snakes especially pit vipers, you need to have a plan.
Other venomous critters in the States include the Bark Scorpion (indigenous to AZ and the only place you can get the antivenin), Coral Snake - "Red touch yellow, kill a fellow, Red touch black venom lack." (vs, Corn snake). Brown recluse spiders have necrotoxin, Black widows have Neurotoxin which hurts like 10 mofos - Treat with Valium emergently. The Recluse will take days of tissue sloughing from an initial pimple-looking bite to a wound large enough to cause concern (Usually nickel to quarter size crater of dead, sloughed out flesh, creating a pit in the skin. Tissue can continue to slough to bone in some cases, necessitating amputation. The same can happen with Necrotizing Fasciitis, primarily served up by Group A Staphylococcus Aureus, which is also known as "Normal Skin Flora".