A 28-year-old emergency physician is bitten by a diamondback rattlesnake on the right middle finger. He applies a tourniquet and arrives to the hospital approximately four hours after envenomation. On physical examination, the patient is in mild distress because of hand pain. His vital signs were as follows: temperature, 99° F; pulse, 118 and regular; blood pressure 130/75 mm Hg. Pulse oximetry on room air showed 100% saturation but not detected on the injured digit. Respiratory, cardiopulmonary, abdominal and neurological examinations were normal. No lymph node tenderness was present. Extremity exam is normal except for mild swelling of the hand that the finger is noted to be necrotic. (left).

The patient had a white blood count, hemoglobin, fibrinogen and platelet counts were normal.

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# Pressure Immobilization is not a TourniquetMorgan Atwood 2011-01-29 18:44
Dr. LoVecchio, I believe you are inappropriately using two different terms as interchangeable here.
A Tourniquet is a different device from a Pressure Immobilization wrap. Tourniquets are applied around a specific point on the limb and cut off blood flow distal to the device' application. Pressure Immobilization does not restrict blood flow, unless performed improperly, and is not applied to a specific point but rather to the entirety of the extremity bitten (according to 2010 AHA guidelines, and as illustrated in Venomous Snakebite in Mountainous Terrain: Prevention and Management by Boyd et al, as well as the Australian WMI guidelines.)
So what was it that this patient performed? Tourniquet application, or Pressure Immobilization Technique?

If the patient applied a tourniquet, we cannot even begin to speculate about the ability to successfully perform PIT as it was not actually attempted. About all we could realistically conclude if that were the case, is that the patient's misapplication of a device was possibly a factor in his eventual finger loss.
# Guiac 2011-02-04 17:03
It is fare to point out that pressure immobilization or a Sutheland wrap is best applied to neurotoxic snake envenomations in which the neurotoxin generally reaches the CNS via venous and lymphatic flow. The ideal goal is to interrupt this flow and delay neurotoxicity onset. Many of these snakes can cause local tissue injury as well. In the USA the principal neurotoxic snakes are Eastern Coral snakes - which generally cause little if any significant local injury.

I agree with the author's conclusion that among most US pit viper bites it is best not to apply a tourniquet or other pressure device. Simple splinting to limit muscular movement and hence venous/lymphati c flow is probably the best.

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