In Response to Management of a Pediatric Snake Envenomation After Presentation With a Tight Tourniquet by Bush and Kinlaw

To the Editor:

I read with interest the article by Bush and Kinlaw ¹ that described their treatment of a child who suffered a snakebite and had a tight (arterial occlusive) tourniquet placed by a bystander in the field. They described ample clinical evidence supporting envenomation by a crotalid, rather than a neurotoxic snake in this patient. They chose to leave the tourniquet in place for almost 90 minutes from the time of its application while awaiting the preparation and initial administration of Crotalidae Polyvalent Immune Fab antivenom to avoid “the possibility of a bolus effect” when the tourniquet was released. Furthermore, they recommend that this should be standard procedure for patients who arrive at a treatment facility with a tight tourniquet in place. They cite 2 studies^2,3 that note possible adverse bolus effects from neurotoxic snakes such as cobras and coral snakes to support their reasoning. They also provide an excellent discussion of local injury by crotalid envenomation and the potential to exacerbate this by tourniquet application. Despite this, they recommend leaving a tourniquet in place.

The primary local effects of crotalid envenomation are caused by vasculopathic tissue damage and the development of compartment syndromes. ⁴ I could find no human reports of adverse bolus effects associated with tourniquet release after crotalid envenomation, but there is a significant body of literature describing adverse effects of arterial occlusive tourniquets, especially those that have been in place for longer than 4 to 6 hours. ⁵ Prolonged placement of arterial occlusive tourniquets directly leads to tissue ischemia, which likely will be worsened and accelerated by the vasculopathic injury caused by crotalid envenomation. Therefore, the application of an arterial occlusive tourniquet may result in severe local injury in the absence of evidence for prevention of a theoretical bolus effect from a nonneurotoxic snake envenomation.

I believe the authors’ recommendation to “keep the tourniquet in place” should be carefully considered by balancing the type of snakebite, the amount of local injury, and the duration of tourniquet application. In the patient who presents quickly to the emergency department, it may be reasonable to keep the tourniquet in place until antivenom therapy is instituted if the local effects are not severe, if it can be released within a couple of hours of placement, or when there is concern that a neurotoxic envenomation has occurred. However, all efforts should be directed to avoid any excessive application of arterial occlusive tourniquets in patients with crotalid envenomations.