Lavonas et al. BMC Emergency Medicine 2011, 11:2 Page 4 of 15 http://www.biomedcentral.com/1471-227X/11/2 and other Rocky Mountain Poison and Drug Center treatment of patients bitten by coral snakes (family Ela- staff. The antivenom manufacturer provided funding pidae), nor by snakes that are not indigenous to the US. support. Sponsor representatives were not present dur- At the time this algorithm was developed, the only ing the webinar or panel discussions. Sponsor represen- antivenom commercially available for the treatment of tatives reviewed the final manuscript before publication pit viper envenomation in the US is Crotalidae Polyva- ® for the sole purpose of identifying proprietary informa- lent Immune Fab (ovine) (CroFab , Protherics, Nash- tion. No modifications of the manuscript were requested ville, TN). All treatment recommendations and dosing by the manufacturer. apply to this antivenom. This algorithm does not con- sider treatment with whole IgG antivenom (Antivenin Results (Crotalidae) Polyvalent, equine origin (Wyeth-Ayerst, Final unified treatment algorithm Marietta, Pennsylvania, USA)), because production of The unified treatment algorithm is shown in Figure 1. that antivenom has been discontinued and all extant The final version was endorsed unanimously. Specific lots have expired. This antivenom also does not consider considerations endorsed by the panelists are as follows: treatment with other antivenom products under devel- opment. Because the panel members are all hospital- Role of the unified treatment algorithm (general based physicians, the panel did not evaluate field first considerations and box 16) aid or other prehospital therapy. This algorithm pertains to the treatment of human In order to create an algorithm that was simple patients bitten by pit viper snakes (family Viperidae, enough to be used effectively, the panel decided not to subfamily Crotalinae) in the US, including the rattle- include specific recommendations for the management snakes (genus Crotalus), pygmy rattlesnakes (Sistrurus), of certain rare manifestations of crotaline snakebite. and moccasin snakes (genus Agkistrodon). Within the These included snakebites to the head and neck, snake- Agkistrodon genus are the copperhead snakes (A. contor- bites causing rhabdomyolysis, and apparent anaphylactic trix) and the water moccasin (cottonmouth) snake or anaphylactoid reactions to venom. In addition the (A. piscivorus). This algorithm does not apply to panelrecognizedthatnotreatment algorithm could Emergency Department and Hospital Management of Pit Viper Snakebite Includes: Rattlesnakes, Copperheads, and Cottonmouths (Water Moccasins) 12 15 When to Call a Physician-Expert Treatments to Avoid in 1 Direct consultation with a physician-expert is recommended in Pit Viper Snakebite Assess Patient certain high-risk clinical situations: Mark leading edge of swelling and tenderness every 15-30 minutes Cutting and/or suctioning of the wound Life-threatening envenomation Immobilize and elevate extremity Ice Shock Treat pain (IV opioids preferred) NSAIDs Serious active bleeding Obtain initial lab studies (protime, Hgb, platelets, fibrinogen) Prophylactic antibiotics Facial or airway swelling Update tetanus Prophylactic fasciotomy Contact poison control center (1-800-222-1222) Hard to control envenomation Routine use of blood products Envenomation that requires more than 2 doses of Shock therapy (electricity) antivenom for initial control Steroids (except for allergic phenomena) Tourniquets Recurrence or delayed-onset of venom effects 2 9 Apparent Dry Bite / No Bite Check for Signs of Envenomation Worsening swelling or abnormal labs (protime, Swelling, tenderness, redness, ecchymosis, or blebs at the bite site, or None Do not administer antivenom fibrinogen, platelets, or hemoglobin) on follow-up visits Observe patient 8 hours Elevated protime; decreased fibrinogen or platelets, or Allergic reactions to antivenom 16 Notes: Systemic signs, such as hypotension, bleeding beyond the puncture site, Repeat labs prior to discharge refractory vomiting, diarrhea, angioedema, neurotoxicity If patient develops signs of If transfusion is considered All treatment recommendations in this algorithm refer to envenomation, return to box 2 Uncommon clinical situations crotalidae polyvalent immune Fab (ovine) (CroFab®). Present Bites to the head and neck This worksheet represents general advice from a panel of US Rhabdomyolysis snakebite experts convened in May, 2010. No algorithm can 3 10 Check for Indications for Antivenom Apparent Minor Envenomation Suspected compartment syndrome anticipate all clinical situations. Other valid approaches exist, None Venom-induced hives and angioedema Swelling that is more than minimal and that is progressing, or Do not administer antivenom and deviations from this worksheet based on individual patient Elevated protime; decreased fibrinogen or platelets, or Observe patient 12-24 hours Complicated wound issues needs, local resources, local treatment guidelines, and patient preferences are expected. This document is not intended to Any systemic signs Repeat labs at 4-6 hours and prior to If no local expert is available, a physician-expert can be reached represent a standard of care. For more information, please see discharge through a certified poison center (1-800-222-1222) or the the accompanying manuscript, available at Present If patient develops progression of any antivenom manufacturer’s line (1-877-377-3784). signs of envenomation, return to box 3 www.biomedcentral.com. 4 Administer Antivenom Establish IV access and give IV fluids 13 Pediatric antivenom dose = adult dose Mix 4-6 vials of crotaline Fab antivenom (CroFab®) in 250 ml NS and infuse IV over 1 Maintenance Antivenom Therapy hour Maintenance therapy is additional antivenom given after For patients in shock or with serious active bleeding initial control to prevent recurrence of limb swelling Increase initial dose of antivenom to 8-12 vials Maintenance therapy is 2 vials of antivenom Q6H x 3 Call physician expert (see box 12) (given 6, 12, and 18 hours after initial control) Initiate first dose of antivenom in ED or ICU For suspected adverse reaction: hold infusion, treat accordingly, and call Maintenance therapy may not be indicated in certain physician-expert situations, such as Re-examine patient for treatment response within 1 hour of completion of antivenom Minor envenomations infusion Facilities where close observation by a physician- expert is available. Follow local protocol or contact a poison center or physician-expert for advice. 5 11 Determine if Initial Control of Envenomation Repeat antivenom until has been Achieved No initial control is achieved. Swelling and tenderness not progressing If initial control is not achieved after 2 14 Protime, fibrinogen, and platelets normal or clearly improving doses of antivenom, call physician expert Clinically stable (not hypotensive, etc.) (see box 12) Post-Discharge Planning Neurotoxicity resolved or clearly improving Instruct patient to return for Yes Worsening swelling that is not relieved by elevation Abnormal bleeding (gums, easy bruising, melena, etc.) 6 Monitor Patient Instruct patient where to seek care if symptoms of serum Perform serial examinations sickness (fever, rash, muscle/joint pains) develop Maintenance antivenom therapy may be indicated Bleeding precautions (no contact sports, elective surgery or Read Box 13 (Maintenance Antivenom Therapy) dental work, etc.) for 2 weeks in patients with Observe patient 18-24 hours after initial control for progression of any venom effect Rattlesnake envenomation Follow-up labs 6-12 hours after initial control and prior to discharge Abnormal protime, fibrinogen, or platelet count at any If patient develops new or worsening signs of envenomation, administer additional time antivenom per box 4 Follow-up visits: Antivenom not given: PRN only 7 Antivenom given: Determine if Patient Meets Discharge Criteria Copperhead victims: PRN only No progression of any venom effect during the specified observation period Other snakes: Follow up with labs (protime, No unfavorable laboratory trends in protime, fibrinogen, or platelets fibrinogen, platelets, hemoglobin) twice (2- 3 days and 5-7 days), then PRN Yes 8 See Post-Discharge Planning (box 14) Figure 1 Unified Treatment Algorithm for the Management of Pit Viper Snakebite in the United States. Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop Lavonas et al. Lavonas et al. BMC Emergency Medicine 2011, 11:2 http://www.biomedcentral.com/1471-227X/11/2 (3 February 2011) Lavonas et al. BMC Emergency Medicine 2011, 11:2 http://www.biomedcentral.com/1471-227X/11/2 RESEARCHARTICLE Open Access Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop Eric J Lavonas1,2*, Anne-Michelle Ruha3, William Banner4,5†, Vikhyat Bebarta6†, Jeffrey N Bernstein7,8†, Sean P Bush9†, William P Kerns II10†, William H Richardson11,12†, Steven A Seifert13,14†, David A Tanen15,16†, Steve C Curry3, Richard C Dart1,2 Abstract Background: Envenomation by crotaline snakes (rattlesnake, cottonmouth, copperhead) is a complex, potentially lethal condition affecting thousands of people in the United States each year. Treatment of crotaline envenomation is not standardized, and significant variation in practice exists. Methods: A geographically diverse panel of experts was convened