UNIVERSAL APPROACH TO THE SNAKEBITE PATIENT

INITIAL PRIORITIES

1. Focus on ABCs (Airway, Breathing, Circulation) and antivenom.

a. Check ABCs first and fix any immediate life threats (e.g., trouble breathing or shock).

b. If the patient has sudden collapse (shock, swelling, confusion, or bleeding within 30 minutes), follow the Sudden Collapse Syndrome Treatment Protocol.

c. Establish IV or IO access in a non-bitten limb for antivenom or fluids.

d. Treat emergent secondary issues that may be present (such as anaphylaxis or hypovolemic shock) according to standard clinical protocols.

e. Establish IV or IO access in a non-bitten limb before proceeding.

2. DO NOT apply constricting bandages or tourniquets as these may worsen local tissue injury and increase the risk of permanent disability.64–66

If a tourniquet is already in place, see Tourniquet Algorithm. Do not remove it until you are ready to treat and resuscitate the patient as a rapid decompensation can occur.67,68

3. If and when conditions allow, minimize patient activity, and loosely immobilize the bitten limb to reduce movement without constricting tissues.

a. If antivenom isn’t available, get the patient to a facility with antivenom as fast as safely possible, even if they have to walk.

b. If conditions allow during transport, maintain the bitten limb in a position of comfort that is elevated below the level of the heart.

c. Once the patient has arrived at a medical facility with antivenom, aggressively elevate the bitten limb (aim for a minimum 60º angle in a supine patient if possible and tolerated by patient) to reduce oncotic pressure on swollen tissues.

4. Evaluate for specific signs and symptoms of snake envenomation. Refer to the STAT treatment algorithms in Appendix A for specific criteria for initial antivenom treatment and repeat doses for additional information.

5. Consult a Medical Toxicologist as soon as possible. Within the United States, a Medical Toxicologist can be reached via a Poison Control Center by calling 800-222-1222. Within the Department of Defense, a Medical Toxicologist can be reached via the Advanced Virtual Support for Operational Forces (ADVISOR) teleconsultation service by calling 833-ADVSRLN (833-238-7756)/ DSN: 312-429-9089.

FOCUSED ASSESSMENT & EXAMINATION

Perform a physical examination and history focused on identifying signs and symptoms of neurotoxic, hemotoxic, cytotoxic, and systemic instability envenomation syndromes. General approach is to identify syndrome à determine severity à administer initial LOW, MEDIUM, or HIGH DOSE antivenom based on syndrome AND current severity à reassess and retreat as needed based on response of key STOP/GO criteria for additional doses.

1. Mark the bite site. Circle the site of the bite wound and write the specific time that it occurred with a permanent marker on the patient. Don’t rely on fang marks—bites may look like punctures, scratches, or nothing at all.

2. Check for cytotoxic signs (tissue damage). Look for pain, swelling, or tissue destruction. Mark the edge of pain (dashed line) and swelling (solid line) with a marker and note the time.

Figure 2. Marking Progressive Pain and Edema

3. Check for hemotoxic signs (bleeding). Look for bleeding at the bite that lasts over 30 minutes or bleeding from gums or other areas (mouth, gums or other mucosa).1,69–72

4. Check for neurotoxic signs (nerve issues).

5. Rapid examination for signs of neuromuscular weakness (neurotoxic syndrome)

- Evaluate respiratory muscle weakness by single breath count (SBC) testing 72 and repeat periodically to trend improvement or deterioration in respiratory function over time.
  - Ask the patient to take a deep breath and count out loud as high as they can without breathing again and repeat periodically to trend improvement or deterioration in respiratory function over time.
  - Normal SBC is approximately 50 and SBC < 20 is associated with the need for mechanical ventilation.
    - If spirometry is available, this can be used in place of the single breath count test by evaluating the negative inspiratory force (NIF) and/or forced vital capacity (FVC).
- Conduct gross assessment and pay particular attention to the following:
  - Signs and symptoms of descending flaccid paralysis: Ptosis (upper eyelid drooping), diplopia (double vision), neck flexor muscle weakness, bulbar weakness, difficulty speaking, difficulty swallowing, etc.1,54,73
    - Signs and symptoms of parasympathetic / cholinergic crisis: SLUDGE mnemonic - Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis.

6. Perform and/or check the clinical laboratory tests listed below (if available).

- Complete Blood Count (CBC), Hemoglobin, or Hematocrit.
- Clotting tests (PT, PTT, INR, Fibrinogen).
  - Simple coagulation test for austere environments: Use the Whole Blood Clotting Test (WBCT) as described in Appendix J to diagnose and monitor coagulopathy if advanced labs not available.
- Comprehensive Metabolic Panel (CMP) and Creatine Kinase (CK).

LAB TESTS

Advanced laboratory tests include:

- Complete Blood Count (CBC)
- Hemoglobin (Hb) or Hematocrit (HCT) if no CBC but separate testing for either Hb or HCT is available
- Prothrombin Time (PT), Partial Thromboplastin Time (PTT), and International Normalized Ratio (INR)
- Fibrinogen
- Comprehensive Metabolic Panel (CMP)
- Creatine Kinase (CK)

Simple coagulation test for austere environments: Use the Whole Blood Clotting Test (WBCT) as described in Appendix J to diagnose and monitor coagulopathy if advanced labs are not available.

TRANSPORT FACTORS

1. If the patient is being medically evacuated from the field or between roles of care, confirm that the receiving facility has an adequate supply of the appropriate regionally specific antivenoms listed in this CPG to ensure treatment coverage against local species of concern. Alternatively, have the antivenom transported to the patient.

NOTE: Evacuation is not an alternative to antivenom administration. A patient whose snakebite warrants evacuation will require antivenom. The earlier it is given the greater the chance of full recovery without permanent disability. DO NOT delay administration of antivenom in the field to a patient with an envenomation.

2. If clinical evidence of envenomation is present and treatment is occurring in a hospital setting, always admit to a bed with continuous vital sign monitoring if available. If treating in the field, continuously monitor patient trends for signs of progression, improvement, or deterioration.

3. If no initial clinical evidence of envenomation, follow the Asymptomatic Algorithm for assessment intervals and disposition guidance.