What are the Indian guidelines for administering Antisnake Venom (ASV) in the management of snake bites?

Indian Guidelines for Antisnake Venom (ASV) Administration

The cornerstone of treatment for venomous snake bites in India is prompt administration of polyvalent Antisnake Venom (ASV), which should be initiated as soon as possible after envenomation with an initial dose of 4-6 vials, followed by additional doses until initial control of symptoms is achieved. 1

Venomous Snake Species in India

The polyvalent ASV available in India is effective against the "Big Four" snakes responsible for most envenomations:

• Indian cobra (Naja naja)
• Common Krait (Bungarus caeruleus)
• Russell's Viper (Daboia russelli)
• Saw Scaled Viper (Echis carinatus) 2

Initial Management and First Aid

1. Rest and immobilize the bitten extremity to minimize venom spread
2. Remove constricting jewelry from the affected limb
3. Keep the victim calm to reduce heart rate and slow venom circulation
4. Position the bite site at or below heart level 1

Avoid these harmful practices:

• Application of ice
• Use of suction devices
• Electric shock
• Tourniquets 1

Diagnostic Evaluation

Perform the following tests to assess envenomation severity:

• Complete blood count
• Coagulation studies (including WBCT20)
• Renal function tests (urea, creatinine)
• Electrolytes
• Cardiac monitoring 1, 3

ASV Administration Protocol

Indications for ASV:

1. Neurotoxic envenomation signs: ptosis, external ophthalmoplegia, paralysis
2. Hemotoxic envenomation signs: bleeding, coagulopathy, abnormal WBCT20
3. Local envenomation signs: severe local tissue damage, swelling extending beyond the bitten limb

Dosing Guidelines:

• Initial dose: 4-6 vials of polyvalent ASV 1
• Administration: Dilute in 100-250 ml of normal saline and infuse over 1 hour
• Monitoring: Observe for signs of adverse reactions during administration
• Repeat dosing: Additional ASV may be required based on clinical response, with some cases requiring high doses (up to 40 vials reported in severe krait envenomation) 4, 5

Management of ASV Adverse Reactions:

• Premedication with adrenaline, hydrocortisone, and antihistamines may be considered
• For anaphylactic reactions: administer adrenaline (0.5 mg IM), hydrocortisone, and antihistamines 3

Supportive Care

Fluid Management:

• Initiate aggressive fluid resuscitation with normal saline at 1000 ml/h initially
• Taper by at least 50% after 2 hours
• Avoid potassium-containing balanced salt fluids due to risk of hyperkalemia 1

Neurotoxic Envenomation:

• Administer neostigmine with atropine for patients with neurotoxic envenomation
• Monitor respiratory function closely and provide ventilatory support if needed 3

Wound Care:

• Clean the wound with sterile normal saline
• Remove superficial debris if present
• Avoid deep debridement unless absolutely necessary
• Elevate the affected limb if swelling persists 1

Monitoring and Follow-up

• Monitor for recurrent neurotoxicity, especially with krait bites 4
• Continuous observation for at least 24 hours after ASV administration
• Long-term follow-up is essential, as renal involvement may persist 1

Pitfalls and Caveats

1. Inconsistent ASV protocols: Studies indicate that many Indian hospitals do not follow a standardized protocol for ASV administration 5, 6
2. Misinformation in product inserts: Current Indian snake antivenom manufacturers often include erroneous recommendations in package inserts 6
3. High ASV requirements: Some envenomations, particularly by kraits, may require unusually high doses of ASV for symptom reversal 4
4. Regional venom variations: Venom composition varies geographically, potentially affecting ASV efficacy 2

Emergency Planning

• Develop an emergency plan including fluid management protocols
• Establish contact information for specialists
• Provide clear instructions for emergency medical personnel
• Consider referral to specialized centers with experience in managing snake envenomation 1