Indication for administration of AS V (Antisnake venom) in Viper bite?

Ans. d (All of the above) (Ref: Pilley Textbook of Toxicolgy 7th edition, p. 450; Harrison's 17th ed., p. 2742)Use of Acetylcholinesterase Inhibitors in Neurotoxic Snake Envenomation1. Patients with clear, objective evidence of neurotoxicity after snakebite (e.g., ptosis or inability to maintain upward gaze) should receive a trial of edrophonium (if available) or neostigmine.a. Pretreat with atropine: 0.6 mg IV (children, 0.02 mg/kg; minimum of 0.1 mg)b. Follow with:Edrophonium: 10 mg IV (children, 0.25 mg/kg) orNeostigmine: 1.5-2.0 mg IM (children, 0.025-0.08 mg/kg)2. If objective improvement is evident at 5 min, continue neostigmine at a dose of 0.5 mg (children, 0.01 mg/kg) every 30 min as needed, with continued administration of atropine by continuous infusion of 0.6 mg over 8 h (children, 0.02 mg/ kg over 8 h).3. Maintain vigilance regarding aspiration risk, and secure the airway with endotracheal intubation as needed.REID'S CRITERIA FOR ADMINISTRATION OF ASV# Leukocytosis > 13,000-15,000/cu mm# Thrombocytopenia < 80,000/cu mm# Renal failure# DIC# Soft tissue swelling involving or crossing joint nearby site of bite# Systemic symptoms/signs of neuroparalytic bite (vomiting, abdominal pain, giddiness, ptosis, etc).Dose of ASVLimb Area InvolvementDose< 1/3 of Limb area50 ml1/3-1/2 Limb area100 ml>50% of Limb area150-200 mlASV should be given within 2 days preferably can be given upto 5-7 days.Comparison of Antivenoms Recently Available for Treatment of Pit Viper Bites in the U Antivenin (Crotalidae) PolyvalentCroFabAvailable since19542000OriginEquineOvineSnakes used in manufactureCrotalus adamanteusC. adamanteus C. atroxC. atrox C. durissus terrificusC. scutulatus Bothrops atroxAgkistrodon piscivorusContainsSkin testing recommended byIgG, equine albuminFab fragmentsmanufacturerYesNoPretreatment with antihistaminesYesNoDry bite-doseNoneNoneMild - dose0 or 5 vials4 vialsModerate - dose10 vials4-6 vialsSevere - dose15-20 vials6 vialsRepeat dosingAs neededRepeat starting dose if patient fails to stabilize.After stabilization, give 2 vials q6h for 3 more doses. (Alternatively, re-dose on an as needed basis with close observation for recurrence of abnormalities.)Volume of diluent1000 mL250 mLAdminister over2 h1 hIncidence of anaphyiacticoid reacn23-56%14%incidence of delayed serum sickness18-86%3%