Page 48 - JSOM Summer 2020

Supportive Care and Ongoing Management – 12. Monitor the patient closely for signs of progression in the
Universal Recommendations initial hours of treatment until control of symptoms has been
11. Provide supportive care and address secondary issues related achieved.
to the envenomation as follows: a. Serial assessments for signs and symptoms of the neuro-
a. Anticipate the need for aggressive airway management toxic, hemotoxic, and cytotoxic syndromes should be re-
with intubation and prolonged ventilation in all patients peated at hours 2, 4, 6, 12, 24 (H2, H4, H6, H12, H24).
presenting with neurotoxic envenomation, particularly 13. Within the first 24 hours, antivenom may be given at hours
those who present late with impending respiratory failure 0, 2, 4, 6, 12, and 24 according to the specific criteria for
or fail to respond to antivenom. antivenom treatment listed under Specific Criteria for Initial
i. For any neurotoxic snakebite producing a cholinergic Antivenom Treatment and Repeat Doses (page 47)
crisis, consider atropine 0.5 mg IV/IO titrated by aus- a. If the treatment criteria have not been resolved at any of
cultation to dry up bronchial and oral hypersecretions these intervals, give an additional dose of antivenom at
posing a risk to airway or breathing. hours 2, 4, 6, 12, and 24 until control is achieved. Refer
1. Repeat original dose every 5 minutes until reso- to Appendix B: Coverage, initial dosing, preparation, and
lution of crackles, rales, bronchospasm has been administration of antivenoms included in this CPG (page
achieved. Pediatric atropine doses should be weight 63) for specific dosage instructions for each product.
based at a dose of 0.01 mg/kg, up to 0.25 mg. b. If symptoms reappear or persist for more than 24 hours
ii. For neurotoxic snakebites in the Middle East, North after the first dose of antivenom was given, additional
Africa, and Central Asia without cholinergic crisis, treatment intervals should be discussed with a physician
but causing ptosis and respiratory muscle weakness, expert.
consider administering trial dose of 0.5 mg atropine c. If 10 or more vials of a single antivenom have been given
followed by 1.0 mg neostigmine IV/IO to temporarily without any indications of improvement, consider chang-
reverse neuromuscular weakness and delay the need ing to second-line antivenom if possible as species may not
for intubation. Pediatric doses should be weight based be covered. If any indications of improvement have been
at a dose of 0.01 mg/kg, up to a maximum of 0.25 mg observed, continue with the antivenom you are using.
atropine with 0.5 mg neostigmine. 54,74–77 14. If the patient is asymptomatic but coagulopathy persists 24
1. Not all patients will respond, but those who do will hours after the first dose of antivenom was given, adminis-
show temporary improvement (reversal of ptosis, ter a dose of antivenom and repeat laboratory tests every 24
increased respiratory muscle strength, etc). If no hours until resolution.
response to neostigmine, do not reattempt. If pos- 15. Continuous monitoring for effectiveness of antivenom
itive response is achieved, repeat every 1–4 hours dose must be done. Occasionally, pockets of venom can be
as needed (maximum dose in 24 hours = 10 mg trapped in swollen tissue compartments and escape into the
adults/5 mg pediatric) until antivenom has defini- bloodstream once circulation has improved. This is called re-
tively reversed the paralysis. current envenomation and is most common within the first
b. For hemotoxic envenomations, all internal and external 24–48 hours after a severe bite with extensive swelling and
active bleeding should cease within 30–60 minutes of blistering. 78,87–93
antivenom administration once the appropriate dose has a. Continuous clinical monitoring includes hourly checks of
been given. Packed red blood cell or whole blood trans- vital signs, urine output, and detailed assessment for new
fusion can be considered if the patient is in hemorrhagic or worsening signs of neurotoxic, hemotoxic, or cytotoxic
shock. 17,69,70,78–82 Platelets, fresh frozen plasma, cryopre- envenomation.
cipitate, TXA, and other agents are NOT EFFECTIVE in b. Serial laboratory studies including CBC, CMP, PT/PTT/
these cases due to the mechanism of the venoms. INR, CK, fibrinogen levels (or WBCT if no advanced test-
c. Ketamine and fentanyl are preferable for analgesia. Hista- ing available) may be repeated every 2 hours while signs
mine release from morphine may mask signs of an allergic of envenomation persist.
reaction or worsen hypotension. c. After signs of clinical resolution, monitoring can decrease
d. It is important to keep the limb significantly elevated to every 6 hours.
(> 60° is ideal) whenever possible to limit dependent 16. If indications of recurrent envenomation are detected more
edema and swelling. than 24 hours after the first dose of antivenom was given,
e. DO NOT routinely de-roof or aspirate blisters, bullae, treat as follows:
or blebs unless they are causing significant discomfort or i. Asymptomatic patient with coagulopathy and no other
uncontrolled rupture appears imminent. If abscess is sus- findings
pected, treat according to existing protocols for abscess 1. Treat according to Step No. 16
management. ii. Symptomatic patient with new or worsening pain,
f. DO NOT perform fasciotomy for snakebites. Compart- swelling, bleeding, neurotoxicity, or other indications of
ment syndrome is rare in snakebites. Even in cases of active envenomation:
confirmed elevated intracompartmental pressure, patients 1. Administer an additional dose of antivenom every 2
who received antivenom without fasciotomy experienced hours until acute symptoms have resolved completely
better outcomes (shorter recovery time and less long term 17. Patients should be held for at least 24 hours after resolution
morbidity) than those who received fasciotomy. 83–86 Ap- of all signs and symptoms, and the following steps should be
propriate use of antivenom should resolve the underlying completed prior to discharge:
issue that is producing the elevated intracompartmental a. Repeat blood tests before releasing the patient to ensure
pressures. resolution of coagulopathy.
g. DO NOT routinely administer antibiotics unless signs b. Administer a booster dose of tetanus toxoid if needed.
and symptoms of an infection are present. Direct infec- c. Patients should be instructed to return if any new or wor-
tions are rare from most snakebites when prompt, appro- rying signs or symptoms develop.
priate treatment is given. 54

46 | JSOM Volume 20, Edition 2 / Summer 2020