cyanide antidotes paul jones september 10, 2010. objectives to review the management decisions in a...
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Cyanide AntidotesPaul Jones
September 10, 2010
Objectives
To review the management decisions in a case of cyanide poisoning
Case presentation
Clinical question to consider
Case conclusion
Case Presentation
Patient brought in VSA to the ED by EMS Roommate found patient collapsed on the
floor and unresponsive – started CPR after calling EMS
No known medical conditions Works in chemistry research lab
Case Cont’d…
GCS 3 Pupils fixed and dilated ETT intubation by EMS PEA Bedside U/S shows no cardiac activity No signs of obvious injury
Case Cont’d… Ongoing CPR IV access obtained Femoral line inserted Blood drawn Epinephrine and atropine administered Sodium bicarbonate boluses given … EMS presents vial found beside patient
at the scene labelled NaCN
Cyanide: Background
Sources: industry, smoke inhalation
Cyanide: Clinical Presentation
Hypoxia and acidosis Coma, hemodynamic compromise,
seizures, apnea, cardiac arrest, death Acute cyanide toxicity: dizziness,
headache, weakness, flushing, diaphoresis, dyspnea, hyperventilation, hyperpnea
Labs: metabolic acidosis and elevated lactate, supranormal venous O2 content
Cyanide: Treatment GI Decontamination Supplemental O2
? Hyperbaric oxygen Antidotes:
Increase endogenous metabolism: ThiosulfateCyanide chelating: Hydroxocobalamin,
Dicobalt EDTAMethemoglobin generation: Nitrites, 4-DMAP
CAK = Amyl nitrite + Sodium nitrite + Sodium thiosulfate
Question to Consider?
Is hydroxocobalamin an effective and safe antidote to administer for suspected cyanide ingestion?
Evidence source:
PICO Analysis Patients
Patients with cyanide poisoning
Lethal threshold = 100 µmol/L
= patients found in Cardiac arrest
PICO Analysis Cont’d...
Interventions Retrospective chart review First-line treatment:
hydroxocobalamin Comparators/Confounders
Time between exposure and antidote administration
Environment/context in which cyanide poisoning occurs
Health/medical status of the patient
Adequacy of supportive measures
Outcomes of Interest Survival Post-treatment
neurological status Adverse events
Methodology
Strengths Measured blood
cyanide levels Pure cyanide
poisoning – eliminates other toxins present with smoke inhalation or co-ingestions
Weaknesses Retrospective study No comparison group Small, heterogenous
sample
Chart review of cases between 1988-2003 from toxicological ICU in France
Study Results…
Study Results… Adverse Events Caused by
Hydroxocobalamin: n = 8Chromaturia (red-colored
urine): n =5Pink-to-red skin discoloration:
n = 3 Increase in HR: n =1Elevated BP: n = 1
Borron et al. Hydroxocobalamin for severe acute cyanide poisoning by ingestion or inhalation.
Uhl et al. Safety of Hydroxocobalamin in Healthy Volunteers in a RCT
Study Results…
Conclusions…
71% of patients survived potentially lethal cyanide poisoning after treatment with hydroxocobalamin
Need for rapid intervention Builds on previous case reports Risk-benefit profile supports empiric use in
both the pre-hospital and hospital settings Uhl et al. Safety of Hydroxocobalamin in Healthy Volunteers in a Randomized,
Placebo-Controlled Study
Case Conclusion… Cyanide Antidote Kit (CAK) retrieved Sodium nitrite and sodium thiosulfate
administered intravenously Further boluses of sodium bicarbonate given No cardiac activity seen on repeat bedside U/S Time of death called after over an hour of
resuscitation Suicide note and printout on cyanide poisoning
found in patients apartment
What Would Google Do?
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References1. Borron SW, Baud FJ, Megarbane B and Bismuth C. Hydroxocobalamin for
severe acute cyanide poisoning by ingestion or inhalation. American Journal of Emergency Medicine (2007) 25, 551–558
2. Rodgers GC and Condurache CT. Antidotes and treatments for chemical warfare/terrorism agents: an evidence-based review. Clinical Pharmacology Therapeutics. 2010 Sep;88(3):318-27.
3. Gracia R and Shepherd G. Cyanide Poisoning and Its Treatment. Pharmacotherapy 2004;24(10):1306-1310.
4. Uhl W, Nolting A, Golor G, Rost KL and Kovar, A. Safety of Hydroxocobalamin in Healthy Volunteers in a Randomized, Placebo-Controlled Study. Clinical Toxicology, 44:17–28, 2006.
5. Alan H. Hall AH, Saiers J and Baud F. Which cyanide antidote? Critical Reviews in Toxicology, 2009; 39(7): 541–552.
Thank you…
“The true harvest of my life is intangible - a little star dust caught, a portion of the rainbow I have clutched”
Henry David Thoreau