We read with interest the review and guideline by Anseeuw et al. 1 titled ‘Cyanide poisoning by fire smoke inhalation: an European expert consensus’. The authors reviewed the current literature succinctly and identified gaps in knowledge. They also elegantly reviewed the diagnosis of cyanide poisoning, which can be difficult. We concur with several of the authors’ recommendations that had not been clearly stated in other guidelines. In particular, we agree that sodium thiosulphate does not readily penetrate cells and its effectiveness is limited, despite older reviews that have reported that it should be used alone for cyanide toxicity. In addition, we conducted a comparative trial of sodium thiosulphate and hydroxocobalamin 2. In this clinically relevant model of cyanide-induced hypotension, we showed that sodium thiosulphate is not effective alone and it had 100% mortality 2. We also agree that although hydroxocobalamin has adverse effects, in sum, it is simpler to use, has less severe effects, has beneficial vasopressor effects and thus may be the best drug to use for severe cyanide toxicity 3. Finally, we agree that hydroxocobalamin is effective in cyanide-induced cardiac arrest, and that additional doses may be needed, as evidenced in our study, which showed that hydroxocobalamin is as effective as intravenous epinephrine for cyanide-induced cardiac arrest 4.
However, we disagree that sodium thiosulphate adds to the effectiveness of hydroxocobalamin. We especially disagree that it improves outcome for severe cyanide-induced toxicity. We compared hydroxocobalamin to hydroxocobalamin with sodium thiosulphate and did not find a difference on group comparisons of vital signs, cyanide levels, other laboratory values and mortality 2. In addition, on the basis of previous animal and human studies, if the patient does not respond to the vasopressor or the antidotal effects of hydroxocobalamin, the patient is unlikely to benefit from sodium thiosulphate, a drug that may take up to 30 min to take effect and is poorly transported into the mitochondrial membrane 2,52,5.
Conflicts of interest
There are no conflicts of interest.
1. Anseeuw K, Delvau N, Burillo-Putze G, De laco F, Geldner G, Holmstron P, et al. Cyanide poisoning by fire smoke inhalation: an European expert consensus. Eur J Emerg Med. 2012 [Epub ahead of print]
2. Bebarta VS, Pitotti RL, Dixon P, Lairet JR, Bush A, Tanen DA. Hydroxocobalamin versus sodium thiosulfate for the treatment of acute cyanide toxicity in a swine (Sus scrofa
) model. Ann Emerg Med. Jun 2012;59:532–539
3. Bebarta VS, Tanen DA, Lairet J, Dixon PS, Valtier S, Bush A. Hydroxocobalamin and sodium thiosulfate versus sodium nitrite and sodium thiosulfate in the treatment of acute cyanide toxicity in a swine (Sus scrofa
) model. Ann Emerg Med. 2010;55:345–351
4. Bebarta VS, Pitotti RL, Dixon PS, Valtier S, Esquivel L, Bush A, Little CM. Hydroxocobalamin and epinephrine both improve survival in a swine model of cyanide-induced cardiac arrest. Ann Emerg Med. 2012 [Epub ahead of print]
5. Fortin JL, Giocanti JP, Ruttimann M, Kowalski JJ. Prehospital administration of hydroxocobalamin for smoke inhalation-associated cyanide poisoning: 8 years of experience in the Paris Fire Brigade. Clin Toxicol (Phila). 2006;44(Suppl 1):37–44