Use of Cyanide Antidotes in Burn Patients With Suspected Inhalation Injuries in North America

Abstract

This study aimed to assess the use of cyanide antidotes and the determine the opinion on empiric administration of hydroxocobalamin in North American burn patients with suspected smoke inhalation injuries. An online cross-sectional survey was sent to directors of 90 major burn centers in North America, which were listed on the American Burn Association Web site. A multiple-choice format was used to determine the percentage of patients tested for cyanide poisoning on admission, the current administration of a cyanide antidote based solely on clinical suspicion of poisoning, and the antidote used. To ascertain views on immediate administration of hydroxocobalamin before confirmation of cyanide poisoning an option was included to expand the response in written format. Twenty-nine of 90 burn directors (32%) completed the survey. For the population of interest, the majority of burn centers (59%) do not test for cyanide poisoning on admission and do not administer an antidote based solely on clinical suspicion of cyanide poisoning (58%). The most commonly available antidote is hydroxocobalamin (50%), followed by the cyanide antidote kit (29%). The opinion regarding instant administration of hydroxocobalamin when inhalation injury is suspected is mixed: 31% support its empiric use, 17% do not, and the remaining 52% have varying degrees of confidence in its utility. In North America, most patients burnt in closed-space fires with inhalation injuries are neither tested for cyanide poisoning in a timely manner nor empirically treated with a cyanide antidote. Although studies have shown the safety and efficacy of empiric and immediate administration of hydroxocobalamin, most centers are not willing to do so.

Diagnosis and management of inhalation injury: an updated review

“…Additionally, symptoms can mimic CO poisoning. Dumestre et al [ 79 ] found that most burn centers do not test for cyanide poisoning on admission and do not administer an antidote on the basis of clinical suspicion alone. Lactate has been suggested as a marker for severity of cyanide poisoning without other comorbidities [ 80 ], but its role in inhalation injury is less clear in a population at risk for CO poisoning and with coexisting hypovolemic shock.…”

Delayed presentation of transdermal cyanide poisoning

“…Cyanocobalamin is stable, non‐toxic and renally excreted. As hydroxocobalamin has a rapid onset of action and does not affect tissue oxygenation, it is typically used as the first line of treatment in cyanide poisoning [3, 5]. Hydroxocobalamin has a rapid onset of action within 15 min and a half‐life of 24–48 h [6].…”

火災現場から搬送された患者における血中シアン濃度の検討(Analysis of blood cyanide concentration in patients transported from a fire scene)

“…シアン中毒については，血中シアン濃度を迅速には測定できないため，臨床的に診断せざるを得ないのが現状であり，北アメリカの調査報告では59%の熱傷センターでシアン濃度の検査はしておらず，31%は経験的に拮抗薬を投与しているとしている 11)。O’Brienらは閉鎖空間で煙に暴露された状況，咽頭喉頭の煤の存在や煤が混在した喀痰の喀出，意識レベルの低下や血圧の予期せぬ低下を認めた場合にシアン中毒を疑うとしている 12)。また熱傷管理に関するreviewにおいては，受傷機転，中枢神経症状，低血圧，乳酸アシドーシスを伴う場合にはシアン中毒の治療を考慮するとされている 13)。また岩崎らの症例報告においては，受傷機転と想定よりも乳酸値が高いことからシアン中毒を疑ったとしている 14)。乳酸値については，10mmol/L以上でシアン中毒を疑うという報告もある一方で 15)，乳酸値の上昇は拮抗薬の投与の指標となり得ない可能性を示唆する報告もある 16), 17)。本検討においても非心肺停止症例において乳酸値とシアン中毒の有無には有意な関係を認めなかったことから，乳酸値だけで判断するのではなく，受傷機転や他の症状も含め総合的な判断が必要と考える。…”