Faculty Bibliography

Objective: Carbon monoxide (CO) generation is a known complication of methylene chloride (MeCl) exposure. We report a patient exposed to 36.5 hours of elevated carboxyhemoglobin (COHb) following MeCl exposure without neuro-psychiatric sequelae. We consider this in the context of similar cases treated with hyperbaric oxygen (HBO) due to concern for "soaking" in the setting of ongoing endogenous CO production. Case report: A 51 year-old man was found unresponsive in his car surrounded by rags and an empty bottle of paint stripper. ED vital signs: BP 160/70 mmHg; HR 118 beats/min; RR 14 breaths/min; SpO₂ 100% RA. VBG on supplemental oxygen: pH 7.4; PCO₂ 5.2 kPa; PO₂ 13.3 kPa. He was intubated and placed on 100% O₂. The paint thinner label revealed components: MeCl 90%; methanol 7%; toluene 2%. COHb one hour after arrival was 3.9%. Serial concentrations revealed a rising CO that reached 7% by 5.5 hours, 8% by 10.7 hours, and peaked at 12.1%, 18.2 hours after presentation, before falling to 3.6% at 36.5 hours. He was extubated 36 hours after arrival and remained neurologically intact until discharge. Telephone follow up was performed one month later and he was well and without complaints. Conclusion: In acute CO poisoning loss of consciousness and a long time span of exposure ("soaking") are risk factors for neuropsychiatric sequelae.¹ In cases of acute CO poisoning, evidence suggests that HBO prevents development of these cognitive deficits.² While HBO has also been used to treat CO poisoning following MeCl exposure with similar COHb peaks (11%, 13%), 3 there is no prospective evaluation of the role of HBO. CO poisoning following MeCl exposure can cause neuropsychiatric sequelae.³ While HBO may be considered in such cases due to a concern for prolonged exposure due to continuous endogenous CO production, patients may recover fully with only 100% O₂