ACUTE NICKEL CARBONYL POISONING

Nickel carbonyl [Ni(CO)4], is formed when metallic nickel combines with carbon monoxide. It is used in the refining process of nickel and as a catalyst in petroleum, plastic, and rubber production. Nickel carbonyl is considered to be one of the most toxic chemicals used industrially and the magnitude of its morbidity and mortality has been compared to that of hydrogen cyanide. A 46-year-old man presented to the emergency department 24 hours after accidental occupational exposure to nickel carbonyl. He admitted to dermal contamination and inhaling the vapor from his clothing after his respiratory protection was removed. On presentation the patient was alert and oriented, complained of shortness of breath, chest tightness, and paresthesias. Examination revealed decreased breath sounds bilaterally and arterial blood gas Po2 of 39% with calculated o2 saturation of 75%. After face mask o2 at 60% his Po2 increased to 85%. The patient required 60% o2 with continuous positive alrway pressure of 5 for 4 days. Disulfiram (Antabuse) was administered for the first 2 days until sodium diethyldithiocarbamate (dithiocarb) was obtained. Disulfiram was used because it is metabolized to two molecules of dithiocarb and is hypothetically of value. Dithiocarb was obtained and continued over the next several days. The patient's urine nickel level on the day of admission was 172 μg/dL (normal <5 μg/dL) and a serum level of 14.6 μg/dL (normal .26-.46 μg/dL). The patient's condition gradually improved over the next 10 days. Nickel carbonyl exposure produces mild transient initial symptoms which are followed within 24 hours by more severe life-threatening events. Fatalities usually occur after 4 to 11 days and are attributed to neurologic and respiratory toxicity. Dithiocarb continues to be the most effective antidote in the treatment of nickel carbonyl toxicity. Dithiocarb is under investigation in the United States and is only available from a sole supplier. Despite improved safety standards, occupational exposures to nickel carbonyl still occur. The successful outcome of this patient illustrates the need for prompt availability of dithiocarb. © 1993.