| [ Summary ] |
The sarin terrorist attack that took place in the Tokyo subways on March 20, 1995 produced more than 5,000 victims and 12 deaths. Sarin is an organo phosphate chemical warfare agent which inhibits systemic cholinesterase. Two hundred and thirteen patients were seen at our hospital. Pupillary constriction (characteristic of sarin poisoning) was observed in the majority of the patients. In 8% of the patients serum cholinesterase activity decreased with hypokalemia. We encountered one patient with severe sarin poisoning, resistant to this pharmacologic therapy, whose condition significantly improved following blood purification. A 45-year-old female was brought to our hospital approximately 2 hours following the gas attack because of severe pulmonary edema and deep coma. Routine hematologic and biochemical tests revealed no abnormalities except for decreased cholinesterase activity at 0.4pH (normal>0.7pH). Following admission, atropine sulfate and the sarin antagonist pralidoximeiodide (PAM) were infused, but there was no clinical improvement. Six hrs after intoxication, the patient underwent hemodiafiltration (HDF) for 4 hrs followed by hemoperfusion (HP) with a Hemosorba CH-350 (Asahi Medical, Tokyo, Japan). After these blood purification procedures, she regained consciousness and her pupillary constriction improved. The cholinesterase activity increased to 1.2pH from 0.4pH. Only the patient who underwent blood purification showed such a dramatic improvement in symptoms and a rapid increase in cholinester ase activity. PAM is only thought to be effective when used within 6 hrs of intoxication and to have no action against the central effects of sarin poisoning, because it does not readily cross the blood-brain barrier. Our findings suggest that early blood purification should be considered in patients with sarin poisoning resistant to standard drug therapy, particularly in those with severe intoxication and central nervous system symptoms. |