INDEX Sarin

According to inpatient records from St Luke s Hospital, the most common laboratory finding related to sarin toxicity was a decrease in plasma cholinesterase (ChE) levels in 74% of patients. In patients with more severe toxicity, plasma ChE levels tended to be lower, but a more accurate indication of ChE inhibition is measurement of erythrocyte ChE, as erythrocyte ChE (AChE) is considered true ChE and plasma ChE is pseudo ChE . However, erythrocyte ChE is not routinely measured, whereas plasma ChE is included in many clinical chemistry panels thus, it can be used as a simple index for ChE activity. In both the Matsumoto and Tokyo subway sarin attacks, plasma ChE served as a useful index of sarin exposure. In 92% of hospitalized patients, plasma ChE levels returned to normal on the following day. In addition, inpatient records from... 

Efficacy of the anticonvulsant usage in antidotic formulas depends considerably on OPC type. Thus, index of protection (IP) for the composition of ChR (HI-6 inclusive), cholinolytics and diazepam is much higher for the treatment of intoxication with soman and tabun, than in poisonings with sarin and VX [93],... 

In a later study (MOD12), 14 subjects exposed to a Ct of 14.7 mg min m 3 of sarin (mean erythrocyte inhibition of 50%) carried one-third of their body weight up and down a 40.5-cm step 30 times a minute for 5 min (the Harvard pack test). This was done 45 min and 24 h after exposure. Their fitness index, which includes heart rate and other measures, did not differ from that of a group exposed to agent but not exercised. 

If the eye exposure is not associated with inhalation of the nerve agent, there is no good correlation between severity of the miosis and inhibition of RBC-ChE activity. The latter may be relatively normal or may be inhibited by as much as 100% (see Table 5-1), so the severity of the miosis cannot be used as an index of the amount of systemic absorption of agent or amount of exposure. On the other hand, an early study52 demonstrated a relationship between the Ct of sarin and pupil size at the time of maximal miosis, and the investigator suggested that the pupil size might be used as an index of the amount of exposure. 

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