Severe poisoning by organophosphate compounds. An analysis of mortality and of the value of serum cholinesterase in monitoring the clinical course.

Abstract

Ingestion of organophosphate (OP) compounds usually results in severe poisoning. We undertook a retrospective study of 52 consecutive patients admitted with severe OP poisoning to determine the value of serum cholinesterase (SChE) in monitoring clinical course. Considering survivors and non-survivors, we evaluate clinical and laboratory baseline characteristics, severity scores (APACHE II, SAPS II), atropine rate (mg/h), SChE evolution at 24, 72 and 120 h and final SChE (SChE at the day of discharge or death). Mortality in the ICU was 28.9% (n = 15). In both groups SChE showed a trend to increase. In survivors, SChE recovery was statistically significant for SChE 24h-SChE 72 h, SChE 24 h-SChE 120 h and SChE initial-SChE 120 h (p = 0.008, p = 0.00003, p = 0.0002 respectively). In this group a simultaneous decrease in atropine requirements was registered. In non-survivors, the rate of atropine remained unchanged up to 120 h. Three groups could be defined in non-survivors according to their final SChE and day of death. Non-survivors-1 (death in the first 24h; 2 patients) and non-survivors-2 (death after the first 24 h; 5 patients) had a final SChE below 10% of normal SChE activity and statistically different from survivors' final SChE. Non-survivors-3 (8 patients) had a final SChE similar to the survivors and death was due to sepsis and multiple organ failure (MOF). We conclude that SChE is useful in OP poisoning diagnosis and also in monitoring clinical course. SChE recovery above 10% of normal seems to correlate with good prognosis. Sepsis and MOF were important determinants of mortality.