Acute
organophosphate poisoning (
OPP) such as
dichlorvos may be monitored by the measurement of the erythrocyte acetyl
cholinesterase (EAChE) and the serum
cholinesterase (SChE) activities. The aim of this study was to look at correlation between the severity of the
OPP judged by certain parameters such as
coma, hemodynamic disturbances,
respiratory failure, and the decrease of
cholinesterases enzymes including EAChE and SChE at admission.
Cholinesterase activity was determined upon admission and then on days 3 and 15 in the morning. Clinical effects, EAChE, and SChE activities data were investigated in 42 patients with
OPP aged of 29.6 +/- 11.8 years with acute
cholinergic crisis in all cases. They were
comatose in 29% of cases, presenting both
hypotension or
shock and
hypoxemia in 17% of cases. Fifteen of them (36%) required
mechanical ventilation. The mean EAChE activity at admission was 24.3 +/- 11.6 micromol/mL per hour at 37 degrees C; it was 1260 +/- 2204 IU/L for SChE. There were no correlations between the EAChE and the SChE activities. The EAChE was decreased only in
comatose patients and those presenting
hypotension,
hypoxemia, and
bradycardia with a cutoff of 23.5 micromol/mL per hour at 37 degrees C. Death was observed in 2 patients with a deep decrease of the EAChE at 5 micromol/mL per hour at 37 degrees C in 1 case and 9 micromol/mL per hour at 37 degrees C in another. The kinetics of improvement of the EAChE activity below the cutoff showed the absence of statistical improvement of the EAChE activity on day 3 (16.6 +/- 9 vs 19.5 +/- 5.7 micromol/mL per hour at 37 degrees C); this improvement was remarkable on day 15 (16.6 +/- 9 vs 27.5 +/- 6.5micromol/mL per hour at 37 degrees C, P = .0004). In summary, the marked decrease of EAChE activity appears in this study as prognostic factor in acute
OPP, and
coma,
respiratory failure, hemodynamic disturbances, and death are associated with a decrease of the EAChE of less than 23.5 micromol/mL per hour at 37 degrees C.