Combined hemoperfusion-hemodialysis in organophosphate poisoning

We report on a patient treated with combined prolonged hemoperfusion (HP, Adsorba 300 C, Gambro, Sweden) and hemodialysis (HD, C-DAK 1.2, Cordis Dow, USA) for severe dimethoate poisoning. This procedure was adopted since the combination of dialysis and adsorption may improve overall drug removal. Combined HP-HD was performed during 24 h using the same charcoal column and dialyser. Adequate heparinization was obtained by monitoring the whole blood activated partial thromboplastin time. The patient (a 34-year-old female) ingested approximately 10 g of dimethoate (Teletox 10) in a suicide attempt, 30 min before admission to the hospital. On admission, serum level of dimethoate (analysed by gas chromatography) was 2340 ng ml-1. She received conventional treatment and combined HP-HD was started within 2 h after admission. At this time serum levels had risen to 3110 ng ml-1. However, they declined constantly during the epuration and after 18 h no more dimethoate could be detected in the serum. She was discharged 3 days after treatment. During the 24 h of HP-HD treatment, 110.8 mg dimethoate entered the epuration system via the plasma. 55.3 mg were extracted by the charcoal column and 25.3 mg by hemodialysis.

Serum and red cell cholinesterase activity in people exposed to organophosphate insecticides

Serum and red cell cholinesterase activities were determined in 2 groups of subjects namely:-I) a group of 10 patients who took organophosphate insecticide and were admitted into the hospital for treatment and II) a group of 65 workers from an organophosphate insecticide factory. Serum cholinesterase levels were considerably depressed in all patients in group I and one patient died. The low serum cholinesterase activities increased very slowly and were still very low on day 4 of admission. Serum cholinesterase level in 65 workers were significantly lower than that of the normal subjects. The exposed subjects had still further lower serum cholinesterase activity than those of the non-exposed subjects. There was no significant difference between their red cell cholinesterase activities and those of the normal subjects. Serum and red cell cholinesterase levels in these workers also showed no correlation to the duration of insecticide exposure. These findings indicated that serum cholinesterase activity was a good diagnostic aid in acute exposure because it responded more rapidly than red cell cholinesterase level but it was not sensitive for follow up of the treatment since its recovery rate was too slow. Findings of low serum cholinesterase with normal red cell cholinesterase levels without signs or symptoms of toxicity indicated that these workers had been exposed to some degree of organophosphate insecticides.

[Hemoperfusion with coated activated charcoal for treating acute poisoning by remedies, plant protectants, and fungi (author's transl)]

From the clinico-toxicological standpoint, the most important plant protectants are the insecticides (bipyridylium compounds). In vitro trials and investigations on poisoned patients have shown that it is fundamentally possible to eliminate such plant protectants from the blood by hemoperfusion with coated activated charcoal. With both the lipophilic alkyl phosphate, nitrostigmine (E605 forte), and by the two hydrophilic alkyl phosphates, demetone-S-methyl sulfoxide (Metasystox R) and dimethoate (Roxion), it was possible to measure hemoperfusion clearance values around 60 to 85 ml/min at a blood flow rate of 100 ml/min. Only the two hydrophilic alkyl phosphates were able to be eliminated by hemodialysis, the clearance values being, however, lower. Thus in severe alkyl phosphate intoxications the use of hemoperfusion may considered alongside the standard therapy. The bipyridylium compounds, paraquat (Gramoxone) and diquat (Reglone), are readily dialysed, but can be better eliminated from the blood by hemoperfusion. This therapeutic measure must be initiated as rapidly as possible independent of the clinical picture, for only when hemoperfusion is begun prior to the fixation of paraquat or diquat at tissue are there any prospects of success.

Probable progress in the therapy of organophosphate poisoning: extracorporeal hemodialysis and hemoperfusion

Whether or not extracorporeal hemodialysis or hemoperfusion with coated activated charcoal might be used in eliminating organophosphates following poisoning with nitrostigmine, demeton-S-methyl sulfoxide, or dimethoate was here examined. Nitrostigmine could not be hemodialysed. The other two organophosphates, on the other hand could be well eliminated from the blood by hemodialysis. The clearance rates for demeton-S-methyl sulfoxide and dimethoate were 52.98 ml/min and 59.07 ml/min respectively, at a blood flow rate of 100 ml/min. The clearance values for hemoperfusion with coated activated charcoal were higher under the same trial conditions, the values being 83.70 ml/min for demeton-S-methyl sulfoxide and 87.84 ml/min for dimethoate. Nitrostigmine, too, could be eliminated from the blood by hemoperfusion, its clearance being 59.20 ml/min.

Exposure to pesticides in agriculture: a survey of spraymen using dimethoate in the Sudan

There is a need for objective data on the exposure of spraymen to pesticides in agriculture in order to assess minimum requirements for practicable protection in tropical areas. To provide data, a survey was carried out in the Sudan on spraymen using dimethoate. No cholinesterase depressions were found and the calculated dose received by each man per day was within safe limits in the circumstances of this survey. Respiratory exposure was only a minor part of total exposure. The methodology of such surveys is discussed and the need for the use of a standard protocol is emphasized.