Abstract
ObjectiveThis study was aimed to analyze the scavenging effect of haemoperfusion on plasma paraquat (PQ) and to evaluate the clinical significance of PQ examination in the treatment of patients with acute paraquat poisoning.Methods85 patients with acute paraquat intoxication by oral ingestion were admitted in West China Hospital from Jun, 2010 to Mar, 2011. A standardized therapeutic regimen including emergency haemoperfusion was given on all subjects. A total of 91 whole blood samples were taken before (0h), underway (1h after haemoperfusion beginning) and at the end (2h) of the haemoperfusion therapy. The clearance rate was calculated and related factors were analyzed.ResultsAs heamoperfusion was going on, the plasma paraquat concentration of the patients kept falling down. After 1 hour of haemoperfusion, the average clearance rate (R1) was 37.06±21.81%. After 2 hours of haemoperfusion, the average clearance rate (R2) was 45.99±23.13%. The average of R1/R2 ratio was 76.61±22.80%. In the high paraquat concentration group (plasma paraquat concentration (C0) >300 ng/mL), both the averages of R1 and R2 were significantly higher than those of the low paraquat concentration group (C0≤200 ng/mL) (p<0.05), and there was no significant difference of R1/R2 between these two groups (p>0.05).ConclusionsThe dynamic monitoring of plasma PQ concentration was not only critical in the clinical evaluation but also helpful in guiding the treatment of patients with acute PQ intoxication. Haemoperfusion can effectively eliminate paraquat from the plasma in patients with high initial plasma PQ concentration, while in patients with low initial plasma PQ concentration (<200 ng/ml), the clearance effect of harmoperfusion was very limited. Increasing HP time might improve the overall clearance rate of HP on plasma PQ yet decrease the elimination efficiency of HP, while repeated HP treatment was helpful against the rebound phenomena.
Highlights
Paraquat (PQ, 1,19-dimethyl-4,49-bipyridinium chloride) was a non-selective herbicide that has been widely used in countryside since the 1960s
The most characteristic feature of PQ poisoning was lung damage, the mechanism of which lay in the selective accumulation of PQ in alveolar cells, inducing the production of large amount of toxic free radicals such as reactive oxygen species (ROS) which lead to lipid peroxidation of cell membrane, exhaustion of nicotinamide adenine dinucleotide phosphate (NADPH) and to cell death [2,3,4]
By analyzing the plasma PQ clearance rate of patients with different C0 (Figure 2), we found that the PQ clearance rate (R2) of patients with C0 lower than 200 ng/mL were all below 40%, while for patients with C0 higher than 300 ng/mL, their R2 were all above 40%
Summary
Paraquat (PQ, 1,19-dimethyl-4,49-bipyridinium chloride) was a non-selective herbicide that has been widely used in countryside since the 1960s. It has been proved safe in occupational use, PQ poisoning has been observed in patients who ingest the pesticide either accidentally or intentionally as a suicide attempt. The mortality rate of PQ intoxication ranged from 50–90% and there was no specific antidote [1]. The clinical manifestations and outcomes of acute PQ intoxication are dependent on the exposure degree of PQ. The ingestion volume and plasma concentration of PQ were often used as important indicators of patients’ prognosis [5,6,7,8,9]
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