Bioscavenger therapy for organophosphate poisoning – an open-labeled pilot randomized trial comparing fresh frozen plasma or albumin with saline in acute organophosphate poisoning in humans

Abstract

Traditional treatment of organophosphate poisoning (OP) with oximes has had limited success. Fresh frozen plasma (FFP) or albumin, acting as bioscavengers to mop up free organophosphate, has been recently proposed as a treatment modality. In this pilot open-label, three-arm, randomized controlled study exploring proof of concept, we evaluated if bioscavenger therapy had a role in OP. Sixty patients with significant poisoning presenting within 12 hours, with suppression of pseudocholinesterase activity to < 1,000 U/L, were randomized to receive FFP (8 bags, 250 mL each over 3 days), 20% human albumin (4 × 100 mL over 3 days), or saline (2,000 mL over 3 days) in addition to atropine and supportive care. Pseudocholinesterase and organophosphate levels were measured pretreatment, post-infusion (Day 2, Day 3), and predischarge and expressed as mean ± standard error. The incidence of intermediate syndrome, need for mechanical ventilation, atropine requirement, and mortality were assessed. Twenty patients received albumin and 19 patients each FFP or saline. FFP increased pseudocholinesterase levels (250 ± 44-1,241 ± 364 U/L) significantly (p = 0.007). Small, nonsignificant increases were observed with saline (160 ± 30-259 ± 78) and albumin (146 ± 18-220 ± 61). Organophosphate levels reduced in all 3 arms; no clear-cut trends were observed. We observed more cases of intermediate syndrome with FFP [10/19 (53%) vs. 5/20 (25%) vs. 5/19 (26%), FFP, albumin, and saline arms (p = 0.15)]. The interventions did not affect ventilatory requirements (14/19 vs. 15/20 vs. 14/19) or prevent delayed intubation. There were no differences in mean (±standard error) atropine requirement (in milligrams) in the first 3 days (536 ± 132 vs. 361 ± 125 vs. 789 ± 334) and duration (in days) of ventilation (10.0 ± 2.1 vs. 7.1 ± 1.5 vs. 7.5 ± 1.5) or hospital stay (12.4 ± 2.2 vs. 9.8 ± 1.4 vs. 9.8 ± 1.6). Two patients developed adverse effects with FFP. Mortality was similar (4/19 vs. 5/20 vs. 2/19, p = 0.6). Despite significant increase in pseudocholinesterase levels with FFP, this pilot study did not demonstrate favorable trends in clinical outcomes with FFP or albumin.