Effect of Intravenous Lipid Emulsion Therapy on Xenobiotic Plasma Partitioning and Short-Term Neurological Outcome in Companion Animals with Suspected Neurotoxicosis: A Case Series

Intravenous lipid therapy (ILE) is used to treat neurotoxicosis in companion animals, but clinical evidence for in vivo xenobiotic partitioning and benefit remains limited. This study evaluated associations between the log n-octanol/water partition coefficient (log P), in vivo plasma partitioning, and early neurological outcome. In a case series from eight veterinary hospitals, dogs and cats with suspected neurotoxicosis received ILE; blood collected before and at the end of infusion was separated into lipid and aqueous fractions and analyzed by gas chromatography-mass spectrometry. Log P values were retrieved from PubChem. Outcome (improved vs not improved) was the change from baseline to 4- 6 h after ILE start. Thirty-four cases were analyzed (27 dogs, 7 cats; 17 xenobiotics). At end of infusion, lipid-phase concentrations exceeded aqueous concentrations in 28/34 cases, and log P did not correlate with the lipid-to-aqueous ratio. Improvement occurred in 14/34 animals and was associated with higher lipid-to-aqueous xenobiotic ratios (geometric mean ratio 5.7; 95% CI 1.73–19.05; P = 0.007). Overall, in vivo lipid sequestration was frequent and related to early improvement, whereas log P alone did not predict partitioning or outcome.