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Background and Aims In certain clinical scenarios, expedited reversal of local anesthetic (LA) effects is warranted, such as with patient dissatisfaction, need for neurologic evaluation, longer-than-anticipated block duration, or side effects like epidural-induced hypotension. We investigated whether Intralipid® 20% can reverse LA action, providing mechanistic support for the ‘lipid sink’ theory and laying the groundwork for clinical studies on accelerating resolution of neuraxial and peripheral nerve blocks.Methods This IRB-approved double blinded placebo-controlled crossover randomized trial enrolled 18 volunteers who were required to attend two in-person study visits: visit 1 saline, visit 2 Intralipid® 20%, or vice versa. Five (3 mL) test solutions were subcutaneously injected in marked injection sites on volunteers’ thighs to form raised skin wheels: Lidocaine 1%, Lidocaine 2%, Bupivacaine 0.5%, Bupivacaine 0.25%, or Saline (control). An intravenous bolus of 1.5 ml/kg Intralipid® 20% or normal saline was then administered. Sensation was tested every 5 minutes at all injection sites using an alcohol swab and a pinprick. Paired t-tests assessed within-subject differences in return to sensation time between intralipid and saline sessions.Results Among 18 volunteers, 14 ( table 1 for characteristics) successfully completed both visits. While not statistically significant, a pattern emerged of faster mean return-to-sensation times among patients who were administered an Intralipid® 20% bolus, compared to saline (table 2). Among the 14 volunteers, a decrease in time to sensation was more commonly found in Intralipid® visits compared to saline visits (figure 1).Conclusions Intralipid® 20% reversal can be seen in our data in the context of skin infiltration. Further research is needed to understand the subset of volunteers that benefited from the Intralipid® 20% reversal. This method may shorten the LA effects in a clinical setting allowing for faster discharge, and reversal of undesirable effects of local anesthetics.Abstract EP066 Figure 1Sensory recovery in individual volunteers by type of local anestheticAbstract EP066 Table 1Demographics of participants (completed both visits)Abstract EP066 Table 2Paired t-test results: mean (95% CL) of within-subject differences in time (hours) to sensation between intralipid and saline infusion