<p>Hemoadsorption with polystyrene-divinylbenzene (PS-DVB)-based adsorbents is explored as an adjunctive extracorporeal therapy in selected critically ill patients with dysregulated systemic inflammation. However, such therapy must not interfere with standard treatments, including antimicrobial therapy and hemodynamic stabilization with vasoactive drugs. As catecholamines are rarely quantified analytically in clinical practice, there are currently no studies reporting actual plasma levels during hemoadsorption. This in vitro study evaluated whether hemoadsorption with PS-DVB-based adsorbents alters plasma concentrations of epinephrine, norepinephrine, and dobutamine. Miniaturized PS-DVB adsorbers were used in 300-minute experiments; serial plasma samples were quantified, and apparent plasma clearance was derived from concentration-time data. Epinephrine and norepinephrine concentrations remained essentially unchanged over 300&#xa0;min, with very low apparent plasma clearance (&lt; 5 mL/min), indicating no meaningful removal under the tested conditions. By contrast, dobutamine demonstrated consistent, measurable clearance (approximately 5–15 mL/min), indicating non-negligible adsorption. Under these in vitro conditions, PS-DVB hemoadsorption did not materially remove epinephrine or norepinephrine but produced measurable removal of dobutamine. These findings are compatible with observational reports of reduced overall vasopressor requirements during hemoadsorption, while highlighting the potential for dobutamine underexposure. Future clinical studies should directly measure therapeutic plasma levels – particularly for dobutamine – during PS-DVB hemoadsorption and assess whether dosing adjustments are required to maintain intended inotropic effects without compromising safety.</p>