Impact of a Pharmacist-Driven Medication Diluent Volume Optimization Protocol on Fluid Balance and Outcomes in Critically Ill Patients

Background: Volume overload (VO) is common in the intensive care unit (ICU) and associated with negative outcomes. Approaches have been investigated to curtail VO; however, none specifically focused on medication diluent volume optimization. Objective: Investigate the impact of a pharmacist-driven medication diluent volume optimization protocol on fluid balance in critically ill patients. Methods: A prospective, pilot study was conducted in a medical ICU during October 2021 to December 2021 (pre) and February 2022 to April 2022 (post). A pharmacist-driven medication diluent volume optimization protocol focusing on vasopressor and antimicrobial diluent volumes was implemented. Demographics and clinical data were collected during ICU admission up to 7 days. The primary outcome was net fluid balance on day 3. Secondary outcomes were medication volumes administered, net fluid balance, ICU length of stay, and mortality. Results: Supply chain shortages caused the study to stop at the end of February 2022. Overall, 152 patients were included (123 pre group, 29 post group). The most common admission diagnosis was acute respiratory failure (35%). Vasopressors and antimicrobials were utilized in 47% and 66% of patients, respectively. Net fluid balance on day 3 was greater but not significant in the post group (227.1 mL [−1840.3 to 3483.7] vs 2012.3 mL [−2686.0 to 4846.0]; P = .584). Antimicrobial diluent volumes were significantly less in the post group. No differences were seen in other secondary outcomes. Protocol group assignment was not associated with net fluid balance on day 3. Conclusion: Despite decreasing antimicrobial volume contributions, optimizing diluent volumes alone did not significantly impact overall volume status. Future studies should focus on comprehensive approaches to medication diluent optimization and fluid stewardship.